Back pressure good or bad?

RAGE_5.0 · 11-22-2001, 05:55 PM

me and my cousin are having a little disaggreement on whether back pressure is good or bad...
i say u need a certain amount of back pressure and he says i should put straight pipes on because it will make it faster and that it will not make u loose torque.......

i personally know he is wrong because the pipe snapped between my muffler and the h pipe on the passenger side and u could feel the loss of torque, the gas mileage went down and the idle went to ****

JAMES

PKRWUD · 11-22-2001, 07:40 PM

He owes you a beer.

Take care,
-Chris

RAGE_5.0 · 11-22-2001, 07:58 PM

k thx for confirming that chris

dinomite · 11-22-2001, 08:25 PM

Yep, if you loose back pressure, you loose torque; thats why all those ricers are f$*king morons, cause they put on "performance" exhaust systems that have extremely low back pressure, and they end up using what little torque they have.

mustangman65_79 · 11-23-2001, 08:11 AM

but what is the fine line in between losing and gainging tourqe?

Unit 5302 · 11-23-2001, 11:13 AM

There is no fine line. You never want to lose torque. If losing torque is a consequence of gaining horsepower, then sometimes it's worth the loss.

When you have an engine that is being restricted by exhuast, then you want to lose backpressure. When you have an engine that is not really being restricted by backpressure, then it's unnecessary to do any modifications for performance purposes.

mustangman65_79 · 11-23-2001, 11:23 AM

My Bronco had a really bad(stock) exhuast so I took off the main cat back, still has the pre cat for now, but I noticed that it got more torque and horsepower(so I think).

Rebel79 · 11-23-2001, 12:15 PM

Quote:

Originally posted by Unit 5302
When you have an engine that is being restricted by exhuast, then you want to lose backpressure. When you have an engine that is not really being restricted by backpressure, then it's unnecessary to do any modifications for performance purposes.

Exactly. However you CAN gain horsepower by putting on less restrictive exhaust, hense reducing back pressure.

Unit 5302 · 11-23-2001, 02:00 PM

No doubt, but if the exhaust isn't what's holding the power back, making it more free flowing will sometimes result in a drop in backpressure which can reduce low end torque.

I have exhaust mods on my car, the H pipe and the exhaust, it's cutting backpressure, but the stock parts hurt power above 4000rpm. My car pulls WAY better up top than it did with the crap exhaust on it.

11-22-2001, 05:55 PM	#1
RAGE_5.0 Registered Member Join Date: Jul 2001 Location: Leamington, Ontario, Canada Posts: 767	Back pressure good or bad? me and my cousin are having a little disaggreement on whether back pressure is good or bad... i say u need a certain amount of back pressure and he says i should put straight pipes on because it will make it faster and that it will not make u loose torque....... i personally know he is wrong because the pipe snapped between my muffler and the h pipe on the passenger side and u could feel the loss of torque, the gas mileage went down and the idle went to **** JAMES __________________ Black 1990 Cobra Mac offroad H pipe, Hooker aerochambers , k&n bunch of stuff that I'm to lazy to type out sitting in my room

11-22-2001, 07:40 PM	#2
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	He owes you a beer. Take care, -Chris __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

11-22-2001, 07:58 PM	#3
RAGE_5.0 Registered Member Join Date: Jul 2001 Location: Leamington, Ontario, Canada Posts: 767	k thx for confirming that chris __________________ Black 1990 Cobra Mac offroad H pipe, Hooker aerochambers , k&n bunch of stuff that I'm to lazy to type out sitting in my room

11-23-2001, 08:11 AM	#5
mustangman65_79 My poor 79 RIP Join Date: Oct 2001 Location: Suisun City, Posts: 2,320	but what is the fine line in between losing and gainging tourqe? __________________ '84 mustang GT turbo '85 LTD '89 Camaro Irocz z28 '94 Lightning '96 Trans am

11-23-2001, 11:23 AM	#7
mustangman65_79 My poor 79 RIP Join Date: Oct 2001 Location: Suisun City, Posts: 2,320	My Bronco had a really bad(stock) exhuast so I took off the main cat back, still has the pre cat for now, but I noticed that it got more torque and horsepower(so I think). __________________ '84 mustang GT turbo '85 LTD '89 Camaro Irocz z28 '94 Lightning '96 Trans am

11-22-2001, 08:25 PM	#4
dinomite The Dude Join Date: Feb 2001 Location: Arlington, VA Posts: 1,262	Yep, if you loose back pressure, you loose torque; thats why all those ricers are f$*king morons, cause they put on "performance" exhaust systems that have extremely low back pressure, and they end up using what little torque they have.

11-23-2001, 11:13 AM	#6
Unit 5302 Registered Member Join Date: May 1999 Posts: 5,246	There is no fine line. You never want to lose torque. If losing torque is a consequence of gaining horsepower, then sometimes it's worth the loss. When you have an engine that is being restricted by exhuast, then you want to lose backpressure. When you have an engine that is not really being restricted by backpressure, then it's unnecessary to do any modifications for performance purposes.

11-23-2001, 02:00 PM	#9
Unit 5302 Registered Member Join Date: May 1999 Posts: 5,246	No doubt, but if the exhaust isn't what's holding the power back, making it more free flowing will sometimes result in a drop in backpressure which can reduce low end torque. I have exhaust mods on my car, the H pipe and the exhaust, it's cutting backpressure, but the stock parts hurt power above 4000rpm. My car pulls WAY better up top than it did with the crap exhaust on it.

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