Test pipe, no cat/muffler

[74goldtarga]

Anyone running a test pipe (no catalytic convertor, no muffler) on their 951? How does it sound compared to stock? What are the benefits HP wise on a stock motor? Would I be sure to get pulled over if driving off boost - I don't need that kind of attention. My exhaust has a rust hole and I am trying to figure out what to do. My car is registered for the street but is not street legal technically anyway, I mostly just tinker with it (unsuccessfully) and drive it to DEs. If I were to do this I would remove my muffler and rear exhaust, cut the muffler off and weld an extension to go past the rear bodywork. I have heard NA 944s like this but not turbos that I am aware of. Thanks.

[running_cold924]

mine is actually quiet, stock downpipe, LR 3 inch, no cat, to a hooker max-flo muffler and out. the turbo actually sounds better with little to no restriction, you'd never know there was no cat unless you'd smell the exhaust

[Techno Duck]

My friend has stock exhaust with no muffler. It is very loud, even on light acceleration. It is not an annoying loud like it is on the n/a though. If it's a weekend and too the track only car I think you will be fine.

The benefit you will see is better spool up, though most if the gains are from removing the cat and leaving the muffler in place.

[74goldtarga]

Thanks guys. My cat is gone already, my car is not too loud at present, if there is no hp gain from removing the muffler as well I will probably just weld a patch over the hole. The NA is annoying loud but obviously the turbo acts as a muffler, I suppose less so the larger your turbo is but mine is a stock K26/8.

[wild man]

With 3" pipe, that should net you 15+ HP. But once you go bigger, noise is more difficult to control. With empty cat, 3" pipe, and 18" long 3" glasspak with 4" chrome tip, my 951S was WAY too noisy for the street. I had to change the muffler to a 3" cherry bomb vortex.

Anybody want to buy a barely used 18" long 3" glasspak with 4" chrome tip welded onto it?

[74goldtarga]

That's probably what I needed to know. If I can't just run a straight pipe and need some kind of muffler anyway I will just patch the one I have as it will be easier/cheaper. Thanks.

[UncleRay]

Hi all,
This may be a bit late as I'm a new member to this forum. My '87 944 turbo has a test pipe and the original stock muffler. There is more resonance and a bit more decibels at idle. Still more than quiet enough for neighbors when warming up. It does not interfere with the stereo at cruising speed. Nice sound when you step on the loud pedal. No blat blat blat, just a smooth subdued powerful sound. This set up is not a cop caller at all. The exhaust does not drown out the whine of the turbo or the other wonderful Porsche sounds.
Enjoy, Uncle Ray

[1982911sc]

I have no cat and a Borla Stainless muffler - I actually cannot believe how quiet the setup is. Nice sound to it for sure, but not obnoxious at all. At wide open throttle at higher RPMs it sounds like an F1 car - especially in tunnels : )

[mikepellegrini]

My son (Trivgar) has a Lindsey Racing 3" cat-less and mufflerless exhaust on his 951 - it does have a small resonater - along with a 38mm Tial wastegate that dumps to atmosphere. It sounds like a race-car, and I like it quite a lot.

If you stand in back of his car, the whine of the turbo is really loud (even at idle), coming out the exhaust, which is pretty cool.

We don't have before and after dyno results, but like the others said, you gotta figure it's worth at least 15 HP or so.

[nize]

the cat is worth about 15hp or so, i doubt the muffler makes any difference in power, especially if you use a straight-through no-baffle muffler.

[nize]

i just remembered i actually did a before/after dyno comparison between stock vs no-cat exhaust many years ago. the cat is what chokes horsepower, not so much the diameter of the exhaust.

you don't make much more HP, but you do make full boost about 1k rpm faster, giving you more area under the curve;