Valiantap6
Member
Hi, I'm new to forced induction and putting vortech v2 on 318 LA engine, what should I do to fuel system, fuel pump, fuel regulator and things etc, please help as I want to do as much as I can myself before starting engine
What fuel system to use
- Thread starter Valiantap6
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Carb? EFI? Turbo Encabulator?
There are calculators out there on the net, make a realistic estimate of HP and use one or more to figure out your GPH needs. Choose your pump based on the GPH need. I would use an EFI pump rather than one of the traditional "racing" fuel pumps.
I'd strongly suggest a rear-mounted electric pump by-passing system where excess fuel is returned to the tank by the Fuel Pressure Regulator. This regardless of induction type.
There are calculators out there on the net, make a realistic estimate of HP and use one or more to figure out your GPH needs. Choose your pump based on the GPH need. I would use an EFI pump rather than one of the traditional "racing" fuel pumps.
I'd strongly suggest a rear-mounted electric pump by-passing system where excess fuel is returned to the tank by the Fuel Pressure Regulator. This regardless of induction type.
Valiantap6
Member
Doing vortech supercharger so will be doing blow through carb, I have heard people using 2 fuel pumps is there any need for that?
67Dart273
Well-Known Member
Oh, NO not the dreaded Turbo Encabulator!!!!
[ame="http://www.youtube.com/watch?v=Ac7G7xOG2Ag"]"Turbo Encabulator" the Original - YouTube[/ame]
I've not gone down that path, but I can't imagine why two pumps would be needed. What you will need is a pump that can supply more pressure than Max Boost + the carb's max inlet pressure at the GPH required. An EFI pump will handle the psi requirement (assuming less than ~35 psi of boost) and I would expect that it could handle the GPH requirement but I don't know that for sure. You'll also need an FPR that you can boost reference. Can mod a Holley by-passing type regulator to do that, but unless they offer such a critter it will be a simple pair of mods rather than an RTR off the shelf solution. I am using a by-passing type Holley on an NA engine and so far I'm not impressed. Might be the pump, but it's inconsistent about fuel pressure. I'd look at other offerings, perhaps Aeromotive or SX?
inkjunkie
Well-Known Member
Have seen folks mention running two pumps...one pump is wired to a hobbs switch that triggers the pump at a preset boost level.
Pardon my French, but that seems like the "stuffing it's arse with bricks method of killing the cat."
Even with a carb the fuel curve is still influenced by the fuel pressure, it needs to raise linearly with the boost. I don't see a stepped delivery being a good plan.
Even with a carb the fuel curve is still influenced by the fuel pressure, it needs to raise linearly with the boost. I don't see a stepped delivery being a good plan.
stop the beast
Well-Known Member
You will be okay with a walbro 255 and a 1:1 fpr, mallory 4309 is great, anything like it will work 5/8 hard line with a return will be good for tons of hp, like 700 with this pump.
That's about it for a really good setup.
Valiantap6
Member
Should fuel line and return line be same size in diameter or different, all information has been very useful
Valiantap6
Member
Also I see edelbrock make high volume mechanical fuel pump 130gph and 10psi, would this work or probably not?
How much boost? The pump needs to deliver normal carb pressure + pressure equal to the boost + some extra for margin or Factor of Safety. If the boost is only going to be a couple psi, then a 10 psi pump might work. I'm guessing more like 10 psi worth of boost, so adding that to carb fuel pressure + some margin I think that you're looking at 20 psi minimum. Pishta's trick of referencing the mech pump diaphragm to boost will raise the fuel pressure with boost, but I prefer having the whole supply line under pressure for vapor lock considerations so I think in terms of EFI pumps mounted at or near the fuel tank.
A 3/8" supply line will feed 90%+ of streetable engine combos, boosted or not. I ran a 3/8 supply and used the existing 5/16 supply for the return.
A 3/8" supply line will feed 90%+ of streetable engine combos, boosted or not. I ran a 3/8 supply and used the existing 5/16 supply for the return.
Valiantap6
Member
Yes I think electric is only way I can go, I plan to run 8-10psi boost, does electric fuel pump need to be lower than the tank? And what regulator do I need to match it? What size holley blow through carb will suit and will it work ok? I just want to get it up and running and change things later on if need too so at moment cheaper is better but needs to work
Sweet5ltr
Well-Known Member
Run twin walbro 255 fuel pumps on anything above 600HP. Run them with an aeromotive boost referenced regulator. One fuel pump can be operated via Hobbs switch for 'x' amount of boost pressure to operate. 8-10AN forward, 10AN return line. You will have nothing but issues if you run anything less with multi pump, high pressure applications. You can't think of this in N/A sense anymore, with 6.5-7.5psi of pressure at the carb and where 3/8 line can support 500HP you will need at minimum 1/2"-5/8" forward and 5/8"-3/4" return. You can't leave it to chance with boost, starving your engine at full boost (leaning it out, detonation) and cracked pistons or rings because you cheaped out on some fuel line. Don't skimp on this, even if money is tight. Use quality fuel line, such as Russel or Aeroquip. You would want the pump lower than the tank to push fuel rather than pull. A good regulator will hold 40+psi (maintaining your 6-7psi base fuel pressure) while increasing pressure 1:1 with boost. Their is no reason to cobble something together with boost, as you have very little room for error. You will also need a good wideband for tuning, AEM Eugo is a nice one, also LM-1/2 from innovate.
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