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I've got a new to me sports racer with a GSXR 1000 engine in it. I have a HPDE event coming up, and was just curious what others experience with fuel consumption? Just trying to get a rough idea beforehand of how much fuel I may be using each session.
You'll typically get about 2.5 to 5 laps per gallon. The best way to determine this, is pump out all the fuel (at least all the fuel the pump can pick up). Put 5 gallons in, and run a session. Pump the remaining fuel out, and subtract that amount from the 5 gallons to you started with to know how much fuel you used. Divide the number of laps (including the in & out lap) by the amount of fuel used to determine the Laps per Gallon.
Knowing your lap time, you can determine about how many laps you will get per session, add 1/2 to 1 gallon margin, and use that as the amount of fuel to put in the car.
Usually after a few sessions, you will know what the mileage is, and can run the car so that it comes in at the end of a race with less than a gallon.
How long are the sessions? ;) How long are the laps? ;)
Typical formula car designed to run 40-45 minutes max.
Some sport racers a bit more - depends on the events it was designed for.
That's the way I look at it.
There are some differences between tracks regarding fuel useage. How long do you spend at WOT, for instance? For a 20 min race, I can use between 2.5 and 3.7 gallons for tracks like the Sebring Club Course and Roebling Road.
A safe fuel level is 4 gallons for a 20 minute session. As Dave said, pump out the remaining at the end of the session and calculate. In your fuel cell, there is probably some fuel level ullage that is left in the cell when pumped "dry", so start with an empty fuel cell.
I had the same question with my (then new to me) Sports Racer/Renault.
After I replaced the fuel cell, I filled it one gallon at at time.
Then, I dipped it with a wood dowel - marked each gallon and continued until full.
After each session I can dip the tank and add - just the right amount - for the next session.
A bit of a "kludge" but it can also help point to a no start condition - if you forget to "dip" and the tank is empty! ;)
Cheers - Jim
Careful not to loose or break the stick!
I wouldn't say I have a super-accurate measurement, since I'm only using the dipstick method to measure fuel before and after, but I'm seeing around 10-11mpg on track at speed.
Not bad for the pace we set - I think the V8 (AS and similar) get something like 3-4mpg? I know my old ITB 924 manages around 7...
What sports racer do you have?Quote:
Originally Posted by bigmackloud
What year is the GSXR 1000?
Is it stock or modified?
There is probably a lot more information that you might need which is dependent on what the car is. Set-up varies between cars. Tire sizes and pressures. Spring rates. Shock settings. Corner balancing. Camber, Toe, Caster. Proper gearing. Chain maintenance. and the list goes on.
Thanks for all of the replies and suggestions.
I ended up using the dip stick method. Since I'm just doing HPDE events, I'm less worried about carrying the bare minimum fuel for a race, but rather not running out on track, haha. Most sessions are 25-30mins, though when TrackDaze does their open track format, the last 2 hours of the day are open track, so that could be a longer session if you wanted to stay out.
I ran 13 laps on 2.25 gallons. Since VIR is 3.27 miles, that equates to roughly 18.9mpg. However, only about half of those laps were at an aggressive pace, the rest were warm up/cool down/ traffic, etc. So I anticipate in the future when most of the session is at pace, for that fuel consumption rate to increase.
Thanks again.