Andial951

What turbo is on the car? And what boost are you running?

420WHP944

Thanks for posting this comparison doc!

Hardly seems worth the effort ( or money ) to change to the 3" exhaust

PorscheDoc

My pleasure John, you hit it right on the nose as usual!

PorscheDoc

K26/6 turbo (not an S), and stock boost levels. Car is completely stock with a fresh overhaul, other than the exhaust and short shifter (which obviously plays no role in this test). The predyno was with a gutted cat, so keep that in mind.

Also, going from a stock exhaust with catalytic converter in place, the gains would be significant going to the 3" exhaust, but they would be very similar by just cutting the cat out, welding in a piece of 2.5" stainless pipe in place of the car and making your own test pipe for 20 bucks....versus the $800 or so for the 3" exhaust system.

Next up, Sh944 and I test the notorious cold air intake for the 944NA

Porschefile

Stock boost?! It's definitely not going to make hardly any gain at stock boost. I'd like to see dynos of a stock exhaust at 1 bar and 3" at 1 bar. There should be quite a bit more of a gain.

Thanks for doing these tests PorscheDoc. That's very nice of you.

SD Porsche Fan

This is all fine and dandy but how does it sound?

fast951

No matter what boost level you run on the K26, the stock exhaust (with test pipe) performs fine.

ST dynoed 407rwhp on a stock setup with a crappy home-made test-pipe..

You will gain from an exhaust upgrade if the stock exhaust is causing excessive back pressure.. This is why with large turbos you do notice from a 3" upgrade...

RK951

now that you have the bigger exhaust you just need a bigger turbo

PorscheDoc

You know, I would love to test one on my car, but now that i see the 2.5" exhaust is quite adequate, I am leary about spending the $800 bucks for a 3" for my car, for little gains. I currently run a 2.5" testpipe with a magnaflow muffler, it sounds great, and I am sure it can handle any of the small upgrades I might do in the future.

I would rather put that money towards a Maf and chip set from John, I think the returns would be much better than anything gained from the exhaust.

Oh, there is no doubt it sounds great!

Lol, we have developed a high flow turbo for the car, we will see what it does. Turbo is done, but I don't know when we will get around to testing. Could be months.

Matt H

The gains came when you ditched the cat, the results are about what I expected.
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SD Porsche Fan

Would a #8 hotside make any difference with a 3" compared to a 26/6?

boxdoc2

There's always Clifford, but I've been told I need a new wastegate. I'd assume that would mess up the numbers. Everything else is totally stock. You knew that though.

d993

The HP gained will solely depend on how much you spent and what name brand it has.
Diameter is not important!
The more you spend, the more HP you will get.
The exhaust knows how much you spent for it, and "opens up" on it's own (the more you spend).

sweanders

Go away Troll.

JET951

you make me laugh sweanders