The not so HARTGE theme'd S50 2dr NOW SOLD!

[bss325i]

I think that's caused by a lack of fuel around the pickup rather than a pump related issue. I have the same issue with my track turd.

Ok explain why i dont get this problem in my sport with less than half a tank. I dont get that problem when its in the red!

The pick up is in the same place regardless of pump.

[Jon_Bmw]

I get a misfire when less than 1/2 a tank after a corner and then hard on the throttle down the straight at about 6000rpm. I guess the fuel all sloshes out of the way of the pickup, sucks some air up which makes its way into the inlet manifold about 3 seconds later. Solution, don't let it go below a half full

More seriously, I suspect standard fuel tanks, Pug and Bmw perhaps have insufficient baffling within them? Bit of an arse to sort properly without resorting to a 'race' tank.

Edit: Farrrrrrr too slow.

[bss325i]

Yes but why doesn't it do it in my 325i?

[Jhonno]

S50B30 requires a fair amount more fuel.. It is a problem with all 24v swaps!!

[bss325i]

But if its a case of the fuel not being at the pick up when cornering right then its the same regardless of pump or engine?

[Jon_Bmw]

It might be because its a more agricultural engine! The s50 probably has less tolerance to fuel supply. Also you said it occured when lapping the ring, when fuel is going to be sloshing side to side quite a bit more compared to the m25.

[bss325i]

It might be because its a more agricultural engine! The s50 probably has less tolerance to fuel supply. Also you said it occured when lapping the ring, when fuel is going to be sloshing side to side quite a bit more compared to the m25.

Accelerating quickly at a right junction has the same effect!

[Simon13]

i've also never had a problem and driven round the ring until the fuel light has come on in a 325i M20 donk and never had a misfire

must be thirsty 24v lumps i don't understand it as they don't corner quicker than M20 engined cars!

[Jhonno]

i've also never had a problem and driven round the ring until the fuel light has come on in a 325i M20 donk and never had a misfire

must be thirsty 24v lumps i don't understand it as they don't corner quicker than M20 engined cars!

7



It must be something to do with the fuel supply required.. Mine does it if you rifle off gearchanges (properly quickly), change gear foot down.. Nothing.. And off

[bss325i]

Well its a problem i dont like as loosing power mid bend can be dangerous.

Lift off oversteer anyone?

[Jhonno]

Exactly.. The fuel pump improves the situation, I am not sure how to cure it though..

[bss325i]

Exactly.. The fuel pump improves the situation, I am not sure how to cure it though..

A tank with a pick up in the middle!

[SUMPCRACKER]

This is a problem I have had in E28 2.8/3.5s when they go below a quarter of a tank.
It is not a misfire because all the injectors still have some fuel but it does cause a bad flat spot as the fuel pressure drops in the fuel rail.(because the pump is starved for a couple or secs)
The m20 may run at a lower fuel pressure and a drop in the rail wont bother it but if your running somthing like 3.5bar or more and the rail is only at 1.5 then your going to feel it.

I have no reference with the FPR rateing but I think the M20 is 2.5 bar.

Fitting a swirl pot fixed my M535i which was running 3.5bar with a racing dynamics FPR,

[bss325i]

This is a problem I have had in E28 2.8/3.5s when they go below a quarter of a tank.
It is not a misfire because all the injectors still have some fuel but it does cause a bad flat spot as the fuel pressure drops in the fuel rail.(because the pump is starved for a couple or secs)
The m20 may run at a lower fuel pressure and a drop in the rail wont bother it but if your running somthing like 3.5bar or more and the rail is only at 1.5 then your going to feel it.

I have no reference with the FPR rateing but I think the M20 is 2.5 bar.

Fitting a swirl pot fixed my M535i which was running 3.5bar with a racing dynamics FPR,

Were did it mount?

[old_skool]

Barry, the fuel pump that I bought and fitted to the touring was the one mentioned in the thread. I don't recall telling you that I used the E36 M3 fuel pump. Buster used the E36 pump for his conversion seeing as the B32 requires 5 bar static/maintained pressure. The B30 only requires 3 bar at the rail.

I did convert a E36 M3 pump into my other touring for use with my B32 - maybe that's where you were mixed up? That was a long time ago now...

You still have the fuel tank yes???

[bss325i]

Barry, the fuel pump that I bought and fitted to the touring was the one mentioned in the thread. I don't recall telling you that I used the E36 M3 fuel pump. Buster used the E36 pump for his conversion seeing as the B32 requires 5 bar static/maintained pressure. The B30 only requires 3 bar at the rail.

I did convert a E36 M3 pump into my other touring for use with my B32 - maybe that's where you were mixed up? That was a long time ago now...

You still have the fuel tank yes???

No i used the tank from the 318i Lux which is the bigger tank. I took the pump out of the touring though and used that.

I haven't had the stavation problems in this car... yet. That was in the touring.

[SUMPCRACKER]

As long as it mounts before the pump it will allways have a few seconds fuel supply without a feed.
My car needed a lift pump as well to feed the swirl pot. I think this is a standard set up on some performance cars.

I think if the swirl was positioned right it would not need a lift pump,mine was on the rear inner arch in the boot.

I would try it without a lift pump first.

