I did the Plenum!!! 28HP, 26Ft-lbs - Gains

OK I did it... I wouldn't believe it if I didn't see it. It's an early 1999 cable car with 44k on it. The Car is Smooooooooooooooth... It keeps going, the only problem I have is running out of gear. Best Mod ever!!!

there you go, thank you ericdee... ok folks flame away... $1k and dont even have to crack the motor!!! Like I said this is the best mod for the buck...

er....that piece is US$ 1,000? And that yielded $ 28hp? 1.4 hp for $ 50....not bad....

I've already contacted them last week for an install... can't wait.

Mtfletch: Are you seeing this? How about we go halves...you run it for 6 months, then I'll take the next 6. Kidding aside...are you going to get one? I was skeptical to say the least...but the dyno chart is "in your face".

If RSS has a dyno, I'll have my 02 3.6L dyno'ed before/after at their shop since they're doing the install and I'll do show and tell.

Wow, 28hp for that one piece of thingie? And like Tailwag said, $1000 for that piece? What is the physics behind the improvement? Is it a DIY? Looks simple enough from the pics.

basic fluid dynamics, something porsche marketeers knows nothing about, yes its a DIY. 1hr tops. To elaborate, which porsche can go faster around a bend, a right angle turn or a "Y" angle turn?

The one that drifts!

We had this debate already, drifting is slower than the right angle method http://www.6speedonline.com/forums/s...ad.php?t=80874

LOL yes, I know...that's the thread I had in mind. Look at post #2 in that thread.

122 views and only 5 posts... dont be bashful fellas

I keep reading this but haven't thought of anything to write because I'm somewhat speechless. This seems too good to be true, but the dyno doesn't lie, assuming no other mods were done between the before and after results. I can even justify the $995 price that I looked up after reading this. Whoever designed this deserves to turn a profit after their time engineering the product. I am interested in hearing comments from anyone else who has installed this.

I hear ya...I just hope RSS dont start charging $15k for this...then again people would probably rather spend that much in order to believe it.

I just read the other post that was revived regarding this topic. It was mainly a bunch of skepticism, which I do understand. However, the skeptics are all people that have not performed the mod. I somewhat include myself in that group, but am open to being convinced otherwise. I will definitely keep an eye on this to see if anyone else performs the mod and shares their impressions.

blackcab996...I dont care what they say about you, your alright in my book

Eric, your the man! Thanks for solving the debate once and for all. I think I need to bust out the credit card when wifey isn't looking. My car is also non e-gas....I can't wait. Thanks again for posting this so the rest of us can benefit. Guys like you make this a great place to hang out. BTW, your car looks fantastic.

Now get us that 1/4 mile time!!!!

Ok,ok... let me see what I can do. So.. we're shooting for high 12's.

Redridge....I will order mine in the morning. Thanks again Eric. My wife will thank you too when she sees our credit card bill....that's what roses were made for. I'll post times as soon as I get it.

Where did you buy from ? I am in France and need mailorder. Mark 1998 996 3.4 Vesuvio.

I had asked on another thread if anyone had done this to a regular 996, I guess now I can believe and will order one. As far as where to buy here is the location from the other thread: http://roadsportsupply.com/IPD_Plenums_Porsche.html Note I do not have any financial interest in this company, own any stock nor do I even know where they are located etc....

I'm not knocking the mod but there are a couple of things to look at. I've spend a huge amount of time on a Dynojet with my race cars. Eric, do you have all the dyno charts? I assume you did about 3 runs before and 3 or 4 after. Did you do all the runs in one session with the mod added in the middle? Please tell us you didn't take the worst before and the best after. What gear did you do the dyno in? What other mods do you have? It looks like a pretty trick car although your before number is pretty low. Your after number is about what we usually would see from a good strong 3.4L. The max HP gains are coming right when the cam timing shifts. It was the same on the RSS website. That's a good thing but I wonder why it is. Usually gains are max hp which is less than 7 hp. Having said that, the 28 earlier is actually more valuable. Understand it's for a very short period of time though. Just when the engine is recovering from the shift. Again, not trying to rain on anyone's parade. Just trying to get to the facts that will help everyone understand the mod. Jim

It'd be interesting to see the "before" run made with a stock airbox.

So to sum things up, will this mod for all 996's, is it a simply bolt on install etc? Thanks,

Good Questions

Yes it's a DIY takes about a hour to put in.

Eric, What size tires do you have? I ask because I'd like to calc the RPMs your cams are shifting at. It still seems strange to me that the mod helps so much with the cam shift. Again, it's good news and seemed to do the same thing on the other dyno but it's not clear why it would have that impact. So are the two runs you show runs 3 and 6? Generally you'll gain some hp as the drivetrain heats up but not the 10+ hp you're gaining throughout the run. Jim

Thanks Eric, whats the best way to order this part?

Stock is the 2nd run and the Mod is the 4th, the car was down for a hour during the bolt on. 295/30/18

Sure, no problemo. http://www.roadsportsupply.com/IPD_Plenums_Porsche.html

Looks like the 3.4 cars will get more bang for the buck than the 3.6 guys. 996 Intake Plenum for 3.4 Liter 99-00 HP Gains: 25 Torque Gains: 22 Part# 96200 Retail Price: $995 996 Intake Plenum for 3.6 Liter 01-04 HP Gains: 15 Torque Gains: 14 Part# 96201 Retail Price: $995

The 3.8 is even better..... 997S 3.8 Liter Intake Plenum 05-Current HP Gains: 27 Torque Gains: 25 Part# 97301 Retail Price: $995

If these numbers are true I think we could get 50+ buyers for a group buy. How many are interested?

Oh I'm in for a group buy.

I am in, I was about to order today

Here's the thing? Why wouldn't Porsche install something like this on their own car? I mean, I know they use a modified plenum on their X51 kit, but since it seems like such a no brainer, easy, and cost-effective, what are the potential downsides to using it? Less fuel efficient? Engine problems? I'm flummoxed here.

Who has the 411 on the group buy? Count me in.

Im down for a group buy!

6speed has a group buy, if I recall correctly.

I am in!

[Image-only post; no author-written text. Original image references:] https://rennlist.com/forums/graemlins/thumbup.gif https://rennlist.com/forums/graemlins/burnout.gif

One potential answer is that the production cost of a modified plenum are much higher than the cost to produce a traditional plenum, so Porsche decided to save cost but sell the improved product to these customers that wish to get the performance with the X51 kit and want to pay for it. I'm working in an industrial environment and there are a lot of lean manufacturing efforts going on, so I think it's too simple to just say: "Porsche would have optimized the performance of their cars if it would be so easy". They only do this if it makes economically sense for them.

