twin fuel pump conversion

[trackm3]

Details of the E36 M3 mod we used

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

[daniel]

I run this on my E36 which had issues from half a tank, now it runs pretty much to empty. Installed by Uncle Benz off here. Worth a PM maybe.

[DuncanR]

Originally Posted by adem.csl

then there is a wieght difference making left side heavier.so really best option is to sit the pump in a bowl that stays full at all times.

Would imagine no problem with weight as right side of car has a fook off big battery in it ! .. reminder to self, fit new battery to CSL !

[Neil M]

Originally Posted by Mike R

I'm sure in my trawling through the site, I saw a post by "The Gorilla" about a cheap way of improving the starvation issue by fitting an extension T-pipe, but I can't find it. Might be worth dropping him a PM?

Could it be this you were thinking of Mike?:

"I have found this thread fascinating.
To address any problem you need to understand
the cause.

The standard E46 petrol Tank pick up operates
from one side of the tank. ie] the fuel pump
is having to 'suck' the fuel as opposed to 'push'
it from one side only.

Thus when the pipe that the fuel is sucked up
to the fuel pump is not below the fuel
level, then air enters the fuel pump, fuel
pressure drops and the spluttering on
heavy cornering on 1/4 tank can and does
occur.

As the standard fuel pump is rated for 5 bar then
its only issue is fuel supply and what it pick
up is, ie] whatever the distance away from
the pump it still sucks up fuel.

So, if you had a short length of rubber fuel hose
fitted to the bottom of the existing fuel pick
up, then a 'T' fitting, and then another length of
fuel hose to the other side of the tank, which would
be no more than about 1.0 mtr in length, you would
ensure that the fuel pump was always able to suck
up fuel, which is the cause of the problem.

Although this is all internal to the tank, access via
the existing pump set up would be quite easy, and
you have to remove this to fit the CA solution
anyway.

The CA fix just creates another part that can go
wrong, adds more weight !!!!!! and the same
results can be achieved a lot simpler and a whole
lot cheaper.

Regards,
The Gorilla"

Hats off to the man in the furry suite

[Mike R]

Hi Neil,
Yes, that was the one .

Where was it LOL?

[shimmy]

Originally Posted by shimmy

I thought thee was a simple 'twin pick up' to the single pump upgrade option!

Ahem!

[Neil M]

Originally Posted by Mike R

Hi Neil,
Yes, that was the one .

Where was it LOL?

Lurking in the annals: a thread to a link and so on, add infinitum

[adem.csl]

Originally Posted by mattCSLnut

They do... mine use to cause fuel starvation around Brands Hatch coming through Clearways, a 180 degree off camber right hander, before the pit straight, with over 1/4 tank of fuel
A replacement fuel pump from BMW sorted this issue and it's been fine ever since

Liking matts route.but I'm gonna stick a walbro 255lph pump in mine Just to be safe.I've had previous with bmw pumps giving up on me.thanx guys For all input.
Knowledge is power.!!!!!!

[cantfind1]

Originally Posted by Neil M

Could it be this you were thinking of Mike?:

"I have found this thread fascinating.
To address any problem you need to understand
the cause.

The standard E46 petrol Tank pick up operates
from one side of the tank. ie] the fuel pump
is having to 'suck' the fuel as opposed to 'push'
it from one side only.

Thus when the pipe that the fuel is sucked up
to the fuel pump is not below the fuel
level, then air enters the fuel pump, fuel
pressure drops and the spluttering on
heavy cornering on 1/4 tank can and does
occur.

As the standard fuel pump is rated for 5 bar then
its only issue is fuel supply and what it pick
up is, ie] whatever the distance away from
the pump it still sucks up fuel.

So, if you had a short length of rubber fuel hose
fitted to the bottom of the existing fuel pick
up, then a 'T' fitting, and then another length of
fuel hose to the other side of the tank, which would
be no more than about 1.0 mtr in length, you would
ensure that the fuel pump was always able to suck
up fuel, which is the cause of the problem.

Although this is all internal to the tank, access via
the existing pump set up would be quite easy, and
you have to remove this to fit the CA solution
anyway.

The CA fix just creates another part that can go
wrong, adds more weight !!!!!! and the same
results can be achieved a lot simpler and a whole
lot cheaper.

Regards,
The Gorilla"

Hats off to the man in the furry suite

Yep this is what I have done, I ditched the twin pump mod I had.....this way is much simpler, easy to fit and solves all fuelling issues....also doesn't effect the guage readings like the twin pump mod did. I have also fitted a Walbro pump however I found the car to run rich with the uprated pump which led to a power loss. I had to adjust the fuel trims in the ecu map to solve the rich running....

[adem.csl]

The Gorilla.Yes well put, however the fundamental floor in your plan is that the crap oem pump is not strong enough to suck fuel through lengths of hose around the tank hence why you install a second pump in place of the sender unit on the left hand side to push fuel to the right hand pump.


Hardly any extra weight as you are replacing the other unit with the same thing any way, it just has a pump in it which weighs grams!


The oem pump degrades over time and does not produce enough flow anyway, hence why i am going with the walbro conversion for piece of mind.


If you want to be tight the just do the walbro conversion and let it suck fuel through pipes from the left and right side of the tank.
Are you being serious?contradicts your posts.cantfind1