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warpspeed
01-27-2004, 10:34 PM
:?: I am about to go to San Jose this weekend. I was wondering if you can really feel the difference in putting a higher octane gas? If so, I will hit the gas station down there and try about $20 worth of 110.

JanSolo
01-27-2004, 10:37 PM
I believe it helps with reducing the chances of detonation since the gas will not explode too soon basically. I suppose it might help on hot days and assist with tuning for more horsepower. I ran a few full tanks of it in my Evo and felt no difference, so I stopped.

warpspeed
01-27-2004, 10:40 PM
Thanks jan for the 411. I am just wondering when I get the Xflash (since it's supposed to be tuned to 91 octane) will I feel any difference? Like you said probably not, any way gas is going back up anyway.

cagefreak
01-27-2004, 10:41 PM
I believe it helps with reducing the changes of detonation since the gas will not explode too soon basically. I suppose it might help on hot days and assist with tuning for more horsepower. I ran a few full tanks of it in my Evo and felt no difference, so I stopped.

Not only that, it also prodives a stronger "bang" when it is finally detonated thus creating more power. <--- this concept is only applicable to engines of somewhat higher compression.

vtluu
01-28-2004, 02:06 AM
100 (R+M/2) is the highest unleaded octane you'll find. As I've mentioned before I'll typically run 3.3 gallons of 100 + 10.7 gallons of 91 = ~93 octane, for auto-x. Well at this point the two Joes (very good auto-x'ers driving stock Evos) are still kicking my butt running plain ole' 91 so clearly I'm not limited by the gasoline I use. :lol:

EvolvedDSM
01-28-2004, 03:16 AM
Actually, you can get 103 unleaded in Ohio. It's about as scarce as 100 is here ;)

vtluu
01-28-2004, 10:24 AM
There is gas available around here with product name "[something] 103" but 103 is probably the research octane number (RON); the motor octane number (MON) for it is 96 so the octane rating comparable to pump gas is the average of the two, RON + MON/2, which is 99.5... rounded to 100. I think the same holds true for Trick or Unocal 100 octane fuel.

It may be that you can get (R+M/2)=103 gas in Ohio. But it would be a long trip to the pump for me. :lol:

If you want to boost your octane further you could always use additives such as toluene, xylene, or MTBE.

evo_dadi
01-28-2004, 10:32 AM
which i should have done on the dyno day :( but oh well at least i know how much i got.

but is mixing a 100 leaded with a 91 unleaded fine just for when its needed and not a daily basis right? off course my cat will be off when i do this :)

EvolvedDSM
01-30-2004, 06:17 AM
It appears Sunoco makes a 104 unleaded R+M/2 (click here (http://www.smithtex.com/racing/fuelcomp.html)). I wouldn't mind a drum of that sitting in the garage ;)