I am in the process of upgrading my charger from an S trim to a T trim, I would like to increase by baseline pressure from 46 pounds vac off to 50 pounds vac off so I have a can get a little more fuel out of my injectors.

I have 57 pound injectors and when I scanned at wot they where at 90% duty cycle.

Does anyone have the formula to compensate for the increased fuel pressure.

Thanks

John

 

now when you change the injector constant the in PCM you are going to defeat the whole purpose of raising the fuel pressure. you raised it to add more fuel. then you'll increase the injector constant, which will shorten the IPW resulting in leaning it out.

 

http://www.rceng.com/technical.htm scroll down a little to find it.

 

He isn't going to defeat anything. His PCM does the correct calculations, based on the injector constant. He isn't trying to "tune" with the increased pressure, he's trying to increase the flow rating of the injectors, to reduce duty cycle. By decreasing the PW, he is decreasing the DC.

At what pressure was your injector flow rated at 57#/HR? You need to know that to calculate the new constant.

 

The injectors are siemens 3172 and are rated 57 pounds at 43.5 psi. I tuned using a higher baseline pressure but it was only 2.5 psi higher than rating on injectors.

I have been told my twin intanks are good for 700 rwhp at 70 psi so thats what I'd like to shoot for. If the pressure is high enough hopefully everything maxs out at the same time ( pumps, injectors, supercharger ).

So if I use a 57 rated at 43.5 at 50 or 55 how much larger would the injector act.

Thanks
John

 

I just checked that link, thanks mrr 23 that was what I was looking for.

Has anyone found the limit of a 57 pound in a supercharged application.

John

 

you're welcome