20 Feb 2018

Synchrotech Transmissions provided pictures of the transmission build. I’m familiar with the insides of engines but transmissions have always been a little mysterious; I would have liked to have been there but the pictures are almost as good at showing what’s involved. Dealing with Synchrotech went smoothly; once they received the parts, the build and delivery happening promptly, can’t ask for more than that.

As part of the transmission change was the thought of also changing the twin-disc clutch; could a replacement be found with lighter foot pressure and possibly quieter (twin-disc clutches have a characteristic rattle when in neutral). The twin-disc also has a feature that for a race car is a non-issue, but for the street is a little annoying; there’s always some slight coupling between the input and output even with the clutch fully disengaged – meaning the gears are still spinning slightly. Shifting into gear from neutral, it can always be felt that the gears are moving, so it has to be done deliberately.

I contacted Competition Clutch, maker of the clutch, and explained the situation. They said that one of their “Stage 4” clutches would do well, even after I explained the 430 ft-lbs of torque, chewing-gum-soft tires, and being mid-engine, traction increases under power rather than decreasing like a FWD. They also said that pedal pressure would be about the same – not sure how I expected it to be less. Part way through the discussion though, I realized that swapping in any other clutch meant also changing the flywheel, since it’s unique to the twin-disc. Separately from that was the realization that because I’m switching back to a synchro transmission, it’s highly likely that any slight gear rotation in neutral will be dealt with by the synchros and no longer be noticed.

I was a little skeptical how a single disc clutch could hold the same torque as a twin-disc, so to get a second opinion, K Series Parts (formally Club RSX) was called. The surprising advice was “stick with what you have, it’s the right solution.” They said that the engine’s torque is too much for any streetable single-disc clutch and it either won’t last or will be a real bear to operate (high pedal pressure). It really impresses me when a business gives an answer that prevents a sale – that right there demonstrates that they’re  more interested in the right solution. They weren’t left empty-handed though, as I bought the Gear-X gear set through them.

Lastly, with yet another engine pull looming, I wondered if there was any way to drop the engine out the bottom rather than pulling it out the top. Looked at the engine bay today and was surprised to see nothing preventing it – other than the cross-bracing of course. It would have to be cut out and then either be converted to a bolt-in assembly, or welding back in after the fact.