Hi all,
I just put in some Accel 26# injectors into my basically stock LT1. What, if any tuning changes do I need to make? I know the flow rates are slightly different and also the Accel's have a different pintle design.

Thanks,
Dave

 

Found this doing some research:
Injector Flow Rate (Injector Constant):
For the stock 24lb injector GM has set this value to 24.91.
For either an Accel or Ford SVO 30lb injector there is a little math that you need to do. The flow on these injectors is rated at 39psi. The LT1 fuel system operates at 43.5psi.
To figure the injector constant based on the difference in fuel pressure take the square root of 43.5/39 and then multiply by the size of the injector. For a 30lb injector you will end up with a value of 31.68.
This can also be applied to other fuel injectors if you know what pressure they were rated at..

Yours were the 26# injectors, therefore the value would be 27.46. To show a percentage of change from stock thats (27.46/24.91) = 110.2% of stock flow, or 10.2% increase. I believe that is enough to give you problems. I do believe a tune is in order!

Jonota

 

Go Jonota!

Cool, I'll have to remember to save that info where I can find it. Where did you dig that up?

I felt like spending money yesterday, so I ordered a tune from pcmforless. Only $50 for the Load Yourself tune. I figured it was worth it at this point. I am still a little wary of doing any programming myself so I figured this was a good place to start.

Dave

 

The computer will be able to adjust for 10% of change without a problem. It'll run rich at first, but closed-loop mode will take care of that small change I'd still recommend a tune though.

The 55lb/hr Siemens injectors (set at 57lb/hr in the PCM due to fuel pressure) in my car "out of the box" were so lean at idle that the car wouldn't run. It needed about 35% more fuel at idle. I recommend a complete tune (not just an injector constant change) after any injector change.

 

I reccomend not running accel injectors.