LT1-LT4 Modifications 1993-97 Gen II Small Block V8

restrictive catalytic converter

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Old Mar 19, 2009 | 05:41 PM
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Question restrictive catalytic converter

hey i heard in in the lt1 z28s specifically in 1994 chevy put a more restrictive cat converter so it wouldnt have the same amount of horsepower as the corvette. it supposedly sucked the lt1 from 300 to 275. anyone know anything about this? i want to open up my exhaust on my 94 z28 so it breaths better i was thinking having two catalytic converters go into my y pipe insted of having my exhausat flow in to one supposedly resrtictive cat into my y pipe. is this true? can anyone offer me any advice on this? does this sound like a good idea? or how can i make it breath more and be less restrictive without buying all new exhaust systum? thanks
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Old Mar 19, 2009 | 05:48 PM
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get a hi flow cat.
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Old Mar 19, 2009 | 06:00 PM
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Originally Posted by 93cz28
get a hi flow cat.
x2.


c4 corvettes had true dual exhaust which bumped up the horsepower slightly, compared to the f-bodies single exhaust. get like a magnaflow hi flow cat.
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Old Mar 19, 2009 | 06:00 PM
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In the land of Chevrolet performance, the Corvette will ALWAYS be the flag bearer of speed. NO other Chevrolet will out perform it.

Having said that, the Camaro has a single exhaust. That, all by itself, will insure a lower HP rating than the Corvette, which has a full dual exhaust system. Even in '96, when Chevrolet installed a "dual cat" system on the Camaro, it only bumped the HP rating by 10, to 285.
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Old Mar 19, 2009 | 06:00 PM
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Originally Posted by 9D4Z28
hey i heard in in the lt1 z28s specifically in 1994 chevy put a more restrictive cat converter so it wouldnt have the same amount of horsepower as the corvette. it supposedly sucked the lt1 from 300 to 275. anyone know anything about this? i want to open up my exhaust on my 94 z28 so it breaths better i was thinking having two catalytic converters go into my y pipe insted of having my exhausat flow in to one supposedly resrtictive cat into my y pipe. is this true? can anyone offer me any advice on this? does this sound like a good idea? or how can i make it breath more and be less restrictive without buying all new exhaust systum? thanks
Do you have to pass emissions? If no, weld in straight pipe to replace the cat.
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Old Mar 19, 2009 | 06:11 PM
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Id get a high flow cat,,,,, or put yours where mine is....in the corner of my shed.
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Old Mar 19, 2009 | 06:39 PM
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Originally Posted by ss.slp.ls1
Do you have to pass emissions? If no, weld in straight pipe to replace the cat.
Regardless its a felony I'd be careful doing that. Theres no cats on the T/A but we know the consequences. Telling someone that may make them do it thinking its ok if there are no emissions in the city or state. Removing the cat is still a felony.
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Old Mar 19, 2009 | 07:00 PM
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Originally Posted by leadfoot4
In the land of Chevrolet performance, the Corvette will ALWAYS be the flag bearer of speed. NO other Chevrolet will out perform it.

Having said that, the Camaro has a single exhaust. That, all by itself, will insure a lower HP rating than the Corvette, which has a full dual exhaust system. Even in '96, when Chevrolet installed a "dual cat" system on the Camaro, it only bumped the HP rating by 10, to 285.
Except the 1989 Turbo TA

And word around the campfire is that dual cat is just a gimmick :\ Who knows though, could be, could not be...
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Old Mar 19, 2009 | 09:59 PM
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lets not forget the late 70's the trans am ws6 could out run and held more g's on the skid pad then the corvette of same year.

and the buick gn would hand a tpi vette its *** on the 1/4 mile too.
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Old Mar 19, 2009 | 10:13 PM
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Originally Posted by 9D4Z28
hey i heard in in the lt1 z28s specifically in 1994 chevy put a more restrictive cat converter so it wouldnt have the same amount of horsepower as the corvette. it supposedly sucked the lt1 from 300 to 275. anyone know anything about this? i want to open up my exhaust on my 94 z28 so it breaths better i was thinking having two catalytic converters go into my y pipe insted of having my exhausat flow in to one supposedly resrtictive cat into my y pipe. is this true? can anyone offer me any advice on this? does this sound like a good idea? or how can i make it breath more and be less restrictive without buying all new exhaust systum? thanks
The converter, itself, was not more restrictive, it was just the whole exhaust system as compared to what the Corvette had. And when you get down to it, the difference was probably not that much. Published HP numbers are often the result of much advertising massage.
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Old Mar 19, 2009 | 11:53 PM
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Originally Posted by goldmecham
lets not forget the late 70's the trans am ws6 could out run and held more g's on the skid pad then the corvette of same year.

and the buick gn would hand a tpi vette its *** on the 1/4 mile too.
You know, I didn't really notice this till now but... He DID say "NO other Chevrolet will outperform", not no other GM... So he's still right, at least from anything that comes to mind. Though...Could a stock Typhoon out perform a same year Vette?
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Old Mar 20, 2009 | 12:25 AM
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thats why they didnt make a turbo camaro in 89.
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Old Mar 20, 2009 | 12:36 AM
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There's more reasons than just the catalytic converter. I don't think a cat, even a really restrictive, would cause a 25hp loss.
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Old Mar 20, 2009 | 01:17 AM
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the power loss is from the manifolds into the y and then the small I pipe and crap muffler. vs the vette true dual.
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