Catalytic converter
#41
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High flow cats today have virtually no ill effects on your flow. At least that's my experience with my wrx and my toyota, and what tuners have told me (And the wrx is protuned) And for those of us in northern CO emissions IS coming back so get a cat on there...
Backpressure is never good but flow is. Smaller pipe allows higher exhaust velocity at low rpms and hence is helpful for low end torque, but becomes restrictive at high rpms and hence limits power up there. Big pipe won't allow high exhaust velocity at low rpms and thereby hurts power down low. This doesn't have anything to do with "backpressure"
Anything that limits your flow like a clogged cat will never be good.
Backpressure is never good but flow is. Smaller pipe allows higher exhaust velocity at low rpms and hence is helpful for low end torque, but becomes restrictive at high rpms and hence limits power up there. Big pipe won't allow high exhaust velocity at low rpms and thereby hurts power down low. This doesn't have anything to do with "backpressure"
Anything that limits your flow like a clogged cat will never be good.
#42
Mud hippy:
unbolt everything from the crosspipe, time it in the 1/4 then bolt it back up and run it in the 1/4 and i will promise you it will be faster with the cat vs the open manifold, that is if you dont bend a valve on the first pass.
I agree with the camo about there being a happy medium between too much and too little backpressure and also with the andycrow regarding the exhaust velocity, he was spot on. If you have no exhaust velocity on the 3.0 you will never get it moving
I guess everybody got caught up in the semantics of the word backpressure.
I was mearly offering my experience regarding my gutted cat, everything the same except gutted cat and junkyard cat, mine performed way better with the cat being reinstalled.
unbolt everything from the crosspipe, time it in the 1/4 then bolt it back up and run it in the 1/4 and i will promise you it will be faster with the cat vs the open manifold, that is if you dont bend a valve on the first pass.
I agree with the camo about there being a happy medium between too much and too little backpressure and also with the andycrow regarding the exhaust velocity, he was spot on. If you have no exhaust velocity on the 3.0 you will never get it moving
I guess everybody got caught up in the semantics of the word backpressure.
I was mearly offering my experience regarding my gutted cat, everything the same except gutted cat and junkyard cat, mine performed way better with the cat being reinstalled.
Last edited by REDYOTA; 09-15-2010 at 05:54 PM.
#44
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Or, you could try one of these....
http://www.o2simulator.com/index.php...&products_id=9
Last edited by Team420; 09-16-2010 at 04:11 PM.
#45
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I live in NC, and my truck passed several times with a gutted cat, so its possable. What i think is funny is they do the testing at idle no load, yet i spend most of my time driving my truck, not idling. LOL
#46
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gutted mine, sounded better, I could actually hear the exhaust over the clutch fan, but it ran like crap.
I had a 40 series flowmaster behind it.
I put the cat back and it runs 10 times better and actually has a powerband again, boy how I have missed that.
My advice dont do it, these motors love back pressure and from my experience a stopped up cat is better than no cat.
Oh, this was on a 3.0 pickup
I had a 40 series flowmaster behind it.
I put the cat back and it runs 10 times better and actually has a powerband again, boy how I have missed that.
My advice dont do it, these motors love back pressure and from my experience a stopped up cat is better than no cat.
Oh, this was on a 3.0 pickup
#47
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i hollowed out my cat recently on my 87 22r and it sounds awesome and even runs a little better. i can hear the sound of my exhaust every time i pass a car and its an awesome sound id have to say haha (drivers exit)
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