high flow cat = ? hp gain?
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From: Rio Vista ca.
high flow cat = ? hp gain?
Got an '89 coupe with a new Corsa cat back exhaust. If I replace the stock cat with a new aftermarket high flow cat what will my horse power gain be? I live in Ca. so headers or precat elimination is not an option.
Thanks, Kim
Thanks, Kim
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From: Rio Vista ca.
Thanks, Badduck.
Don't know if it's clogged or not. Car seems to run well and sounds great with the Corsa catback. Not looking for a lot of horsepower gains at this time but don't want to spend money for nothing. Planning on doing the cut lid K&N filter mod and wondered if replacing the factory cat would round out my modest exhaust mod.
Don't know if it's clogged or not. Car seems to run well and sounds great with the Corsa catback. Not looking for a lot of horsepower gains at this time but don't want to spend money for nothing. Planning on doing the cut lid K&N filter mod and wondered if replacing the factory cat would round out my modest exhaust mod.
Melting Slicks
Joined: Nov 2000
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From: Winchester Ontario
I'll tell you one thing. Don't cheap out on a high flow cat. Just because it says hi flow , doesnt' mean it really is.
I went ebay cheapies and on a dyno run, I only made like 15 more hp after 4000 rpm. It almost flatlined there. The cats that were supposedly hi flow simply weren't and they couldn't flow much after 4000 rpm.
I went ebay cheapies and on a dyno run, I only made like 15 more hp after 4000 rpm. It almost flatlined there. The cats that were supposedly hi flow simply weren't and they couldn't flow much after 4000 rpm.
Team Owner
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From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
I'll tell you one thing. Don't cheap out on a high flow cat. Just because it says hi flow , doesnt' mean it really is.
I went ebay cheapies and on a dyno run, I only made like 15 more hp after 4000 rpm. It almost flatlined there. The cats that were supposedly hi flow simply weren't and they couldn't flow much after 4000 rpm.
I went ebay cheapies and on a dyno run, I only made like 15 more hp after 4000 rpm. It almost flatlined there. The cats that were supposedly hi flow simply weren't and they couldn't flow much after 4000 rpm.
WTF did you expect?
Dollar for dollar the PYPES cats at $60 are the way to go.
Team Owner
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From: San Pedro CA
A lot depends on your smog station... I would loose the precats... and if you are concerned, you can gut them and no one will know. The main cat does 99.9% of the work after everything gets hot, and since the smog stations test hot... see my point?
Personally, I don't like the precats.....
with that said, get a good center cat, like a random tech or carsound.
As for the comment above regarding the 4000 rpm flow limit, I suspect the intake and inherent design had more to do with the flat line than anything else, but I recommend a quality unit, cause they will last longer.
Personally, I don't like the precats.....
with that said, get a good center cat, like a random tech or carsound.
As for the comment above regarding the 4000 rpm flow limit, I suspect the intake and inherent design had more to do with the flat line than anything else, but I recommend a quality unit, cause they will last longer.
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From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
A lot depends on your smog station... I would loose the precats... and if you are concerned, you can gut them and no one will know. The main cat does 99.9% of the work after everything gets hot, and since the smog stations test hot... see my point?
Personally, I don't like the precats.....
with that said, get a good center cat, like a random tech or carsound.
As for the comment above regarding the 4000 rpm flow limit, I suspect the intake and inherent design had more to do with the flat line than anything else, but I recommend a quality unit, cause they will last longer.
Personally, I don't like the precats.....
with that said, get a good center cat, like a random tech or carsound.
As for the comment above regarding the 4000 rpm flow limit, I suspect the intake and inherent design had more to do with the flat line than anything else, but I recommend a quality unit, cause they will last longer.
In your opinion does price=sinificant increase in quality and performance? Espeically if you're going from one cat to two as in the L98s.
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From: Rio Vista ca.
