# Do I need my Cat



## rustyholtzen (Apr 9, 2005)

Do I need the backpressure from my cat for the car to run good? or will it run like crap and f stuff up with cleaned out cats?


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## Zen31ZR (Mar 24, 2004)

When I removed my cat, I noticed a shift from midrange torque to more top end. But it shouldn't affect how the car runs. You'll need it for emissions, though.  You can get a higher flow cat if you want to stay emissions legal but get more flow capacity. I forget if your car is turbo or not, but a catback exhaust should get you some nice gains either way...


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## rustyholtzen (Apr 9, 2005)

♣Zen31ZR♣ said:


> When I removed my cat, I noticed a shift from midrange torque to more top end. But it shouldn't affect how the car runs. You'll need it for emissions, though.  You can get a higher flow cat if you want to stay emissions legal but get more flow capacity. I forget if your car is turbo or not, but a catback exhaust should get you some nice gains either way...


Its a non turbo but it will look like the cat are there. I just happy to have it started. today i going to look at an 87 for part he went 500 ill see if i can jew him down. thanks for your help


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## JAMESZ (Mar 12, 2004)

Needing back pressure is a myth; so that answers your question right there.


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## Zen31ZR (Mar 24, 2004)

JAMESZ said:


> Needing back pressure is a myth; so that answers your question right there.


 Sorry, I'm gonna beg to differ. Backpressure is a fact. It helps low and midrange torque because velocity is kept fairly constant. Top end requires more flow capacity. He'll notice the difference between when the exhaust is installed and when it is not. I did. Definitely more low end with it installed, on the VG30. Same on my bike. I bought and installed a factory system to replace the performance pipe that was on there, and I now have a lot more low end. I suppose it depends on your driving style which you prefer. I deal with a lot of stoplights and traffic, so I need more low end.


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