325i track car, misfire under heavy cornering, mostly right

[tomislav]

Now on to more pressing matter (cock jockeys at work fuckin with the computer)!!!

My mates got a 325i track car and under certain conditions it will misfire coming out of corners.

If the fuel tank is full it doesn't do it, however, once down to 3/4 of a tank or less, if you throw it into a hard right corner, or especially if its a left then a right, it will bog down for a few seconds, cough, then power is restored.

Any ideas?

Thanks

[ThomasGTT]

Sounds like fuel starvation. I have the same problem with my touring, but only from 1/4 a tank and less...

[Curr946]

I would agree with the above post this is a case of fuel starvation.

your options depends on the budget of the track car.

[Demlotcrew]

Sounds like a rusty return Venturi in the tank.

Can be fixed with a swirl pot (adding weight/expense and safety concerns) or you could fit a 4 pot tank with a lower cross over pipe and save yourself a lot of money and have a better handing car.

[tomislav]

Well he's got a new tank and pump waiting to go into it (tank is second hand as is the pump).

Where is the return venturi, is it part of the tank itself or separate?

When the 'new' tank goes in we'll have a good blow thro of the fuel lines too and see what happens.

Demlotcrew, isnt there issues with the fuel gauge readings if you swap tanks?

[tomislav]

Bump

[Speedtouch]

Also check for any aftermarket fuel filters fitted in the fuel line. I had a bad flat-spot on a Fiat twin-cam at certain revs, and once I removed the aftermarket fuel filter, all was well.

[DanThe]

It will be the pump pickup, early tanks are shoite and will still give fuel starvation at about 1/4 of a tank, later tanks with no link pipe are the better ones

[tomislav]

The little gauze bit you mean? He has a later tank already fitted (its ians white 328i touring that you supplied loom for etc) and has just bought another, no link pipe that i know of.

Are the link pipes only on the 4 pot tanks?

His has problems once below 3/4 of a tank, not 1/4

[Demlotcrew]

3/4? Are you sure its not a faulty gauge and its actually much lower?

[DanThe]

Is it plumbed in right? Has it been removed/changed/bodged etc?

55l tank has the link pipe and one hole for sender/pump
63l tank has no link pipe and two holes, sender each side, the gauge is also different

[tomislav]

Definately a 63 litre tank, no connecting pipe and yes the fuel gauge is right.

You can brim it (to the neck) then go out, do 2 laps of the 'ring fine, then 3rd or 4th lap it starts to do it coming out of the Brunnchen viewing area, the corners before being left, right, right.

It'll do 8 to 10 laps of the ring on a tank.

Dunno about the plumbing yet, haven't had the tank out yet but once its out we'll c whats what hopefully

[Darrenr]

fuel deffo, i had this with my drift car i had to run basicly a full tank, ive now got a fuel cell and swril pot in the boot and standard tank removed and its spot on

[Demlotcrew]

Ive never had a fuel surge and I run a stock 4cylinder tank, ive even had it low enough to switch the reserve light on while lapping the ring.

Personally I don't think its quite an upgrade to do relocate 50+kg over the rear axle high up, the stock tank location is more than Ideal, (when its working!).

Andrew

[Darrenr]

i run a 4L v8 drift e30 a bit more weight over the rear doesnt bother m8 its only a 20L tank, the standard tank for me never worked thats why i switched

[tomislav]

Well i've near enough ran my old e30 dry round the 'ring, it only misfired cos i had no fuel left lol, should have paid attention to the fuel light

Fuel cell isnt really an option due to demlots reasons mostly, ya raising 5kg 3 feet up and behind the rear wheels which is gonna do the balance no good at all.

We'll get this new tank in over christmas and see what happens.

Thanks people

PS, darrenr, i've just bought a 4 litre v8 converted e30 for the same reasons, how do you get on with yours, brake servo set up, wheels, problems etc. Please PM me

[Darrenr]

Love mine no problems at all now, i know the car you have bought, i run 4 a stud still not the 5 stud you have, we put rhe brake servo under the dash in mine

And trust me unless you are competing in TOP CLASS drifting 5kg over the back wheels doesnt make a difference, i agree with a track set but not a drift set up

[Demlotcrew]

I would have thought for drifting you need to be able to switch direction quickly, the more weight you put over the rear axle the greater pendulum effect the more you have to work to get the car pointing the right way.

[tomislav]

Nah, i wouldn't want any more pendulum effect than i have already!!!

More weight higher up at the back i cant imagine helping, plus i do nurburgring 3 times a year, i'd rather the handling stayed as it is for going round there