cats vs. no cats
Thread Starter
Racer
Joined: Jun 2009
Posts: 326
Likes: 0
From: Texarkana TX
cats vs. no cats
im going to pick up a set of lg streets hopefully sometime this week and im not sure if i should get cats. has anyone done a back to back comparison with and without? off road in our area is not a big deal just dont want it to be obnoxiously loud...ill be keeping the stock ti cat back and installing a 228/232 112 lsa cam
thanks for the input
thanks for the input
Melting Slicks
Joined: Feb 2007
Posts: 3,191
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From: New Smyrna Beach Florida
I had the same question when I had my headers installed. Get the cats. Cars without cats tend to be stinky and there is virtually no extra power to be gained. I had random tech cats installed and I am glad that I did.
Safety Car
Joined: Jan 2007
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From: The Great Truth: "There ain't no free lunch"
St. Jude Donor '08-'09-'10-'11
Safety Car
Joined: Jul 2005
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From: Chicago-NW Burbs Illinois
I've tried both with and without cats. Without the cats I noticed it being a lot louder and you'll **** people off behind you with the smell..especially if you have a big cam 
. I didn't dyno it back to back or anything, but I'd say you gain a few hp...probably not worth it unless you're after every last HP. I'd just go with the Hi-Flow cats.
. I didn't dyno it back to back or anything, but I'd say you gain a few hp...probably not worth it unless you're after every last HP. I'd just go with the Hi-Flow cats.
Last edited by black98c5; Feb 27, 2010 at 11:54 PM.
Race Director
Joined: Apr 2007
Posts: 18,048
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From: long Island NY
You don't get the fart smell but general gas fume smell is bad. Sometimes I think I'm starting a 70's car. Really should have them you will never notice a power loss with the hi-flows and if you ever have a problem with getting inspections at least they will be present for the visual.
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Racer
Joined: May 2008
Posts: 298
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From: Quad Cities Iowa
My Ion Redline no longer has a cat. It smelled a lot at first, but the smell was less and less over time. After a few months, it didn't smell anymore.
When I had the CPU tuned, they turned off the down-stream O2 sensor so the check engine light wouldn't turn on. I've heard you can modify a spark-plug defouler and put it inline with the down-stream O2 sensor to reduce exposer and trick the CPU into thinking there is a cat.
Unless you can get high-flow cats for free, I would leave them off if I were you.
When I had the CPU tuned, they turned off the down-stream O2 sensor so the check engine light wouldn't turn on. I've heard you can modify a spark-plug defouler and put it inline with the down-stream O2 sensor to reduce exposer and trick the CPU into thinking there is a cat.
Unless you can get high-flow cats for free, I would leave them off if I were you.
Race Director
Joined: Oct 2002
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From: Gone
CI 6-7-8-9-10 Veteran
St. Jude Donor '03
Burning Brakes
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Pro
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From: North Port Florida
Racer
Joined: Dec 2004
Posts: 372
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From: North West, Georgia
cats also make a noise difference...
NO cats on mine was really REALLY nice at idle ...
stomp the pedal .. and i felt like my ears would ring for 20 minutes
no cats gave mine a really harsh metal ring to it in the range of 2500-3100 RPM .. right where i cruise
had to put them back on ...
I vote Cats. (and a dog .. and some fish)
NO cats on mine was really REALLY nice at idle ...
stomp the pedal .. and i felt like my ears would ring for 20 minutes
no cats gave mine a really harsh metal ring to it in the range of 2500-3100 RPM .. right where i cruise
had to put them back on ...
I vote Cats. (and a dog .. and some fish)
Race Director
Joined: Apr 2007
Posts: 11,150
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From: South Western Ontario
Cats should be a little quieter and more enviromentally friendly and the exaust won' stink or at least won't stink as much. I have a fuel injected '65 Impala and I'm considering cats because even my clothes stink after driving it.
Peter
Peter
Le Mans Master
Joined: Oct 2000
Posts: 6,209
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From: Texas-out west
you guys complaining about smell must be youngsters
back in the day when cats were unheard off you didn't notice smell because all cars that way....sidepipes, 427, solid cam, headers, smell no problem, only power
back in the day when cats were unheard off you didn't notice smell because all cars that way....sidepipes, 427, solid cam, headers, smell no problem, only power
Safety Car
Joined: Jan 2001
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From: Boise ID
