A friend wants to put a Pro Charger with 12psi boost using air/air intercooler. His Corvette 355 LT1 has a CR of 8.5.

What will be his fuel requirement. What injectors size should he use. Not sure if he will run an FMU or not but in both cases what injectors size should be enough.

I guess he will be near 500HP if not more at the flywheel.

Will the stock fuel pump be upto the job.

Is it better to use an FMU with upgraded injectors or just injectors and try to tune them done for proper A/F ratio at idle.

 

I would recommend ditching the FMU and going with 55lb injectors. He will also need an aftermarket fuel pump to support his setup.

 

What size pump is good for the job.?

I guess 55Ib injectors will run rich at idle.?

 

If the car is tuned properly then it will not run rich at idle. I would recommend getting a Walbro 255lph. Also I would recommend contacting Racetronix.

 

Its all in the tune, I wouldnt worry about it running rich at idle. That kind of thing can be delt with with some tuning. As far as a fuel pump, I would think a Walbro high volume intane pump should be alright along with a 1:1 fuel pressure regulator like the one from aeromotive with the boost reference fitting.

 

I have a procharger witht the 12# pullys, although it only make about 7-8# of boost with my motor

Power is under 450-480 rwhp (guess)

Im using a walbro 255 intank and bosch 42# injectors. My duty cycle it 104%

Recomendation for both me and you is bigger injectors.

 

Im at 10-12psi using 42 injectors, gs340 pump and msd boost a pump. No fmu or rail pump.

 

Do you know what is your Fuel pressure and A/F when under boost?. What is your duty cycle.?

 

What's your fuel pressure?, stock 43psi I guess.

Are you running any FMU or boost a pump.

 

I would also like to knwo what you dusty cycle is b/c I see some people are running 42's making 480-500rw with bigger pump. What do your numbers look like?

 

Yes stock FPR and no FMU

 

He is going to need at least 42 pound injectors and bigger pump, possibly bigger fuel lines and aftermarket fuel pressure regulator. I made 525 rwhp with 42 pound injectors with more to spare, but my entire fuel system has been upgraded. Basically you need to upgrade the entire system for big time power.

 

Thanks for all the responses. The guy has put 42# injectors and the Vette ran very rich. He says it's smoking alot.

I guess he is not at 12psi, maybe 6 psi. I recommended that he get a boost gauge and an A/F ratio gauge to try to tune it better.

 

500HP is well within the range of a single in-tank system from Racetronix. If you need more at a later date you can always add a pump booster as a PnP option.

The LT1 PCM generally has problems with injector DC's over 80% and so do many injectors. 42# injectors will support 500FWHP but be marginal at 500RWHP depending on the BSFC of your motor. Remember in order to keep injector timing stable a 42# injector equates to 33.6#. Time to inject is another item which you must factor into your injector selection equation.

 

If he just swapped out the injectors without changing it in the computer it will smoke. The computer thinks it still has the 24lb injectors in.