Cats add torque?
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From: Palos Hills, IL
Cats add torque? there was a guy on here asking how he can gain more torque and somebody told him to get cats for his Y-pipe?...i thought restriction was bad?...how do they add torque is a restricted exhaust better for adding torque? or what actually will factor in the torque? cam specs have anything to do with it...cuz the way it llooks to me is that more intake less exhaust makes torque...so it seems to me form the looks of it thnaks for the info
On The Tree
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When you have cats on, you're restricting your exhaust flow, which is causing you to have more back pressure than us guys/gals with no cats at all, which increases your torque...but it will get you where you need it...high end...that's where you need the Horses
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oh alrighty....so its alll backpressure...so does the backpressure only come form the cats? or would a muffler do it also...for instance say i have Kooks LT's Catted Y and GMMG....if i was o install a cutout on the I-pipe...which would have more torque full catback...cutout or it woukldnt make a difference?
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your car is also tuned...and the Magnaflow muffler probably helps with backpressure correct?...the ASP pulley might possibly have something to do with it no?...
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From: MD
Originally Posted by 02WS6Bird
your car is also tuned...and the Magnaflow muffler probably helps with backpressure correct?...the ASP pulley might possibly have something to do with it no?...
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While it is possible that the addition of slight backpressure will gain some low end torque, or atleast move the curve down, it will only help torque at the bottom of the RPM range. It will not likely affect torque peak. The restriction will however reduce your high rpm HP numbers. Good high flow cats should only reduce peak HP by 3 - 5 HP on most cars vs no cats, but I cant tell you how much you gain down low, especiall since it doesnt take place at tq max. Ill bet its not much though.
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From: MD
Originally Posted by GuitsBoy
While it is possible that the addition of slight backpressure will gain some low end torque, or atleast move the curve down, it will only help torque at the bottom of the RPM range. It will not likely affect torque peak. The restriction will however reduce your high rpm HP numbers. Good high flow cats should only reduce peak HP by 3 - 5 HP on most cars vs no cats, but I cant tell you how much you gain down low, especiall since it doesnt take place at tq max. Ill bet its not much though.
backpressure = torque is MAJOR 
next that "guy" will be saying "ricer fart cans will give you loads of HP"
backpressure hurts ALL kinds of power (HP AND torque) as it robs energy from the pistons on the exhaust stroke as they must PUSH the exhaust out of the cylinders
if you want more torque then get "smaller" (not small enough to make backpressure) long tube headers as they will keep velocity up and improve scavanging at low RPM to build torque.
long, small diameter primaries (with no backpressure) = low RPM torque
short, BIG diameter primaries (NO backpressure) = high RPM HP
next that "guy" will be saying "ricer fart cans will give you loads of HP"
backpressure hurts ALL kinds of power (HP AND torque) as it robs energy from the pistons on the exhaust stroke as they must PUSH the exhaust out of the cylinders
if you want more torque then get "smaller" (not small enough to make backpressure) long tube headers as they will keep velocity up and improve scavanging at low RPM to build torque.
long, small diameter primaries (with no backpressure) = low RPM torque
short, BIG diameter primaries (NO backpressure) = high RPM HP
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Guys backpressure will help torque. One time I tested it on the dyno. 2 runs with cutout open, two with cutout closed. When the cutout was opened I gained peak horsepower and lost peak torque(as well as area under the curve). Same principle with cats. Maybe this is moreso true for less heavily modded cars but I know when I have the cats in on my FLPs the the torque curve feels fatter and smoother than without them.
Mike
Mike
Originally Posted by Dal1as
No, someone who takes out there cats will see an increase of torque all through the range. Now maybe the increases will be higher at higher RPM but there will be increases all through the range. Even at lower RPM's. This has been dyno proven.
backpressure is crap.....why else would true duals work so well? 2001CamaroGuy nailed it.....free flowing exhaust is where its at. thats why people want cats GONE. you keep them only for sound and/or emissions.