My final word on this mod. If you have the $1k burning a hole in your pocket, go for it. Unless Eric is pulling a fast one, the dyno runs seem to legitimately show an increase across the entire RPM range which is pretty hard to come by. Not even the X51 does that. Don�t be fooled into thinking you now have a 328 hp car though. If the dyno runs are accurate, you have something around a 305 hp car. That�s not a bad deal but you might not want to go picking on your neighbors Viper just yet. Jim

Wow. A 13% hp gain to the wheels at the most 'desirable' part of the curve for a $1,000, 1-hour DIY bolt on part. Miracles do happen. +1 for group buy asap.

Isn't the data on the Road Sport Supply site wrong? The 3.4 part should be for MY 99 - 01 right? And those are performance gains for just that plenum? Not a chip, intake, exhaust combo type thing right?

Jim, you are holding out on us man. I can see from your new sig that you've got pics of the race car in action. Post em up, or I'll sick Tim on you!!

What would the group buy price be?

If the plenum alone makes that much horsepower, then why didn't Porsche just use it for the X51 kit and save themselves the hassle. Boys, this just doesn't add up. I mean, I love mods as much as the next guy, but something smells in the land of Stinkville.

And does anybody have a link???

beacuase this is a race design part, x51 is there to give more horsepower and that is it. Porsche wants us to buy gt3's and cup cars if you want to see these type of design...it is more common in these (race bred, dry sump) type of engines. The 996 NA (not gt3) cars are for the regular guys and Porsche wants it that way. If you want to play, you have to pay.

People have got to stop thinking about horsepower alone, or at least assuming that this is what car makers think about. All engineering is about compromises. Car makers have to think about reliability, durability, NVH, emissions, fuel economy, cost to build, cost to buy, 'driveability' (using a lowest common denominator standard), and so on. It's totally possible that a mod like this could make power. It might just make it in a way that Porsche won't or can't accept the consequences of. (A big part of the reason they went to water cooled engines, for example, was because of German noise laws. More to the point, X51 is what it is because they weren't willing to compromise anything except cost). When you add an intake or an exhaust or whatever, you aren't discovering power that Porsche was too dumb to realize was there. You're not even making the car better, objectively speaking. You're just making it better for you, and getting away with something that German law or Porsche lawyers or some dumbass focus group wouldn't let them. You're just changing the compromise to suit yourself. That's the fun of it. If this mod makes power - and I have no reason to question that - you can be sure that it does so by compromising something else, and that compromise might be just fine.

Funny thing is, is everyone is basing this on ONE car (not knocking the OPs results or car), lets see about 5 cars make the same improvement and I will get one for sure. That car was a low power 3.4 from the get go. I am not knocking the OPs car but like JimB said, those stock runs seem a little low for a Dynojet. Actually those seem to be in the ballpark for a stock car, misread the graph. Not trying to start any beef but this only one car on Rennlist with dyno pulls posted, we need more to make sure.

I agree with Tippy, if I see a few more good examples, I'm in.

I'm thinking i'll go ahead and order one today, I don't see any threads on 6speedonline for the GB?

As excited as everyone is over 263 hp, I think I'll post a dyno for my 996 tonight and raise the price to $100k.

Yea Ray, someone posted a couple of pics on the Kansas PCA site from last weekend. I'll add them to the 996 pictures thread sometime.

Thanks for the pics, Ericdee. It looks like on that pic showing the 2 intake plenums side-by-side that the RSS one has a dip in the middle creating the increase in air velocity via the bertouli effect. Looks like these guys have done their homework on these designs. Your HP/torque gains accross the rpm range look impresive and the max numbers looks a la par with their website claims. The 3.4L engines from '00-'01 (non-cabled engines) seem to have even further max numbers. I wonder how these would fare in the range of rpms below maximum?

In looking at your dyno chart, if I am reading it correctly, the gains that you claim are at 95mph on 4th gear (as you wrote earlier) and not at max output as it seems by reading your original post. The increase in HP/torque at max output are +7hp and +13lbs/ft torque according to the side notes on the dyno chart. Still on the plus side and definitely all around the rev range. The +28/26 at 95mph on 4th should be definitely noticeable on everyday driving.

I think the same This mod could help something but it's not a miracle. In our spanish forum there are some people who like to install catalytic bypass just added to a foam air filter. The results are very nice and the sound is great! Sporty! We know this kind of mod is not legal when we talk about emissions but we can run with it. We must pass a Vehicle Technical Inspection at the age of 4 years since the first purchase, and after that, every two years. We change the bypass to be legal, and then redo the mod. It's cheaper than RSS

???

that's just too damn nice...... a little bit of more r&d and this thing is the next best mod on ALL our list of mods......

Eric, the dyno #'s look impressive...how is the "seat of the pants" feel? Do you think you could notice a big difference driving the car? Thanks,

We've been installing these plenums for awhile now, and the customers feel they are getting their money's worth. The latest improvement to the 99 MY seems to be a good one, we had installed some of the first MY99 plenums, and they were received well. Turbo guys luv em too. Mike has put quite a bit of work into his product.

Sorry. My english is not so good... What I mean is to substitute the catalyst by a tube. Just like the pic Here is the link: https://shop.fvd.de/?VID=198828&VCD=...t=3&display=20

Oh it feels great, The Car is Smoooooooooth... It just keeps pulling to redline.

I'd be in for a group buy

That is the best post I've seen in quite some time and goes a long way to explain how things like the plenum and (God forbid) the K&N CAI actually can and do add power. I'd like to see a before and after of stock vs. those two mods and a muffler bypass. Might be pretty interesting.

Laura (H), I didn't know you were on this forum. I signed Dawn and myself up with the POC yesterday.

Just an FYI they are running a group buy on another thread so I thought I would add it here. Note this is just a repost of what another member posted. Hi Guys, I just called Greg at RSS and ordered my new plenum. Thanks again to Eric for the Dyno results. I asked about a group buy price. JW had previously provided me with his name and number (thanks JW). He gave me a limited time preferred Rennlist member price of $850 for my 99 non-egas 996. He authorized me to post this information. His number is [phone removed]. He was a pleasure to deal with. I am looking forward to posting before and after 0-60 and 1/4 mile times with my G-tech. __________________

Fair point.

+1

I did a search on the plenum manufacturer, and there is an article on EuropeanCarWeb that details a turbo that was modded to all hell. http://www.europeancarweb.com/featur...che_911_turbo/ In the article, you'll notice that on top of all the mods, he also did an EVO CAI and an Innovative Pro Design plenum (same as the one that RSS is selling). Perhaps that makes some of you who are interested a bit more comfortable. UPDATE: also, from looking at the comparative pictures on this thread at 6speed (halfway down the page), it's easy to see why Porsche used the plastic one. It's cheaper and looks a heck of a lot easier to produce. I'm starting to get convinced.

