LS-ONE_DAY

I was hoping to find something in the stickies of this section but didn't so I'm looking for information on necessary fuel system upgrades for engine mods. I keep thinking "oh yeah a cam package isn't all that bad on the wallet" then I think about install but I always forget about fuel! Would a cam swap require changes to the fuel system? If so, what would fit the bill? If not, would it be necessary for a mild h/c/i setup? I was planning on something around a 228R or VRx4 cam, heads would probably just be ported 243 castings like TSP stage 2.5 LS6 or maybe TFS 220 as cast if I decide I want a h/c over cam only. Intake manifold would either be an LS6 or a FAST 92/90 combo...

Perhaps one day running a small nitrous setup, something for a 100 shot but that bridge is a ways off.

ZL1Killa

iTrader: (17)

Here it is: Fuel Sticky

your stock fuel pump is a 190 liter per hour pump, supports a maximum of 8 x 38LB injectors. The stock 28LB injectors are only good for about exhaust or just a cam swap to be honest.

Grab some 32# or 36# @ 43.5psi injectors (which are actually 15% larger at 58psi, which is your actual fuel pressure). Contact FIC - Fuel Injector Connection. This size of injector on a head cam setup with other bolt ons will get you to 450HP. Do not forget, if you change injectors, you must have the car tuned also, an additional cost unless you do this yourself and own the software.

LS-ONE_DAY

Yeah that's the sticky I looked it, it just seemed like it wasn't as fleshed out as stickies in other sections. So pretty safe to say I'd probably need injectors if I want to go into the motor with a cam, not to mention h/c or nitrous then I assume. If I got 8 36# injectors would the stock 190lph pump reliably handle that or would it be better to get a walbro 255 for peace of mind at an additional cost?

The tuning isn't a big deal because I wouldn't JUST be changing injectors, I'd make sure to do that with the other things that would require a tune, new MAF and intake at least if I wouldn't want to wait until cam time for everything.

LS-ONE_DAY

I just went to Fuel Injector Connection and I did their injector calculator....I entered the following settings (or kept whatever they had in there)
385hp at flywheel
8 injectors
B.S.F.C 0.5
Max duty cycle 80%

With that info it says the required static injector flow rate is 30.08# / hr...I remember reading that LS1's came with either 26.6 or 28# injectors. So basically I'm running out of fuel as it sits?

ZL1Killa

iTrader: (17)

you need to get a scan of the car to see the duty cycle, but with your mods currently I'm betting you are around 70% duty cycle or more.

the 28.8LB injectors in your car flow that at 58psi (***IF I remember this right) and the references at FIC are at 43.5psi (3bar) and your fuel pressure is 58psi

so that 30# injector is actually 34.6# injector at your application and that is what you would tune the car with. download the file in the sticky. I will admit, that particular sticky does need to be ironed out. I need to do a basic write up on selecting injectors & in particular understanding them/the system.


To answer your question about the 255 kit w/harness, with needing 30# @43.5psi (34.6# @58psi) you are within the flow limits of the stock pump, so no you don't need to spend the extra dough as of this time. HOWEVER, adding more power or nitrous (dry especially) I would advise going ahead and buying the 255 pump kit.
The 255 w/harness kit is one of the first mods I did to my car, just after my intake & exhaust mods way back in the day.