Fuel useage per run

[Joe_914]

I am confident we have enough gas, 7 gallons of 110 and 5 gallons of 100LL

for the 1st time EVER we are going to attend Atlanta NT. So working on a 60 second course how much fuel will this Kent motor burn per run.

I have it down to a quart per run for my kart single cylinder spinning 12 -14K RPM. I suspect the 4 cylinder engine wold burn twice that if turning 5-7K RPM.


I guess I could make a stick to measure after the 1st few runs. and go from 1/2 gallon in tank make a mark. then add 1/2 more and make a mark.

How much does everyone start out with? I would like to avoid the hassle of re-fueling in grid.

[Dick R.]

I typically use no more than 1 gallon per six run event including warm up time, reruns, driving to tech or impound, etc.

Since I'm never sure about fuel cell pickup, reruns, etc. I generally start each day with 3 gallons in the fuel cell as determined by a calibrated fuel hose dipstick in a pvc pipe inserted in the cell. "Calibration" was done by adding one gallon at a time to an empty cell and putting tywraps on the hose at the wet line.

The only times I've added fuel between days at an event are BIG events like Nationals with Practice or Pro Solos at the same event and I don't want to start with more than 4 gallons in the cell for a multi-day event. There are other things to focus on between runs than worrying about whether or not I'm carrying any extra fuel weight or that I might run out of fuel.

Dick
CM since 1992 in the same car

[Joe_914]

Thanks for the great advice.

Yea that would be another issue. Fuel useage and them blasted scales.

Ed should be getting a current wieght as I am typing. Bringing all my shifter kart ballast 60 pounds worth just in case. I got 1lbs, 2lbs, 5 lbs lots of them and a few 10lbs.

[Dick R.]

Thanks for the great advice.

Yea that would be another issue. Fuel useage and them blasted scales.

Ed should be getting a current wieght as I am typing. Bringing all my shifter kart ballast 60 pounds worth just in case. I got 1lbs, 2lbs, 5 lbs lots of them and a few 10lbs.

You are welcome. Some of the other guys may have more precise info but mine may be enough for a ball park number.

How would you secure the ballast?

Fuel is easy even if it is higher than optimum over the floor as long as you don't need more than what the cell holds, of course. I've seen real serious guys add fuel on grid before the car's last run . . . I was always too busy to see if they appeared to be adding more than one run's worth of fuel . . .

Dick

[-pru-]

I've seen real serious guys add fuel on grid before the car's last run . . . I was always too busy to see if they appeared to be adding more than one run's worth of fuel . . .

Dick

At the 2010 Solo Nationals, there were random weight checks between runs to discourage this practice. That is, just ballasting the car for the final run.

[Locked]

I am confident we have enough gas, 7 gallons of 110 and 5 gallons of 100LL

for the 1st time EVER we are going to attend Atlanta NT. So working on a 60 second course how much fuel will this Kent motor burn per run.

I have it down to a quart per run for my kart single cylinder spinning 12 -14K RPM. I suspect the 4 cylinder engine wold burn twice that if turning 5-7K RPM.


I guess I could make a stick to measure after the 1st few runs. and go from 1/2 gallon in tank make a mark. then add 1/2 more and make a mark.

How much does everyone start out with? I would like to avoid the hassle of re-fueling in grid.

Yikes!! Leave the 110, and 100LL at home! 93 is plenty high of octane. Last year at a divisional event the Dulon sputtered all over itself.. We had just made a gearing experiment change, taller.. Mark blamed that and started adjusting timing, and raising the idle substantially. Turns out also as an experiment he put CAM2 in the car...

These low compression motors don't want race gas. I thought Ed and I had this conversation.

[Joe_914]

. I thought Ed and I had this conversation.

You have GOT to meet Ed !!!!!!!!!!!!!

Wide open in 5 directions all at once does not come close.

He said it pinged on 93. I dunno.

Bringing my timing light. No idea what to set it too. But I am the only one of his friends that still has one.

[Dick R.]

It should not ping on 93 . . . says the guy who has been running 93 for autox's since 92.

Dick

[Jim Garry]

I can pretty much back up what Dick said. At Forbes Field we used 1.5 gallons for 6 runs plus warmup and the long drive from paddock to the course and back. Haven't measured it since then.

[Will Velkoff]

So it would be safe to say that a unloading the car with a full cell + 5 gallons extra would be sufficient for a Regional weekend?

