my a1 is now an a4! cheap mod! thanks guys!

[kirk90]

so i went to pullapart and got an a6 exuast mani. then got the down pipe from the a6 and had to get the rest of the pipe from an a4. just welded it all up. had to move the o2 sensor to the down pipe.which i had an extra length of wires from an old harness that i sodered together. then wrapped electrical taped the lenght of it. and took out the cat insides becuz i have an extra cat that i can use when i go get a smog test done. doing this i have seen a significant boost!
got the idea from the threads ive lookd over. thanks guys!
p.s. i spent about a total of $65 buks! woohooo! cheap mod!

[SpdJnky93]

Good job buddy, keep it up!

[deevergote]

You gutted your cat? Way to go numbnuts. You just lost about 10hp.

[kirk90]

hows that? less restriction right? people say u gain by doing that!

[deevergote]

A gutted cat creates a significant amount of turbulence in the exhaust flow. Turbulence is far worse than the "restrictive" part of the cat (I put it in quotes because our cats are actually quite free flowing). The turbulence created will probably make you feel like you have power down low, it'll choke up high, and eventully reversion will occur. Reversion is when the exhaust gas is pushed back into the combustion chambers, contaminating the intake charge, and causing a serious loss of power.

A4 manifold was a good idea. Gutting the cat was not.

[TypeG]

now you need to get the a6 manifold, cam, and ecu. later.

[honda_kid]

A gutted cat creates a significant amount of turbulence in the exhaust flow.

it seems very few people are aware of this fact. i witnessed it first hand at school on the dyno. good stuff.

another interesting fact from the dyno. flipping the round air cleaner cover on a tbi chevy truck with a 5.7 gains about 20whp!

[deevergote]

it seems very few people are aware of this fact. i witnessed it first hand at school on the dyno. good stuff.

another interesting fact from the dyno. flipping the round air cleaner cover on a tbi chevy truck with a 5.7 gains about 20whp!

Seriously? Sweet!

I wish our cars responded as well to simple mods as those old domestic designs. Those designs had such weird restrictions that opening them up created a ton of gains. Our cars are built to very efficient and tight tolerances. Our biggest bottleneck, aside from the usual breathing parts, would be the exhaust ports. Open those up, and gains can be seen... If only something gave us an easy 20whp!

[kirk90]

so then ive learned something new! thank u. so then would a test pipe wouldnt be a good idea? they have them on ebay ect.

[deevergote]

A test pipe would be better, as long as it's the same diameter as the downpipe and exhaust. Still, the gains are minimal. Just put a cat back in there. The 1hp you might gain with a test pipe isn't worth killing the planet, or having a car that smells like shit.

[honda_kid]

the test pipe is nice and smooth on the inside so it does flow smoother but you dont need it with the power you're making. plus they are raspy as hell. just use the stock cat.

[Accrdwgnguy]

I believe the test pipe is basically the same as the gutted cat. Get a real Hi-flow cat.

I didn't feel any loss when I gutted my cat, of course I did it out of necessity, because the engine was barely running due to the cat being clogged. Fo' real

[JTEK24]

A test pipe would be better, as long as it's the same diameter as the downpipe and exhaust. Still, the gains are minimal. Just put a cat back in there. The 1hp you might gain with a test pipe isn't worth killing the planet, or having a car that smells like shit.

x2

[dano28]

A gutted cat creates a significant amount of turbulence in the exhaust flow. Turbulence is far worse than the "restrictive" part of the cat (I put it in quotes because our cats are actually quite free flowing). The turbulence created will probably make you feel like you have power down low, it'll choke up high, and eventully reversion will occur. Reversion is when the exhaust gas is pushed back into the combustion chambers, contaminating the intake charge, and causing a serious loss of power.

A4 manifold was a good idea. Gutting the cat was not.

I didn't think you guys living in the British Channel Islands even had catalytic converters. Your explanation sounds a bit silly.

[kirk90]

k will do thanx guys!