Cat delete with LM1 sucks
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From: Hereford, Tx (near amarillo)
Cat delete with LM1 sucks hey guys i have a 94Z A4 with stock manifolds. i deleted the cat cause it wa clogged. i put a strait pipe in place of it and i have the LM1. performance wise it took ALOT of my power down and didn't even gain alot up top. the only reason i took off the cat was cause it was clogged. has anyone ever done this and if you have what are your opinions on it? i think its not worth any gain. it just hurt my performance. i don't like it. i think i'm gonna put a high flow cat for a while till i get my LT's.
i had mid length headers when i gutted my cat. i didn't put the straight pipe in tho i just left the shell of the cat, i felt like i picked up a few plus a few extra exhaust tones, but i definately did not LOSE power.
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From: Hereford, Tx (near amarillo)
Originally Posted by LT1MAN
i had mid length headers when i gutted my cat. i didn't put the straight pipe in tho i just left the shell of the cat, i felt like i picked up a few plus a few extra exhaust tones, but i definately did not LOSE power.
see but i'm running stock manifolds. their flow really sucks. lol. yeah i understand with some headers you don't need a cat cause headers are WAY better flowing than manifolds.
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From: Hereford, Tx (near amarillo)
Originally Posted by 3pnt4maro
seems to me you lost your backpressure cause the lm is straight through
yeah i think i lost ALOT of back pressure cause down low it just flat out sucks. i thought i was gonna gain alot up top but i didn't gain much. lol. i'll be putting a high flow pretty soon.
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From: Holland Twp/Milford, New Jersey
with the manifolds not flowing too well, you wouldn't lose power due to lack of backpressure. there's already significant amounts of backpressure through the manifolds. how do you know you lost a lot, down low? maybe you heard a different/maybe louder exhaust note and just EXPECTED more but didn't get anything... 
Originally Posted by 3pnt4maro
seems to me you lost your backpressure cause the lm is straight through
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Originally Posted by LT1_King
yeah i think i lost ALOT of back pressure cause down low it just flat out sucks. i thought i was gonna gain alot up top but i didn't gain much. lol. i'll be putting a high flow pretty soon.
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Originally Posted by 3pnt4maro
but wouldnt a loss in backpressure cause a loss of torque down low which is why he thinks he lost power
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Originally Posted by UnitZ28
if they were electric i would close them right after my tq rpm peak so you might get the hp up top back where you need it
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From: Hereford, Tx (near amarillo)
see the cat wasn't completely clogged it was getting there. see it felt a whole lot stronger. it was a high flow cat that the previous owner had on there. the pipe that i put in place of the cat is a 3" pipe.
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From: Hereford, Tx (near amarillo)
the cat wasn't completely clogged but it was getting there. the pipe that i put in place of the cat is a 3" pipe. the throttle felt a whole lot different once i put the strait pipe through. see the way i noticed the difference was because me and my brother both have the same exact car with the same gearing. we would be side by side every time we would race. now he just beats me like nothing. that's why i noticed a big difference. see and when ever i gave it full throttle it didn't feel like it started pulling till about 2800 rpms.
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Originally Posted by Revelation Z28
with a V8 backpressure is your enemy. with a 4 banger, you need that back pressure, but not that much of it.
