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Help! Pit stops & fuel mileage


DanElam
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Guys, I thought I would turn to the home crowd for a little info. We're trying to figure out what car to run for an SCCA enduro a little later in the year.

 

Toward that end, we are doing some modeling on pit strategies and fuel mileage comparisons. Since I have run Thunderhill with you guys a few times, I was hoping to get some estimates/data from you so I can extrapolate from there and apply it to our situation.

 

1. One key difference (except for ES with NASA) is that we aren't limited to the 10gal of fuel. We will be running against some Porsches and other cars, so my first question is what is the longest time you think a car can run on a tank of gas? Maybe 2 hours? If you have some estimates for your car, can you tell me what kind of a car it is?

 

2. How long does a driver change take you? We've done plenty, but I am not sure I have a good idea about the actual time it takes us. I am hoping you can help with our modeling.

 

3. How long does a fuel-only stop take you? I know most of you guys just do 10 gallons, but if you could make an estimate of the length of time for a full fuel stop that would help. ES teams, please weigh in with your real data.

 

4. Finally, each time you come through pit road, how much time do you think you lose on the track? I am trying to come up with how many seconds to add to each pit stop to reflect the slowing down, the travel down pit road, and the acceleration back up to speed.

 

Thanks!

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Hey, Don - gonna run the 13 Hours? Most excellent.

 

Unfortunately, there is NO way to really know what you can expect mileage-wise, except to test your own car. We kept track of how many miles and minutes we got out of every gallon of gas that we put in to the car before the first VIR enduro and STILL missed by enough that we were surprised.

 

Ditto stop time - you can check how quickly fuel goes in with whatever hardware you actually have. We move 5 gallons in about 45 seconds with the non-so-quickfill jugs we have. The car (VW Golf) takes about 12 gallons at a stop, after about 1:45:xx of track time. We've changed the engine this winter, so of course all of that goes out the window.

 

One hint on the stop time question: Go to mylaps.com and look for the long laps - they include stops.

 

Have fun!

 

K

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We move 5 gallons in about 45 seconds with the non-so-quickfill jugs we have.

K

 

That sounds faster that me pouring into the funnel method that we used, and the only constaint there was the funnel that very well matches the cars opening.

 

Did you do anything to the car to accept the fuel faster? Any pics of the cans other setup?

 

My 130whp accord went a little less than 1:45 on a full 17gal tank before I came in. We than put 9.5 gal in the car and it was starving for fuel at 3:10. We dumped another 3 in for the last three laps, our time was off by 10-15min.

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Knestis-

 

Yeah, we'll be back at the 13 Hour. Got the pole last year, but had apparantely already damaged the engine earlier at Summit. We know our own numbers pretty well, except for the acceleration/decelleration and maybe the driver changes times. The problem for us is that we get terrible gas mileage. For last year's 13 hour, we worked out that we could lap the field once an hour, but wasn't sure that was enough because of our increased number of fuel stops. Our driver changes are also longer than most because the roof is so short and the car is hard to get in and out of. Depending on what the models tell us, we're thinking about going with a smaller engine package that would get better gas mileage. The problem is that we might not be competing for overall wins if we do that. And that is pretty much our emphasis.

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dumpcan.jpg

 

The 45-sec. version has the restrictor that you see in the end of the hose removed, since we took the unleaded plug out of the tank neck. (It's an emission control device, right Dickita [cha, cha, cha]?)

 

They work pretty good, actually - just like real dump cans - and are easy to control so we don't have spills, like we got with a funnel full of gas when the tank topped up...

 

K

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dumpcan.jpg

 

The 45-sec. version has the restrictor that you see in the end of the hose removed, since we took the unleaded plug out of the tank neck. (It's an emission control device, right Dickita [cha, cha, cha]?)

 

They work pretty good, actually - just like real dump cans - and are easy to control so we don't have spills, like we got with a funnel full of gas when the tank topped up...

 

K

 

 

That is cool.... You just gave me an idea.

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Thanks Kirk

 

Where did you get those fittings, and does the tubing need to be anything special so that it wont react with teh gas?

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Yep. Biggest keys to fueling are removing the unleaded flapper valve, (if equipped) and opening the diameter of the vent line.

 

In the case of the cell, our biggest problem was over filling.

2 days to our first 3 hour of the year on the west coast.

 

Marcus

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