Edward, it also melts....ask me how I know.

OK I am not Edward, but I will bite Mfletch what melts and how do you know?

He may know because he bought a burnt 996 and brought it back to life. He knows what burns and what doesn't, I'm guessing. CP

From 6Speed: Yes i spoke with Greg from Road Sport SUpply Thursday afternoon and questioned him about the stated hp gains. From what he said it was due to further modifications of the plenum. HE said that they used an "equalization tube" (what it is i don't know). But to their surprise it netted an extra 12hp from the slight change. So i went ahead an ordered a plenum for my 2002 996. There is a 100% satisfaction gaurantee with this product. So if you don't like the performance they will accept a return no questions asked. I do know that since this thread was started the plenums flew off the shelves. They are out of stock, but the production is under way and they should have more next tuesday. I will also perform a before and after dyno of this product and let you guys know. Bao What say you?

I presume he's referring to the OEM plenum and anything else that's made out of plastic in the car.

My original intake manifold melted when the previous owner had an engine fire. The plenum is made out of the same plastic that the intake manifold is made out of.

Let me know when you go to dyno so I can have my car dyno'd too.

That would be greatly appreiciated.

Wasnt me. It's some guy on 6speed.

Check out the response Joel Reiser of PCA gave to the same question. The old adage comes to mind; if it sounds too good to be true it usually is. Even at half the hp gain $1000 would be good price. My only concern would be; what is the down side. There usually is one. A CAI lets in more air so the engine breaths better but it also lets in more contaminates. http://www.pca.org/tech/tech_qa_question.asp?id={6CFA8B0D-0D04-4B49-9360-B60C43938235}

Some had asked what rpm the max hp came in at, it was 5500rpm. I'm going to see if I can get a chart with rpm rather than speed. Stay tune. Oh and the pull was in 4th gear.

Anyone want to sell me their OEM intake plenum cheap? PM me please.

Why not modify the stock plenum? Like drill a hole in the back of it and use that as a mounting hole for a wedge that can be attached to the inside. It may not get the exact same gains but it might be close. My major in college was Fluid Eng and I learned that it is surprising how small changes in airflow can lead to great improvements in flow velocity.

Interesting thread,.... I for one, would like to see the AFR plots from the dyno tests to see the effects on air/fuel mixtures at all throttle settings as well as WOT. Some software changes might be needed.

Steve W: Good to see you back with us....it's been a while. I always enjoy your input. I wonder how long it's going to be before we see these on eBay being manufactured in China or Taiwan. Chuck

i'm new to the forum, who makes this plenum, and did anyone else get results like this?

http://www.roadsportsupply.com/IPD_Plenums_Porsche.html Run a search under plenum. Try http://www.6speedonline.com/forums/ as well.

There is a patent . (if only Chinese manufacturers respected them).

My thoughts exactly, but I was thinking about drilling 2 holes. I've been building Harley-Davidson high performance motors for years and the stock Porsche plenum is of the same design as the Harley intake manifolds prior to 1966 when they got rid of the 90 degree T design. They went to a Y design which is like putting a wedge in a T to help direct the intake charge into the ports with less static pressure. Anyone want to donate their stock plenum to sceince? PM me

Hi guys, I was also thinking of that direction. I installed a Votex air booster on my 996 (cost only $20) & there was a improvement except that I didn't put it on a dyno. I was thinking of using similar concept on the stock plenum. Will be working on it tomorrow & keep you guys updated.

Hi Eric, I join this forum when I had my 930 turbo, I changed to 993 last year & now 996. I didn't realised that I had a total 131 post. I enjoy reading your threats & learn alot from here. Do I need to be a member? btw, can I change my user ID since I don't own the turbo anymore?

https://rennlist.com/members.htm#Pay%20for%20your%20Membership%20Using%20Paypal!

Do you have a problem with that?? I have way more posts that you or he does...

Yeah I do, pay your dues... Thanks for pointing that out.

Says who? YOU?? Why don't you ban all us users then. It's arrogant people like you that give this great site a bad ambience. You think you are superior coz' you paid a few bucks and can post insulting remarks to others.

It�s getting hot around here. It�s also getting hot on the coast, 80 degrees at 10:00 am. Should I switch to 15w50 oil?

C'mon guys....let's be civil. There is nothing in the bylaws or prerequisites for joining this forum that mandates a user to pay the fee. The only stipulation I'm aware of is the one that requires you to be a paid member to sell something on the forum. If the site administrator had wanted everyone to pay up at the onset, he would have made that a requirement from the beginning. But he didn't...so that tells me that he wanted folks to come here....see how valluable and relevant this forum is for us Porsche people...and eventually...in the spirit of comaradarie and appreciation...donate to the cause. It might well come to the point that the membership is large enough, and the reputation of Rennlist is extensive enough.... that the site administrator might make a fee the requirement for joining....but that's not the case now. If someone doesn't pay, then I would imagine that's their prerogative....would I like to see everyone with an "Addict...Rennlist Member" next to their name? Yes...because I think this is a really worthwhile site, and anything we can do to keep it going is simiilarly worthwhile. There's nothing wrong with a little friendly prod...like I've seen several times before...but we really don't need to get all heated up. rleeq: Nice attempt to divert the "heat".....but stick with the 0-40

Thanks for your wise words, Chuck. There is no heat on my side, except for the nice Florida weather today. I just couldn't let that one go by without saying something, I mean, check that attitude, shouting out "Hey USER!!!" to turbo138, which was completely irrelevant, and uncalled for. And that sarcastic remark like "Geeeez.... 131 post... And not a member?" You're right, a little friendly prod and a joke here and there is perfectly fine. And just when one is thinking "Hmmn...maybe it's time to chip in and contribute to the wonderful site here..." Wham! Some superior member tells you what he thinks. It wouldn't be right for one to feel obligated to be a member becoz' he's intimidated, becoz' he wants to belong to the upper group, or becoz' he doesn't want to be an outcast and have to tolerate insults from superior members.

These quotes were posted early last year and the site has grown quite a bit since then, I believe this place is now delivered on two fiber optic lines.

I just read through the claims of this patent and think it should be pretty easy to beat it. I could come up with an extermely similiar design and claim it is for the purpose of eliminating the heat caused by the friction of air molecules bouncing off the back wall of a common T-shape plenum. Different claims = different patent. There are a few other claims and modifications that could be made which would also allow one to side-step this patent. The art of writing good patents is to be specific while also being broad. I think they needed to be a little more broad. BTW, I am just passing on what I have learned through my own interaction with patent attorneys.

