twin fuel pump conversion

[adem.csl]

I was looking at a thread regarding fuel starvation on track.no body had a conclusion as to what the solution was in the end?if anyone has done this conversion I'm interested in doin the same.just wondered how it plums in.do fuel pump electric wires run onto the existing pump wires and does the fuel line t into the fuel feed line or into the tank.thanx

[alexk]

search ?

[adem.csl]

Have done.couldn't find anything.thanx

[azrael]

cantfind1 looked into this quite comprehensively

[adem.csl]

There was no conclusion to it.I don't think twin pump would work anyway.a swirl pot system is whats needed or a fuel cell.both more expensive than simply filling the tank and not dropping past half way.

[shimmy]

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

[adem.csl]

just a simple pic but makes sense.lol

[adem.csl]

so basically the pic is of a tank wid 2 pumps sitting in fuel.now second pic is of what would happen as you hit a hard right corner on low tank.both pumps would starve as they both have same amount of fuel.UNLESS the left side stays full and only works when cornering?????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.

[daniel]

http://gticlub.net/forumpics/forsale/pumpkin/pumpkin.pdf

[adem.csl]

http://gticlub.net/forumpics/forsale/pumpkin/pumpkin.pdf

excellent find thank you.confirms my suspisions on fitting.still jury out as to whether it works.love the idea though.
thanx again

[trackm3]

We ran this same setup on 3 E36 M3 race cars all fitted with around 1200lb springs with no surge at all ;)

[adem.csl]

im guessing the lower the car the less the roll???

[shimmy]

im guessing the lower the car the less the roll???

The harder you drive.........

[northernjim]

The harder you drive.........

:supz: the higher the G forces, the more the fuel sloshes about.....





Adam did you read the part where it says not all cars suffer from this?


I think the answer is that not all fuel pick ups sit in the same place in the tank....

[shimmy]

:supz: the higher the G forces, the more the fuel sloshes about.....





Adam did you read the part where it says not all cars suffer from this?


I think the answer is that not all fuel pick ups sit in the same place in the tank....

Mine def was there in 2006 but has got marginally worse over time, now stutters on 3 RH corners just above qtr tank, whereas used to be well below qtr tank it would start.

[northernjim]

Mine def was there in 2006 but has got marginally worse over time, now stutters on 3 RH corners just above qtr tank, whereas used to be well below qtr tank it would start.

Fuel pump getting weaker over time too?



I am not a technical man.... But is it possible to look inside the tank to see how everything is sitting?

[adem.csl]

:supz: the higher the G forces, the more the fuel sloshes about.....





Adam did you read the part where it says not all cars suffer from this?


I think the answer is that not all fuel pick ups sit in the same place in the tank....
they say prevention is better than cure!!!!!
imagine you get out there hit a hard corner and bang spluttering.wish i had done that conversion now.im only exploring the idea.bmw have already checked my tank as ive had fueling problems before.(down to exhast)
but your right to open the tank and check its all good costs nothing.thanx nice input:thumbs:

[mattCSLnut]

Fuel pump getting weaker over time too?

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 :banghead:
A replacement fuel pump from BMW sorted this issue and it's been fine ever since :smokin:

[adem.csl]

[QUOTE=shimmy;140391]The harder you drive.........

love it shimmy.gonna try that!!!!:thumbs:


northernjim has a point.the previous owner has definately used this car on track.i may already have an uprated pump.
will pull it out over weekend

[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?

[trackm3]

Details of the E36 M3 mod we used

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

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 !:-D .. reminder to self, fit new battery to CSL !

[Neil M]

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 :thumbs:

[Mike R]

Hi Neil,
Yes, that was the one :).

Where was it LOL?

[shimmy]

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

Ahem!

[Neil M]

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:thumbs:

[adem.csl]

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 :banghead:
A replacement fuel pump from BMW sorted this issue and it's been fine ever since :smokin:

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]

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 :thumbs:

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

[adem.csl]

Cantfind1 honestly what did you do in the end?after all the discussion you followed the gorilla?

[shimmy]

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.
d1


So what would be the difference between a CSL with a new pump with full flow and a CSL with a tired pump with degrading flow.(I'm assuming you are on about flow and not pressure)?

Tbh that does sound like a quote from a whole load of US forums all rolled into one!

[northernjim]

The Gorilla.
Yes well put, however the fundamental flaw ( sorry had to correct that) 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 a kilogram!




you seem to be heading in your direction Adem no matter what......



a fuel pump will suck fuel thru a single length just as ( near as dammit) easily as a t piece....... have you flow tested a pump to see how much pressure and flow is affected?

[adem.csl]

That's not my post that was cantfind1 reply to gorilla post.the one that Neil m has added about making up the t pipe system.lol..sorry should have put it as a quote.read from Neil m post and it wil make sense.sorry im tryin to do this on a phone:whistle:

[adem.csl]

you seem to be heading in your direction Adem no matter what......



a fuel pump will suck fuel thru a single length just as ( near as dammmit) easily as a t piece....... have you flow tested a pump to see how much pressure and flow is affected?

Sorry I'm not disputing just gathering info before i open my tank.measure twice cut once kinda thing.lol

[adem.csl]

http://www.cslregister.com/forum/showthread.php?t=5440&highlight=Fuel+Starvation
This link is where I'm finding the info.all I'm asking is did twin pump work on csl and how did it plumb in.got the answers to both questions.I was just asking cantfind1 if he was bein honest about using a walbro pump and t piece after discussing wid gorilla that it was cheap route that wouldn't work.

[cantfind1]

Ah...yeah ok...little confused....To be honest I have only made this change over this winter...have not read that other thread for a while.

