High Flow Cat vs. Test Pipe

[Vaders Sy]

Are there any differences in performance from a high flow 3 in cat vs a test pipe? I have the ATR exhaust with the high flow cat. Just curious to see if there are any performance gains going to the test pipe. I am sure that it would be much louder and possibly spool up faster, but is there a real performance gain?

I searched and this very question was asked but no responses.

 

[dgoodhue]

Re: High Flow Cat vs. Test Pipe

My intuition tell me their would a gain, but I would try it at the track with and without.

Years ago I tried a test in an import N/A 6 cylinder with and with high flow cat, SOTP I felt like the cat had more torque. At the track I had better times with the Cat in place (only did 2 runs with a test pipe), but the MPH was .3-.4 higher on a low 15 sec car.

 

[Vaders Sy]

Re: High Flow Cat vs. Test Pipe

So, from your experience it is not worth it? That's interesting.

 

[MasterBlaster]

Re: High Flow Cat vs. Test Pipe

Its also not really worth it from a legal standpoint, if you get caught.

 

[It's just a six]

Re: High Flow Cat vs. Test Pipe

Going from stock converter to a test pipe is a day & night difference!!!!!
:tup: :tup: :tup: :tup: :tup: :tup: :2cents: :2cents:

 

[crawlinGT]

Re: High Flow Cat vs. Test Pipe

well the reason why you have more torque is because there is more pressure in the exhaust because of less flow and the higher mph is because a testpipe will flow better.

In a nutshell keeping the cat will get you bottom end where getting a testpipe will get you more topend

 

[It's just a six]

Re: High Flow Cat vs. Test Pipe

:2cents: The better free flowing your exhaust system is the better it is. You will have more bottom end, mid ,top end torque. It's better everywhere. Again, jusy my :2cents:

 

[crawlinGT]

Re: High Flow Cat vs. Test Pipe

:2cents: The better free flowing your exhaust system is the better it is. You will have more bottom end, mid ,top end torque. It's better everywhere. Again, jusy my :2cents:

you wont have more bottom end because there will be less back pressure, but there will be mid and top end gains.

 

[dgoodhue]

Re: High Flow Cat vs. Test Pipe

That is not necessarily true. In Naturally Aspirated engines, yes. With Turbo's the lower restriction equals quicker spool up and better low end torque. I am not sure if it would make that much of difference when no in boost as well, since we already have a restrict in the exhuast (turbo)

 

[crawlinGT]

Re: High Flow Cat vs. Test Pipe

That is not necessarily true. In Naturally Aspirated engines, yes. With Turbo's the lower restriction equals quicker spool up and better low end torque. I am not sure if it would make that much of difference when no in boost as well, since we already have a restrict in the exhuast (turbo)

good point i guess i was thinking of naturally aspirated but really dont know enless its tested.

 

[It's just a six]

Re: High Flow Cat vs. Test Pipe

I have tested them ..that's why I stated it is a day & night difference!!!!!

 

[crawlinGT]

Re: High Flow Cat vs. Test Pipe

yean but he said a performance cat which is a bit different

 

[It's just a six]

Re: High Flow Cat vs. Test Pipe

The stock Sy cat is as good a flowing cat for a 2.5 inch ID. cat ,aftermarket ones do not flow anymore unless you increase the size of the inlet & outlet. + people have had problems passing smog w/free flowing cats that are larger in ID, they do not heat up as good. :2cents:

 

[dgoodhue]

Re: High Flow Cat vs. Test Pipe

Their is a difference between a high flow cat and the stock cat. I have a random tech cat on my truck with the solenoid bypass (ie base boost) I get 13 psi pretty easily and it creeps to 15psi In the cold weather I have over boost issues. (this is with the factory wastegate adjusted to factory specs) With the factory cat my truck would only make 8-9psi base boost. (I never held it to see if it would creep up though)

 

[It's just a six]

Re: High Flow Cat vs. Test Pipe

My factory cat.. I can boost up to 20 PSI if I want to. Stock converter, original. How many miles were on your stock converter? And yes,with original torque converter, 2100 RPM tops.
Was the random teck the same dimentions as the stock one ? inlet, outlet, lenght?
Just curious.

 

[dgoodhue]

Re: High Flow Cat vs. Test Pipe

My factory cat.. I can boost up to 20 PSI if I want to. Stock converter, original. How many miles were on your stock converter? And yes,with original torque converter, 2100 RPM tops.
Was the random teck the same dimentions as the stock one ? inlet, outlet, lenght?
Just curious.

I could raise the boost up as well with my factory cat, the stock cat wasn't plugged or anything, I never went higher than 18-19 psi with it. Without the boost solenoid and ECM controlling Boost, the high flow cat and Borla exhaust caused higher boost than the stock setup.

My stock cat had ~47-48K miles. I wasn't planning on replacing it, but one the cat exhaust bolt snapped of in the cat flange, so I had to pull it off anyways. Yes the Random tech cat is the same spec as the stock cat, 2.5" In/2.5" out and bolted the factory rear cat bracket.