2-rotary Mazda engine swap, smartasses need not apply Options

[bd1308]

I migth have the opportinity to get a free rotary engine (1.3L) 2-rotor motor. Apex seals are good from what I hear, which is good.

There is exactly one member here that has done this, could you pm me or something....?

b

[lapuwali]

I owned two rotary cars: an '85 RX-7 GSL-SE (13B) and an '87 RX-7 Turbo. Both got about 18mpg in daily driving, with as much as 24mpg on gentle highway drives. Flogged on a good road, mileage would often drop to as little as 10mpg. This would probably improve a bit on a 914, since you're dragging around about 300-400lbs less weight.

The OEM control systems are fiendishly complex, with a zillion vacuum hoses to leak, and solenoid valves to break. You'd want to do a custom injection setup. Weber manifolds are available, and you could bolt on a TWM throttle body. I know there are manifolds for DCOEs and big Holley carbs, but I'd use an IDF manifold if one was available, with an IDF-style throttle body. The DCOE manifolds wrap around the top of the engine, and, like the OEM injection stuff, make it difficult to impossible to reach the OEM oil injection stuff, which often leaks. Unless you want to pre-mix all your gas, you really want to keep the oil injection.

The earlier engines used a distributor, or a fake distributor that triggered multiple coils. These would be easier to adapt to DIY EFI than the later systems.

They generate enormous heat and sky-high exhaust temps, so a rear-mounted radiator would be unlikely to work. You'd need as much radiator area as a V8.

They also sound NASTY (not in a good way) w/o very good muffling, and require LOTS of muffler volume to kill the noise w/o also killing the power. However, because of all of that, they do turbocharge very well. The early factory Turbos had lots of lag, but the later variable inlet turbos were pretty good. The turbo kills the worst of the noise, so you can use a normal muffler after them.

For their size and weight, they can be made to produce big power. Their torque characteristics would be a pretty good match for a 901, too.