Confusion on the air Intake options

I keep reading about these various Air Intake options, and have no clue how they fit together, or whether they are mutually exclusive. IDP Plenum Schnell Air Intake EVO V-Flow Ram Air Induction system They all say that they are very desirable, and that they help the performance of the car. Are these three separate, desirable things, or would you only do one/two of them? As a newbie, wanting to get into the modding of my 996 for the benefit of the driver (me), I need to understand what I would/should be getting into. TIA larry

IPD plennum is the "T" section after the throttle body. There are positive reviews about it.... its pricey though. Schnell... Id skip this. Not a fan of the name. Evo CaI... is the most popular. Sounds great and thats about it. If you want to do mods like these... you have to open up the exhaust end as well. And if you want to tie these mods together.... I would do a flash. Welcome to modding....

I have the IPD $1000, and the K&N air charger , filter $250 I love it

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Does the Fister D exhaust do what you would consider "opening the exhaust"? They don't claim any HP increase, just better sound. Others, like Fabspeed and Billy Boat claim increased horses. It would seem to me that even if you change out the mufflers, you are still constrained on the exhaust end because of the Cats. Isn't that true? And, if you flash the chip, do you put additional strain (increased wear) on the engine? Just trying to understand all of the pieces involved here. larry

The fister mod isn't opening up the exhaust in a performance sense, it's just a different sound. The purpose is flashing the ECU is to have the engine produce more power so you could call that more strain on the engine parts under heavy load - not something you'd typically describe as extra wear.

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well.... yes, opening up means, sports mufflers, sports cats and headers, but you dont have to do it all, every little bit helps.... it gets expensive but you do it to personalize and add 20-30hp. Chao's 3.4 (chsu74) has done the intake and exhaust (with stock cats) and a flash. Im very impressed with its performance.

Who do you recommend to do a proper flash?

I have a EVOMS intake from my '03 996 C2 for sale. PM me if interested...

Larry, I've done the Fabspeed cans ($550 used) and the Fabspeed cold air intake $100 used). The is just the red tube and airbox muffler delete. The exhaust sounds much better and the intake does make a bit more sound at WOT. Well worth the $ especially when you can pick them up second hand.

I've done some research and believe I'm going to get the K&N intake system for my '03 C4S. It eliminates the airbox for a cone-style filter with a heat shield behind it. K&N has a blurb on their website specifically about the performance gains on the 996 3.6, claiming 20 more HP and 23 lbs. TQ (validity of these claims is probably in question, but at my altitude any air is good air) Relatively inexpensive at $350.

got my K&N and i like the sound alot...feel like maybe lost a bit of low end but after 4,000 RPM i can feel the pull and the sound is great

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And BTW, you can buy it on Ebay for $255.95 with FREE SHIPPING EBAY Power Seller - Selling K&N So, the K&N ends up being $300 cheaper than the EVO cold air intake. Looking at the pictures, they are very similar. Can anyone explain to me why the EVO is worth $300 more, or is it just their name that sets the price? I am getting a bit less confused, but I still have the same question: Does the K&N or EVO CAI (cold air intake) replace the airbox on the 3.6 L engine? And, if I buy one of those, do I still need (use) the Schnell Air Intake, which seems to go between the CAI and the top of the engine? I don't really understand the purpose and/or replacement value of these things, except that it seems that cold air going into the engine for combustion produces more HP than hot air going into the engine for combustion. Can anyone explain this to me - Do I need the CAI (either K&N or EVO), the Schnell Air Intake, AND the IDP Plenum? larry

Never having seen the EVO, so not going to guess why it costs twice the price. I did however have a K&N in my previous car. The "pod" style filters like the one you've linked to replace the airbox. K&N do also make a drop in replacement that goes into the existing airbox. Looking at the Schnell CAI, seem to replace the standard plastic pipe with silicone to help keep the heat out, the K&N looks to have all the hose needed. As for the Plenum, I believe it's meant to increase the efficiency at the point the intake air is split to the two banks. I would imagine this could be used with any of the other products? I seem to remember quite a thread about this some time back? Final thought, I did wonder how much cold air these CAI solutions get compared to the hot air already in the engine bay? With mine I build a chamber to isolate the filter from the engine bay a much as possible. Would be easy enough to test, intake air temp is measurable via the OBD port. Good luck, hope this helps. Robert

1. The EVO intake does replace the airbox, filter and tube running to the MAF. 2. I've never used the K&N but several people have commented on the build quality and fitment in a negative light. 3. The fitment of the EVO is VERY tight and can rub on your pulley if you aren't careful. I had to create/modify a bracket to give myself a little peace of mind. 4. The EVO does seem to allow ~10% greater airflow above 4000 rpm based on my MAF readings. 5. The sound of the EVO is slightly more aggressive than stock, but it's a very minor change. -Shawn

Evo, schnell and wound upgoing with the k/n intake, there is no way to measure such small gains w/o a dyno. I would recc. doing an exhaust upgrade if sound is the main reason.

