How does a surge tank work?. If you have a in tank pump and that39s pumping 500 horse power and you run a external 1000hp how do

snowballs4, May 30, 6:39am
If you have a in tank pump, and that's pumping 500 horse power, and you run a external 1000hp, how does this work!

40wav, May 30, 6:49am
I think you might need to explain that one a bit further.

grangies, May 30, 6:51am
Buggered if I know. Lol.

guider1, May 30, 7:13am
A surge tank is mounted (usually) in the boot compartment. You can feed the surge tank with a conventional fuel pump such as a Holley blue for example. From the surge tank you run an external EFI pump such as a Bosch/Paxton/Aeromotive etc which will supply the fuel to your regulator then to the fuel rails.
If you have a 500 Walbro (I assume) intank pump then you dont need a 1000hp external pump; if you require a 1000hp external then the 500hp intank wont keep up anyway.
The ones i've seen in big HP cars all run a larger "carburetted" fuel pump to feed the surge tank, such as a big Mallory, Magnafuel or Barry Grant.
Obviously you need a pump large enough to cope with your engines horsepower needs but normally you run a larger pump to keep the surge tank full. Just remember that once that surge tank is empty you have lean-out & potential disaster if you're running a boosted engine.
The one i'll be using for my EFI setup is belt driven, but only because I would need to run 2 big Weldon electric pumps which draw 44 amps each; that's a huge drain on battery power when you also need an uninterrupted power supply for the ECU & ignition, so i've opted for a big Waterman belt driven pump which can supply 415 litres per minute at 600psi if needed.

bae13, May 30, 7:44am
ha ha ha pumping 500hp. sounds like those v8 people that go and buy 400hp cams. thats funny

snowballs4, May 30, 8:00am

snowballs4, May 30, 8:04am
I like the sounds of than wow that must cost a bit to run

guider1, May 30, 9:38am
So long as your engine isnt going to require more than the smaller pump can supply you'll be fine. Just remember that the smaller pump is your limiting factor, regardless if the supply pump is good for 1000hp the other one can only supply enough for 500hp.

guider1, May 30, 9:40am
It's not finished yet snowballs. but yep, it's going to drink fuel like an alcoholic in a brewery!
I'll never run it over 65psi, but it's nice to know there is ample fuel supply.

guider1, May 30, 9:48am
In other words; if your chasing 1000hp then the smallest pump (the one supplying the surge tank) needs to be able to supply enough fuel for 1000hp. That's why i'm saying "usually" the pump to the surge tank is rated higher than the one feeding the engine because you do not want that surge tank to ever empty while under power.

snowballs4, May 30, 9:54am
so why go to all the hassle! installing a surge tank and another pump for!

snowballs4, May 30, 9:59am
and 65 psi of fuel pressure far out,. i thought 45 was heeps,you got any suggestions! im runing a rb30det 1000cc injectors forged pistons confrods, holset 55x turbo"rated to 1200 hp" 46mm wastegate, i have got another 5650intank pump, but i want to go even better, seen alot of cars on here twith surge tanks etc, i thought it was the way to go , but i just couldn't work it out why they have a 500 in tank pump and a 700bosh external

guider1, May 30, 10:02am
The reason being is (example) if you're doing donuts with, say, a small amount of fuel in the tank & the fuel line pickup in the tank gets a suck of air because the fuel has surged away from the pickup & you're under boost. ka-bang; you've got detination & possible meltdown.

snowballs4, May 30, 10:07am
ok cheers mate, you have been a huge help

guider1, May 30, 10:12am
Personally, I would ditch what you have. Mate is building a VL with turbo'd LS1; he has fitted an 80L RCI fuel cell, has a Magnafuel ProStar 500 pump drawing from the tank feeding a 4 litre surge tank then an Aeromotive Eliminator pump drawing from the surge tank feeding the engine. It's pretty overkill for now, but he intends on doing quite a bit of work to his engine later on & doesnt want to have to uprate his fuel system again.
Always consider how many amps the pumps will draw when looking at pumps too.

clark20, May 30, 11:32am
It works because you are not running 1000hp (LOL) all the time, the 1000 hp one does the peaks to feed the engine, however the 500 hp onlyhas to average it out ie its still pumping when you are braking and cornering, you are not going to use (eg) 4L of the surge tank in one straight too easily.

guider1, May 30, 11:36am
You will if the lift pump cant keep up with the engines required supply. The idea is to keep that surge tank full at all times.

clark20, May 30, 11:49am
No, the idea is to have enough capacity to cope, it does not need to be fill, just enough never to run out.

snowballs4, May 31, 7:18am
ok cool, will this carburetored pump, would as a EFI pump

guider1, May 31, 8:43am
A carburetted pump cant supply adequate pressure for EFI, but it's ok to use to keep a surge tank supplied with fuel PROVIDED you arent using more than it can supply.
That Aeromotive is a bargain provided it's in good condition.
I have a VN Commodore in my shed that's getting fitted with the hell 308 for circuit racing & even though that's carburetted it's still running a surge tank.

snowballs4, May 31, 8:46am
ok cheers so you think something like this would do the job!

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