exhaust, cats question
Thread Starter
Instructor
Joined: Oct 2009
Posts: 212
Likes: 4
From: Parkersburg WV
exhaust, cats question
ok so i got my borla exhaust on today, and to put it lightly i'm not impressed, the pipe is the same size as factory pipe. So i'm sending it back....my question is my exhaust guy said he could cut the cats off, put on a custom X pipe, (even though he says the factory H pipe is good enough) and run straight pipes off the manifold back to 2 dual tips..will this make the car run rich from the cats being gone? Is there a big performance gain without the cats, or mufflers to restrict it?
Melting Slicks
Joined: Apr 2009
Posts: 2,479
Likes: 36
ok so i got my borla exhaust on today, and to put it lightly i'm not impressed, the pipe is the same size as factory pipe. So i'm sending it back....my question is my exhaust guy said he could cut the cats off, put on a custom X pipe, (even though he says the factory H pipe is good enough) and run straight pipes off the manifold back to 2 dual tips..will this make the car run rich from the cats being gone? Is there a big performance gain without the cats, or mufflers to restrict it?
Thread Starter
Instructor
Joined: Oct 2009
Posts: 212
Likes: 4
From: Parkersburg WV
I don't think it's a good idea. As you know, these cars are heavily dependant on electronics and sensors. I'm not sure what it will do as far as running rich but from what I've heard, you won't gain much HP by eliminating the cats. The noise will probably be unbearable and it will stink like hell. But, it's your car so it's up to you.
Last edited by cody123; May 22, 2010 at 10:31 PM.
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
Before you make a snap decision, take a read. You may find the system is not as bad as it looks. As for the cats, from what I have read a 3" Random Tech cat gives up nothing to a catless system.
Exhaust article by David Vizard
Exhaust article by David Vizard
Thread Starter
Instructor
Joined: Oct 2009
Posts: 212
Likes: 4
From: Parkersburg WV
Before you make a snap decision, take a read. You may find the system is not as bad as it looks. As for the cats, from what I have read a 3" Random Tech cat gives up nothing to a catless system.
Exhaust article by David Vizard
Exhaust article by David Vizard
Last edited by cody123; May 22, 2010 at 10:31 PM.
Melting Slicks
Joined: May 1999
Posts: 2,365
Likes: 0
From: Vancouver BC
Rear O2 sensors only detect emissions, so it has no effect on air fuel ratio. But no sensors will trigger a code, unless you program them out or use simulators.
I would do it, but we have emission testing here in Vancouver
I would do it, but we have emission testing here in Vancouver
Thread Starter
Instructor
Joined: Oct 2009
Posts: 212
Likes: 4
From: Parkersburg WV
alright
Last edited by cody123; May 22, 2010 at 10:32 PM.
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Drifting
Joined: Aug 2009
Posts: 1,288
Likes: 2
From: Richmond Virginia
To my knowledge not on a Corvette. On my daily driver, which is an LS1 powered firebird Formula I have LT headers 2 high flow cats, which I would recommend over no cats due to the fuel problem you will have and not to mention with no cats your rear 02 sensors will be going crazy so you'd have to get 02 sims, and I also have no muffler. Its extremely loud so if loud is what you want go for it. If power is what you are looking for don't go Flowmaster. I took a flowmaster off of my car and picked up .5 off my et it the 1/4. Magnaflow is the least restictive of an actual muffler but they are quiet.
Burning Brakes
Joined: Nov 2006
Posts: 979
Likes: 1
From: Jacksonville Florida
Your post is really confusing. First of all if your exhaust guy said the factory H pipe is as good as an x pipe, then find another exhaust shop because he doesn't know what he's talking about. Second, when I initially did my exhaust I put on Borla Stingers and the sound and fitment to the stock setup was great. Nice low muscle car rumble. Third, you talk about wanting to "free up HP", but you are running stock manifolds. Get a good set of long tube headers. I currently run long tubes, no cats, x pipe, to borla stingers. With a dyno tune I gained a little over 40 hp at the wheels. Find a good tuner and get the headers and the car tuned. If you want to run no cats then just have then tune it out, remove the AIR system while your at it.