Thanks guys for the reply. I just read the link from ericdee I have been reading & posting on Rennlist from 930 to 996, it is great to share among Porsche owners our passion toward this great machine. There are many nice & knowledgeable people here, many have a great sense of humour. It has become a daily event for me even if I have nothing to post, I even made rennlist my home page on my PC. If there's a reason for me to join Rennlist as a member, it would be to support the operation.

NO, I don't get it, and I also don't get why you don't know when to quit. Again, you are just bringing up irrelevant nonsense to use as insults. Are you 39?? You sound like a 20 year old to me by your comments. But that's okay...I'm just a USER, so I'll just suck it up and be quiet. Besides, I shouldn't lower myself to your level and continue a senseless fight. Oh by the way, yes I do drive a stick shift, I have one at the moment, and I have been driving stick shifts since my first car many many years back. In fact, I've only owned 3 autos out of the many cars in my past. So does driving a Tip make me even less than a USER now? That's okay too.

And your 4? Because it seems like it.

Please Why don't we go back to the real business of the post?

+1

I'm going to do the throttle body next. I'll have pics and a dyno chart on that soon

Nick49, I think you would spend a small fortune on R&D. Dyno time isn't cheap. I'm kind of surprise how it's gone from its snake oil to let's see if we can get a knock off. That's really not right. They spent over two years in development on this product. The bottom line is there are very few products that produce these types of gains for the money. Also they have a money back guarantee.

It would be more honest to post all dyno reads, not just the best one. I have done this in my car and the dyno showed two pulls with increased horsepower, half a dozen without any change, and 4 with a measurable loss. The one that was used for marketing was the increased hp, none of the rest. If taken as an average, with all of them, there was an effective loss of 2hp. Of course I'm hoping that most of the time my actual output is with the one that did read increased hp/torque, but either way, it does sound a bit different and 'feels' faster, so I kept mine. Do your own research, and those who have all the dyno sheets, you might want to post them all.

Ok folks thanks for the wildride all over the place .....what about a group buy and will this thing have any affect on emissions?

I like green beans. Do you like green beans?

Wow Green beans...isn't that a little slow for Tha Killa

12 Runs!? Wow! In order which run showed the increase and decrease? How long between each run?

Yes, 12 pulls, trying to get increased hp/torque more than once or twice, and by some significant margin. We were there for hours, and even had an hour and a half break between to let the engine cool down enough, riding along at a slow speed to let the intake cool it, then letting it sit and trying to start fresh.

How long between "each" run and what was the engine temp on your positive HP runs and the temps on the negative runs? I know you weren't there for 12hrs, were you?

I was there for about 6 hours total. Time between runs varied - we figured the readings were poor because the car was too hot, so that's why we gave it a span of time to cool down back to cold temps.

It's fun to talk and think about it, and different approaches, but in reality, I don't care if my car is faster. I've got several motorcycles that are much faster and to be honest, I feel that over 8 years of roadracing in hundreds of races, I've got it out of my system. I still find enjoyment approaching a turn at a high rate of speed and watching my passengers natural reaction to reach for the brake with their right foot and hold on to the dash anticipating a crash without saying anything. Then with either very little or no braking cranking the wheel and negotiating the turn without incident and easing back on to the throttle.

I'm not sure if I understood your post correctly. Your car was used for the dyno charts that the RSS plenum manufacturer are using in their marketing? We need to find someone that can try this mod on a dynopack with the engine lid CLOSED and to monitor & match the engine temperatures, etc. with a PST2 or PiWiS.

What temp are you considering too hot?

I hate to hijack (again) this thread, but I couldn't read all of that crap from that idiot against CosmosC4S without responding. I was going to send him a PM, but I think his reply and restraint is worth a public word of recognition. We "users" have to stick together!

Ditto.

How about "We Porsche fanatics have to stick together !!!"

****e, this thread is way backwards............... I think I want one of these gizmos. I was going to exchange my throttle body but FVD talked me out of it..........

Posts like these just get old after awhile. I spent time and money to see if it worked. Sorry it did... Next time I'll just keep it to myself.

Hi, my name is Washington DC Porsche and I'm a "user". Step one complete.

Pretty sad. So many people proud of not supporting a site that they use so often.

Thank you Users !! At first, I tought I was out of place as a "user" I think this forum is about Porsche & supporting our interests as Porsche owners. There is nothing to be proud of just because you pay a few dollars a year to be a member. We prefer to deal with humble "users" than arrogant "member". btw, I've complete my "test" plenum mod. All "user" & "friendly members" are welcome to PM me for details.

Correction: So many users are proud of themselves for being a part of this site by being gentlemen, and having respect for fellow users and members alike. Maybe you do not understand how online discussion forums function. Yes, one way to support a site is to make a membership donation, as on rennlist. Out there on the world wide web, there are thousands of discussion forums, MOST of them do not require paid membership, how do those sites survive? Sponsorship, advertisement. BUT...the most important of all is the members, or users as you like to call it. Members and users are the LIFE of a discussion forums site. They fill it up with activity to keep it alive, to attract sponsors to the site. Now, if you donate a million dollars to a start up a new site, oh yeah, you're THE SUPER ALMIGHTY MEMBER! Without any other "Users" your site will not be successful. So please get this straight, it doesn't mean you are supporting the site more just coz' you paid a few bucks. A User could be a more valuable asset to the site by contributing more and by being more active on the site. A member who pays a few bucks and is not active is not necessarily contributing anything to the success of a site. In other words, if you see a User with high posts, you should see them as loyal contributors to the site with their time and dedication, making up for not paying a few bucks to the cause.

Agreed, non paying users are essential to the existance of rennlist and other forums!

Just for the record, there isn't a patent yet. Only a published application. Go here: PATENT PROSECUTION LINK to see all of the PTO interaction. -td

It's $17.95 a year, get over it.

Again, well said! Send me your paypal information Cosmos, I'm going to pay you instead of getting a membership!

Can we get back to useful posts about the Plenum on this thread and if you all would like start a new posting thread about users ect.

Eric, Like many, I appreciate the fact that you went to the time and expense of testing the plenum. I challenged your process (you passed) and I still challenge the 28 hp claim but I think you proved that at least on your car its a good solid 10-12 hp mod. There aren't many of those out there. So from one long-time Rennlister, thanks. As for the user vs member deal. This site isn't run by some big company. It's run by a husband and wife team that love Porsches. I very much appreciate what they do for us and would never think of using the service for free. I'm not sure what to say about those that think they contribute so much in knowlege that they don't need to contribute in dollars. I guess the world and the forum need all kinds. Have a great day. Jim

Without us "users" providing the answers to all the "member's" questions, what good would this forum be?

