Fuel tank mod

[GrandRoyaL]

for the vw part : # 533 201511a
http://www.rmeuropean.com/Part-Numbe...N_A58C52C.aspx

i just bought a 63l tank, but it will take a while until i can try to solve this... i will try the 2 pumps method... if it fails i will try the cilinder surge tank and back to low pressure internal , high pressure external fuel pump

[IronFreak]

It'll be on it's way in about 1.5hrs!

[ffej]

Chiming in and bringing this back to life. Last weekend I got my first real test of this fix at the BMW CCA Club Race at MSR Cresson. My review?

Wonderful.

I ran the car down below 3 gallons without any issues whatsoever in the one fast, long-ish left hand turn the track offers up in that direction. Highly recommended. Thanks Jim!!!!

[GrandRoyaL]

Does anyone know the part number for the 318is pump ?
does anyone have the specs of flow for this pump ? How much can it handle ?

my engine is an s14 with 2.5 crank, motec , s38b38 head valves , flow job ... expected about 250hp or more in the future with cams etc...

[petrolhead]

OK, I read this topic through and noticed people are saying that a good solution is hard to find..

I fabricated a 1,7 litre narrow and high collector tank. Fuel pump in the tank feeds it, plus fuel return from engine fills it. It has overflow/return at the top, and from bottom pipe goes a fuel line to high pressure pump. I haven't tested it yet, can't see a reason why it shouldn't work. Thoughts?

[GrandRoyaL]

and where did you mount it ? trunk ? it is best to be in a safe location in case of crash...

[petrolhead]

and where did you mount it ? trunk ? it is best to be in a safe location in case of crash...

I'll cut a hole in the trunk floor and make a "box" for it. So it'll be above trunk floor but essentially outside chassis, all fuel lines also. So If it leaks, it'll leak outside. Difficult to explain in english :).

[mcr_driver]

If it's hard to explain in english then let pics do the talking :)

[petrolhead]

If it's hard to explain in english then let pics do the talking :)

Like THIS. Collector overflow goes to that small pipe in the filling up-tube.

[roguetoaster]

Meant to post this ages ago, after the swap we have been experiencing some ugly sounds from our low pressure pump. It was a new pump two Chump races ago and it sounds like intermittent air in the pump inlet to me. We have not tried swapping another pump in yet, but we have triple checked all connections and hoses.

Anyone else having any odd noises from the low side pump?

[Leebo]

Hi - I’ve read about this mod in several places and finally found the original thread. I’m looking to do this mod and want to make sure I’m plumbing and wiring this correctly (I have an ‘88 with the 63L tank originally and this is a dedicated track car.)

From what I’ve found, I want to put a low pressure pump on the left side and from Realoem, that looks like part number 16141179415 or 16141179414. For the high pressure pump, I want part number 16141181075 or 16141180233. I already have an in-pump fuel level sender from an older car.

To plumb this, I run a 12mm hose from the low pressure pump with a step-down to 8mm hose to the return side of the high-pressure pump on the right side, and then run the high-pressure pump outlet normally. Also, the low-pressure pump I got has a return fitting that I was just going to cap.

To wire the low pressure pump, I was going to run a new wire back to the engine bay, but was wondering if it’s ok to just spice it into the wiring for the high pressure pump (would certainly be easier). If I do the long route and run it back to the engine bay, what should I feed it off of?

To wire the fuel level sender on the left/driver’s side I picked up a wiring connector for the in-pump sender but it has 3 wires and the existing sender has two. Guessing for the 3-wire connector, the brown goes to ground and the two brown/green wires from the 3-wire connector are spliced to the brown/green and brown/white from the existing wiring.

Does this sound right? THX!

[redneckvtek]

The low pressure to high pressure solution works, but its complicated and costly - IE sourcing a 318is pump for the two inlets or using the 325E 55l tank pump and 14 adapters to get the sizes back right.

Its (in my opinion, anyway), much simpler and more robust to just install two high pressure pumps.

Just buy another 88L high pressure pump (just like the one that goes on the passenger side). Put that in the hole on the driver side.

buy a 5/16" tee. Cut the fuel line near the passenger side pump. insert tee. Clamp it up.


The fuel pumps all have a factory installed anti-drainback valve in the outlet of the pump itself. Not on the metal hanger, but actually IN the pump.

The little plastic white connector between the pump and the hanger is a failure point also. I've had two give me issues. Standard procedure is to replace with submersible fuel line at this point. Gates 27093. Yes, its $20/foot. Thats enough for 2-3 cars with 2 pumps per car.


I've won a few enduro's with E30's with this setup.
For extra fuel range, there is a Holley Hydramat which will attach to the OE pumps and fit into the stock tank.



Leebo to directly answer your questions though.

To wire the 2nd pump, its better to go back to the engine bay. Then you wont be putting twice the expected amps through the stock wire. There is a nice Aux fuse box on the side of the normal fuse box with two populated slots (and 2 empty ones). One of the populated ones is "key on" and one is "always on". That should get you what you need.


The 3 wires include the wire for the "low fuel level: light.



On the driver side one you are adding, you will attach the two car wires (both BR/GN) to the pigtail Br/GN and BR wires. The BR/GY wont be used.

[Leebo]

Thanks, REALLY helpful!

If I understand this correctly, the thought process for running 2 of the high pressure pumps (in addition to being cheaper/simpler) is that when one starves for fuel, the other delivers fuel and slams shut the check valve on the starving pump?

So all you need is for one pump to have fuel? And by the sound of it, running both does not wear them out faster?

I’ve already got the low and high pressure pumps, but am thinking I go this route. THX!

[redneckvtek]

Thanks, REALLY helpful!

If I understand this correctly, the thought process for running 2 of the high pressure pumps (in addition to being cheaper/simpler) is that when one starves for fuel, the other delivers fuel and slams shut the check valve on the starving pump?

So all you need is for one pump to have fuel? And by the sound of it, running both does not wear them out faster?

I’ve already got the low and high pressure pumps, but am thinking I go this route. THX!

The driver side pump isn't needed at all until the car has been on track for about 90 minutes (assuming stock or mild power modded M20, M50, or M54).
After that, the fuel bowl on the passenger side (in conjunction with the venturi powered crossover, called the "sucking jet pump" in more modern terms) is not sufficient to keep fuel at the passenger side pump.

What we do is turn the driver side pump on about half way through a fuel run.
Running both the whole time hurts nothing. this happens occasionally when the driver forgets to turn the 2nd pump back off after a pit stop.

With two "high pressure pumps" already in the car, failure of either pump results in a shorter fuel window (about 90 minutes).
With one lift pump and one high pressure pump, failure of the lift pump is a shorter window (again, 90 minutes). Failure of the HP pump is a ride on the roll back.

[Erik]

Such great information! Legend!