MPG or gallons per lap

[Scany]

This might be a dumb question, because of a "secret" answer, but what are you guys operating with as far as fuel per lap (hotlap) at SPM and VIR? I don't want to fill up the tank, run a session and fill it up again, because then my tank is full, duh!

 

I believe I have used about 1,25 tanks of fuel throughout a weekend with a total of 6 sessions at SPM. With our tank holding 17 gallons that will make it about 21 gallons total, 3,5 gallons per session with about 12-16 hotlaps (?), making it 0,3 to 0,2 gallons per lap at SPM (average 0,25 gpl). My data is a bit inaccurate so , GIGO goes here. But am I close? How does this differ to VIR? Making it into gallongs per mile gets VIR gpl up to 0,4, close?

 

[Scany]

...or could we say that our cars use about 0.17 gallons per minute at full speed?

[Jon M.]

Are you managing to a certain weight when you come off the track?

 

Basically, I assume 4 gallons of a tank will be burnt durning the race. So I ensure that prior to going out, I have enough fuel to still make weight if called to impound.

[Scany]

Are you managing to a certain weight when you come off the track?

 

Yes but it's also interesting to see what fuel usage the car has from hot lap, fuel saving lap, out lap etc. Races vary in minutes, so does TT and HPDEs. Getting the numbers in gallons per minute would work well for me. So a 55 minute race on Sunday you will use about 10 gallons according to my 0.17 gallons per minute. That sounds like a lot! 4 gallons will give you about 23,5 minute of flat out racing. That sounds more normal. 0.17 might be a bit high, so maybe 0.16gpm is more accurate to use. Of course it varies with temperature and so on, but as a benchmark it might work

[Jon M.]

I guess the only way to respond is that it's not Formula One, so having an extra 2 gallons onboard is worth the 13lb penalty, especially given that these cars behave better when there is more than a half tank onboard to help settle the rear end.

[Scany]

I guess the only way to respond is that it's not Formula One, so having an extra 2 gallons onboard is worth the 13lb penalty, especially given that these cars behave better when there is more than a half tank onboard to help settle the rear end.

 

What do you mean it's not Formula 1? I will certainly hire a Shell engineer to test all my fuels before I put them near my car

[VaTechM3]

I tried keeping track of miles driven starting from a full tank of gas going out for an HPDE-3 session for a day at VIR. I'll have to check back to see what I had written down as I was also trying to determine how much fuel I use during a session out on track.

 

There are obviously a ton of variables to consider, but I'm sure we could come up with a pretty decent approximation that would work.

 

What I was doing was filling the car up, run out on track, track miles on the odometer, and then refill to the same point to get the amount of gas consumed.

 

From that you can get your miles per gallon and your gallons/minute depending on how long the session ran.

 

You might also be able to ask Bimmerworld if they have any advice on their calculations for their cars as they've been in the e36s and might have something to help you out.

 

Regardless, we should get some folks still in HPDE to get us the data since us TTers don't want the extra weight