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      11-07-2021, 07:59 PM   #26
Michael9218
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Drives: 2007 Z4 M Coupe
Join Date: Oct 2012
Location: Woodstock, GA

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So, unfortunately, I'm gonna have to eat my words here a bit...

This last weekend at Barber Motorsports Park, I had a fuel starvation episode. (y'all jinxed me!)

I was definitely a bit low on fuel on the last couple laps of a 30 minute session (though not the lowest of the weekend...but, the previous day the track was cold and wet). My AiM was reading 4 gallons when it happened. The first time it cut power for about 2 seconds and I got a warning from the AiM that I had low fuel pressure (I installed an AiM pressure sensor on the fuel line). The next lap it cut for about 3 seconds. I had 3.8 gallons when I pitted in on that last lap.

The situation where it happened was after a prolonged high G right turn complex that starts with a carrousel pulling 1.3 - 1.55 G's with part throttle that lasts for 7 seconds followed be a hard charge at full throttle up a hill while still pulling close to 1 G that also lasts for 7 seconds. At the top of the hill it cut out. Fortunately over the hill is a hard downhill braking zone and both times the motor came back to life before turn entry at the end of the braking zone.

While this has not happened before, I was turning consistently faster laps than before with a PR improvement of 1.2 seconds (1:35.7 while being chased by a GT4 Clubsport. He didn't catch me). Perhaps the increase in lateral G's and the low fuel in this session was just enough to cause the starvation.

My assumption on the situation would be that the carrousel pushed the fuel to the left side of the tank leaving little in the baffle chamber, but part throttle allowed the siphon valve to keep up with demand. Once I was hard on the gas for 7 seconds while still pulling G's the siphon couldn't keep up.

The next session out, more fuel solved the problem.
Appreciate 0