[Dick R.]

So it would be safe to say that a unloading the car with a full cell + 5 gallons extra would be sufficient for a Regional weekend?

We have been talking about autox fuel use. If you mean regional road racing you might want to try a different forum.

Dick

[Joe_914]

But welcome to the madness Will.

So if I were to check timing how would I do this? On my old 914 I used to run it up to 3500 RPM and set max advance at 29 degrees. Let idle fall where it may.

[Locked]

You have GOT to meet Ed !!!!!!!!!!!!!

Wide open in 5 directions all at once does not come close.

He said it pinged on 93. I dunno.

Bringing my timing light. No idea what to set it too. But I am the only one of his friends that still has one.

38 degs

[Dick R.]

38 degs

The next question is where is the timing mark on the car. My 85 VD has the mark visible from the front of the flywheel/ring gear on the right side of the engine. The "pointer" is the very bottom of the block (below the mechanical fuel pump area). Very obvious once you know that this is the spot. Not so obvious before then. I have no idea where it is on an 88.

If you have an adjustable timing light and the flywheel is marked for zero and what appears to be 38 you can verify easily.

Dick

[Will Velkoff]

We have been talking about autox fuel use. If you mean regional road racing you might want to try a different forum.

Dick

DOH! I was thinking, no way in hell the Kent is that fuel efficient


I'll get back to my section of the forum and leave you cone monsters alone!

[Scootin159]

I know you guys are talking CM/FF cars, but since this is a "fuel usage per run" thread in the "solo formula cars" category, I'll provide my autocross/FM (F440) experience:

My car is setup to run on the rich side (I've got other things to worry about than jetting right now, so I keep the jetting a little on the high side to be safe), and I've found that 1 gallon of fuel = ~8x 60-second autocross runs. Because I have a 1-gallon tank, this generally means I have to top it up in the morning and at lunch at most regional events. For a two-driver day at a NT-type event (3 runs) I could probably get away with not refueling in grid.

[Joe_914]

Well final numbers this morning on my corner scales is 1119 lbs with Ed in the car and 1 gallon of gas. I am 10 lbs or so lighter. We are going to add another gallon and see if we can get a read on it during Friday's T&T. Roll on the SCCA scales and then pull our hair out.

[ahowe]

Last weekend we ran about 3.5-4 gallons for 28 runs on a 60 second course in our 82 Reynard FF.

Andy H.

[Joe_914]

Update due. Been a few weeks since ATL NT and wanted to re-confirm the scales seem to be the same crazy randomness as always.

Made our test and tune runs and then back to the trailer workd out some issues. Added water to the car I don't know why but it needed it. Burned 1/2 gallon of gas in four 26 second runs. Hmph that's a lot.

So we added 1.5 gallons of fuel for a total of 2.5. Rolled over to the scales Me= 1109 Ed = 1119. Cool now we know where we stand. I have a 5 pound molded lead plate I can sit on so I bought it with to Grid Saturday am.

On my 3rd run I figured we would be getting close to too light so I sat on my lead plate made my fastest run and went to the scales. Me=1120 Ed= 1131 Hmpf again.

Back at the trailer we discovered we were bone dry on fuel. Hmph again.....

Not wanting to run out of fuel we topped up with as much as it would hold. added 16 oz. of water and a quart of oil.

After last run scales put me=1129 with no butt lead and Ed=1137. about 1.5 gallons left in tank. Sumpn ain't right with fuel comsumption and it does appear to be running very rich. Like the plugs fouled 1/2 way through the last run. Yup pissed that run away.

We have a list of glitches as long as my arm and enough time to fix them.

[Dick R.]

Joe,

How much gas in total or when you filled it?

How are you measuring how much is left in the cell or tank?

Does the car still have a normal road racing fuel cell? (capacity 5 - 7 gallons as I recall).

If so that is a LOT of gas to even leak out without noticing (or catching on fire)

I don't know how you could burn that much.

FYI what plugs? I run "street" heat range for autox.

Dick
CM 85
85 VD RF-85

[Joe_914]

Not sure about any of your questions Dick except we measured fuel in tank with a highly calibrated wooden dowel rod with marks on it for each 1/4 gallon of gas.

Spark plugs? No idea

No signs of leaking fuel.

Excessively rich as I would have expected the motor to be "snappier"

But thanks for adding more stuff to the list