Quote:
Originally Posted by 86_IT
I can confirm this. I did a full lap at Laguna Seca with the gaslight on. No starving.
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The fuel flapper delays when you'll get fuel starve, but it does not prevent you from fuel starving.
Long, high g left handed turns cause fuel starve (because of the geometry of the fuel tank).
The lower your fuel level, more g's you pull, longer the corner, and greater your fuel demand the more likely you are to fuel starve.
If you don't pull enough g's, don't have any long lefts, or aren't using full throttle you won't fuel starve.
The flapper valve will only help if you are just barely in the fuel starve danger zone. If you are far below or above the conditions that cause fuel starve, the valve won't help.
At my home course (Motorsport Ranch Cresson) there are two long lefts back to back that in a stock car with real 200tw (not RE71r's) tires you can get fuel starve with as much as half to a third of a tank. In my STX prepped BRZ (93octane, headers, and full suspension) without the valve I could consistently hit fuel cut at a half a tank or less.
With the valve installed I can run down to about a quarter tank before I hit fuel starve, this allows me to run three twenty minute sessions before I have to fill up, which means I can wait until the lunch break to get gas instead of needing to fill up every other session. So in a typical track day I can start with a full tank, run until lunch, refill, and drive home without needing a second refill (no fuel starve on the drive home to worry about). Without the valve I'd have to fill up 2-3 times which would make instructing more difficult.
If I was running slicks, aero, or E85 the flapper valve wouldn't be enough and I'd have to go to a surge tank and/or fuel cell which would require me to wear a fire suit and would impact classing for the SCCA Time Trials and autox that I compete in.
So, for me, the flapper valve is the easiest solution. It's application is very narrow and it isn't a perfect fix, but it does serve a purpose.