E36 In-Tank fuel pump setup

[GT110]

So I am finally going to use the instructions found here: http://www.evosport.com/tech/e36_twin_fuel_pumps.pdf

And install a second pump, hence running a duel intank pump setup and dual return also. The reason why I am not going the Bosch Motorspor 044 way is that this would give me hell at the yearly inspection (MOT roadworthy test). With dual in-tank setup nobody will ever notice.

I currently have a single in-tank Walbro 255 and it seems to work fine, I have monitored the fuel pressure. Off course I have not monitored the flow, that is a bit more complicated but my Wideband does not show any leaning out.

So to the question: If I keep the single Walbro 255 on one side, and put a standard EURO M3 pump on the other side, and run them togeather, is there any possibility that this will alter the flow rate?

What I am looking for is solving possible starvation. I am confident that the single Walbro is keeping up.

[mcoupemindy]

So I am finally going to use the instructions found here: http://www.evosport.com/tech/e36_twin_fuel_pumps.pdf

And install a second pump, hence running a duel intank pump setup and dual return also. The reason why I am not going the Bosch Motorspor 044 way is that this would give me hell at the yearly inspection (MOT roadworthy test). With dual in-tank setup nobody will ever notice.

I currently have a single in-tank Walbro 255 and it seems to work fine, I have monitored the fuel pressure. Off course I have not monitored the flow, that is a bit more complicated but my Wideband does not show any leaning out.

So to the question: If I keep the single Walbro 255 on one side, and put a standard EURO M3 pump on the other side, and run them togeather, is there any possibility that this will alter the flow rate?

What I am looking for is solving possible starvation. I am confident that the single Walbro is keeping up.

Why not try a single bosch 040 intank first?

[GT110]

Why not try a single bosch 040 intank first?

This mainly has to do with potential starvation in high-G bends, not that I need more flow in general. So the trick is to flow from both sides of the tank.

[dcvee]

This mainly has to do with potential starvation in high-G bends, not that I need more flow in general. So the trick is to flow from both sides of the tank.

The better trick is to return to the drivers side pod and pump from there to the pass pod where your walbro is feeding your fuel rail. Put the pump outlet from the drivers pod directly into the pass side sump tray of the walbro. I did this to a 95M3 turbo track car 3 years ago and I can run down to the light is on!!

There's some plumbing drawings somewhere if you search on the track section.

Don

[GT110]

The better trick is to return to the drivers side pod and pump from there to the pass pod where your walbro is feeding your fuel rail. Put the pump outlet from the drivers pod directly into the pass side sump tray of the walbro. I did this to a 95M3 turbo track car 3 years ago and I can run down to the light is on!!

There's some plumbing drawings somewhere if you search on the track section.

Don

So in fact you are turning the passenger side into a giant swirl tank . I guess the gravity controlled way beetween the two tanks takes care of the problem of overfilling the passenger side.

This actually sounds much better, and much simpler to install. No T-pieces needed, I can utilise the original return hose and the only effective change is a more powerfull pump on the drivers side.

Thanks.

[herrubermensch]

The better trick is to return to the drivers side pod and pump from there to the pass pod where your walbro is feeding your fuel rail. Put the pump outlet from the drivers pod directly into the pass side sump tray of the walbro. I did this to a 95M3 turbo track car 3 years ago and I can run down to the light is on!!

There's some plumbing drawings somewhere if you search on the track section.

Don

This is precisely what I am doing on my E39 M5 and what my shop does on their E36 racecars. They have found it is the best solution for avoiding fuel starvation during hard cornering while retaining the stock fuel tank.

--Peter

[boosted 528]

Call me silly, but I thought this was the only way to hook it up (Driver feed to pass).
I thought the drivers side was the return from the rail, then the pump from the
drivers side pumps in the pass side, which that drivers pump then feeds the rail.

My understanding of the drivers side pump is that it doesn't run continuously like the pass pump. Its only activated to level out the fuel in the tank.

So now this draws the question of :
1)Why would one replace the driver side pump with a bosch or walbro
2)what are our options in ways of hooking the bmw fuel pumps/systems

[dcvee]

Call me silly, but I thought this was the only way to hook it up (Driver feed to pass).
I thought the drivers side was the return from the rail, then the pump from the
drivers side pumps in the pass side, which that drivers pump then feeds the rail.

My understanding of the drivers side pump is that it doesn't run continuously like the pass pump. Its only activated to level out the fuel in the tank.

So now this draws the question of :
1)Why would one replace the driver side pump with a bosch or walbro
2)what are our options in ways of hooking the bmw fuel pumps/systems

No, the drivers side pump runs when the pass side pump runs. The theory is simple, the pass pump returns to the drivers side. The drivers pump pumps to the pass side. Hence, you get an almost "level" situation automatically. It DOES run a little heavier in the pass side on my setup anyway...which is good since it balances out the weight of the driver.

Works great...I use the stock pump in the drivers side and a walbro in the pass. There's pictures of my setup in my build thread....I think.

Don

[GT110]

I was looking for the pictures, could not find them .. (for now at least)

[boosted 528]

No, the drivers side pump runs when the pass side pump runs. The theory is simple, the pass pump returns to the drivers side. The drivers pump pumps to the pass side. Hence, you get an almost "level" situation automatically. It DOES run a little heavier in the pass side on my setup anyway...which is good since it balances out the weight of the driver.