Be careful of installing an oiled air filter. Excess oil deposits itself into the MAF (just upstream of the filter) and can lead to MAF failure.

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I've run the EVO (with oiled filter) for over 2 yrs...no MAF problems...

I've run the EVO (with oiled filter) for over 2 yrs...no MAF problems... I'm happy to hear that. Mt experience was the opposite. Had the EVO with oiled filter installed in 04?05? by the tuning division of the local P dealer (Pfaff Tuning in Toronto). It was the first one they installed and MAF went shortly after. Their analysis was oil from filter caused the problem and they replaced the MAF at their expense. All their further installations use a non-oiled filter.

What was the non-oiled filter they replaced it with? I need one for my Evo. Thanks Sam

The new Evo has a funky filter with a wide mouth. The older models will except an AEM dry flow filter, I believe. From what I read they are very good. Check out their website. They have a sizing chart. I recently did the research on buying a dry filter for my Fabspeed CAI.

Hi Sam Sorry, I don't know the brand. It is a paper conical filter with a sock over it. I have no idea if the combo of EVO intake, IPD plenum and GIAC chip flash gained any more power, but it sure sounds good! PSS9's with Yoko Advan AD07's and a very agressive alignment made much more of a difference on track than the other mods.

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I have the EVO intake and EVO's exhaust, plus the IPD plenum and a Revo flash, along with the B&M short shift kit and recently the RS engine mounts. I actually feel quite strongly that I did get more power from the 'breathing' mods, but I don't care enough to try to quantify that and certainly wouldn't defend it on a dollars-per-horsepower basis. But what I will say is that all of the above mods combined make the car massively more communicative, responsive-feeling and Porsche-like to my taste. It's got to be all about the drive. If you plan to track your car or live where the roads are glass smooth, I think suspension mods make a ton of sense as a performance upgrade. But if you live in city like mine, they don't make any sense at all. Bolting stiffer springs and shocks with compression and rebound damping designed for deflections at 100mph will produce a lousy ride and actually hurt performance at real world speeds on bad roads. The idea behind your suspension isn't to be stiff per se, it's to keep the center of gravity of the car where it belongs and keep all four contact patches planted on the road. I ended up opting for Bilstein HDs on stock springs and sway bars for my car, and I would bet you that it will get around 'real' roads more quickly and predictably than a lot of lower/stiffer setups, as nice as those often look. I'm a big believer in the right tool for the job.

Bruce P I agree that the breathing mods make the car "feel" faster but it's very difficult to quantify, especially when they were all installed at the beginning of a season after the car was up on the lift for 6 months. I don't regret any of them. On the suspension, my car ('01 996 C2) was ordered with the M030 suspension and 18" wheels. Terrible ride in the city and over freeway expansion joints but that's not where it spends most of its life. EU Autowerks in Toronto installed the PSS9's and the ride on freeways/city streets is either no worse or improved....depends on who sets the car up I'm sure. Set up is modestly lower, probably equivalent to ROW M030. Based on a previous thread that you posted on, solid motor mounts are on the list for next spring...thanks for the review. Ian

I was sorely tempted to go the RoW M030 route, figuring that Porsche would have the damping sorted out for the road. But in the end, I didn't want to give up any ground clearance at all, so I punted. Glad it worked out for you. If I had a bottomless bank account, I might experiment with a beefier sway bar in the rear, and lighter wheels (I'm on the 18" turbo-looks, which are heavy. With all that inertia, I doubt I'm getting the most out of the shocks. In fact, the reference wheel for early 996 suspension calibrations was the 17"). I would want to figure out how to perfect the stock setup, so to speak. In keeping with my 'real world sports car' vision

When I dyno'd the fabspeed CAI without the heat shield installed it did make 5Hp difference but we also saw a bad shift in the Air fuel ratio for some reason. With some compensation I believe that a free flowing filter will have a better positive effect. However the downsides outweighed the gains (IMHO) and I sold it.

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Can you tell me the downsides vs the gains (HP Increase)? Just curious. From what I've seen, you are one of the few that had it on, and then took it off. larry

The putative downsides are less filtration of the air going into your engine, and possible oil damage to the MAF sensor. I periodically do oil analysis and haven't found any impurities that shouldn't be there, so the first isn't an issue for me. For anyone who doesn't operate the car in dusty conditions, I would imagine the same is true. As far as the MAFS is concerned, I have had to replace this, but can't say what the cause was. My indie says these things are consumables, but who knows. The putative benefits are more power and more/better sound, particularly at WOT. The latter is subjective. The former is contentious. I personally don't give a fig for peak horsepower numbers anyway, because they don't matter much in the real world. What matters is how the engine makes its power, and to know that you need a dyno. To me, this is one of those bolt-ons that you 'like' or don't, and which only offers any real performance value as part of a bigger tuning process.