I am a bit confused about the injectors on my LT1. I believe I understand they are rated by #XX for pressure right? If so then how do you determine the type injector to use with your motor? When and what advantage is there when increasing or decreasing the pressure rating of the injectors used? I am not any kind of mechanic. I can do simple things like change oil, plugs, flush break lines and radiators and replace calipers and rotors, things of this nature.

Thanks in advance.

 

You'd need to determine the injector size to use by your expected horsepower, and buy injectors that flow that amount at the fuel pressure you plan to run. The simplest way to pick a fuel pressure would be to go with your stock fuel pressure unless you have a very good reason to change it (which is pretty rare on an LT1). Here's a link to some online calculators for minimum injector size and converting flow rates between different pressures.

http://www.megamanual.com/v22manual/minj.htm#size

 

The design of the fuel delivery system of your car is very complex and the purpose of the system to to achieve an air to fuel ratio of 14.7 ot 1. This air to fuel ratio achieves the best emissions and fuel mileage for your engine. There are tables called BLM or block learning mode that allow your engine to compensate for all the normal driving conditions that are expected by your engine. When you have the designed flow delivery of your injectors, the ECM will operate about in the middle of the BLM tables (cell #128). This allows for variation above and below normal. When you place higher flow injectors, your ECM can make some adjustment for the larger flow, but you will not be operating in the center of the fuel delivery tables. Operating in one extreme area with yield either lean or rich condtions that cannot be controlled by the car computer. More gas does not make it go faster! The critical area is the air to fuel ratio number.

You have a closed loop fuel control system in your Corvette in that the oxygen sensor is constantly checking the exhaust system for unburned fuel. If either a rich or lean condtion is found, the ECM with either add or remove fuel by changing the injector pulse time (time injectors remain open in milli seconds).

The flow rate of your injectors is given in pounds of gas per hour per injector. Since pressure and flow are related, you have a base pressure for your stock injectors. The base fuel pressure for my L98 is 43 PSI presssure. I am not sure about the fuel pressure rating for your LT1 engine.

This make sense to you?

 

Matt & Sam,

Thanks, I was reviewing the link Matt gave and there is a tremendous amount of info regarding injectors. I can see that if I don't do any engine mods I should stick with the factory rated injector settings. Thanks for the great info.

Sam the air to fuel mixture does make sense because I played with the carburated pinto 2.3 ltr 4s in the 70s and the combination of CFM (carb) and fuel pump delivery were my major headaches. Of course timing had a hand the issues also. Again thanks, I need to take some time to absorb that link.