61# to 80 lb injector conversion.

I have tried all day to find this info so if there is a concise post existing please excuse me and post that link. I need more fuel for my 383 and did an injector swap on my holly 670 cfm tbi. I went form the holly set up injectors which were 61lb'ers to 80 lb 454 injectors. I just had the truck tuned and thats how I fond it was running short of fuel(and I have the dyno charts to prove it:mad1:) I would like to try and just update the tune to note my new injector sizes so I don't have to pay for another one so soon. I cant seem to find what I need to change or where I need to change it, I thought I found a post suggesting to multiply several tables by .71% this lead to the truck running poorly and a check light. If I run the tune as is, it runs increadabl rich as would be expected. Thank you in advance.

You can change the injector constant but the acceleration enrichment may still be way off. What are you using for software to make the change? What ecm / pcm is in your truck?

Im running tuner pro with a moates box, truck is a 93 chevy with the original computer. using -Advanced $E6 TP5 v250.xdf- hope that helps, I'm new to this and not sure what info is all needed to get a question properly answered yet.

I don't use TP very often and don't have a copy here at work so hopefully someone else can jump in and help. There is a value named "injector size" or "injector flow rate" which needs to be changed. If you have the correct definition for your calibration then the existing value should be close to the old injector size. The new injector size is about 78 #/hr at 13 psi. If you're running more pressure you need to determine the actual flow rate before changing the injector flow rate.

Do you happen to know where that constant is located?

I'm sorry, but not off hand. There's a feature called "parameter search" that should help find it.

1Project2Many - you mention you don't use Tuner Pro much... do you use something else then? Just curious.