800 hp - Fuel set up. Advice

[Mik]

Thanks...it sort of does, but why will the rail pressure = fuel pressure + boost pressure?

[BBQ]

Thanks...it sort of does, but why will the rail pressure = fuel pressure + boost pressure?

Because when you have a rising rate regulator.. The high the boost level the higher the Fuel pressure goes to compensate for more air..

Eg.. 10psi from the turbo = 50Psi rail pressure if you run 15psi you will have 55psi of rail pressure..

Depends on your regulator if its 1 or 2 psi rising rate..

[R32-GTS]

The single Bosch 044 supplies enough fuel for ~730bhp at 12 volts.  But you will have to use a relay and wire it back to the battery/alternator as the standard wiring won't handle the current.  So the 044 will see 13.8 volts, which puts it up around 840 bhp.  You don't have to run a surge tank for drag work, just make sure there is enough fuel in the tank for each run.   So you could mount the 044 in tank.

From experience, the Sard 700 cc injectors usually flow around 730 cc's on the flow bench at 38 psi.  The Bosch 044 is capable of 73.5 psi, so it depends on how much boost you are running as to how much you can increase the rail pressure.   Around 45 psi rail pressure will see the Sards flow around 800 cc's, that leaves 28.5 psi for boost (1.9 bar).

The standard fuel rail is as large internally as most aftermarket rails, the only issue is the fittings.  I am not a fan of rubber hoses and screw clamps on fuel supply at up to 73.5 psi.  A bolt on Nismo fuel pressure regulator ($180 from Nengun)  will fix one end, but the other (fuel supply) end of the rail will need to have a proper dash fitting welded on.  I strongly suggest using bolt on fittings all the way back to the pump, fuel fires are ugly.

Personally I would save some money and use the 044 in tank with the Sard injectors and the standard fuel rail.

Sydneykid what sort of hp do u think a a single 044 and sard 700's would be capable of ? Aiming for 550-600rwhp

Im running this setup with a HKS fuel rail and HKS fuel reg.

[Sydneykid]

Sydneykid what  sort of hp do u think a a single 044 and sard 700's would be capable of ? Aiming for 550-600rwhp

Im running this setup with a HKS fuel rail and HKS fuel reg.

I suspect the limit of the Sards will be around 800 bhp. But that is dependant on how much boost you run, as that will determine the maximum fuel pressure and hence the injector flow rate. The 044 should supply that, provided you have the necessary wiring and relay to handle the current and the voltage is stable ~13.8 volts. The 800 bhp would be around 720 rwhp in a 2wd application and 690 4whp.

Hope that answered your question:cheers:

[R32-GTS]

Highest hp ive seen from one 044 is 530rwhp. Im hoping i could get a bit more.

[The Alchemist]

looking for posts on fuel regulators, came across this one....I have a small problem I hope some one can help me with.

Dynoing a car today RB26 in a R33 GTS-T, rebuilt but run in engine with high flow turboes std housings. std head std cams , making 272RWKW at 18psi boost on a 2WD Dyno Dynamics Dyno, running a Bosch 044 pump & surge tank with a (dear I say it) Malpassi reg.

The AFR showed a slight but sudden lean out at 6000rpm from 11.6:1 to 12:1 despite the fuelling numbers on the computor increasing to try & compensate. made no difference.

We checked the fuel pressure gauge (one of those cheapy's that go in the other side of the reg) during subsequent runs and found that at about 5800rpm the fuel pressure would go from 80PSI steady and drop down to 70PSI.

Obviously this is a symptom of the lean out but what is the cause of the presure drop?

Has anyone had problems with malpassi not holding line pressure?

WHAT about fuel supply line diameter, at what point do you need to increase from dash 6 standard line size to dash 8 or bigger?

cheers Mike

[Sydneykid]

My suggestions follow;

Fuel pressure regulator would be my first guess. Is the boost supply to the regulator stable?

Second choice would be fuel pump, do you have a dedicated power supply circuit and relay for the 044? If you are using the standard wiring (for anything other than switching the relay) that can be a problem.

What pump are you feeding the suge tank with?

Where is the fuel filter in the ciruit? What size is it? Too small and it can be a restriction?

You should get well over 350 rwkw before the standard lines become an issue.

[GeeTR]

Hey,

All good stuff, I might be outa line, though i dont like the idea of running the twin pumps for push. Not common maybe, but if a relay or pump stops wont u get a massive lean out, instead of a quick lowering of fuel pressure from a dead single?

thanks

[super26]

My advice to you is to use two aeromotive pumps and the regulator, the fuel pressure should be at 38to 40 psi the stock rail is good and 1000cc injectors is good also this the setup i am using in my car and it is making over 800hp, this setup was also working on a supra with a 2jzgte and made a little over 800hp too, i am planning to do the same setup with an rb26 head and a 30 bottom end if u have advise i would appriciate it.