So I used 112 octane racing fuel this weekend versus 93 w/ 104 boost. The car ran actually crappy compared to the way it use to. I had a hard time keeping the car running, fouled a set of plugs and went to rejetting as a result.
Question: Is high octane really not a benifit if you don't have an extremely high compression ration? My motor is 12.5 to 1. I was told that the higher the octane the heavier the fuel actually is and requires a higher spark to ignite it. I use a 6al box but may not be a hot enough spark still.
My goal was to build this motor being able to run pump gas. I thought that it would be a plus to run better fuel.
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Building it right from the beginning is always better than starting over to build it better because it was temporary.
93' LX hatch, 460 with mods, TH400 trans, 9" w/ 3.89 spool. Best (so far!) of 10.18 @ 131 mph with 1.39 60'
Your motor at 12.5 :1 should be running race fuel but you would need to tune the motor for it to get the benefits. To much octane can hurt also. There is other stuff in race fuel that is much better than pump gas. This will effect the tune of the car. Put race fuel in the car and get it to a dyno.
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1988 coupe race car 2700lbs 366rwhp
1965 2+2 fast back 4 speed tri power
1968 gt/cs 347 5 speed
1970 mach 1 428scj 4 speed v code 410 rwhp stock
1990 gt drag car 780hp on motor
1994 gt, 1998 svt cobra
2003 svt cobra 456rwhp
So I used 112 octane racing fuel this weekend versus 93 w/ 104 boost. The car ran actually crappy compared to the way it use to. I had a hard time keeping the car running, fouled a set of plugs and went to rejetting as a result.
Question: Is high octane really not a benifit if you don't have an extremely high compression ration? My motor is 12.5 to 1. I was told that the higher the octane the heavier the fuel actually is and requires a higher spark to ignite it. I use a 6al box but may not be a hot enough spark still.
My goal was to build this motor being able to run pump gas. I thought that it would be a plus to run better fuel.
at 12.5 you are in the 100-104 octane range....
But if tuned there is a good chance it will run on pump gas (93 min)
the down side is you will lose some horsepower.....
The 6AL will provide more than enough spark......
i have run a 6AL on many different combo's never had a problem on any of them
you may want to experiment with heat range of your plugs.....
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Reggie
Real Racers Don't Street Race
PERIOD.......
'88 LX Hatch With A Little Of This & A Little Of That...... 10.39 @128 MPH Soon to be faster....
But if tuned there is a good chance it will run on pump gas (93 min)
the down side is you will lose some horsepower.....
The 6AL will provide more than enough spark......
i have run a 6AL on many different combo's never had a problem on any of them
you may want to experiment with heat range of your plugs.....
I been trying to asked these ya hoos at the auto part store for different heat ranges in plugs but if it is not a stock application they can't tell me squat! They can only go by 69' Galaxcie because a 460 in a 93 Mustang don't exsist!
Looks like I may have to cough up some money and get it on a dyno to see what the motor likes.
__________________
Building it right from the beginning is always better than starting over to build it better because it was temporary.
93' LX hatch, 460 with mods, TH400 trans, 9" w/ 3.89 spool. Best (so far!) of 10.18 @ 131 mph with 1.39 60'
Race fuel question?? 
My motor is 12.5 to 1. I was told that the higher the octane the heavier the fuel actually is and requires a higher spark to ignite it. I use a 6al box but may not be a hot enough spark still. 
