(Photo likely stolen from MurileeMartin.com)
Some of you may remember the FX32, a twin-engine Corolla/MR2 mashup that the insane crew of Stick Figure/Volatile RAM racing put together back in 2013. Well, it still runs, and it’s still racing – now with MOAR manual transmissions!
The original design was sort of a “soft-coupling” system where the rear engine had an automatic transmission and the front was manual. We would just put the rear in “Drive” and then drive the car as if it was a single-engined manual car.
The problem with that approach was it didn’t maximize the power of the rear engine. It would get all confused about what it was supposed to be doing, as the driver had the throttle wide open through second gear, then closed for a beat then wide open again. It would shift up when the throttle was lifted, then downshift again, etc…
So, I, because I hate automatic transmissions, and because I wanted to know if it could be done, converted the rear to a manual transmission. A double-standard, if you will.
The additional clutch master cylinder was mounted under the dash in the driver compartment, with a reversing mechanism to depress it with the one clutch pedal. It has functioned perfectly since it was tuned to exact (precise-ish) specifications.
The shifters were the biggest hurdle. I originally come up with a design that just attached two stick shifts together, and had a sort of pantograph arm for the side-to-side movement. It worked very well for 3-4 shifts, but not great for dropping into second gear. Our drivers ended up abandoning second gear, using third out of slow corners and being patient waiting for the torque-less 4AGEs to wind up to their happy place, which is well over 4000 RPM. That setup lasted through most of day one, when we blew a head gasket in the rear engine and finished the race on only the front.
The latest iteration can be seen in this video. As you can see, it’s much more sophisticated (in much the same way that a cassette tape is more sophisticated than an 8-track). The shifter cables need to do exactly the opposite action for either end of the car, so I built reversing mechanisms, and with precise accuracy, I fabricobbled them together.
This setup will be race-tested this weekend at Thunderhill. Stop by and say hi and feast your eyes on this amazing feat of engineering. Or just have a beer with us and try to figure out why it failed so hard.