How much seat pressure O/C on a turbo car at 20+psi
08-30-2011, 05:36 PM
#21
<facepalm> let me try to connect the dots better since I am being vague....
From your post:
The OP is running 20+ # of boost. The OP is not going to see 15# of backpressure at 20# of boost.
The backpressure is 1.5:1 at a MININUM and possibly more.
Boost = 20, Backpressure = 1.5
20 x 1.5 = 30# of pressure
2.01 area x 30 # per square inch = 60
at...
Boost = 20, Backpressure = 2.0
20 x 2 = 40# of pressure
2.01 area x 40 # per per square inch = 80
180# of seat pressure = 80# of backpressure = 100
Would you run valves at 100# of seat pressure on a performance engine?
From your post:
if you take that on the exhaust valve: 1.60 radius is .80 so area is 3.1415x (.80x.80)= 2.01
The backpressure is 1.5:1 at a MININUM and possibly more.
Boost = 20, Backpressure = 1.5
20 x 1.5 = 30# of pressure
2.01 area x 30 # per square inch = 60
at...
Boost = 20, Backpressure = 2.0
20 x 2 = 40# of pressure
2.01 area x 40 # per per square inch = 80
180# of seat pressure = 80# of backpressure = 100
Would you run valves at 100# of seat pressure on a performance engine?
08-30-2011, 05:46 PM
#22
No, I would get an appropriately sized turbo 
With twin T4 you would be looking at around 19-20 psi of backpressure.
With a big single T6 you should be able to maintain about the same with an appropriately sized turbine housing.
Even with a T4 with a decent 1.10 AR turbine housing you should not be above 32# at 20 psi.
With twin T4 you would be looking at around 19-20 psi of backpressure. With a big single T6 you should be able to maintain about the same with an appropriately sized turbine housing.
Even with a T4 with a decent 1.10 AR turbine housing you should not be above 32# at 20 psi.
08-30-2011, 05:48 PM
#23
Here is a cool link that you can play with various turbo sizes and it will give a backpressure that we have found to be pretty darn accurate!
Turbo Match Bot
Turbo Match Bot
