Fuel tank mod

[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!

[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?

[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.

[mcr_driver]

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

[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 :).

[GrandRoyaL]

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

[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]

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...

[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!!!!

[IronFreak]

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

[GrandRoyaL]

for the vw part : # 533 201511a

http://www.rmeuropean.com/Part-Number/Fuel-Filter-for-Fuel-Expansion-Tank-__533201511A_GEN_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

[TobyB]

Hey, Jim,
nice trick- thanks, all for bumping it back up ttt.
Timely, too, as I've got both early and late tanks, and all the pumps from both,
but haven't started putting one back together in the car.

And yes, if you get some tubing, you can compress fuel cell foam and then feed it into
the tank to foam it. Perhaps not a perfect solution, but it might help with fuel movement
and certainly with explosion.

t

[einstein57]

Nice mod. Didnt the e21's and some vw have some sort of fuel "capacitor" thing? I swear I've seen something like that to battle our starvation issues.

Yes the early model vw golfs and jettas that used a dual pump setup similar to the e30 used a fuel accumulator. They cost a shit ton so don't run out to your local vw dealer to get one. IIRC ireland sells a cheaper accumulator for under $100. Its rumored to be a cheaper audi accumulator but no one ever post a picture or part number. I plan on purchasing one when I get my car back together.

[jlevie]

Did it fix your starvation? Seems everyone I've talked to that's tried to fix it has only made it worse, us included.

There are two ways to prevent fuel starvation. A surge tank fed by a transfer pump and that tank feeding a high pressure pump is one solution. The other solution is to a pump move fuel from the left side of the tank to a high pressure pump in the right side.

Well, I guess there is a third solution. That being installation of a fuel cell.

[priapism]

Did it fix your starvation? Seems everyone I've talked to that's tried to fix it has only made it worse, us included.