To that husband and wife who run this site, thanks!

Any dyno numbers on a N.A. 3.6.Ive seen deputy dogs dyno,but thats supercharged.

Will you buy me a membership? I can pay you two cheeseburgers on Tuesday.

lol

Just put my order in through the 6speed/ rennlist groupbuy through RSS. Greg was very easy to talk to and I can't wait to get mine done.

I put in my order too just an hour ago. Greg says 8 addicts did too so far. Can't wait to put in my 996 3.4L cab...

Or one octoburger

So true! I still smell snake oil.

are these the same plenum that GMG and all the other ones are selling? or do we need to place the order with RSS?

Mfletch: did you take delivery of the plenum? Give me a holler when you get it. I'd like to help you put it in and go for a drive.

Still waiting Chuck..I'll let you know. Thanks for the kind offer. I'll take you up on it.

This is a good offer from Gregg for Rennlist and 6speed. Just call him and tell him you want the Group Bye price! Dont delay...

I just ordered mine. As Rodney Said, Gregg is offering a good deal, call him if you are on the fence and get on the Group Buy. Thank you very much Eric for doing the mod and getting me excited about it. I appreciate you taking the time not only to do the mod but also to post your results!!

Johaness, deputydog on 6speedonline did just that: dynapack and lid closed i believe.

Hey thanks!

I have a total of one post here. I recently became a "member" only because I am a lurker and use this site for information but have not posted. I think you can contribute time, i.e. posts, or money, or both. So, in my small way, I will give money to support the website, whereas others give a lot of time to make this a nice site.

From the 6speed post, they are at 18 or 19, and when I order mine on Monday, it'll be 20

Any one know how to join 6speed online?? I have tried with mulitple email address and it keeps saying "my email address has been banned." It gives a link email them but the link does not work either.

Try using a email address from your server, eg. @comcast.net instead of a webmail like gmail or hotmail.

I have had the same problem from repeated attempts using AOL. They must just reject certain hosts. I have also tried on four occasions to contact the site administrator through the email address provided on the website and get an error message of "undeliverable". They obviously don't give a rat's *** about new members.

Chuck, I too read about all the problems of signing up at 6speed, but I got thru' at first try, and was a little surprised. They do use Admin validation/approval for new registrations though. Can't blame them, these days with so many spammers, you just have to manually screen thru' all new registrations.

If you haven't read on 6 speed, the gruop buy iat or past 20. JW

Any further discount for 30 orders? You're at $765 now, right?

Cos: I was going to try to get in on the Plenum Group Buy since the price is getting attractive....but I be damned if I can get past the annoying and redundant automated message of "the administrator has banned your email address"....or I can't get the dogone guy...whoever the administrator is, to respond to repeated attempts to contact him. I have no idea why I keep getting this banned message. I have never even been on that forum, so it's not like I've been blacklisted or anything. I guess I'm just not destined to go there, and I saved myself from getting sucked into buying the plenum.

I have tried to join numerous times with the same results. The site monitor sucks. You can call Greg at RSS and tell him your from rennlist and mention my name, I ran a group buy and I believe he will work with you on this gruop buy. JW

I was actually going to say a whole hell of a lot more than simply "sucks"...but other than provide a ventilation point for my frustration, it probably wouldn't set well with the other forum members. BUT......that doof who's running that show over on Speed6 has to have his head up his ***. There, I feel better already. Thanks JW....but I tried a Google search for RSS and only got directed back to this forum. I'll go try another search. Chuck

RSS [phone removed]. JW

JW: I tracked down an email in another forum with a URL on it and emailed Greg at RSS...so I'm on the list, so thanx for the info. Hey MARK!! Hear that? I'm going for it. I can't let your Vesuvio outdo me. I was going to save the money towards the tt, but that's going to have to wait for a bit.

Chuck, I'm excited about this...think of all the money that you are saving by not needing the turbo. We'll have to get together for the install and G-tech testing.

Sent an emil so I guess I would be around #30-31. My guess is RSS [phone removed] is the special code for the group buy?

Maybe the phone number.......

Definitely the phone nr. for Greg @ Road Sport Supply.

Getting back tot he plenum, has anyone who installed it driven it around? Any comments on streetability and feel?

OK I'm in with the Group Buy price; just ordered the Plenum (the money is really burning a hole in my pocket and I don't want to waste my designer jeans). The product actually seams to be based on a nice idea and I'm sure it'll bring some performance gain (although nothing like 28hp). However, it seams to have a good $/hp value and real production cost are obviously much lower but it's like ECU chipping. You pay for the idea and R&D. Finally I've to say it's clever marketing to have the advertising user post a dyno sheet with a 28hp gain and not deliver any further items until the group buy time slot is closed, so nobody can report on the actual 5-10 hp gain.

Now this is a sweet little modification.

Maybe, I'll wait to buy from an unsatisfied customer who thinks they will actually feel 10hp in the seat of their pants.

In RSS's defense, there have been some independent dynos already by people who bought prior to the group buy pricing.

Just signed up for the group buy. Can't wait.

I, the king of bolt on's, just signed up five minutes ago.

Although I ordered one, I'm wondering just what I'm really going to see out of this. I already have the GIAC flash, headers, mufflers, and EVO CAI....and now the plenum. I'm not sure there's really that much horespower "wiggle room" in there....but I guess I'm going to find out. Logic seems to tell me that I'm not going to see the same sort of increase as the other guys who don't have the mods. That's an issue that really hasn't been discussed either in the forum or by RSS. I.E. what sort of HP can a guy expect if he's done the other mods??

Yeah, basically I have the same mods as you, minus the headers, we'll see.. though I already know I'm quicker than stock 996's.

I'm In, Maybe I missed the ordering info, Can someone re-post. My old eyes are getting the best of me.

RSS [phone removed]. JW

Thanks Amigo !

Last Question - Is RSS the Company Name ? Location ? URL, etc ? Thanks again...

Here is their link.... http://roadsportsupply.com/IPD_Plenums_Porsche.html The RSS stands for Road Sports Supply.

Hah I'm in too. Can't let hkw72 catch up to my horsepower. Think we can get a two for one special on the install?

It'll be interesting to see. Mark (Mfletch) has a 99 tip, and I have the 996 manual tranny...We both have the EVO CAI. I have the headers and GIAC flash and he doesn't....we're going to put the plenums on together and go against each other. The outcome will be interesting. Maybe we should book a session on Pinks.

HA! From my experience with other cars with automatic tranny's and ECU upgrades is that they take better to ECU mods than do manual tranny's. You'll still take him off the line though.

3 for 1.5 wouldn't be bad. I thought he had a guy who'd do it?

