KeninBlaine

OK, I've been reading many previous posts about Fabspeed, Borla, AWE, etc etc and am not really clear where the best bang for the buck is to be obtained for my 05 997S cab with stick and sport chrono.

I am not a tracker, I just like solid performance for daily enjoyment of the car. I wouldn't mind a little boost in power if it can be done reasonably. A little more noise at high rpm, or switchable, is fine but I don't want it for "regular" driving.

Is it safe to say that there will be a reasonable gain by going with new headers (such as Fabspeed) and leaving the cats and mufflers stock? How about doing the headers and mufflers, but leave the cats stock? Is the intake mod really any benefit? Sounds great in theory ("25% gain in air flow"), but I have a hard time accepting this makes much difference to the performance of the car. Fabspeed's intake closes off the factory flap on airbox. How is this normally controlled (closed) by the car? Is it closed in Sport mode? And what does closing this opening do to the performance (or is it just sound difference?).

I tend to be a little skeptical about some of the manufacturer's claims, so would appreciate real life experiences.

Dave07997S

Very little hp if any are going to come from the mufflers regarding the claims you may read. The major restriction in the exhaust system is going to be the 4 400cpi cats that are on the car. To really get any advantage from the exhaust is going to take a system approach. If I was to do one part that would give the best bang for the buck is the cats. There is probably 6-10rwhp in the cats, headers and mufflers by themselves do very little. The whole system is probably worth in the 15-20rwhp range, I know manafactuers are claiming more but that's my opinion.
Dave

RonCT

Honestly, if I didn't track my car, I wouldn't spend a penny to change the intake, exhaust, or software. The car needs absolutely nothing for the street...

Rolf Stumberger

1. Keep in mind that whenever you lessen the exhaust and intake restrictions on a NA engine, you will get a few hp at high rpm's, but at the cost of losing torque at the lower and midrange .
That's fine when you go racing, but may not be desirable on a daily driver where you rarely spend your driving above 6000 rpm's.
There is a reason why Porsche put different headers on the 3.8 liter 997 S engine than the 3.6 997 .

2. At most , you will get about 15 hp if you change your entire exhaust system .
I doubt you will "feel" any difference from an 355 hp engine . I doubt you are using it to anywhere near it's actual capability in daily driving as is .

3. For what you stated you want ,more agressive sound, but not always , get the PSE . It sounds like a Porsche should, and you can have it quiet when you want to have a conversation with your passenger .
And you will not have any undesirable resonances( droning) in your car , as you may get from many aftermarket mufflers.

4. Regarding the Fabspeed air intake . there simply is NO WAY you can get 25% more air flow into a NA engine . Especially not into a state of the art Porsche engine and not from a 6" long rubber elbow.

What Fabspeed does is to remove the factory intake connection from the air filter box to the engine ,including the Helmholtz resonator outlet hose.

The resonator is designed to cancel out some of the engine air intake sound at lower rpm's , to conform with noise restrictions in some countries, while maintaining the "Porsche" sound .
It has a vacuum activated butterfly valve at the outlet from the resonator chamber , which is open at lower rpm's and closes at higher rpm's , thereby disabling the resonator effect.

You can do the same thing by just putting a plug into the resonator outlet hose ( the smaller hose )
It does not affect engine performance in any way . Open or closed .

Because the car will "sound" more agressive with the resonator disabled, many people think they are getting more performance from the Fabspeed intake ( the human mind works in mysterious ways.)

Others may have different opinions. Lol

RonCT

The only thing I'd add is that you should take a look at the dyno charts for systems like AWE. I think you'll find there are gains to be had. I can tell you that I clearly am putting out more HP and TQ with the AWE headers, cats, and mufflers I had installed -- and it shows on the track.

You can see there's no loss in TQ -- only gains especially above 3800 RPM.
http://www.awe-tuning.com/pages/info...cfm?content=38

larrytrk

Added X-51 headers, PSE and a home depot rubber elbow to my S. Sounds great, feels good!
No claims for extra power, butt dyno feels good plus the sounds alone!!

