Does an aftermarket exhaust make a difference?

I am new to the board and to Porsche. I just purchased a 2003 996 and noticed its very quiet. Do any aftermarket exhausts like Fabspeed make a noticable difference? M

yes.

A high qualty aftermarket exhaust will make a huge diference in the sound of your car. I also experienced a noticeable performance gain. The Evolution Motorsports cold air induction system will improve the sound of your car during acceleration almost as much as the exhaust. I have Billy Boat mufflers and headers. I am very happy with them. You can go to their website and hear a sound clip of their mufflers on your car. Congratulations on your new Porsche purchase. Welcome aboard and let the mods begin. Check out the member to member classified ads here...someone has a pair of Fabspeed mufflers for your car right now for $875. I have had great luck buying and selling 996 parts to fellow members of this site.

Welcome aboard M....if you do a search, you'll find plenty of info. on this, as well as videos that document different sounds. PSE is a big mod over here, and many of us have obtained that type of sound with a simple mod of your stock mufflers....it should pop up. Oh...and I might as well inform that you we would all LOVE to see some pix of ur car. Can you give us some details about your ride? It's customary to post some pix....I know you need to have 5 posts before you can post pix....but go ahead and burn them right here if you want. Best and welcome again, J

I recommend a set of GHL mufflers. They are easy to install and you can use the stock tips. The sound is fantastic and if you can wait till winter to buy them, they usually go on sale for around $700.00. Your car will go from sounding like a Honda to sounding like (almost) a "Cup" car. Best $700.00 you'll ever spend....

I can double this one! I love the sound of my GHL exhaust. Great mod for the money. Beside the sound improvment you reduce weight. The stock exhaust is really heavy and much biger than the aftermarket mufflers.

Buy mufflers for better sound and less weight. Power gains are imaginary. I had B&B headers & mufflers on my 996C2. Personally, I like the sound of the Fabspeeds best.

M, I have a 99 996 with a tipronic transmission. I added Billy Boat mufflers & headers, EVO cold air induction, and a RSS plenum. The stock 0-60 time for my car was 6.0 seconds. After the modifications, my 0-60 time dropped to 4.76 seconds. I don't believe this was an "imaginary" performance gain.

Welcome. I have a 99 996 tip. The car sounds awesome but I dont know the brand. The exhaust tips are larger than others I've seen too. My wrench says yes the car "probably has the sport exhaust" but didn't elaborate on what manufacturer. BTW I have had aftermarket exhausts(SSIs etc) on all my 911s so never had a quiet Pcar . Anybody have pics of their aftermarket exhausts ( I would like to id the make of mine). Thank you. Regards,

Mfletch - I have the same setup Here's a link to what it sounds like. http://youtube.com/watch?v=okru3YLgRHI Tough sound to beat and way better than stock. I drove mine and a stock car back to back and the stock sound was like flacid lettuce on a cold day old burger. Not a hard decision to buy the car I did.

What's wrong with flacid lettuce on a cold day old burger? yumm.

- cold and lifeless.

BTW, here's my setup: http://youtube.com/watch?v=kAUI3VOByHM Schnell intake tube, RSS Plenum, Evo/Suncoast headers, Muffler bypass'ed exhaust (PSE-Style MKII)

Wellardmac, that clip was great...your car looks and sounds fantastic. My favorite part is the sound near redline going under a bridge. A quality exhaust and CAI really transformas the car.

Thanks! Yeah, I love the echo going under bridges. 4500 rpm is my favorite noise.

Very scientific. Who could argue with that? Any engineers here who can calculate the incremental HP/torque needed to get that improvement in 0-60 times for your ~3,400 lb car?

Wayne - that clip sounds good! BTW - what does B&B stand for?... Belly Button? I know it is Billy Boat.

I thought it stood for Bad Boy.

Holger, I'm not an engineer, but I do know that my car weighs 2990 lbs, not 3400 (Randy Leffingwell-Porsche 911 Buyer's Guide). I'm not sure what isn't scientific about starting with a baseline and measuring the difference in 0-60 times after the addition of each modification. 0-60 times are very repeatable with a tiptronic transmission. I can't think of more accurate way of measuring performance gains. You and I live pretty close, I'm sure that we will run into each other at Infineon or Thunderhill...I'll be happy to let you take mine for a spin and see if you disagree after driving it. I would love a ride in your GT3.

