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PostPosted: Tue Nov 21, 2017 6:16 am 
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Dave Gomberg wrote:
You don't need to write to Sunoco.

With regard to Dielectric Constant (DC), Sunoco lists this for each fuel in their detailed specs. Go to https://www.sunocoracefuels.com/fuels and click on a fuel you want to know about. For example, for the 260GT Plus, scroll down the Technical Details until you find the DC, which in this case is 19. This number is for the old G-01 or FTK-O1 meters. The allowed GCR DC range for those meters is 0-15. Thus, the 260GT Plus will fail the DC test. On the newer meters, this will read over 200.

260GT DC is 11. 260GTX DC is 1.6.

All of the leaded fuels have negative DC readings.

At least at the time that the new (several years ago now) fuel rules went into effect, Sunoco told SCCA that nothing on the list of prohibited substances were in any of their fuels (except for high alcohol in some fuels).

Dave


Dave, really great info, thanks.

I remember someone (Mazda Jon) being tossed for fuel at Pueblo a few years ago, despite running plain old pump gas and maybe some 2-cycle in his rotary. Maybe the rules got an update after that, and the oxygenated fuel became legal.


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PostPosted: Tue Nov 21, 2017 6:27 am 
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blamkin86 wrote:
Dave Gomberg wrote:
You don't need to write to Sunoco.

With regard to Dielectric Constant (DC), Sunoco lists this for each fuel in their detailed specs. Go to https://www.sunocoracefuels.com/fuels and click on a fuel you want to know about. For example, for the 260GT Plus, scroll down the Technical Details until you find the DC, which in this case is 19. This number is for the old G-01 or FTK-O1 meters. The allowed GCR DC range for those meters is 0-15. Thus, the 260GT Plus will fail the DC test. On the newer meters, this will read over 200.

260GT DC is 11. 260GTX DC is 1.6.

All of the leaded fuels have negative DC readings.

At least at the time that the new (several years ago now) fuel rules went into effect, Sunoco told SCCA that nothing on the list of prohibited substances were in any of their fuels (except for high alcohol in some fuels).

Dave


Dave, really great info, thanks.

I remember someone (Mazda Jon) being tossed for fuel at Pueblo a few years ago, despite running plain old pump gas and maybe some 2-cycle in his rotary. Maybe the rules got an update after that, and the oxygenated fuel became legal.


Dave, thanks for the info there. obviously I hadn't researched whether Sunoco published their additives and whatnot. If the 260GT doesn't pass the DC test, then it's not legal, regardless of what's actually in it.

Bill, I dug through the GCR fuel section for several years of updates, and there used to be a 'rotary exemption' to allow a higher DC number- I'm guessing to allow it to pass while including 2-cycle oil. and then some years ago, the fuel rules were updated so that basically everyone had to meet the 'rotary standards'.. wonder if this was a bit of 'clean up' to give everyone a single fuel rule and accomodate the E-10 pump gas within the rules....
Regarding rotaries and pre-mix, I usually mix about 6oz of 2-stroke oil to a 5 gal jug of whatever 91 octane pump gas is near the track. I've never had a problem passing fuel tests at the track. however, never been to runoffs so that's a different beast.

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PostPosted: Mon Dec 04, 2017 7:10 am 
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Speaking of fuel....
I've got about four (4) gallons of fuel leftover in my fuel cell after completing my last race.
What would you say is the best way to approach this as I enter winter storage of about four(4) months:

*Leave as is .
*Drain the fuel cell completely
*Fill up the fuel cell.
BTW, the fuel I use is 100 octane unleaded

Thanks for your input.
Tom B.


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PostPosted: Mon Dec 04, 2017 10:39 am 
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Plug the vents and/or completely fill the tank to remove airspace and limit 'breathing' and sucking in humid air as the temps fluctuate.

Either that or you can drain the tank and pump it back into a fuel jug..

I only run 93 pump gas, but have never had a problem with the fuel doing anything funky in the cell during storage. previously the car sat for ~4-5 years between owners, and the fuel varnished during that time. I cleaned the varnished gas out, sucked out the crumbled foam, cleaned the screens in the fuel filters and pumps, and then flushed the lines with a couple gallons of fresh gas. everything was fine when I started the car.

only problem I had surfaced at the track when vent check valve thingy got stuck when the old rubber swelled up and pressurized the fuel cell enough that the return line on the pressure regulator backed up and it stopped flowing fuel to the carb, causing the engine to starve on the last couple laps. replaced the valve and voila, no more problems. I've since purchased spare check valves and keep one in the trailer, and check regularly.

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PostPosted: Mon Dec 04, 2017 11:10 am 
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Location: Philly
I use the left over fuel from the last season as lawn mower gas the following year.

It makes cutting the lawn smell like racing!

-Kyle


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PostPosted: Mon Dec 04, 2017 6:15 pm 
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Location: Kannapolis N.C.
Visit Sunoco's website about shelf life of various fuels. I keep it in sealed cans or full cell with vent plugged. Temp controlled environment is best.

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PostPosted: Tue Dec 05, 2017 8:11 am 
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Location: Costa Mesa, CA
I was told by my fuel cell manufacturer that leaving fuel in the fuel cell is bad for the internals of the fuel cell. I always pump the fuel out after every race weekend and store it in a sealed metal container. I have no problem using fuel that was stored over the winter that way.

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PostPosted: Mon Apr 30, 2018 11:01 am 
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So what fuel will be at the Sonoma Runoffs. Heading to the dyno tomorrow.


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PostPosted: Wed May 02, 2018 2:00 pm 
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Location: Martinez, Calif
Currently the fuel sold at Sonoma is Sonoco. I have been buying it there for years.

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