Fuel Starvation

[busbeagle]

I have a 91 318is that I have made into a moderate track car/daily driver. When I acquired it the previous owner had put a jack under the fuel tank, right side. While I had the car apart I changed the tank to one from a junk yard that appeared to be externally identical. I believe it came from an early model 318i. On my first track day when the tank got down to ½ I started to experience fuel starvation on left corners, with the fuel pump making all kinds of noise as it was running dry. Filling the tank solved the problem and eventually the fuel pump has quieted back down. This was repeated on subsequent track days as well. When I replaced the tank I did inspect the pump and was not deformed from the jacking. The one other 318is track car in the Northwest does not report any such problems. Any one have any ideas if the internal baffling in an old 318 tank and a 318is is different? Any one having similar problems? Any other ideas?


Thanks
David Beagle
M3, 318is, 325is

[2002maniac]

Sorry I cant offer much help, but I have had the same problem when the tank gets under 1/4 at the track

[Alpine003]

Sorry can't help either but if this is a moderate to mostly track car, maybe it might be worthwile to invest in a surge tank setup. I know a lot of the Japanese racers use these quite a bit.

http://www.mrtrally.com.au/performance/photo/mrt262.jpg

[GuySchalnat]

Even with a stock tank, at an autocross with Kumho 710's, I can get that at about 3/8ths tank. Once I learned to drive, that was. So you are probably not looking at much improvement.

-Guy

[e9nine]

Yup happened to me a few times. Once during auto-x doing the skid pad and a few times @ Road ATL. The m42 @ WOT is VERY VERY THIRSTY :rolleyes:

[BrandC]

Here's a thought:

Some E36 folks have that same problem. There are quite a few DIY's on how to make a "double fuel pump" so that starvation never occurs on track days, even with less than 1/4 tank.

Now, there are some ppl who do have E36 24V's, and I know some of them have switched to a larger E36 tank.

Maybe there is a way to double up our fuel pumps or even use a high-flow one (e.g. Walbro or later model BMW 4/6-cyl.)

[StreetSpec_iS]

yeah. ALWAYS used to get it on one specific corner at the track. it actually sometimes seemed to happen regardless of how much fuel was present.

very hard tight top of 2nd gear right hand hairpin.

[///Motorsport]

I get it a lot when canyon carving. Attributed it to maybe a worn pump at the time, maybe its more normal than I thought. When I replace this one, will a Wallbro help?