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PSI Adjustment 7,4 litre BB

Posted: Tue Sep 25, 2012 10:55 am
by Heerlen78
Hi,

I own a Corvette 1978 Pace Car,automatic,Engine ZZZ (V0109 ZZZ) from 1989, 345 HP.
Magazine:Hot Rod March 1989, Engine tested on Katech's fully instrumented dyna in Mount Clemens, Michigan.RPM 5600,Torque 323, HP 345,BSFC .506, tested with Holley 750 cfm 4 barrel carburator.
Convert into Injection: TBI of 454 7,4 litre BB with 2 injectors, GM injectors pn. GM5235231 RPD flow rate 90 lb/hr by 13 PSI.
Calculation flow rate and PSI. 345 HP x .506(BSFC) = 174,57 : .85(duty cycle) = 205,38 : 2 = 102,69 lb/hr per injector. 102,69 : 90(flow rate) = 1,141 x 1.141 x 13(Standard PSI) = 16,92 PSI.
We did focused PSI in Megasquirt software on 15 also VE table and fuel pressure regulator.Is this correct or must we focus PSI on 17(16,92) or lower or higher.

Thanks in advance
Harry

Re: PSI Adjustment 7,4 litre BB

Posted: Thu Sep 27, 2012 5:53 am
by Matt Cramer
There are a lot of people running 17 psi on the 454 TBI injectors at your horsepower level. However, you may need to bore the throttle body oversized if you haven't already done so.

Re: PSI Adjustment 7,4 litre BB

Posted: Thu Sep 27, 2012 12:55 pm
by Heerlen78
The throttle body is already drilled to 54 mm.

Thanks
Harry