Garys1969RR
Well-Known Member
Wed nite using a 50/50 mix of 91 octane premium, and E 85, this 451 propelled a 3600 pound RR to a best ET of 12.54@109 MPH. And it was running too lean. Plugs were white to a small amount of tan. Plus it was difficult to stage as there was a big flat spot between idle and 1/4 throttle. So the next day I went from 82 to 84 primary jets, and from 84 to 86 sec jets. This 850 dbl pumper has stock jet size of 80 all around. Also bumped the total timing to 40 degrees, as E-85 needs more timing advance. These changes nearly eliminated the flat spot, and the motor pulls hard.
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May go to 86 jetting all around. E-85 requires larger jets. I drive this car to the track, and always check for ping when the mufflers are on it. So bottom line is 13 to 1 C/R on pump gas? Yes its possible with careful tuning, and the power output is amazing! Also the fuel price is less than premium, as E-85 costs less than premium in my area.
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The motor needs to be run just shy of pinging, tight quench, and alot of C/R. Will continue to experiment with this combination and see what happens. I am at 5400 feet, so 13 to 1 would be too much at a lower elevation. I would stay at or below 12 to 1 with a motor that is running at an elevation of 2500 feet or less.
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May go to 86 jetting all around. E-85 requires larger jets. I drive this car to the track, and always check for ping when the mufflers are on it. So bottom line is 13 to 1 C/R on pump gas? Yes its possible with careful tuning, and the power output is amazing! Also the fuel price is less than premium, as E-85 costs less than premium in my area.
- - - Updated - - -
The motor needs to be run just shy of pinging, tight quench, and alot of C/R. Will continue to experiment with this combination and see what happens. I am at 5400 feet, so 13 to 1 would be too much at a lower elevation. I would stay at or below 12 to 1 with a motor that is running at an elevation of 2500 feet or less.
