Our new engine combination is mechanically identical to this previous combination except for a new rotating assembly. Different rods, pistons, & crankshaft now measure 478 cubic inches with 8.3 to one compression. With only these changes, the old nozzle & jetting setup was drunk rich. New nozzles & jetting were quickly revealed in testing that makes a lot higher air to fuel ratio. It is now 4.2 pounds of air to one pound of fuel. All else in our racer combination including the fuel injection & fuel pump remain the same.

We were all surprised how much difference the changes affected the ratio of pounds of air to pounds of fuel. Even with all of our experience with this combination, the determination of nozzles & jetting for the different rotating assembly required a lot of time on the calculator as well as the test track. The calculator allowed us to easily determine a new jetting combination with the same fuel pressure as before (for good engine response) by holding the total jet area the same. It allowed us to stagger the nozzle sizes, holding the total jet area the same.

We converted to port nozzles soon after the first test runs. The calculator allowed us to determine fuel split (illustrated in our fuel injection books) between the hat & port nozzles and the new jetting sizes to achieve that fuel split. It allowed us to determine the nozzle and main bypass sizes to adjust for air density changes from day to day and from hot afternoons to cool evenings.

METHANOL VAPOR ISSUE: We found in our methanol publication development that only methanol vapor burns. So much of the methanol in the cylinder is liquid, and large & small droplets. And not vapor. Anything that is not vapor does not burn. There is not enough time to vaporize. Furthermore, with liquid methanol in the cylinder, you get ignition vaporization at the expense of ignition.

MAYBE GOOD, MAYBE NOT: In some racer combinations, cooler fuel will be better. That would be the case for a hot day with an engine tuned to the edge of detonation. Yet in another engine, say on a cool day, that is somewhat rich and tuned with more spark advance than the norm, also tuned to a leaner idle than norm for more staging temperature, cooler fuel may not help at all. It will only reduce vaporization and make less power.

TEMP: Below 50 degrees in one atmosphere, there is little to no vaporization. Above 149 deg. in one atmosphere, there is all vapor. At boost and compression, different tune-ups make different temperatures and different amounts of vapor. There are so many different effects on vaporization and the horsepower result that a blanket rule will probably not work across the board.

REFERENCE: We discuss this in great lengths in our methanol publication with a lot of engineering and racer data. Over 30 pages provide Information about temperature. Over 60 pages provide Information about vaporization.

An extensive index of TERMS (6 pages single spaced) can be downloaded from our website; from the book description page. To give an idea of how vast the subject matter is.