"Curb weight.....3149 lb" http://www.caranddriver.com/longroad...era-page4.html And the Tip weighs ~100 lbs more, plus the driver, fuel, fluids ,etc, easily equals ~3,400 lbs. Let me point out the obvious: how accurate can that gizmo be (certainly not the 100th of a second)?, same route?, same conditions (very unlikely, that's why chassis dyno numbers are so suspect and easy to manipulate)? If you're happy with it, that's all that matters. But, the gains you claim are highly suspect given those mods (a turbo or sc would be a different story). Common sense says that you'd need to a big jump in power to lower your 0-60 time by that margin and there's no way those mods are going to get you there.

Holger, the article you quoted from Car and Driver put the 0-60 time for a 40,000 mile 99 996 at 4.8 seconds. At 4.76, it sounds like I'm pretty close. All I did with my modifications was make up for the difference between a tip and a 6spd. I relied on Porsche's factory claimed 0-60 time of 6.0 seconds for a 99 tiptronic 996 as my baseline...I never measured my car stock. When I rebuilt it, I tossed the factory mufflers and air box. My slowest measured time was 5.4 seconds with the B&B bufflers & headers and a first generation EVO CAI. My 0-60 time with the second generation EVO CAI dropped to 5.0 (the first gen EVO CAI caused problems with my car). The RSS plenum dropped my time to 4.76. The Gtech is one of the timing devices used by car magazines to do their timed runs. I bought it after reading an article in Road & Track or Car and Driver comparing the accuracy of the different timing devices. Redridge has a S/C on his 996 and has shared both 0-60 times and 1/4 mile times...I'm not even in the same league. His car will do the 1/4 mile in the 11s. I have a pretty extensive library of Porsche books. I think Car and Driver is inaccurate on their weight of the 99 996. The 99 non egas 996 is the lightest of all the 996 models. I have three Porsche books that put the weight at 2911 lbs for a 6spd and 89 more lbs for a tip.

Mark, if you're comparing the factory 6 second time with your Gtech time, that's clearly apples and oranges (you know PAG is conservative for obvious reasons), so if there are any gains they're not as substantial as you would lead people to believe. Like I said, do the math on the amount of power increase it would take to decrease your time by over 20% as you claimed. There's no way your mods are doing that. Also, there a number of other factors (environmental, fuel, engine & tranny temp, traction, etc) that are going to influence the results between different runs. I had a 99 C2 and it didn't weigh less than my GT3 and certainly not sub 3k lbs. It's funny that when it comes to P-cars & F-cars, none of the owners that weigh their cars ever come close to the factory numbers (which used to be with no fluids, no a/c, etc...not a real number by any means). (There are currently some interesting comments regarding this over on the RS board.) I don't know if C&D actually weighs the cars, but even their number sounded low to me from my own experience.

^^I agree. For G-tech, the road has to be perfectly flat for it to be precise since it measures G forces (hence the name), any road imperfection or inconsistency would lead to faulty data.

Holger, you are corect about my baseline time...if the posted factory claim of 0-60 in 6.0 for a tiptronic is not accurate, then my gains may not be as dramatic. I never drove my car stock, so I never had the opportunity to test it in stock condition. I have found that it is very easy to repeat results with the tiptronic transmission and traction is not an issue with my car (I was running 285/30/18...I'm now running 295/30/18 rear tires). My goal from day one was to make my tip as fast as a stock 6sp car. I have never weighed my car personally...I am relying 100% on what I have read in both Porsche books and magazines. I am looking at purchasing a GT3 identical to yours..would you mind if I PM you to ask a few specific questions?

Not sure why one guy is running down another owners results. Perhaps too much unconscious display of cognitive dissonance about the superiority of his gt3...

You clearly missed the point about what performance gains should be expected from certain mods, that I've owned both cars and that I did some of the exact same mods to the same vehicle.

Mark, I'm happy to answer your questions re the GT3. PM me. Also, I'll be at Thunderhill on 8/31 if you want to ride along and see what the GT3 is capable of on track. There will be at least one other GT3 there too and I'm sure he'd take you for a ride also if you wanted. http://www.hookedondriving.com/category.cfm?category=1 And those different sized tires will also impact your car's performance.

