does a stock LT1 need backpressure?
Registered User
Joined: Jul 2000
Posts: 694
From: Brighton, IL
Re: does a stock LT1 need backpressure?
Originally Posted by wrd1972
My 2 cents on this statemant.
Low end torque is most effective during the initial launch and only in 1st gear.
High end torque will be used for acceleration in 2nd, 3rd and 4th gears.
So for an actual 1/4 mile run with maximum performance and if i had a choice of where to place my torque I would prefer to use in the powerbands of 2nd through 3rd gears rather than 1st.
Low end torque is most effective during the initial launch and only in 1st gear.
High end torque will be used for acceleration in 2nd, 3rd and 4th gears.
So for an actual 1/4 mile run with maximum performance and if i had a choice of where to place my torque I would prefer to use in the powerbands of 2nd through 3rd gears rather than 1st.
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Joined: Aug 2003
Posts: 2,925
From: Detroit
I figured id follow up on this one but it seemed that the computer had to adjust to it because it feels faster now than it did before. I havent had it to the track yet, but ill post times when i do.
Registered User
Joined: Jul 2005
Posts: 747
From: Baton Rouge, LA
Good writeup on why backpressure is not needed for low end torque.
http://www.uucmotorwerks.com/html_pr...torquemyth.htm
Proper fuel control is needed for low end torque
http://www.uucmotorwerks.com/html_pr...torquemyth.htm
Proper fuel control is needed for low end torque
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Joined: Aug 2006
Posts: 3,705
From: Kansas
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Joined: Nov 2000
Posts: 1,937
From: Ft. Worth, TX
The exhaust would exit at the front of the car if you needed backpressure...thus the faster you would go, the more backpressure it would create since the exhuast pressure would have to overcome the ram air effect in the exhaust pipe facing forwards 
the faster you go, the more backpressure for even more power
the faster you go, the more backpressure for even more power
Registered User
Joined: Jan 2005
Posts: 1,388
From: Moore Oklahoma
I run dual open collectors w/ 18" extensions at the track. I installed two 40 series FlowMasters (slip-fit on the collectors) for some street driving and the car slowed-down two tenths (0.20) in the 1/4. So much for the back-pressure theory. 
WD
WD
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Joined: Jun 2003
Posts: 3,557
From: Carol Stream, Il.
Have you tried slightly shorter or longer extensions to see if it makes a difference?
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