Am I dense, or do I just keep missing the "group buy" info? I've been through all 13 pages of this thread twice, and even survived two hijackings!!! ;-)

Here is the latest group buy info. It expired yesterday...but you might try anyway. The normal price is near $1000. " New group buy price on RSS Plenums" check this post, one or two pages back.

Damn, I guess I really need to get a SC to catch you on the track! Cool, now we're three! I'll contact my friend the mechanic to see that we can do the install together. It'll be much faster for #2 and #3 once we figured out how to put it in on the 1st car.

Gents, I am ready to buy, but I did not see a DIY on the sellers website ?

Mine should ship tomorrow! Can't wait!!!

I'm local to RSS so I was able to stop by at 5:07 pm on 5/7. Despite being 7 minutes past the deadline, they sold it to me at he group buy price. I also got a tour of their facility which was very impressive. Th owner has a red 959 amongst the many other fabulous collection of Porsches. They do race car conversions and were setting up several Boxsters for a new race class. I suggested they hold an open house, which they thought was a good idea. We'll see. As for the plenum, it was harder than I thought to install. By looking at it, I expected perhaps 30 minutes tops, but when all was said and done, it was more like 1.5 hrs. The difficulty lies with inserting the new plenum in place of the stock one, since the left and right flex ducts do not budge very much sideways, and there is minimal spacing between the plenum's outlets and the engine's intake ducts. I removed the worm drive clamps completely and lubricated the flex ducts and that allowed sliding the plenum between the flex ducts. I then had to work the edges of the flex ducts to get them to encircle the plenum's outlets and replaced the worm drive clamps. I must report that I am pleased with the resulting driving experience with the plenum. The engine pulls more smoothly and eagerly that is particularly noticeable in 2nd and 3rd gears. The post 4k rpm surge seems more noticeable as well, and I certainly hope it's due to the power improvement and not because of a reduction in low end torque. The engine characteristic now reminds me of my E36 M3 although more powerful - much more so. I do have pre-plenum dyno results, but since my 996 is a 4S, I need to go back to the MAHA dyno for retest at $200 to confirm the SOTP result, which probably isn't going to happen. RSS does offer a satisfaction guarantee, and based on my experience with it so far, I don't think I'll be returning it. So, to answer the quoted question, I'd say my 996 is more streetable with the new plenum and feels like it's more fun to run through the gears.

As far as loss of low end torque, typically you lose low end torque with larger throttle bodies morso than with Plenums. "I" don't think you lose any backpressure with Plenums it's meant for mid range performance. Speaking generally of course I don't have a new Plenum yet. I know how special Porsche's are when it comes to bolt on's to you guys.

Thanks for your report slaaw! Makes me feel better again after jumping in the group buy on Monday.

man.... i keep reading on this and so tempted to buy one.......

...ditto....

Here's what you do: Take out your stock plenum. Clean it well, and apply a thin coat of automotive wax. Buff carefully, be sure no lint or dirt remains. Reinstall. Double-check all of your fittings and connections. Go for a test drive. Notice how the wax has reduced all of the friction and turbulence in the intake manifold. The effect is amazing! I guarantee you that you will notice a huge difference in the ole' seat-of-the-pants meter. Accelerate in third from 3400 RPM to 6000 RPM. Feel how much smoother it is, how it pulls better? You're damn right! Then, send me the $1000. I don't charge for shipping and I guarantee the results. Michael

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I realize your post was tongue'n'cheek but just incase someone thinks about trying this, it is a reallllllllly bad idea! Most automotive waxes contain silicone which is the only naturally enemy of the oxygen sensor. If you get some anywhere near your intake manifold it will migrate to and damage the O2 sensors. There are silicones that are O2 safe but it will say so directly on the packaging.

dammit.... and i thought it would work...... but i am trying to save the $800...... not try something and spend $1K........ now if your method works, i'll send you $1............. how's that for profit? all you need to do now is replicate it 1 million times and guess what??????

Whelp, I'm installed! I started as soon as I was home from work 6:15 and was in the car ready to drive away after bringing all the tools in the house at 7:20. The problem I had was getting that 1/2 inch "breather hose?" of the d@ma stock plenum. The difficulty level of this project is basically the same as installing an aftermarket intake. I'm just getting back from some high, high speed runs so this is what I've noticed so far. I drove the car about 1 mile and only noticed the classic whirling sound I've heard described about plenums. As I pulled to a left turn light (where I make my U turn to do the high speed run) I noticed I just reached the 180 temp mark. As I cruised forward, I tapped the throttle a bit while in 2nd gear and noticed it feel a bit jumpy/peppy. I laughed to myself because this is the first time I've actually felt "better throttle response" on a N/A breather bolt on Mod. I tapped the accelerator a couple more times in disbelief. lol! The U turn. Still, as usuall, I didn't feel a difference in the seat of my pants, my a$$ just ain't that sensitive. Still, clearly I feel more throttle response. The response is enough that I will slightly have to adjust my shifting timeing habits. On my runs, I was exceeding the 7k mark because the RPMS after 5k "seemed" to come alot faster than normal. Still though, I don't really feal any diference in HP, but can "see" an obvious change in RPM acceleration. I mean, I found myself looking at the RPM's like "did it really accelerate that fast?", it's very distracting. *stuck in serious traffic this morning but my observations are as follows*: I don't notice the smoothness that others describe, the car seems the same in that regard. I did try to rev match but only once this morning. LOL! The car reved way too high, though I applied normal pressure onto the accelerator. Adjustments to my driving habits will be needed. This is that last engine mod for me. I need a suspension, I'm tired of bouncing around.

hmmmmmm ..... thanks for that washington....... get the suspension, waaaaaay more of an effect in driving.... especially when you start taking those corners........ enjoy......and keep us up to date with the plenum........like to hear more about it when your cpu kicks in.....

As far as fitment goes I noticed the following: There is a gap between the rubber inlets to the engine and the end of the Plenum, especially on the left side(facing the rear of the car). Note, the gap can only be felt when I have completely installed the RSS Plenum on the inside. It's very hard for me to describe. The gap isn't an air leak gap noticiable on the outside (there are no leaks). it's a what I'm describing as a turbulence gap where the parts don't seem to be flush with each other on the inside. What I don't know is, if there was a gap with the stock version but I doubt it. Also, I noticed the bolt hole in the top left of the Plenum doesn't seem to be as deep as the other 3 and certainly not as deep as the stock version.

Yeah, second that. Thanks a lot Wash. Good review and nice observations. Like you, I'm holding out for a suspension that I promised myself I would get last year. Sadly, the responsible bug in me had me buying new winter wheels instead of springs, but I'll get there.