Welcome to the Board! I'm using Tubi/Champion Motosports Headers and Sport Mufflers. I had them dyno the car before and after and got a 19 rwhp gain and 20 ft.lb. increase in torque. At the drag strip I was not impressed as my best time prior to the upgrade was 13.12 at the 1/4 mile, but was only able to reach 13.35 afterwards. Weather conditions were about 10 degrees hotter and much more humid. Testing conditions were also uneven as the prior run was achieved by reaching the track on empty and filling up with 100 octane race gas. Hoping to clear up the performance gap the next time at Moroso. BTW - The sound is incredible especially over 2700 RPM. Sounds like a cup car when you run into the 6000+ range. ____________________ SpeedPhreak 02 996 C2 - K&N Aircharger, B&M SSK, Tubi Headers and Mufflers

Thanks to al for the welcome message. I think i am moving forward on Fabspeed exhaust and 19" Rennworx wheels as a beginning to the long list of upgrades. I will post the newbie pictures shortly. M

I have GHL exhaust on my '03 and find it to be too quiet! It's about the same volume as the stnd stock system. My understanding is that there are two systems, one quiet and one louder. Mine is definitely the quieter of the two. Is there any way that anyone knows that I can modify it to be louder?

Minimal power gains, but a dramtic improvement in sound. Fabspeed is the best sound IMO.

Is there only 1 Fabspeed exhaust for my car or are there choices. Recommendations would be great.

I have a lightly used Fabspeed for sale...$875 plus shipping...PM me if you're interested...

I just spotted this on the LA Craig'slist....."Porsche Fabspeed Exhaust 996 (01-04) - $500 -------------------------------------------------------------------------------- Reply to: [email removed] Date: 2007-08-14, 5:50AM PDT Less than six months old. Selling car and will sell parts first. Adds 10 hp, 10 torque and throaty sound. best quality on market." I have no affiliation with the seller.

i don't see it... the CL one...... do you have a link to it?

PSE is absolute incredible sound! Techart and RUF exhausts are among the best also.... personally I'm not a fan of the fabspeed... the above 3 exhausts have more character in their sound IMO.

OK, I will pitch in with my YouTube video as well. PSE ; on/off/on http://youtube.com/watch?v=85143TXV0Ug

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To do the calculation properly, we would need a torque dyno curve, through all gearshifts. However, a rough back of the envelope calculation can use the average force (directly proportional to the average torque), which is simply the ratio of the 0-60 times. You would need an average of 26% more force (torque) to go from 6 sec to 4.76 sec. Anyway, 4.76 seems pretty damn quick for a tiptronic under any conditions! Appendix: F=mV/t, mV=constant, so F1/F2=t2/t1.

Power gains are far from "imaginary" for a Fabspeed exhaust. I gained 22 RWHP (increased from 270.1 to 292.1) on a dyno 248C from a Fabspeed exhaust (mufflers only) and a K&N 63-series intake. PSE is the one exhaust that won't get you power gains as they use the same restrictive exhaust cans as the stock exhaust.

how much did you gain with the exhaust alone? your 22 WHP probably had something to do with the K&N series intake more than the exhaust... and you probably flashed the ECU in there somewhere to take advantage of the extra hardware correct?

As reported earlier, my GHL mufflers made a nice difference in sound. However, since about 1 week I've in addition JVT equal lenght race headers on my car, did resent the ECU by disconnecting the battery (no re-flash) and wow! The car sounds like a race car! Even with low RPM I always hear the exhaust; really cool! Probably too loud for a daily driver in rush hour but really nice for my weekend/track toy.

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I sure hope that this is the case for all 996 because 22hp gains are hard to believe.

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You can run the exact same car in different conditions on a chassis dyno and get that kind of variation in results. Therefore, it's not so surprising and not necessarily due to the mods.

