Low Fuel Issues?

[Raucky2000]

Out of the guys who track and auto-x...Have you had any issues "racing" with very low fuel levels?

[Richbot]

I've autocrossed down to 6 miles of range (ended up being about 1.5 gallons left in the tank). No starvation, and I'm on very wide A6's, the car sustains well above 1G and peaks even higher

[CanAutM3]

I know it is not very smart on my part, but I did track the car until the displayed range was down to an indicated ---.- km .

When I went to the pump, it drank 61.5 litres of fuel (63 litre tank). I never had any fuel starvation symptoms. This shows how well the fuel tank and pick-up are designed

However, my fuel pump may have run a little hot...

[Merked M3]

Never had any fuel starvation at Autocross and I have run it down to less than 10 miles left on the range. My friend's G35 started having fuel starve when he switched to racing slicks and another friend with a fully prepped WRX has an extra part that prevents fuels starve. Our stock M3 seems to just be better prepared for racing!

[Porschefile]

I've gotten to 1-2 gallons left on various road courses without a problem (except that I was about to run out of gas!).

[Car54]

I've run it way down as well...I've become accustomed to getting some starve, then pulling off for gas. I think the M3 would run itself dry and leave you stranded on the straight.

[Raucky2000]

Yeah, that's what I was getting at...Has anyone tuned on E85 yet with good or bad results????? I'm debating on trying it for autocross only if the power is that much better, like with boosted cars. Then switching back to 93oct after events.

[NRBRNG]

Related to consequences on track. Well, perhaps not exactly starvation, more running low and engine shutting off...
Ridge Motorsports park this summer; towards end of a session I got the low fuel warning and figured one more hot lap plus cool down and call it. I only got half we through the hot lap and all systems shut down. Engine off, insufficient fuel warning light- or something, but most scary of course...no power steering. I was hard braking entering a tight complex after a big elevation change at a reasonable speed and had to (try) to brake to scrub speed to turn and avoid leaving the track. Our cars do not turn well with engine off. Trust me.I only just kept it on the tarmac. Car re-started (in limp mode) and got me to the pits.

So, be extremely careful when getting low. This had never happened previously on the odd occasion I hit the low fuel warning. It may well have been the elevation change or something.
Nobody needs an unnecessary reason to be stopped on track.

[Raucky2000]

^ how much fuel do you think was left when that happened?

[Gearhead999s]

Originally Posted by CanAutM3

I know it is not very smart on my part, but I did track the car until the displayed range was down to an indicated ---.- km .

When I went to the pump, it drank 61.5 litres of fuel (63 litre tank). I never had any fuel starvation symptoms. This shows how well the fuel tank and pick-up are designed

However, my fuel pump may have run a little hot...

I did the same thing at Mosport at a charity day as I did not want to stop for fuel as people were lined up for rides.The low fuel light came on at the start of a 4 lap run and I put 62 litres in at the track pump.No stumbling or anything on track but not a very smart thing to do as you could damage the fuel pump with no fuel to help cool it.My e30 race car would let you know it was almost out with stumbles while blipping while downshifting into the hairpin.

[swartzentruber]

Originally Posted by CanAutM3

I know it is not very smart on my part, but I did track the car until the displayed range was down to an indicated ---.- km .

When I went to the pump, it drank 61.5 litres of fuel (63 litre tank). I never had any fuel starvation symptoms. This shows how well the fuel tank and pick-up are designed

In the general M3 forum, there was a recent thread suggesting that the M3 fuel tank is slightly larger than in normal 3 series, perhaps by .5 gallons, and BMW didn't bother to recalibrate. I haven't looked it up myself, but others have reported a different part number on RealOEM (aluminum vs steel). If so, this may explain how you can run it to 0 and still not yet have starvation.