Hi, Would like to get some peoples idea on setting up my fuel system. I have 2 x MSD 500 hp fuel pumps surge tank! My thinking was to use the standard fuel pump to fill the surge tank and then use the 2 x msd pumps to pressure the system? is the ok Second thing was i don't believe that i need 2 have both fuel pumps running when on low boost (which will be standard ) high boost will be between 15-18psi so i was wondering if i should hook a relay to the boost switch that ingauges the second pump when i go to high boost ? any peoples thoughts thanks!

Lars, how much power are you aiming for? Basically 500hp pump is a lot of power on pump fuel, so if your not aiming for much more 1 pump will be sufficient. If you want to run both pumps, i would be inclined to run both pumps at once simultaneously using relays to power them. You 'may' be better using a carter or holley low pressure hi volume lift pump to prime the surge tank as it could keep up with fuel demand. If your making a big power output the standard pump and lift pump will run out of puff if your on full throttle for a long period of time, eventually drinking all the surge tank fuel dropping of fuel flow up high and 'boom'. Cheers.

I'm aiming for around 350hp at the wheels on high boost Would running both fuel pumps at low rpm make it run rich? And the High pressure standard vl pump won't keep up with the 2 x 500hp pumps I have troyvk's old surge tank, it's about 1litre 2 1.5 litres looking at buy the size Areovl Probably what i need to know with my current set up and what i have right now what the best option would be! I have a standard vl na high pressure, vlt high pressure (maybe the same as na ?) 2 x msd pumps current engine set up, Hypertechnic Pistons, 20thou Head fully rebuilt and crack tested T3/T4 hybrid/hyflow rated at 375 HP GTR Injectors Crow Cam valve springs Crow Cam 3" exhaust from turbo to tip. microtech mt8 All parts like water pump, timing belt and idler replaced at time of rebuild.

Ok, 350hp @ wheels you should be able to get by with just 1 pump if they are rated at 500hp. Running both pumps at low rpm won't make it run rich, that's what the fuel reg is for at base fuel pressure any unused fuel goes back to the surge tank, however i assume you have a aftermarket ecu, so it should be tuned to run spot on anyway. You could get away with running the standard vlt pump as the lift pump for a while as long as it's not held wide open for ages. The std pump can't support 350rwhp so how is it supposed to keep the surge tank primed if your burning it at a higher rate than supply, you will eventually run out of fuel? You must match your lift pump to your engine fuel requirements. litres per hour flow. I have not seen or used MSD fuel pumps before, only bosch products. Doesn't sound like the turbo will cope with your target of 350rwhp. Prob not efficient enough. Cheers.

okies, yeah that's what i was thinking about the turbo!, but like i said that's what i would like to get for the moment! have to wait till next week to see what it's capable of ! supposedly and from people talking they are efficent to 375 but have been pushed a bit more, What would i need the turbo to be capable of to flow to get 350hp and the wheels?

also, how do i match my lift pump to my engine's litres per hour? can u give a little more info on that if possible!

Lars, as for turbo, suck it and see i guess. you may get the results you want from it, as it may be a conservitave rating. With better fuels etc you can push the turbo harder and make the power your after but a ore efficient turbo would be better, so you not pushing it to the limit to make the power. ie anywhere from 450-600hp turbo would be great for that power output. It's up to you. As for matching fuel pumps to a motor, all i meant was for example if fuel pump 1 supply's the surge tank 1.5 litres per hour and pump 2 pumps at 3 litres per hour, guess what happens at WOT when you motor is drinking all the fuel pump 2 can supply? Make sense? You will run out of fuel in the surge tank pretty quick and run lean. 500hp pump should be sufficient, just make sure you have a lift pump that can keep up with the flow rate required. That's just my opinion anyway. Cheers.

thanks you heaps! I understand if u have one pump not able to flow as much as the others, just miss understood! and thanks for the info about the turbo! understand less boost but same power is better! just quickly should i use one of the msd fuel pumps to purge the surge tank then but then i would i need to change my internal fuel pump to match the external one?

No worries, i would be inclined to use an actual 'lift' pump like carter or holley low pressure high volume pump, because chances are the msd pump is not designed to suck fuel and will most likely get very hot and possibly burn out if starved. Most of the efi pumps like to be fed the fuel. So you 'should' remove or upgrade your intank pump to suck the fuel out of the tank to fill the surge tank. The in tank pump would prob only be rated at a similar amount to the std vlt pump. Cheers.

Just hook it all up and get it dyno tuned, the dyno operator will soon tell you if your lacking in fuel supply. Cheers.

a bigger surge tank may be the answer.i had 335rwhp with a 3l surge tank standard lift pump(new) bosch 044. i never had any problems with fuel supply.the 3l surge tank would take a long time to run dry.

Duz360 is right, you will prob be right with the standard lift for up to 330-350rwhp. I had dramas after 380rwhp+ with flow dropping off. the lift pump i used was still good when i was making 450rwhp. I only used a smallish surge tank as it was just for the strip, running 20litres or so in the tank without problems at top end...

one thing to bear in mind is that the less pressure you have across a pump, the more fuel it will flow. this is why you need to look at how the manufacturer rated the pumps, and at what PSI head pressure. so there is every chance that the standard pump MAY keep up in a lower pressure situation. but chance nothing, make sure and if in doubt, dont run it.