Differential pressure over throttle body
10-25-2007, 12:04 AM
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Car: 1985 Camaro Z-28
Engine: 385
Transmission: th700r4+Edge 2800 stall
Axle/Gears: 3.42
Differential pressure over throttle body
If I measure differential pressure over throttlebody at wot,how much is too much(ie when I need bigger tb)?
10-29-2007, 07:20 AM
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Car: 1985 Camaro Z-28
Engine: 385
Transmission: th700r4+Edge 2800 stall
Axle/Gears: 3.42
Re: Differential pressure over throttle body
Measurements are done.Results:diff.pressure from air cleaner snorkel (after filters)to plenum ->2.4 kpa at wot.Vacuum at plenum at wot ~2kpa.So I think original 2x48mm tb is enough to my combo.
10-31-2007, 03:46 PM
#5
Re: Differential pressure over throttle body
When my motor starts out at the track under wide open throttle the KPA will read somewhere around 100 to say 101 kpa in the plenum. As the rpm's get up around 6200 rpm the kpa will drop to the 98-99 range. So that is what I meant by the 2+ kpa drop. Heck that could mean 5 or more horsepower I'm losing. 
In my quest for 500hp at the motor I can't have that.
In my quest for 500hp at the motor I can't have that.
11-01-2007, 01:22 AM
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Car: 1985 Camaro Z-28
Engine: 385
Transmission: th700r4+Edge 2800 stall
Axle/Gears: 3.42
Re: Differential pressure over throttle body
When I yesterday talked with local enginebuilder ,he was sure that there was benefit a bigger tb.He told that they found +40hp when they went from 52mm tb->monoblade at 377ci(de stroked 400ci) miniram Vette engine.He told that with 52mm tb there was ~3kPa vacuum at plenum.
Last edited by z 28 jari; 11-01-2007 at 01:26 AM.
11-01-2007, 02:15 AM
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Car: Red 1987 IROC Convertible
Engine: 305 LB9 TPI
Transmission: T5 5-Speed
Axle/Gears: 9-Bolt 3.45
Re: Differential pressure over throttle body
When I yesterday talked with local enginebuilder ,he was sure that there was benefit a bigger tb.He told that they found +40hp when they went from 52mm tb->monoblade at 377ci(de stroked 400ci) miniram Vette engine.He told that with 52mm tb there was ~3kPa vacuum at plenum.
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11-01-2007, 01:46 PM
#9
Re: Differential pressure over throttle body
I'm just data logging the info off the computer and reading the KPA. Atmospheric pressure usually reads somewhere between 100 and 101 KPA. So if I'm dropping down to 98 to 99 KPA in the plenum I have a slight depression.
There is a local head porter called the Air Doctor who claims good horsepower gains on LT1 motors by going to a monoblade. I'm going to give it a go.
There is a local head porter called the Air Doctor who claims good horsepower gains on LT1 motors by going to a monoblade. I'm going to give it a go.
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