Exhaust project

[slammed_e30]

Going to start to fabricate a down pipe to replace my cat. this weekend, shouldn't be too hard. Anyone else here driving without a cat? what kinds of gains have you seen? How much louder is it? Opinions welcome.

[bimmer8604]

im driving without a cat. i noticed mainly a sound difference, seems a bit louder imo.

also, the car seems to revv a bit smoother up in the higher numbers

kyle

[nitro325is]

i have removed the cats on all my cars.you gain a few lb-ft and hp....but mostly you regain lost power due to a clogged cat.But the difference IS noticeable.I use ansa sport freeflow's on all my cars and the sound is great.Nice mellow tone and turns some heads...but nothing close to those ricer exhaust sound.I use ansa because i would rather spend an extra 300 elsewhere then a shiny exhaust with nice welds.

Try an get the exhuast pipes sectioned and clamped..not welded.It will make removing the exhaust, tranny or any undercar project much easier in the future.

[bimmer8604]

Nitro- I also run Ansa, I ended up taking off my cat, cutting open the top, gutting everything out of it, then having it welded back shut. It still looks liek I have my cat, but infact I dont.

Kyle

[M-technik-3]

They are already made for your car, It's called the early euro cat less down pipes for early euro cars.

[slammed_e30]

Nitro- I also run Ansa, I ended up taking off my cat, cutting open the top, gutting everything out of it, then having it welded back shut. It still looks liek I have my cat, but infact I dont.

Kyle

This will actually reduce your car's performance, might want to rethink that, uless you just want the sound.

[Jand3rson]

Nitro- I also run Ansa, I ended up taking off my cat, cutting open the top, gutting everything out of it, then having it welded back shut. It still looks liek I have my cat, but infact I dont.

Kyle

Would have been easier to have a muffler shop chop out your cat and weld a new piece of pipe in.

[M-technik-3]

If you really wantthe cat look take a long screw driver and pry out material the sleeve the cat with an inner pipe to prevent turbulance in the system.

[slammed_e30]

muffler shops wont do that where i live, it is illegal.

[E30godz]

yea they said they couldnt here either, but he was a nice guy and did it anyways hehehe

[Rob]

They are already made for your car, It's called the early euro cat less down pipes for early euro cars.

what he said.

[rwh11385]

Nitro- I also run Ansa, I ended up taking off my cat, cutting open the top, gutting everything out of it, then having it welded back shut. It still looks liek I have my cat, but infact I dont.

Kyle

Would have been easier to have a muffler shop chop out your cat and weld a new piece of pipe in.

but then it wouldn't look like he had a cat.......

Do what Eric Lukas suggests! 1) Have a shop weld in a straight pipe. 2) Buy an universal cat (or use stock) cut it open 3) Place over straight pipe
It's look like a cat.....but will have the benefits of a straight pipe.

Maybe e9nin will post here with some comments. He's ran straight pipes.

http://www.r3vlimited.com/phpBB2/viewtopic.php?t=1046&highlight=

Ted, i know you already posted on this thread I linked to, but it's a good reference for this current one.

I had a severely clogged cat that was hindering the car a lot....... I got a used front pipe section that had straight pipes replace the cat and boy what a noticable increase in perf. on the butt dyno and by comparison in 1st, 2nd and 3rd.......The car smells funny as is expected and it is noticably louder. Being that i have a new factory OEM muffler the car sounds loud, less throatier and high strung when you get on the gas.......IMHO straight pipes are best combined with an aftermarket muffler for better sounds.

[bimmer8604]

Im actually taking the cat back off, re-cut open, and having the guy weld in the straight pipes on the inside. This was my original plan, but we ran out of time as I needed my car for some business. The greatest thing of all is its only costing me 50 bucks, including labor.

I like the sound I have now, but I dont really see how i can loose power from it?

Kyle

[Spaz]

you are not losing any numbers, but neither are you gaining any. bmw have very well designed exhaust. if your removing your cat all you can expect to get from it, is a louder car.

but if you had a chevy, totally different story chevy can't build exhaust so if you take out the cat's your going to feel a difference.

so in final

remove your cats if you don't have to do smog, and when you do, only expect a louder car.

-cam

[UNHCLL]

Leave the fuggin cats in your damn cars.
There is NO NEED to run around without a catalytic converter. :roll:

If you want a better exhaust note, save up for a new muffler.
If you want performace, then buy a high-flow cat and have that welded in.