Cats/No cats?
05-25-2010, 10:56 PM
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Cats/No cats? I have a 2000 trans am. A few months ago, I did an engine build, everything i did is in my signature. I have qtp long tube headers y pipe, to 3inch piping back (magnaflow exhaust) No cats. My tuner said I should be pushing a little over 400 at the wheels. I feel like having no cats and no back pressure (although it sounds good) is actually hurting my performance & think it will hold me back at the track. I want to opinions on if i should put highflow cats on or leave them off? thanks in advanced
05-26-2010, 04:17 AM
#2
NOOOO! The whole backpressure = torque story is myth. The less restrictive the exhaust the more power EVERYWHERE as long as there is enough restiction to support scavenging. The only reason I have cats is they are strict on the visual inspection here in NC....
05-26-2010, 03:09 PM
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I see you have a 2000 but you don't have an LS6 intake listed in your sig. If you still have the LS1 intake on there, that would be the power robbing culprit not the exhaust.
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06-12-2010, 12:54 AM
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I was able to get to the track last night. Ran 13.2 @ 111mph (mods in my signature), wasnt too pleased with the time. I have small 17x7 torque thrust 2s in the back that are not helping me get a very good launch, but Im still thinking about putting high flow cats on, I think some restriction may help me a bit. I am hearing both sides, deleting the cats will give me more torque, and putting high flow cats on & having some back pressure may pick me up a few tenths?
06-12-2010, 01:42 AM
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+1 for wider wheels and tires, this will make a massive difference in how the car drives and launches. I just went from 7" to 10.5" and it's like driving a whole new car.
+1 for LS6 intake (if you don't have one already)
-1 for cats, back pressure is a myth
+1 for LS6 intake (if you don't have one already)
-1 for cats, back pressure is a myth
06-12-2010, 02:48 AM
#11
As I told another guy who was coming from a ricer car system, back pressure matters only in turbos and 2 stroke engines. We have 4 stroke engines which opperate completely different.
Turbos need back pressure for compression, but the pressure is between the turbo and your intake.
2 stroke engines need back pressure for valve opening and closings to bring in and expel exhaust.
Our engines use cams for valve opening and closing and therefore back pressure actually hampers how much air/fuel the engine gets, which hamper power. We want a free flowing system, or better yet, one that actually increases suction (scavenging) in the exhaust to draw more air in.
So forget everything you know about back pressure and buy an ORY if you live in an area with no inspections.
Turbos need back pressure for compression, but the pressure is between the turbo and your intake.
2 stroke engines need back pressure for valve opening and closings to bring in and expel exhaust.
Our engines use cams for valve opening and closing and therefore back pressure actually hampers how much air/fuel the engine gets, which hamper power. We want a free flowing system, or better yet, one that actually increases suction (scavenging) in the exhaust to draw more air in.
So forget everything you know about back pressure and buy an ORY if you live in an area with no inspections.
06-12-2010, 10:30 AM
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+1 for ory if possible
+1 for no cats if possible
+1 for ls6 plenum
+1 for wider/stickier tire!
Back pressure is A myth...
tune tune tune!! Tune your car if deleting egr and air... Otherwise it will run like dog **** just like mine did! Went 12.9 last year this year put on a ls6 intake and could not break 13.1 all day! Car runs way to rich!
+1 for no cats if possible
+1 for ls6 plenum
+1 for wider/stickier tire!
Back pressure is A myth...
tune tune tune!! Tune your car if deleting egr and air... Otherwise it will run like dog **** just like mine did! Went 12.9 last year this year put on a ls6 intake and could not break 13.1 all day! Car runs way to rich!
06-12-2010, 03:53 PM
#16
gary i live in kittanning.pa not far from u i have an ory and i cant get my car inspected til i get cats back on and im in armstrong county,with no emissions they are crackin down on visuals if the car came with cats u need them on so now i need a high flow cat y pipe to pass,i would just put them on and save the hassle.
No cats!!!!! 