(This car originally had an M20) Have you got the pump in tank set up?
If so use that as a lift pump feeding the swirl pot and then an early under car pump dragging the swirl pot.
Dont worry about the extra pressure as the FPR will send the unused extra down the return.

[bss325i]

As long as it mounts before the pump it will allways have a few seconds fuel supply without a feed.
My car needed a lift pump as well to feed the swirl pot. I think this is a standard set up on some performance cars.

I think if the swirl was positioned right it would not need a lift pump,mine was on the rear inner arch in the boot.

I would try it without a lift pump first.

(This car originally had an M20) Have you got the pump in tank set up?
If so use that as a lift pump feeding the swirl pot and then an early under car pump dragging the swirl pot.
Dont worry about the extra pressure as the FPR will send the unused extra down the return.

It had an M40 in it before but yes it has the in tank pump. Not keen on a boot mounted swirl pot but need must and all that.

[old_skool]

I took the pump out of the touring though and used that.

In that case you have the same pump fitted Barry.

[bss325i]

I took the pump out of the touring though and used that.

In that case you have the same pump fitted Barry.

Anyone wanna buy a walbro 255?

[SUMPCRACKER]

If you run the two pump set up you can hide the swirl,second pump and filter under the car,but I would like it in the boot as you can get at it,clean/maintain it and it wont get bashed.

[buster]

Hi Barry,
I think i've got a solution to this.I have fitted a 4 cylinder fuel pump cradle and re fitted the evo pump to it.The reason is the fuel return on the 4 cylinder cradle dumps back down the centre of the cradle and into the pick up area unlike the 6 pot pump cradle which is blanked off and has the return on the other side of the tank.
I haven't tested it yet but i think this may help.I noticed i had problems really bad at a track day at croft where i had to have more than half a tank or it would cause problems.On the road, no less than about a quarter of a tank or it'll do the same.
The only thing next to try if it still gives me bother is a swirl pot, but fitted under the car.

cheers
andy

[SUMPCRACKER]

There wont be much going down the return when its on full chat so I cant see it eliminating the problem.

[buster]

well i noticed e30 m3s never have the same problem and i know of an s50 powered m3 that hasn't had the fuel pump changed, and guess what , he has no fuel surge problems despite doing track days .

[Theo]

My 335i got fuel surge with the 4 pot type fuel pump fitted. Will be using a swirl pot setup now that it's turbo.

[SUMPCRACKER]

Is the m3 tank baffled? or is the pick up different? It may have a swirl pot as standard given its handleing abilities?
Im no expert,im just going by my own expieriences,

[buster]

yeah maybe it does, not sure on that one.

[Theo]

It doesn't.

[SUMPCRACKER]

I would be suprised if the M3 tank is the same as standard inside and out if they dont have a swirl pot.

[bss325i]

Hi Barry,
I think i've got a solution to this.I have fitted a 4 cylinder fuel pump cradle and re fitted the evo pump to it.The reason is the fuel return on the 4 cylinder cradle dumps back down the centre of the cradle and into the pick up area unlike the 6 pot pump cradle which is blanked off and has the return on the other side of the tank.
I haven't tested it yet but i think this may help.I noticed i had problems really bad at a track day at croft where i had to have more than half a tank or it would cause problems.On the road, no less than about a quarter of a tank or it'll do the same.
The only thing next to try if it still gives me bother is a swirl pot, but fitted under the car.

cheers
andy

Hi, the problem i get is exactly as you describe it. I have a 4 cylinder cradle that i can use to try this out and i have a track day on the 27th so will report my findings. I'll also take some pics of the two cradles to compare and post my findings.

Failing all this, i guess a swirl pot is the only way to go.

I did have thoughts of fitting another in tank pump but on the nearside to feed the offside pump nut this i think will mean modding the tank to take another cradle where the sender goes on the n/s.

[SUMPCRACKER]

What buster said could be bang on. If you used a "porn star" fuel pump WITH the 4 cylinder fuel cradle there would allways be surplus fuel going down the return to feed the pick up

[bss325i]

What buster said could be bang on. If you used a "porn star" fuel pump WITH the 4 cylinder fuel cradle there would allways be surplus fuel going down the return to feed the pick up

Is a walbro 255 ltr ph "porn star" spec?

[SUMPCRACKER]

As I have no stats on fuel pressure reg, pump delivery rate or injector delivery it will be a case of suck it and see.
Ill get my coat..

[SUMPCRACKER]

There may be an issue getting enough fuel down the return to feed the engine when dry,but I think you could make a small swirl pot/resov type thing on the end of the pick up to make this work,kind if like an in tank swirl pot filled by the return pipe which will fill on light/no throttle.

Use a bean can or somthing? drill it near the bottom (but well above the pick up)so the tank can also fill it,baffle effect?

Sell bmw bean cans on ebay?

Im 99% sure this would work,it would cost 20p,take half an hour and look standard-IE nothing in the boot.

[Jhonno]

Barry..

Ive just been giving mine beans with the fuel light on.. Walbro 255 pump and 4 pot cradle, no starvation, inc some sweeping 3rd gear, full throttle 2nd etc.. Looks like it could be the answer.

My hesitation would appear unrelated to the pump!