Currently running Bosch III Blue 24lb one. Thinking of changing to the red 30lb Bosch III's
In a nut shell running on a 2.1 mile road course for track days I'm hitting 74-75% for the injector duty cycle.
Car is an '88 IROC 5.7 with 113 ported heads and 1.6 rockers and a Comp Cams 260XFI HR13 cam (installed straight up 109° c/l)and Dyno Don's headers.
Single 3" exhaust no cat running an EBL P4 for the ECM.
700R4 with 3:42 gears and stock size 245/50-16 tires

The car runs good but I am doing the following mods...
LT1 T56 2:66 1st and 50% overdrive
4:10 gears still 245/50-16 rubber
Replacing the stock ported TPI base with port matched Edelbrock base and Arizona Speed & Marine runners. Plenum will be port matched as well and the step behind the throttle body was removed when I did the 113 heads.
Goal of the setup is to optimize the power band from 2500 to 4750-5000 RPM
The car should be geared now so most of the track is 3 & 4th gear with just the last part of the main straight going into 5th.
Then have 6th for cruising on the street.
I know I could get more power with better heads but the budget does not allow that
I do need to look into opening up the air cleaner to throttle body piece. From my data logs it does not look like it's hurting me yet however.

Would it be worth changing to the 30lb Bosch III's while I'm swapping the intake or do my 24Lb one have enough "room" left for the extra air flow with the bigger intake ports and runners.

Thanks for any and all thoughtful comments and suggestions!
Dave

 

How do you know you're at that DC%?. ALDL reporting generally does not include the voltage offset PW which will affect DC% calculation.

 

24’s should handle that. Else do you have an adjustable fuel pressure regulator? Bump it up 5-8 psi to get more capacity

 

That's the value that is reported by the data log from the EBL P4 it reports the injectors duty cycle.

 

I have an adjustable fpr that is maxed out but according to my gauge I am running 48psi with the vacuum line off. I can't get any more pressure on of the pump (still has the original '88 53k mile fuel pump)

 

what kind of horsepower are you looking to run? Turbo?

 

Currently per the desktop dyno it's estimated 345Hp @ 4500 and 464 tq at 3500. I have a friend that has a chassis dyno that I am planning on getting the car on this summer.
I am hoping to find another 10-20hp with the bigger intake. The motor is NA I have no plans or desire to run boost or NOS.

 

You should be fine with 30-32lb injectors

 

Thanks for the advice. I think that it's better than taking a chance on running lean. As I'm not far from the 85% guideline for the max duty cycle.
Dave

 

Can you confirm that? That's interesting! I had noticed a difference between my calculated INJ PW and the ALDL reporting.

 

The datalog from the EBL P4 has a column in the datalog titled "DC" for the injectors duty cycle. You can't easily use the pulse width as the duty cycle as you need also to factor in the RPM along with are the injectors firing in synchronous or asynchronous mode