If I understand you correctly, the gap you are describing is greater with the stock plenum than with the aftermarket one. I compared the width side-by-side (outlet-to-outlet) between the two and saw that the aftermarket unit is slightly wider, hence there's less gap when fitted between the ducts.

Still though, I don't really feal any diference in HP, but can "see" an obvious change in RPM acceleration. I mean, I found myself looking at the RPM's like "did it really accelerate that fast?", This one has always puzzled me.... If you have an "obvious change in RPM acceleration", and your clutch is holding, then on a 6 speed car the crank revs are DIRECTLY connected to the wheels thru the fixed gear ratios. So an obvious change in RPM acceleration MUST be an obvious change is CAR acceleration. (assuming you are in gear of course and not just bliping the gas in neutral) Newtons laws of motion say F=ma (force, mass and acceleration). Your car mass hasnt changed, so to get more acceleration, you must have more torque... and much more for it to be obvious.... right ? Am i missing something ?

I said I don't "feel" but I "see". I did not state there was no HP/TQ increase. Zesh!

I'm stating, I did not stick my hand inside the stock version to feel if there was a gap between end of the stock plenum and the rubber fitting on the inside. I did though with the RSS version to ensure all the rubber around the fitting was properly seated due to the fact that I couldn't the bottom nor the back from the outside. I really didn't want to even bring this up because it's worthless without pictures and that I don't know the terms for the parts since there were no instructions on how to install.

It's called the placebo effect. You think it is going to work, therefore, it does.

I went to my buddy's today...he's an indy who specializes in turbo charged trucks...but he has a new dyno. I asked him if he'd be willing to do a before and after dyno on my car with the Plenum, so that I can post a little more to this forum than "it feels so much more powerful". He has agreed to dyno my car, so when i get the plenum, I'll schedule a before....then an after. I'll post all the relevant info like ambient temps, barometric readings, time of day etc.. My car has some mods...so I'll be running the test with an EVO CAI, GIAC flash, Schnell headers, and MKII onversion of the 3.6L mufflers. Is there anything you guys can think of that I should consider before I do the dyno runs? I'd like the info to be as informative and relevant to the group as possible. There is just so much "yes it does....no it doesn't" discussion going on that if I can bring a little more objective information to the group, I'd like to do that. I know it's not going to be the "final word" because there's still going to be the yes it is...no it isn't sort of discussion, but at least this will bring something a little less subjective to the party.

Make sure you choose the gear closest to 1:1 ratio and that you strap the car down for the after dyno at the same points and tension as the before. Also, note the operating temps of the car at the before and after stages, keep them as close as possible. Reset the ecu, however that's done on these things, between the before and after. Then once you bring the results to the board expect arguements on how you should have used a dynapack dyno and/or you are a down right lyer who's using photoshop because you just want the mod to work to justify your expense. This is of course if you have any gains at all. If all else fails be prepared for the "well 7hp to the wheels is not a significant gain". LOL!

The 1:1 gear is 5th although most dyno in 4th. I've done both the results are very similar. You really should use 5th though. Two factors really influence your results. You gain noticable power as your drivetrain warms up. You lose power was the air around your intake heats up. Make sure to warm your drivetrain up before the dyno run. Do what you can to maintain the temp around the intake. Open hood, fans etc. Have fun. The first time you mash the pedal while strapped to the floor is pretty fun.

I figure I'll just throw the results out there, shut down the computer, and go on vacation for a couple weeks and let God sort it out. I guess last man standing will prevail. I really don't expect to solve anything, or convince anyone of anything....it's just something I want to do becasue there's so dogone much conjecture. I'm sure there will still be issues ...like the relative humidity was off, or the moon was in the second quarter....or it was low tide in Honalulu....but yutta hey....make of it what you all want. I'm paying for it so you can't bitch about that part of it.

Do you plan to do a dyno, make the mod and then dyno again? If so, who can argue. As long as you follow a good process and take the best before and the best after. Or some sort of average. The only issue I had with the original poster was his claiming 28hp when that was the result of the cams shifting. I think he proved a good strong 10 hp increase. Granted 10 hp will result in performance increases very close to running with 1/4 of a tank of gas rather than on full but what the heck. Hp is hp. It's all good.

Yeah, 28whp is crazy.. I'm expecting 7whp across the range with his mods and 12whp, peak if he/we are lucky.. LOL!

So whats the conclusion.? Expect 7-12 HP increase ? Expect a "did i really accelerate that fast thru the revs" ?.... sorry but if you see the revs changing faster then your car is going significantly faster and you have made a big gain in HP/Torque Expect the placebo-effect to feel better about spending the money on snake-oil ? $1000 for the same benefit as running with 1/4 tank of gas.... hmmm

Do you feel better now? You probably shouldn't worry so much about us plenum buyers, we'll live.

I wonder what the added weight takes away from the car's performance along with the increase in intake temperature?

I just did a couple of 0-60 runs with my G-tech performance computer. My best time so far is 5.00 with a tiptronic, EVO CAI, Billy Boat headers and muffler, and no spare tire. My goal has been to make my tiptronic as fast as a 6-speed. I'm pretty close...if the plenum gets me below 5.00, I'll be a happy camper.

Mark: Let's run it with your G-tech before and after and compare it to the dyno runs. It might be interesting to see how the G-tech results stack up to the dyno.

I wondered the same thing, about temps increasing, since it's a metal part suspended over the engine instead of plastic.

I remember the first time I saw (and heard) a car being dyno'd. It scare the living poop outta me! Damn! The most impressive dyno I ever saw was a late model (2003-ish) Ford Mustang SVO with the supercharged V8 and probably some tweaks... it pulled a solid 400 RWHP. Oh Mah Gawd! I mean, yeah, it's still a cheap FMC product, but it surely was a strong engine. Well... for a while anyway. I'm sure they grenade fairly often. Anyway, FWIW, I've always seen cars dyno'd in fourth gear. Looking forward to the results. Michael

The X51 kit uses an alloy intake so Porsche must not think it's a issue. On the other hand, drag racers shoot a little nitrus into their intakes before each run. Not for the gas, it evaporates, but because the expanding gas cools the intake. Who knows.

While waiting for my turn I saw them dyno Mustang drag car that maxed out the Dynojet. I think it as 1100 or 1400 hp or something like that. I was almost embarassed to take my turn. Somehow my 320 RWHP didn't get them too excited.

You shouldn't be taking any artificial pains to keep the new plenum any cooler than you would the stock peiece. After all, are you going to do that everytime you mash the accelerator in the future. Keep it honest.

You mean like dynoing the car with the trunk lid open and fan blowing on the engine. I don't ever recall seeing a car driving down the road with a fan behind it.