[QUOTE=bogus;1562934004]. The main cat does 99.9% of the work after everything gets hot, and since the smog stations test hot... see my point?
Thanks, Bogus. I don't much care about performance until the car gets hot since I never "get on it" until my coolant temp has reached 180 deg. or more. Since I'm probably going to have to get a muffler shop to install a new high flow cat for me, eliminating or gutting the precats is not an option. I was just wondering if replacing the factory cat is worthwhile.
Thanks, Kim
Thanks, Bogus. I don't much care about performance until the car gets hot since I never "get on it" until my coolant temp has reached 180 deg. or more. Since I'm probably going to have to get a muffler shop to install a new high flow cat for me, eliminating or gutting the precats is not an option. I was just wondering if replacing the factory cat is worthwhile.
Thanks, Kim
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Burning Brakes
Joined: Nov 2003
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From: Redding Ca
A lot depends on your smog station... I would loose the precats... a
Not sure how this car would pass the visual part of the bi annual inspection with a set of aftermarket headers and no precats. But the cars are getting old enough, the smog station people might not be aware of precats on earlier years. The cars are nearly as old as they are!
A couple years ago I chatted with a Ca smog station guy. He said if they see "aftermarket", they immediateely get on their computer and look for an EO exemption unless you have the EO sticker handy.
A couple months ago, my car (406, 219 cam, SR intake, AFR 195's) barely passed with the pre cats on. So I think I am happy they were there. I have toyed with the idea of taking the car to the drags "as is" to see what performance loss comes from stock exhaust headers w/precats vs. my TPIS long tubes.
Not sure how this car would pass the visual part of the bi annual inspection with a set of aftermarket headers and no precats. But the cars are getting old enough, the smog station people might not be aware of precats on earlier years. The cars are nearly as old as they are!
A couple years ago I chatted with a Ca smog station guy. He said if they see "aftermarket", they immediateely get on their computer and look for an EO exemption unless you have the EO sticker handy.
A couple months ago, my car (406, 219 cam, SR intake, AFR 195's) barely passed with the pre cats on. So I think I am happy they were there. I have toyed with the idea of taking the car to the drags "as is" to see what performance loss comes from stock exhaust headers w/precats vs. my TPIS long tubes.
Safety Car
Joined: May 2002
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From: Toronto ontario
I had an article on a Lingenfelter 383 LS1 that dynoed stock cats vs high flow cats vs no cats. If I remember right.. the motor made 447 rwhp with cats, 468 rwhp with high flow cats and 471 rwhp with straight pipes. I'm fairly certain on that ls1 stroker (one of the first c5 strokers by lpe) the straight pipes only got roughly 3-4 hp and only at the very peak of the curve.
Team Owner
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From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
I had an article on a Lingenfelter 383 LS1 that dynoed stock cats vs high flow cats vs no cats. If I remember right.. the motor made 447 rwhp with cats, 468 rwhp with high flow cats and 471 rwhp with straight pipes. I'm fairly certain on that ls1 stroker (one of the first c5 strokers by lpe) the straight pipes only got roughly 3-4 hp and only at the very peak of the curve.
Very different animal than a 1989 L98
Remember, these motors had one cat. Going to dual cats alone is a big plus.
Melting Slicks
Joined: Nov 2000
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From: Winchester Ontario
On the dyno run, after 4000 rpm to peak rpm hp, there was only a 15 hp difference. Basically the engine was running out of breath. This was on my old SR 383 motor.
The dyno graph ramped and then when it hit 4000 rpm all the way until peak rpm, it only made 15 hp after the 4000 rpm point.
Team Owner
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From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
From what I understand there are only three manufacturers of cats. I could be wrong, maybe not.