TBH now that I have changed the OEM pump for the walbro one and added an extra length of fuel hose to suck from the left hand side of the tank, it seems to have made no difference to flow or pressure. Dyno results confirm AFR is thet same as before the mod.

However I did not add the walbro and the extra suck from the left at the same time.

I originally fitted two pumps...replaced the sender on the pax side with an oem pump and the oem pump on drivers side with walbro, this led to drop in power due to increased flow and rich running hence the change in fuel trim in ecu map...this also buggered up fuel guage reading but i lived with it.

I eventually wasn't happy with this solution....

I then spoke to various people I know and discussed ditching the second pump and just running a second feed from left side to the walbro pump on the right....so far it works, fuel guage is back to normal and AFR seems to be unchanged...I have not tested on track yet....I only used to get fuel starvation at Spa(this was with OEM pump as well)....seemed to not happen on other tracks i have used...

However my walbro pump is fairly new so I will be keeping an eye on this mod to make sure the walbro is coping wih sucking fuel from the other side of the tank...so far so good as i can hear a lot of fuel returning to the tank when idling, not sure whats happening at high rpm though....

I would not suggest doing this mod with your old OEM pump as they are crap. At a later date I will be running a swirl pot....


So what's the question?? lol

[alexk]

Why do you say OEM pump is crap ?

[adem.csl]

Ah...yeah ok...little confused....To be honest I have only made this change over this winter...have not read that other thread for a while.

TBH now that I have changed the OEM pump for the walbro one and added an extra length of fuel hose to suck from the left hand side of the tank, it seems to have made no difference to flow or pressure. Dyno results confirm AFR is thet same as before the mod.

However I did not add the walbro and the extra suck from the left at the same time.

I originally fitted two pumps...replaced the sender on the pax side with an oem pump and the oem pump on drivers side with walbro, this led to drop in power due to increased flow and rich running hence the change in fuel trim in ecu map...this also buggered up fuel guage reading but i lived with it.

I eventually wasn't happy with this solution....

I then spoke to various people I know and discussed ditching the second pump and just running a second feed from left side to the walbro pump on the right....so far it works, fuel guage is back to normal and AFR seems to be unchanged...I have not tested on track yet....I only used to get fuel starvation at Spa(this was with OEM pump as well)....seemed to not happen on other tracks i have used...

However my walbro pump is fairly new so I will be keeping an eye on this mod to make sure the walbro is coping wih sucking fuel from the other side of the tank...so far so good as i can hear a lot of fuel returning to the tank when idling, not sure whats happening at high rpm though....

I would not suggest doing this mod with your old OEM pump as they are crap. At a later date I will be running a swirl pot....


So what's the question?? lol
Question answered thank you cantfind1.that's all I was after because the other thread left no conclusion.thanx again.

Which pump did you use?255lph or 450lph?thanx

[cantfind1]

Walbro 255, a little noisey but once you're running you can t hear it! You get a lot of flow with this pump way more than OEM, pressure obviously is the same due to regulator....

It seems more than able to handle the extra pipe to the left side of the tank.

However as I said you may find your car will run rich so best to get dyno run before and after to get a rough idea of AFR's

[Mike R]

Surely it would be better to find a pump that flows the same (or just fractionally better) as the OE item, to avoid having to remap the car?

Does anyone have the flow info of the stand pump or the make and part number of it?

[cantfind1]

There is one more option I have been considering trying.

That is to take the fuel return line from the left side of the tank and run it to the right side instead. Through the top of the pump.

So this means that any return fuel would be placed in the side with the pump if by any chance the right side started to fill up it would just flow across the bridge to the left side anyway.....

If anyone can see any downsides to this then let me know, but I have been thinking about this recently and may solve the problem of the right side of the tank running low while the left side still has more fuel in it.....

It would only involve a bit of fuel hose some connectors and a couple of clamps....and is also reversible if it doesn t work....

[Mike R]

There is one more option I have been considering trying.

That is to take the fuel return line from the left side of the tank and run it to the right side instead. Through the top of the pump.

So this means that any return fuel would be placed in the side with the pump if by any chance the right side started to fill up it would just flow across the bridge to the left side anyway.....

If anyone can see any downsides to this then let me know, but I have been thinking about this recently and may solve the problem of the right side of the tank running low while the left side still has more fuel in it.....

It would only involve a bit of fuel hose some connectors and a couple of clamps....and is also reversible if it doesn t work....


Sounds logical to me - the proof is in the pudding - keep us posted ;).

[shimmy]

You the are just FIDDLERS :)

[cantfind1]

Thats rich coming from you! :gayfight:

[Kev Ush]

Hi folks! Sorry for jumping in on your thread. I'm not really much of poster, I'm just more of a lurker in the backround (reading through all your tech threads and keeping an eye on your for sale section ;)) but this thread has caught my attention. I'm building an M3 trackcar and although I haven't tracked it yet (so I don't know if I'll be going quick enough to get fuel stavation issues) I'd like to do something that would help just incase.

I was having a think about all the options that people have listed and I'll apologise now if I'm stating the obvious. Feel free to correct me if I'm wrong.

Single Pump, Twin Pick up Option: Surely this would be no better if not worse than a single pump with a single pick up? I would imagine that as soon as one pick up starts sucking air the pump would loose prime completely and you'd be back to square one...This would be an issue on both left and right hand turns now.

Twin Pump, Twin Return Option: Seems to me like it could work well. You'd just need to sort the fuel pressure out. My only concern would be if you're low on fuel and cornering hard you might end up with one pump loosing prime more than the other and it would end up overheating and siezing up???

Single pump with return line relocated to the same side as the pump : Seems like the best option to me. Its also the cheapest. You'd just need to come up with a way to keep the fuel around the pumps pick up.

Kev.