Dave07997S

I differ from you on this Ron...I don't track my car and love the way a really tuned car feels on the street. I thought my M3 was quite a bit more visceral than this car as is right now. I haven't had a chance to put the AWE cats or X51 headers in yet, but I will then I will make a decision on how I really feel about this car.

Dave

Dave07997S

1. Keep in mind that whenever you lessen the exhaust and intake restrictions on a NA engine, you will get a few hp at high rpm's, but at the cost of losing torque at the lower and midrange .
That's fine when you go racing, but may not be desirable on a daily driver where you rarely spend your driving above 6000 rpm's.
There is a reason why Porsche put different headers on the 3.8 liter 997 S engine than the 3.6 997 .

This is a old wives tale..unless you go to big on the primary tubes which will cut down velocity. Also with the advent of variable camshaft technology this just really isn't ture anymore.

2. At most , you will get about 15 hp if you change your entire exhaust system .
I doubt you will "feel" any difference from an 355 hp engine . I doubt you are using it to anywhere near it's actual capability in daily driving as is .

I flog those 355ponies every chance I deem it necessary. People who have drag raced knows that I am speaking fact here that you will feel 15hp.

3. For what you stated you want ,more agressive sound, but not always , get the PSE . It sounds like a Porsche should, and you can have it quiet when you want to have a conversation with your passenger .
And you will not have any undesirable resonances( droning) in your car , as you may get from many aftermarket mufflers.

The thing weights a ton and way to expensive..you can buy X51 headers, cats and mufflers end up with less weight and more performance to boot.

4. Regarding the Fabspeed air intake . there simply is NO WAY you can get 25% more air flow into a NA engine . Especially not into a state of the art Porsche engine and not from a 6" long rubber elbow.

Agreed 100%

Dave

dndodd

Check out APR. At the DE this weekend they are claiming and additional 43 HP with their set up. Headers, Cats, and Muffler designed by them made by B & B. In addition a BMC a/f and their software.

Their software claims to move the torque lower which in my opinion is very desirable. They offer a 6 hour trial on their software which I was going to try but they need to develop a work around for my option package.

Talk to Keith at APR.

dstrimbu

Dave, isn't the X51 exhaust system PSE?

Dave07997S

The PSE is included in the complete X51 performance package. You can buy the X51 package and don't get the PSE for something aftermarket or even the stock mufflers. The X51 headers and PSE are two different parts.

Dave

Stuart

keninirvine-I just finished with the AWE mod(full exhaust, intake and Giac flash).Everytime I start the car I can't help but smile. The sound and feel will bring a lot of enjoyment for an everyday car.I can't quote you figures on power gains but can tell you I do feel the difference, and you won't have any trouble talking to your passenger at 3-4000 rpms on the road. You'll probably listen to your radio less and keep the windows open.

axhoaxho

I would rather spend the money on saving weight instead -- more effective on overall performance I guess...?

May be a set of nice lightweight wheels and tires. Not only they save unsprung weight and won't void warranty, they make the car looks good too.

Just my thought.

With best regards,

shlbrn

I just put on AWE cats, mufflers and tips. Yes, there is an increase in the butt dyno especially in the power band. I like them because under 4k the engine sounds pretty much stock. Wind it up and it sings. I must say I really enjoy the sound and feel running up through the gears. Now the car feels and sounds like it performs. I won't argue the efficiency of the modification just the sheer pleasure of the sound it makes.

Deacon

RonCT

These are $100k cars -- why not do both? Upgrade the headers, cats, and mufflers which WILL NOT void warranty (heck, my dealer put mine on and said so) AND get a nice set of low-weight wheels like the Fikse Profil 13s I just got at 19 / 20 lbs front and rear. As to weight savings, if I remember correctly, my AWE system is about 20 lbs lighter to boot and per the dyno, I'm about +25-35 HP and TQ.