Mixing Gas - F&L GoR Help!

[DrumrBoy]

The track car is reportedly tuned for 104 octane (nobody really knows since its a flashed OEM PCM from 2001 without documentation, but that's beside the point); interestingly, 104 is hard to find....most tracks offer 100 and either 110 or 112.

So the question is, can I mix 2 parts 110 with one part 93 (which averages close to 104...on the high side) and be OK?

I've gotten different stories speculating that the octane ratings, when mixed, do not average linearly.

Tom, or someone else who has experience with this, can you set me straight?

 

[plumcrazy]

havent seen tom around much. might wanna PM him or find him thru his site.

 

[99 R/T 10]

I have mixed fuels with no ill effects. I usually mixed 93 and 110 (50/50) to get around 100 or so.

 

[Tom F&L GoR]

Nice to be missed. I have a real job again, so for those "important" questions, PM me. VCA forum *** are forwarded to my email, so I'll get it right away.

You will be pretty close using the average of the two fuels mixed. When you purchase 89 midgrade, it is a blend of the 87 and 91 (or 93) octane fuels; most stations don't have three tanks.

If you purchase really odd fuels they may have very different "sensitivities." Sensitivity is not Dave6666's personality, it is the difference between Motor octane and Research octane- the R and M that are averaged in the yellow sticker on the pump - and is usually around 8 to 10. If you are buying a race gas, you should get these values from the supplier. Then do the same calculation of the average.

 

[DrumrBoy]

Thanks for the scoop. It seemed like it should be OK, but enough people were on the con side of this argument that it seemed worthwhile to ask folks who really know! At $10/gal for 110, its worth mixing!

 

[GTSnake]

It may be cheaper to just get Toluene and mix it.

 

[Tom F&L GoR]

Toulene is low volatility and will make the engine harder to start when cold. Cold as in cold engine and ambient temperature - I was at Lime Rock Park in CT once and a Viper would barely start and then stall. The owner had to keep his foot on the gas to keep it running and thought the idle air control valve wasn't working. One smell from behind (that lovely rich aroma) indicated the fuel wasn't vaporizing. After 2-3 minutes it was fine. Toluene is high octane, won't hurt the engine, but just be aware of the tradeoff.