3.8redbird

iTrader: (3)

Upgrading the fuel system in my C4.

400 centri charged Gen 1 SBC with a Holley Stealth ram with the stock rails that came with it.

These rails are about 3/8inch and I will be supplying the feed end with -10AN line and have a 6AN return.

Will this rail support 700rwhp on E10 and ~750rwhp on E85? 80lb injectors.

Pump is a fuelab that will support 1300hp with E10. Was told 10AN was good for feed and 6AN for return. Does the cross over need to be 10AN or 6AN?

Forcefed86

iTrader: (4)

With alot of fuel pressure you could do it. 65psi or so base, then add your boost pressure on top of that.

Those fuel lab numbers are bogus without pressure. You need to know at what pressure the pump will support 1300hp.

That single fuel lab pump won't flow enough at high fuel pressures to reach your goal with the 80's. Other option is to get larger injectors so you can drop the pressure requirement on the pump.

The OEM rails have made 850+whp on e85.

3.8redbird

iTrader: (3)

they claim 1300 on 43.5psi and 1100ish on 60psi. By my calculations to be at 80%dc I need around 78-79lb injectors at 650FWHP. So if I were to get FIC 1000s which are ~95@43.5psi I should be ok for gasoline at 43.5 and E85 at ~60psi?

Forcefed86

iTrader: (4)

You are forgetting to figure in your boost pressure. Add your base FP to your boost to get total pressure required for the pump. So if you had 60psi base FP and ran 20lbs of boost, you need to know what the pump flows at 80psi of total pressure.

Take your pump gas injector requirement and multiply it by .43 for e85 equivalent injector.

So if you need 60lb injectors to meet your requirements for pump you’d need roughly 86lb injectors to meet your E85 requirement.

Upping the pressure just makes your injectors act larger. Use the calculator here to figure out how much they change with the pressure increased.

A 1000cc inj at 43PSI will flow 1174.4cc @ 60 psi.

http://witchhunter.com/injectorcalc1.php

3.8redbird

iTrader: (3)

Using that site for 800FWHP ~ 680rwhp with 15% loss through T56 and rear.

I would need 75lb injectors for 80% DC with 0.60 BSFC on E10.
Would there be noticible drivability issues if I were to use a 95lb injector in this setup?

The 1000cc injetors are perfect to cover the E85 but are large for the gasoline.

I only want 700rwhp max as any more will be untrackable for what I plan to do.

Forcefed86

iTrader: (4)

1000's were about the limit in my experiance with pump gas. I dropped the fuel pressure down to 35 or so when I ran pump and it allowed me to run higher pulse width and idle fine. My 120lb injs won't idle with pump fuel well.

3.8redbird

iTrader: (3)

Sounds like a good plan. Looks like I can knock it down to 35 and be around 76% DC.

Thanks for the help.