What exactly is a "PSE" modification? I am looking into a purchasing a sport exhaust for my 2001 996 and viewed a number of posts regarding this specific type of modification that uses the factory exhaust. Any details appreciated. Your help greatly appreciated. Cheers

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It is possible to get even a greater difference that you mentioned. I have seen high boost/hp vary by over 50 rwhp (uncorrected) on a Dynojet. That is why you put in temperature and humidity readings into the dyno sofware everytime you run and look at corrected numbers. Despite the raw number differences, the corrected numbers were within 1%. SAE correction standards are applied to compensate for varying climate conditions. My correction factor was 1.04 for my baseline and 1.03 with the intake and exhaust. In my case, if you look at just the raw/uncorrected numbers; the difference is actually greater (at 24 rwhp). On the second dyno it was cooler, but more humid resulting in a slightly lower correction factor. Being able to compensate for varying climate conditions using correction factors is the reason why a chassis dyno is the most accurate way to measure power variances next to an engine dyno in a climate controlled room. Keep in mind that not everyone inputs climate data and corrects corrections factors when they operate a dyno. Make sure they do it whenever you dyno or the result of the runs will be useless. Feel free to read SAE white papers on dyno calibration and correction standards to understand more about how climate can effect engine performance and is compensated by standardized mathmatical formulas. One other thing to think about is in a similar thread someone made a comment that they measure changes by using a Gtech or other manually trigger motion sensing box. These devices have no abiltiy to compensate for varying climate conditions and hence provide no accuracy in measurement.

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You cut the cap off the end of the muffler and add a 2-1/4" pipe from the "cap" to the exit pipe. This is called the MK II PSE mod. This allows some of the exhaust to bypass two of the three chambers in the mufflers and gives you a louder and lower sound. The muffler on the right is stock and the muffler on the left has had the MK II mod completed.

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I'm no engineer and my dyno knowledge is all secondhand. I'm also aware of the correction factors. But different dynos produce differing results. Also, there are other factors that aren't corrected for and tuners can use to game the system (tranny oil temp, for example). So, I remain a skeptic when it comes to mods and "proven results". If it sounds too good to be true, it probably is...

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I generally agree with this, and I think if you have to look that hard for proof, it's probably not worth the trouble. But I think exhaust is different, dyno or no. It's the most tunable part of an engine without opening the motor up, and the component most likely to be deliberately compromised by the manufacturer for marketing or compliance reasons. A good exhaust lets the engine come closer to making the power it was built with. If you understand how exhausts work, and I think you probably do, you'd have a hard time arguing with that statement. Worth the money? That's subjective. But gains, yes.

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22hp from switching mufflers? Tell that to an engineer in Zuffenhausen and he'll laugh in your face.

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I didn't say anything about 22hp. Now, about this engineer in Zuffenhausen. Can I pick any engineer I want to tell it to? Does he have to be able to speak English, or work for Porsche? Could he be, like, a train engineer? Or a sanitation engineer? Can we have beer after he laughs in my face? Could I use this as a standup routine in a Zuffenhausen bar on open mike night? Would I win?

There definitly is some power to be had. I just took off my bypass pipes and went back to stock. The car has a wee bit more grunt down low (who the f**k cares about this), and has less ***** in the mid/high RPM.

PSE Rocks

Sound = yes, Performance = no IMHO did it would do it again but outside hearing it you will never know.

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+1 PSE audio samples: Sample One Sample Two Not so much performance gains, but the sound makes the car feel faster, plus it gives a nice aural indicator of when to blip and shift.

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Corner balanced weight (pulled from one of my posts). My car weighs 3084lbs and 3259lbs with my weight 175lbs (lightweight 02 5 spokes F/R 8�/10�, PS2 235/265, no floor mats except for 1 weathertech driver mat at approximately 5lbs, a hair over 1/4 tank of gas, a stereo amp at approximately 10lbs, heavier GT3 sway bars and TRG drop links, engine protection plate, no spare tire, no toolkit/jack, JICs which weigh the same as stock from my measurements, and the rear strut brace). The car is a 99 996 6spd, w/lsd, rear wiper, heated seats, and tinted windows.

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Do you think that plane in your avatar has 'mufflers'? And if not, do you think it's just because flying without them made it sound cooler? Just puttin' that out there.

Yeah I don't understand why people think performance exhausts are nothing but sound. I think exhausts like the Fabspeeds, GHL, and others would certainly boost hp a bit. I seriously doubt it's 22whp (or bhp for that matter), but I think ~10hp is certainly possible.

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Do you think it was designed that way...or did the pilot yank them off?

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... to impress chicks, maybe?