Former Vendor
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From: Social Circle Georgia
construction and materials. I have not had a pypes cat in my hands so I can't comment on them. I have held other companies "hi flow" cats and the build quality was crap. The design obviously limited flow. The catalyst can either be ceramic or metal. Ceramic is fine. It costs less than metal, flows less metal, and is fragile, but it can still be in a hi flow cat and work. The metal cats are the best. They are not fragile, they flow much better than the ceramic, and as for Random, the body is made from stainless steel. Metal cats unfortunately cost a lot more than the ceramic. I'm willing to bet that the pypes cats have ceramic guts which helps keep costs down. But again, I haven't held them in my hands, so I don't know for sure.
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From: Phila., PA burbs
Team Owner
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From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
construction and materials. I have not had a pypes cat in my hands so I can't comment on them. I have held other companies "hi flow" cats and the build quality was crap. The design obviously limited flow. The catalyst can either be ceramic or metal. Ceramic is fine. It costs less than metal, flows less metal, and is fragile, but it can still be in a hi flow cat and work. The metal cats are the best. They are not fragile, they flow much better than the ceramic, and as for Random, the body is made from stainless steel. Metal cats unfortunately cost a lot more than the ceramic. I'm willing to bet that the pypes cats have ceramic guts which helps keep costs down. But again, I haven't held them in my hands, so I don't know for sure.
I don't know what Pypes guts are, however, they are stainless with a 60,000 mile guarantee.
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From: Rio Vista ca.
[QUOTE=jsup;1562950899]All true. However, allow me to be more specific. On an L98, which the OP has, going from a stock single cat, to dual "high flow" how much is that couple of CFM per cat going to matter?
I'm not going to dual cats. I just want to replace the single factory cat with a high flow cat. I guess I'm wondering if it will give me any added horsepower or torque with the cut lid K&N filter mod and my new Corsa cat back. Also, I don't want to have to redo the Corsa system. Will any high flow cats just bolt up in place of the factory cat?
I'm not going to dual cats. I just want to replace the single factory cat with a high flow cat. I guess I'm wondering if it will give me any added horsepower or torque with the cut lid K&N filter mod and my new Corsa cat back. Also, I don't want to have to redo the Corsa system. Will any high flow cats just bolt up in place of the factory cat?
Team Owner
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From: Bergen County, NJ Democrats, doing for the country what they did for Michigan
[QUOTE=ragged claws;1562952196]
Oh, different story.....get a direct fit high flow with the AIR tube.
I was doing a little hijacking, asking for my specific situation too....
All true. However, allow me to be more specific. On an L98, which the OP has, going from a stock single cat, to dual "high flow" how much is that couple of CFM per cat going to matter?
I'm not going to dual cats. I just want to replace the single factory cat with a high flow cat. I guess I'm wondering if it will give me any added horsepower or torque with the cut lid K&N filter mod and my new Corsa cat back. Also, I don't want to have to redo the Corsa system. Will any high flow cats just bolt up in place of the factory cat?
I'm not going to dual cats. I just want to replace the single factory cat with a high flow cat. I guess I'm wondering if it will give me any added horsepower or torque with the cut lid K&N filter mod and my new Corsa cat back. Also, I don't want to have to redo the Corsa system. Will any high flow cats just bolt up in place of the factory cat?
I was doing a little hijacking, asking for my specific situation too....
Former Vendor
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From: Social Circle Georgia
I would go for duals over a single as well. However, you are still pushing everything into one pipe. My response was directed to the original poster and his particular situation.
Ragged, the Random cat looks like a stock replacement cat and has the air tube. It's a direct replacement for OEM. Your Corsa will bolt right to it. If your car passes a sniffer test now, it will pass it with the Random cat and you will make more power. I do not know about Cali law with visual inspections and paper work though. So I'm not sure if you'll have to prove it has a CARB number or not.
Ragged, the Random cat looks like a stock replacement cat and has the air tube. It's a direct replacement for OEM. Your Corsa will bolt right to it. If your car passes a sniffer test now, it will pass it with the Random cat and you will make more power. I do not know about Cali law with visual inspections and paper work though. So I'm not sure if you'll have to prove it has a CARB number or not.