Works great...I use the stock pump in the drivers side and a walbro in the pass. There's pictures of my setup in my build thread....I think.

Don

Thanks for clearing that up don.
Now why would someone want to replace both oem driver and pass pump
with a walbro/bosch. That wouldn't make sense ,would it?

[dcvee]

Thanks for clearing that up don.
Now why would someone want to replace both oem driver and pass pump
with a walbro/bosch. That wouldn't make sense ,would it?

Replacing both with a walbro would not make sense. Putting 2 walbro's in the pass side tank and leaving the return loop as BMW designed would make sense(good for street/drag racing)....except in road racing. Putting a walbro in the pass and relocating the stock to the drivers tank would make sense for road racing.

Don

I was looking for the pictures, could not find them .. (for now at least)

Hmmm....I'll have to take a look too. I ran a fuel rated hose(3/8" me thinks) from the drivers side pump "out"(I used my old stock pump)under the sheet metal that is the bottom of the seat area and then into the extra plastic fitting on the stock holder(drill it out). I then used a piece of aluminum tubing that I pressed into the holder that directs the returning fuel(from the drivers pump)directly into the pass sump tray. I removed the gravity/siphon stock system from inside the tank and just allowed the return from the fuel rail to dump into the drivers tank.

UPDATE...sorry I DON'T have pics...I did this AFTER I kept suffering from fuel starvation on the track. Never took any shots.

Don

http://www.pumpkininc.com/content/doc/guide/ag-8.pdf

Here, these guys do it similar to the way I did it. Except the "T"'s that return to both sides and pump from both sides. Look up the "bimmerworld" starvation kit and essentially it's what I did...except for the part where I ran a separate line from the drivers tank that puts the returned/pumped fuel directly into the sump tray on the passenger side.

Don

[rt turbo]

Replacing both with a walbro would not make sense. Putting 2 walbro's in the pass side tank and leaving the return loop as BMW designed would make sense(good for street/drag racing)....except in road racing. Putting a walbro in the pass and relocating the stock to the drivers tank would make sense for road racing.

Don, I think he is thinking the car comes from the factory with a drivers side pump. This is not correct right? it is gravity fed from factory correct?

Also, wasn't there someone who setup a dual intake on drivers side who used ventury effect of returning flow to pull gas from drivers to pass tank?

[GT110]

my car did not come with pumps on both sides, but I have upgraded to that system (the one from the S50B32 (or the EURO EVO)).

What about the fuel level? If you pump to the pass side non stop with the OEM pass side pump in the right side does that not screw up the level sensor?

[boosted 528]

Don, I think he is thinking the car comes from the factory with a drivers side pump. This is not correct right? it is gravity fed from factory correct?

Also, wasn't there someone who setup a dual intake on drivers side who used ventury effect of returning flow to pull gas from drivers to pass tank?

Yes you are correct! That was my exact thought.I thought there was 2 pumps in our cars (1 on each side) I guess i'll have to just crack it open, take a look, and get a better understanding.

[dcvee]

Min did car did not come with pumps on both sides, but I have upgraded to that system (the one from the S50B32 (or the EURO EVO)).

What about the fuel level? If you pump to the pass side non stop with the OEM pass side pump in the right side does that not screw up the level sensor?

No it doesn't screw up the reading. Due to the open part of the tank in the center it free flows from right to left and evens out. Mine works perfectly. Check out the track forum for more information on this too.

Yes you are correct! That was my exact thought.I thought there was 2 pumps in our cars (1 on each side) I guess i'll have to just crack it open, take a look, and get a better understanding.

Nope, just one. On the pass side. There is an internal siphon device that pulls fuel from drivers side tank and keeps the fuel relatively level. The stock fuel rail returns to the drivers side tank.

Don, I think he is thinking the car comes from the factory with a drivers side pump. This is not correct right? it is gravity fed from factory correct?

Also, wasn't there someone who setup a dual intake on drivers side who used ventury effect of returning flow to pull gas from drivers to pass tank?

Exactly. Didn't catch that. The stock system uses venturi effect to provide the siphon that levels the tank. And yes, many have used dual fuel pumps in the pass side..which works great for drag cars. Not so well for road racing however.

Don

[herrubermensch]

Nope, just one. On the pass side. There is an internal siphon device that pulls fuel from drivers side tank and keeps the fuel relatively level. The stock fuel rail returns to the drivers side tank.

This is the way the E39 M5 is setup as well. The modification consists principally in replacing the siphon mechanism with a pump.

--Peter

[boosted 528]

Thanks guys for clearing it all up for me!

[MrBlonde]

You've done a twin turbo conversion but the MOT will worry about an inline fuel pump?

[GT110]

You've done a twin turbo conversion but the MOT will worry about an inline fuel pump?

Yes, I have not found a company that makes TUV (TUeV) or ABE approved fuel systems, but in order to be street legal here (and in Germany) I need those documents.

I have TUV/ABE documents for all the things in my car (except the exhaust, which I revert to stock once a year), the rest is covered, the suspention, cage, seats, belts, steering wheel....

Regarding the engine conversion and also the Ceramic brakes I have had that specially TUeV'd in the same order as the big tuners do (Hamann, Hartge, G-Power, ESS.....) and I had to pay a fat bill for that. I actually could start manufacturing a kit now