tod84944

Those who have gutted the cat on there car, how did you do it, and what were the results. Can't decide if I want to put in a pipe at the exhaust shop, or take the cat off of the car and gut it.
Todd

Boricua944

Dont our cars suposedly sound horrible with a gutted cat? and loose Hp from lack of backpreasure? Maybe i'm way off?

PorscheDoc

If you are going to take the cat off, just remove it competely and weld in a piece of SS pipe in it's place, its too easy.

eohrnberger

From what I understand, on the 944, a drop in backpressure does in fact drop the low end torque, but then has more torque and HP in the upper rev range. Some have said that this makes driving on the street more of a chore, but had also said that on the track it's better.

This is all hear-say, as I've not done anything like that to my S2, so I can't vouch for this personally.

pearldrum944

I was considering doing this, I even had an extra pipe ready to be gutted. I decided not to after hearing from so many people that it sounded horrible.

Campeck

um.

gutting your cat = way better sounding exhaust. apparently there is a "tinging" around 3000 rpm that is very brief and some ppl don't like it. but overall the car sounds WAY better. method. remove cat. bang with broom. HARD. if you have a jack handle, use that. again.... HARD. that honeycomb is tough.

and not sure what yall mean by "backpressure" but if yall mean that if i put a pressure gauge in the exhaust and it read a + number. then yall need to think again. backpressure is not good for anycar. turbo or NA. when there is overlap its just going to force exhaust air into the AR mixture. result. better emissions....not low end. the loss of low end may be contributed to messed up resonance ( which in itself does send high and low pressure waves through the exhaust. but this is "resonance" not backpressure. so please get the words right or many ppl will get confused and start sticking restrictors in the exhaust ) in the exhaust. but not a loss of backpressure. i say do it. if you don't like. im sure you have plenty of spare cars around to get a stock one back.

as for welding a peice os SS in its place. please dont. it will sound HORRIBLE. get a resonator if you want to do that.

hope that helped.

theedge

N/As always need some backpressure.

joseph mitro

don't gut the cat.......just weld in a straight pipe. it will sound raspy and you will have debris left inside that rattles around. with that said, i gutted mine using a long barbell then used a hooked piece of metal to remove the debris. but again, just weld in a straight pipe instead of punching the cat out.

as for increased hp or loss of torque......i can't say my butt dyno felt anything different. result.....stinky exhaust with raspy sound and no change in power.

tod84944

I already have a Flow Master muffler, and a drop in K/N air filter. It souds pretty good now, but I don't want it really loud. I'm not too concerned with lack of back pressure, the muffler will help with that.

Boricua944

what kind of flow master muffler you put in?

Campeck

no joseph

dont weld in a pipe. you will hate it....just like joseph says....lol
i gutted the cat. then ran water though it after shaking it out thuroughly (sp) if you do it right there wont be peices.

theedge.
backpressure in exhaust is the killer of performance. i already stated why. why must you fight it. if you want to go more technical i will....

Lemming

Well, I gutted the cat from my 924S trackcar and to be honest, I didn't notice any difference in performance or sound. Having said that, I've got a gutted cat that I'll trade for other parts or will sell for cheap!

PorscheDoc

How will welding in a piece of SS sound horrible...the NA exhaust is stainless as well is it not? I did it to my turbo, it sounds great, exact same thing as buying a test pipe.

tomrc

My car had the cat hollowed out when I bought it, it also had a crappy muffler. I replaced both with a stock used muffler and welded in a pipe to replace the cat. I felt a difference only because the crappy muffler was clogged. As far as sound I don't find anything annoying about the sound of the exhaust. It sounds great all the way to redline.

So all in all this was a useless post.

Carrera51

My car has a Bursch header and had the bypass pipe as well, with a FlowMaster 50 series. The bypass pipe rattled and made the car sound like a POS. My wife hated it and referred to the car as the "9 Farty 4."

I removed the bypass and put the cat back in (had to weld a flange on to the cat so I could bolt it to the Bursch header). Now the car sounds much better. The Flow Master gives it a nice deep sound.