The engine is a stock bottom end with p&p heads and the gm847 cam. Also running 1.6 nsa rockers and a LTX style sheet metal intake that i made. 58mm tb. All the normal bolt ons(headers, intake, etc). My question is, is running the stock injectors going to cause a big problem? I'm running a A1000 pump, all an lines to the fuel rails, and an adj. fuel pressure reg. so can i just turn the pressure up to increase the # of the injectors?

 

Depends....

Injector size is determined by the flywheel HP and how efficiently the engine is tuned. Lacking specific data for your car, a safe way to pick an injector size is to assume an 0.48 #/Hr/HP BSFC and an 85% duty cycle. That will tell you that at 350 flywheel, you might want to pick a larger than stock injector. (Yes, there are people with 0.45 BSFC tunes and willing to push theinjectors to 100% DC, who make over 400 flywheel HP, but that's not the best way to do it).

Using the suggest conservative approach, multiply flywheel HP by 0.07 to get the injector size.

e.g. 450 HP x 0.07 = 31.5 #/HR

Now that's based on the injector running at the fuel pressure it was flow rated at.... 43.5psi for the stockers, 39.15psi for the SVO/FMS/etc. injectors. Raising the pressure will raise the flow rate, but the stock RP ball and seat injectors do not like to go too high on pressure. Might be able to raise the pressure to 4 bar (58psi) max. That would increase the capacity of your stockers to 28.77 #/HR (based on the stock programmed flow constant of 24.92 #/HR).

 

Thanks for the help Fred.