Dennis5374

I've got a single 78mm turbo , ls1 m6 Camaro. I'm running Holley hp efi , sd 60 lb injectors, racetronix 255 Hotwire kit, with a kenne bell boost a pump. I'm currently running 9 psi intercooled, and also have a tsp 228r cam. In the monitor on my LCD touch screen, I'm showing 38% fpdc at 9 psi and 5800 rpms in 4th gear. My question is , numerous people on this site have told me, this fuel setup is only good for 550 max. At 9 psi with a cammed ls1 with upgraded valve train, shouldn't I be approaching that ? I just wanna know where this thing will run out of fuel , as im trying to get the most power from my car, before snow covers the ground .My iat are around 40* here at night, and never exceed 65* in the day. Ambient temps are in the 50-60* range right now.

Old Geezer

iTrader: (3)

60pph injs at what base psi?
I'd revisit the log setup w/ only 38% at that boost/rpm.

ScottyBG

You will run out of pump before you run out of injector. I believe those injectors flow 69lbs/hr, at a pressure of 4 bar, which is what your in tank regulator should provide, or 552/hr lbs for the set of 8. This equates to 350 lph is the max your injectors can squirt as a set. Even with a booster,a 255 can't push that much volume at 4 bar fuel pressure, thus my opening statement. You should have enough pump run to about 70-75% injector duty cycle, I'd say 60% to be really safe. This is injector duty cycle I'm talking not FPDC.

How does your ECM determine FPDC? I wouldn't trust that number until I knew how it was derived. I'm guessing it is a mathematical calculation based upon some data you give it, because I don't think it has a fuel flow sensor, or any way of actually reading it? Remember the term GIGO, if the computer doesn't have good data it can't give you good numbers. I know the Holley Dominator ECM will tell you fuel flow in lbs/hr, when data logged. I believe it calculates this based upon the data you input for the injectors, and their duty cycle. Does the one you have show you that? If it does, calculate your fuel flow from the pump using the tables from your boosta pump, it is probably something like 260 lph. The base is 255 which will be reduced by the 58 psi, the 255 rating is at 40 or 43 psi. but then increased by the additional voltage provided by the booster. Take that number and multiply by 1.6 to get your fuel flow in lbs/hr. For example 260 lph= 416 lbs/hr. When you get this number, you can see how close you are coming to it based upon what the computer data logs for fuel flow rate.

My hunch is you still have some room, but don't trust this, do the math yourself. The plus side of that is you can add more boost, the down side is your probably not making as much power as you'd hoped, if you not out of pump yet.

Dennis5374

It calculates the same way as the dominator based off injector size, fuel pressure etc. i ordered a 100psig sensor, for fuel pressure at the rail . I don't know if this will effect how the ecu reads , if if it will just let me monitor pressure drop.