install test pipe on 91 si?

[franchise817]

What's up all im new to this forun and just introducing myself/car and would like an opinion. I have a 91 SI with Greddy catback that sounds great not too loud not too low and not ricey. I recently picked up a stainless directional test pipe from Impo performance in warminister, PA. Who's runnung test pipes and what are your results. I barely see this topic ever discussed so I figured id open up the floor on it and get some opinions. TIA.

[mattliston]

Unless its a resonated testpipe, you will be raspy as fuck. My testpipe was a straight through 2.5 on a 2.25 catback, sounded terrible. I put a new stock catalytic converter, ZERO performance loss that i felt, but goddamn, sounds better

[franchise817]

It is resonated 2 1/4 to 2 1/2 and it got a twist in it for directional flow. I heard my cars gonna smell bad and sound bad but the question is this. With the flow freed up can I see/expect any sort of gain?

[mattliston]

like i said I had a 2 1/2 inch testpipe to 2.25 piping. I felt zero loss when I put my stock cat back on. its dyno proven, even on a tuned motor, its only like 5hp, which is impossible to feel

2.25 to 2.5? its still bottlenecked at 2.25

Ive never heard of the directional flow thing, wouldnt matter anyways.

even on a motor fully built NA, Im talking completely built, and the test pipe was the last thing to do, it would maybe free up 15hp.

sorry dude, but on your motor it wont make a difference except in sound. should sound okay if its resonated

[jordan_myers]

Originally Posted by franchise817

It is resonated 2 1/4 to 2 1/2 and it got a twist in it for directional flow. I heard my cars gonna smell bad and sound bad but the question is this. With the flow freed up can I see/expect any sort of gain?

I have a short-tube 4-2-1 header and a 3" test pipe non-resonated flowing into a 3" exhaust and entering into a 3"-->4" HKS muffler all straight-through and my shit is loud, I won't deny that. But as far as the sound at least it doesn't sound like a coffee can of pissed off hornets. The closest comparison I can think of would be a track car. As for the smell, I have my interior completely removed and can't smell anything different.

[jordan_myers]

As for gains, really you shouldn't expect to see a whole lot. Especially when exhaust is part of what I call "mandatory bolt-ons" such as I/H/E, I just feel that all cars should be able to breath and exhale without restriction.

[charliemopps24]

Originally Posted by jordan_myers

As for gains, really you shouldn't expect to see a whole lot. Especially when exhaust is part of what I call "mandatory bolt-ons" such as I/H/E, I just feel that all cars should be able to breath and exhale without restriction.

Eliminating cats is a must on any car with a power adder. My budd got a turbo back and a catless uppipe for his scoobie and it made a world of difference.

[Darkness]

they did a test on it and the test pipe on stock setup my yield .5-1 hp gain if any over a functioning cat

[DuderMagee]

Originally Posted by WVU97GS-R

they did a test on it and the test pipe on stock setup my yield .5-1 hp gain if any over a functioning cat

x2
not worth going deaf or police attention

[mattliston]

Originally Posted by charliemopps24

Eliminating cats is a must on any car with a power adder. My budd got a turbo back and a catless uppipe for his scoobie and it made a world of difference.

so? thats on a totally car and motor.

Cutting emissions equipment for that tiny difference is stupid.

Also, on his scubbie, i bet the difference was the exhaust being opened up with the down pipe and cat back, not the cat.

[Darkness]

Originally Posted by charliemopps24

Eliminating cats is a must on any car with a power adder. My budd got a turbo back and a catless uppipe for his scoobie and it made a world of difference.

not really

scoobies have ultra-restrictive exhausts from the factory