Duty Cycle with 55s

[lost2a6]

Well, I have just got my car up and running after installing the WB with powerlogger and alky, along with Eric's 6.1 chip for alky. I made some runs to try to log some data. My DC is around 93% with 23lbs of boost. This is with a A/F ratio of 10.8. I want to run 25 lbs of boost however I'm wondering if I have enough injector to run 25 lbs. My fuel pressure is set on 45 with the line off. I'm getting the 1 psi of pressure per 1 psi of boost rise. Do you guys think that the DC is too high and that I need bigger injectors? The car is really pulling hard, I can't wait to run it through the lights.

 

[pacecarta]

if pump is keeping up (1:1 says it is right now ) ...its time for injector upgrade
keep in mind that if you are on a single walbro 255lph that after you reach 55lb/hr per injector you dont have much pump left and it would be a wise move to step to a larger pump or go double pumper

 

[Nick Micale]

Could be other factors than the injectors causing that high DC?

Fuel pump output due to old/faulty pump and not enough voltage to run it at capacity could be an issue, and also it is running very rich at WOT.

I would lean it out to 11.2 and log that run, then raise base fuel pressure ~5#'s and see what that data will give you for DC.

 

[lost2a6]

Forgot to mention that I have Red's double pumper, I thought that it was in my signature, sorry. Both pumps are on a separate hot wire kit. I have a hood mounted FP gauge it doesn't drop off one bit. Thanks guys!

 

[pacecarta]

are you firing on all cylinders
if you are ..
at 3700lb fuel calcs put you at 615hp ...enough for 10.60@128mph , not impossible on your combo

 

[87GN_70GS]

93% is getting close to no safety margin. Although 10.8 is kinda rich. With your DP, you can always run more base fuel pressure, may have to re-tune idle and part throttle but more bfp will bring down WOT duty cycle.

 

[pacecarta]

more base FP will also make his car rich at idle

 

[lost2a6]

I could probably lean out the idle with my translator, idk. I might just get some 80s so I can have more of a safety margin. Do you guys think that I would still be safe at a 11.2 A/F? I forgot to mention that I do have the power plate, if that matters.

 

[JT'sV6]

Go with some 80's. Coming from a reputable tuner down my way, you dont want injectors to be above 80% dc.

 

[87GN_70GS]

more base FP will also make his car rich at idle

Thats why I included this "......more base fuel pressure, may have to re-tune idle and part throttle....."