peejay

Gasoline: $3.20-3.60/gallon currently

Kerosene: $5.00/gallon (with tax) currently

Back then, Mazda was probably trying to de-octane a spec fuel. (I suspect, but don't have it on authority, that a spec fuel is why even the full race engines used an oil metering pump instead of premixing)

On the other hand, current think involves higher octane fuel and a tune to match.

On ANOTHER hand, race fuels tend to burn a lot more quickly than pump fuels. (One way to eliminate detonation is to burn the fuel before it can happen!) So maybe there is some merit to de-octaned race fuel.

youngfc

iTrader: (1)

for the flame front speed for deisle the rotor spins at 1/3 the e-shaft speed so that 5500rpm limit now turns into a 15000rpm limit give or take a cople rpm.

Hyper4mance2k

iTrader: (40)

I wonder if you could get an alternative fuel emissions exemption for running Kerosene here in Cali?

Broke Mechanic

Kerosene and diesel will do nothing for you in a 13b. You can really only turn to lighter fuels or higher grade gasolines or synthetics like tolulene's or nitro methane or alcohols if you want more power. If you care about mazda's kerosene mix objective I have tried to explain the basics of rotary engines and heavier fuels below.


I looked at the racing heritage page on mazda racing about their kerosene gasoline experimentation and don't really understand the whole thing and I am a chemical engineer(not by trade but that is what my undergrad is in). The idea was to improve inefficiencies in the awkward combustion chamber design by combining two fuels with different ignition points. The basic idea is that the heavy fuel gets ignited at a high compression first, near TDC. Because this requires a compression ratio of at least 16:1, the gasoline(especially the end chains/gasses) are condensed into a liquid at that pressure and will not burn. As the rotor advances and the CR decreases, the unburned gasoline(ideally mostly end gasses will be left/gasoline chains with single C bonds) vaporizes and is ignited by a trailing plug and the kerosene flame. That is a major over simplification of what they were attempting to do, basically a dual fuel-variable compression engine. The problems they encountered was that it was not possible to modify the rotors to get a high enough compression ratio for auto ignition/maximum combustion. Therefore the kerosene had to be lit by a plug prematurely. The second problem was the engine timing had to be extremely precise otherwise the kerosene leans out and there is not enough 0 left for the light fuel. Again this is just such a complicated undertaking, i think the mazda engineers new it was a long shot to start with-but the only idea to drastically improve power without going to forced induction. Mazda's conclusion was that there is no point in running kerosene or diesel in a 13b or similar series rotary unless you can figure out a way to increase the CR to >16:1 Remember diesel/kerosene is a much heavier fuel, containing more energy. The hydro-carbon chain containing the most power are double bonded chains(circular) of 10 (cetane) rather than gasoline's which has 8 carbons-the ones with the double bonds are an octette. So the result is you need a higher CR to take advantage of this and you will end up with much greater cylinder pressure = more power. Thats why diesel engines are built with such a long stroke and the cyliner walls, heads are thicker. Kerosene at 9.7:1 CR will not be under enough pressure to undergo complete combustion. In theory you will be unable to harness anymore energy than with gasoline, in reality you will probably harness less because the flame front moves slower.

my 13bpp na runs 87 and i have a cool nitrous setup using different fuel if anybody is interested. Seems like most of the 13b's are all about turbos.