997 C2

Thinking abount putting headers and mufflers on my 997. If I do so, do I need to change the ECM chip? If stock ECM settings are optimized for stock exhaust, will the less restrictive exhaust reduce performance or reliability? I understand that the stock ECM will not maximize the possible performace gains, but I don't want to mess with the stock ECM.

teflon_jones

Why do you want to put headers and mufflers on the car? For HP? For sound? Or both?

Stick with just doing the mufflers. The headers aren't going to get you much HP and will cost you low end TQ. Not a good trade-off IMHO.

997 C2

I was hoping for both HP and torque. I'm pretty rev happy, so don't mind if get the benefit at 3500 or later.

JohnnyBahamas

I have Fabspeed's headers, a BMC F1 washable filter, and their Cold Air Kit on PSE cans. Love the sound increase and it's all easy to do yourself.

The catch is the headers are expensive... beautiful, well made... but expensive. I'd suggest starting with the BMC filter and the cold air kit to get a little more loud air into the system and see if that fills the bill. If you decide to go headers after that I believe there are used sets for sale here and around.

Oh, if you do the headers, the torque settings are 21 ft. lbs. at the cat flanges and 19 ft. lbs. at the heads... and, God love Porsche, every fastner on the exhaust is 13mm socket.

997 C2

Johnny,

Good thoughts on the intake. What was you perception of performance pre/post header install? Did you feel less down low, more up high?

JohnnyBahamas

Well, in fact with both headers on there did seem to be a noticible loss of torque at the off the line and up through 3rd but the sound was absolutely rightous. So, because sound is GOOD but torque is GREAT, I did an experiment... I went back to stock and ripped her around. Then I mixed one header with one stock manifold, short side/long side and vice versa, and I came to find that the stock exhaust manifold on the short side, US driver's side, and the Fabspeed header on the long side actually seemed to be the winner. More torque than both stock or both headers and more sound, too.

So now I drive around with the BMC filter, the Cold Air Kit (which shuts off the resonator thingy) and one Fabspeed header on the long side AND the PSE pigtail unplugged so that the computer can't quite the exhaust at those neighborhood speeds.

Strange combo, and silly to have one header hanging on the wall, but more torque and more rightous flat six howl.

tcetta

I would love to hear your comments after you do map it out. There use to be an australian company that had an excellent chip for 996 but they have disapeared.

Are all the mods with stock CAT. Anyone use the fabspeed or other cat by-pass or race CATS for a 997.

My car (996) is running the V-flow and muf by-passes. Same application for the 997, I like the gt3 sound for DE days, but also switch back to the Fabspeed muffs for every days. I had headers but found they only gained in the midrange, without the mapping, and I dont want to waist the money for mapping on a 996 when there is a 997 on order.

The CPU mapping is a must to get not only the low end back but also get peak hp at peak RPM, and that is where you will feel the benefits of the headers at 5500-6300-7100 RPM. If you have all the hardware it would make total sence to get it mapped, with the best option to be one of the flash programers to switch between stock and mapped.

tagheuer

That does sound strange. Have you dyno'd for actual perfomance gains or is it just a butt dyno?

JohnnyBahamas

Just butt dyno. There is private in ground DynoJet nearby... I should get off my "butt dyno" and give them a call to ask if they still do public runs for cash. If they still do, this time I will get my run on video. There's nothing like running a car flat out on a dyno.

Oh, stock cats.

synergy

I am seriously considering the AWE full system for the 997S. By far some of the best gains out there at +39HP with the full setup: headers, mufflers, cats, ECU. About $5k, but the best of the best!

Le Chef

Have AWE,or any of these tuners for that matter, published independent dyno figures to prove their claims? If you can get +39hp for a $5K outlay then why bother with X51? On the other hand why didn't Porsche achieve this in the way that AWE claims to have done? Why go to the expense and complexity of the X51 kit for a measly 26hp if an independent tuner can do so much better than Porsche's engineers?

Am I missing more than the independent dyno numbers here?

OCBen

Here's a thread that shows AWE's published claims:

https://rennlist.com/forums/997-forum/230033-997s-exhaust-systems-are-back-in-stock-and-shipping.html

Le Chef

Wow! They covered off all the obvious questions. I like the idea of being able to make changes as and when budget allowed. Drivability looks improved with the torque bump low down. Impressive!

I still wonder why Porsche didn't do the same thing, but went for X51 instead?

tcetta

if you add a AWE like kit and the X51 then do you call the 997S a GT3

997 C2

Thanks OC Ben and others. Sounds like I would need an ECU change or else get loss of torque in the low end and nominal benefits on the high end. Given potential warrantee issues, doesn't sound worth it. Am I missing something?