I have an 87 turboII, & I have a spare OEM fuel pump. I was wondering if I can put the spare pump in series with the stock located pump, but with the "extra pump" being located outside the tank? Would it get too hot, would it provide more fuel under heavy load? I would bridge the wiring with the stock pump.
Thanks, Stew

 

Not a good idea. The failure of either pump would still shut the car down.
A better idea would be in parallel, with a checkvalve on each pump output to prevent backflow through the weaker pump.

 

Two pumps in series would put out more pressure. Not more volumn.

Rob

 

Parallel is the way to go. You'll get twice the flow. Series will just increase pressure.

 

There is a very popular way to run 2 pumps in series, but 2 stock pumps would have very little benifit in this case.

A low pressure intank pump supplying an external reservoir and high pressure pump.

Stock or upgraded intank pump supplies fuel to a "swirl pot", since this in not a pressurized system it supplies max volume of flow. Then a 2nd external pump draws from the "swirl pot"; this 2nd pump is a high pressure/flow aftermarket unit (turbo Porsche Bosch's are popular) and supplies the fuel under pressure to the fuel rail. The fuel rail return flow also flows to the "swirl pot" before overflowing to the stock tank.

Some advantages are, the swirl pot serves as a reservoir so there is no starvation in high G situations w/ out having to "sump" the fuel tank. The aftermarket high flow pressure/flow pump is external so you do not have to monkey w/ getting it to fit/work in the tank. It can supply A LOT of fuel at reasonable cost. It is JDM circuit sytle, baby!

 

Your technical info is spot-on, but there's nothing "JDM" about it. This set-up is used on circuit cars, rally cars and street cars in every corner of the world.

 

Yeah, I am making fun of myself there w/ that last comment NZconv.

I find the "ricer" in me drawn toward copying the Horizontal mount ICs, complex fuel systems etc. that are popular on Japanese circuit tuner cars.

I will be doing this fuel system soon and have found the Australian/NZ sites to have some great info, pics and even parts available for this type of thing- plus, I can read those sites much more easily.

Yo, I shift mad quick- JDM circuit style, baby!

 

Seems in Aussie your 13BT RX-3 ain't the real deal without a polished surge tank in the boot.

 

Thanks for the input folks,probably simpler to just put in a hi flow pump.
Stew

 

Some older Volvos (740) used two pumps in series, stock. (But they were designed to work that way.)