GreaseMonkey83
11-26-2003, 01:28 AM
I have a dyno program(dyno 2000) that asks for the turbo flow in cfm's, its effeciency, surge flow in cfm's and pressure ratio. I dont know the exact specs of my turbo so im using a Turbo-Garrett TO4B 60*50 turbo because i believe its the closest one i have to my turbo and that i have the specs for. My actual turbo will be a T-61 q-trim turbo. Now, since my setup is a twin setup, does this mean i just double the pressure ratio? Also, can i figure out any of these paremeters using a flow map, which uses lbs/min to measure air flow?
SMOKNZ
11-26-2003, 06:09 AM
Pressure ratio is boost pressure in psia (pounds per square absolute) divided by atmospheric pressure in psia. For example if you are running 10 psi of boost that = 24.7 psia (boost + atmospheric press), so you take 24.7/14.7 and you get a press ratio of 1.68. The efficiencies can be found off the compressor maps. And no you don't double the pressure ratio with twin turbo's. The turbo's run in parallel therefore if you have one turbo putting out 10 psi, and the other putting out 10 psi, that doesn't = 20 psi of boost, it is still 10.
Bill
mongse_1
11-26-2003, 10:45 AM
You’re not going to get the best results from DD with FI motors. N/A, it’s not too bad, but WAY off on forced induction.