Oh yeah and my car is really loud at wide open....
Oh yeah and my car is really loud at wide open....
Heel & Toe
Joined: Nov 2008
Posts: 16
Likes: 0
Not true, the rear 02s are used on startup as the exhaust is cleaner and more stable then the front ones and from the rear 02s the PCM decides what the average part throttle injector pulse width will be
LOUD may be cool for the OP but the sound level will be around 102 DBA, under noise standards any longer then 1 minute at that level will degrade your ears to the point they over time will be ruined for life and have to live with a whine in one or both ears
The stock H at the back is only to balance the sound, it is too far back to help exhaust pulses pull exhaust from cylinders so a X pipe close to engine is best placement.
Exhaust mods with stock pipe size will not give much performance gains for the price and can effect the 02s and what they report the AFR is to the PCM in it making fuel adjustments.
Burning Brakes
Joined: Oct 2008
Posts: 898
Likes: 25
From: Dallas, TX
Cody,
Save your money!! Part for theses cars are engineered and tested to squeeze out power from the motor AND associated computer controls. Anyone who tells you they can just cut and weld something for you and do better (or even close), probably can't back up their claim with real numbers on a Corvette. I'm sure he's a great guy and does his job well, but this is not a hotrodded '72 Nova.
Well engineered parts are expensive, and then there's the Corvette tax.
But hey, we all knew that when we bought a Corvette right? I think you will be dissapointed if you go in this direction. You'll get a loud car for sure but are you really extracting the power that you could?
Don't get me wrong, I know it's your car, do what you want. There are folks here that have bought exhaust systems for cheap with good results. Maybe give that a look, you can always mix and match the tail section to change the sound. Check out this post:
http://forums.corvetteforum.com/c5-t...ars-later.html
I'm guessing you posted here to get honest feedback and I think you're seeing it now. I'd hate to see you throw money down a hole, these cars suck enough of it on thier own.
Chad
Save your money!! Part for theses cars are engineered and tested to squeeze out power from the motor AND associated computer controls. Anyone who tells you they can just cut and weld something for you and do better (or even close), probably can't back up their claim with real numbers on a Corvette. I'm sure he's a great guy and does his job well, but this is not a hotrodded '72 Nova.
Well engineered parts are expensive, and then there's the Corvette tax.
But hey, we all knew that when we bought a Corvette right? I think you will be dissapointed if you go in this direction. You'll get a loud car for sure but are you really extracting the power that you could?Don't get me wrong, I know it's your car, do what you want. There are folks here that have bought exhaust systems for cheap with good results. Maybe give that a look, you can always mix and match the tail section to change the sound. Check out this post:
http://forums.corvetteforum.com/c5-t...ars-later.html
I'm guessing you posted here to get honest feedback and I think you're seeing it now. I'd hate to see you throw money down a hole, these cars suck enough of it on thier own.
Chad
Instructor
Joined: Jun 2008
Posts: 124
Likes: 0
From: Ft Lauderdale FL
ok so i got my borla exhaust on today, and to put it lightly i'm not impressed, the pipe is the same size as factory pipe. So i'm sending it back....my question is my exhaust guy said he could cut the cats off, put on a custom X pipe, (even though he says the factory H pipe is good enough) and run straight pipes off the manifold back to 2 dual tips..will this make the car run rich from the cats being gone? Is there a big performance gain without the cats, or mufflers to restrict it?
I eliminated the cats and replaced them with Dynomax Bullet straight flow race mufflers (part # 24215) and also replaced the factory H-pipe with Borla X-pipe and finally out to Borla Straight pipes. Sounded AMAZING don't regret it at all.
