I was looking for a way to increase my Mpg and make my car sound better at the same time when I thought of removing the cat and mabey even installing some flowmaster super 44's. Theres a vid on youtube of a 2nd gen with no cat and 40's and it sounds pretty sick but i dont know. If I did this I heard it may reduce low end torque due to a decrease in back pressure and since its not tuned to handle this, it could put more wear and tear on exhaust valves or other internal components. Is that even true? would it be a good idea to do this? I dont really care about not being able to pass smog because if i had to get my truck smogged i could remove the test pipe and re-install the cat in minutes.
Using a test pipe instead of a Catylitic converter?
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ovrrdrive
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I've heard a flow 40 on a 22re and it was loud as hell. I haven't heard a 44, nor have I heard a 40 on a 3.0...
Playing with backpressure can move your horsepower peak around in the RPM curve but it has been proven time and time again that less backpressure yields higher peak horsepower. It might just not be in a place where you can use it all. You only burn valves if you get the motor running too lean.
Playing with backpressure can move your horsepower peak around in the RPM curve but it has been proven time and time again that less backpressure yields higher peak horsepower. It might just not be in a place where you can use it all. You only burn valves if you get the motor running too lean.
rustyrazor
New member
I hollowed out the cat on my saturn last year and I'm planning on doing the same on my 4runner. It made a huge difference in throttle response and top end power. I didn't notice any loss of low end power.
So if you don't want to spend any money all you have to do is unbolt the exhaust in front of the cat and then use a really long punch or metal bar to ram through the cat. There were two sections of ceramic honey cone in the cat and once it was cleared out I bolted it back up.
The air fuel mixture is not a concern because the oxygen sensor is always located ahead of the cat and it will sense if more or less fuel is needed to maintain the ideal air fuel mixture.
So if you don't want to spend any money all you have to do is unbolt the exhaust in front of the cat and then use a really long punch or metal bar to ram through the cat. There were two sections of ceramic honey cone in the cat and once it was cleared out I bolted it back up.
The air fuel mixture is not a concern because the oxygen sensor is always located ahead of the cat and it will sense if more or less fuel is needed to maintain the ideal air fuel mixture.
its going to be loud inside if you do that. the interior design of the runner will capture the exhaust note and drone on the freeway. rather annoying imo. None of these motors were designed to be powerhouses so why bother? The flowmasters are just noisy. check out magnaflow if you want a nice sound with improved performance. You can also upgrade to a high flow cat or larger exhaust if you want to open it up and let it breath. a motor is basically an airpump. less restriction on the intake and exhaust sides means better performance.
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