Maybe you don't drive with a fan behind you, but the car moving at 70+ mph in 4th is going to be getting some significant cooling from the 70+ mph wind... I think the concern about overheating is probably best tested on the road. If that is a concern, maybe put a temp gauge on the stock plenum and do a run, then do the same run with the new plenum after install.

So, are your saying that a dyno chart misrepresents the actual power of the engine when on the road below 70 mph? Or is it overstated above 70 MPH? I'm sooooo confused. Maybe the fan they use on the engine is variable, accurately simulating air flow over the engine based on engine speed and gear being used? I wonder if the dyno shops use a heat lamp on the engine too, simulating the intense warming effect the sun has on the engine and intake temperatures? Or are the results of the dyno only accurate on cloudy days? And maybe the fans placed in front of the car accurately simulate the intense heat from the black pavement that is passing through the radiators? So many questions....so little time. The point is, no dyno comes close to simulating real world conditions and is no more than a rough estimate of changes in engine output in the real world on real roads.

Mark, as a 99 tiptronic owner, I would be so stoked if you could get your car under 5 seconds! If you do, I think I'm definately going to have to go for the plenum and some headers at some point! I can't wait to see your results. Scott.

Sorry, I was only saying that putting a fan on the engine when running a dyno is not 'cheating' on the evaluation of any potential heat problem with the new plenum. If the car was putting out that much power in normal conditions, there would be airflow helping the cooling of the engine, so adding a fan when running on a dyno seems perfectly reasonable to me. I'm not commenting on accuracies of the dyno process, since I really haven't got a clue.

An open hood and fan are perfectly normal and appropriate for a dyno. Car's weren't designed to run at full speed in a little room standing still.

Jim, I'm not debating whether you should have a fan on the engine when dynoing a car. Only a food would not. My point is that current methods of dynoing a car do not give an accurate picture of the performance of power to the wheels in the real world where you cannot control the variables. I suspect that most people would get the same increase in performance if they simply learned to drive (particularly shifting) as they would by adding 100 more hp. Jim

I follow you and agree but it's the only way to measure the effectiveness of an engine change so it's very valuable. If I was a betting man faced with selecting between stock 996 with a novice DE driver and a 996 with a regular street driver but with a plenum, I'd take the DE driver any day. Even in a drag race.

OK, my Plenum is in! It took us less than 1 hour, hardest thing was to push the new Plenum in the gap between the intakes as the RSS Plenum is a little wider than the stock Plenum. I've noticed the same thing as washington DC porsche, the needle of my tachometer just flys between 5k and 7k RPM. I'll report more impressions after my DE event on the weekend.

Frankly, I don't know why some guys think this is just subjective (which it very well might be). However, if the RSS plenum delivers smoother flow as a result of it's design (and it's design looks vastly improved to my eyes), then as the air intake velocity increases with higher rpms, the V shape on the bottom of the plenum could conceivably help force the air into the manifold in a more efficient and higher velocity manner. Ultimately, it could result in achieving higher rpms faster. In other design words, it would seem that to get air to go in two opposite directions, adding a little V stopper at the bottom of the plenum would do this resulting in a smoother transformation of air into the new direction as opposed to straight into the flat T junction. As for the holes in the V stopper, it would seem that they are used to help distribute any pressure buildup (from the air rushing past) more equally from one side to the other other. Then again, I could just be rambling. My physics and aerodynamic memories from university are pretty weak after all these years. EDIT: By the way, hwk, how's it drive across the torque band?

I've not yet had enough chance to really test the plenum and I'm sure my ECU needs more time too. However, I'll be 2 days on the track this weekend where I'll drive a lot in high RMPs, so I'll report back on Monday. I'm further interested if my shift points on the track get mixed up with the new plenum. I've some turns where I just hit redline at the exit and shift from 2 to 3 as soon as the car balances. This might change now.

Well it's obvious that some of you folks have already gotten your plenums and have installed them. I know I ordered mine about a week and a half ago and they were supposed to have shipped the thursday before this last one. Has anyone heard anything from RSS on delivery dates? Is there some sort of hang up that has occurred? If so, can anyone advise when we can expect to start receiving them? Chuck

I am still waiting on mine also. They said ship this week but still no word so not sure.

This thread is waaaay toooo loooong

So, I was on the track this weekend with my new Plenum. What should I say? I think the ECU adjusted compared to the first miles after the installation and my car seems to be smoother on the gas and I might even have a better throttle response at around 3k RPM, so when I floor the gas around this spot, my car seems to counter this input faster with acceleration. I further believe that I've a better and more linear acceleration between 5-7k RPM. After all, I still think it's a good mod but it's hard to say w/o a before/after dyno (maybe it's just the placebo effect).

Can we get some banter from those of you who have installed the new plenum?? Love to hear some subjective opinions and hear the results...

I just did the install...my first real attempt at *any* kind of real mod on a MY02 C4S...which I have owned for all of 3-1/2 months! I live out in the country, so even going the 5-6 miles to the grocery store can offer a bit of spirited driving, once I'm up over 180 degrees...and I would have to say that in the short time I've owned this car I do understand how it responds. I do *not* have access to a dyno, btw, but I have seen enough here, and in chatting with Greg at RSS, that I am comfortable this will be money reasonably well-spent. Okay, my C4S *is* a Tip, but that aside, I *do* drive occasionally in "manual" mode...and again, being out in the country I do get frequent chances to rattle the roof, so to speak. The bottom line for me is that my wife and I both noticed a smoother growl to the engine, and while I couldn't tell you where, rpm-wise, since I was watching the road, we also both noticed a *noticeable* (dept. of redundancy dept.!) increase in get-up-and-go. I'm ignorant enough about all of this to *not* know how much other hp/torque boosts cost, but from reading this thread it appears that the RSS plenum has a winner...and I would have to add my voice to the chorus, having noticed a real seat-of-the-pants difference. Cool. How's that for subjective!

Allllrightttty... So people seem to feel or think this mod has "better throttle responce,smoother engine, better revving" Is this worth $800-$1000? It's a fair question I'm thinking I could get the same thing out of turning off the A/C Ah, has anyone tried dyno with and without A/C

I'm going to be dyno'ing mine before and after....and no, I hadn't considered going thru the exercise with the AC going. (snicker) I contacted RSS today asking why the non e-gas folks still hadn't received their plenums. I was advised that they had a production issue and that the final shipment of the non e-gas models would be shipped out today, so you should be getting them in the next day or two depending upon your location.

Anyone want to sell me their plenum?

Perfectly subjective!

You will have to ask yourself that question. The engine definitely revs easier in the upper RPM range in higher speeds and even from a dig. I did not do a dyno when I got it a month ago since I did not want to bother looking for a 4-wheel dyno in my area.