Piston Slap: Of manual transmissions in C8 Corvettes and Supras

Christopher writes:

What manual transmission would fit into a C8 Corvette? How about a manual in a 2021 Toyota Supra 3.0?

Sajeev answers: 

This is a fun and thought-provoking question; I love it! I think manual transmission swaps will become increasingly popular in internal combustion vehicles, as they transition away from being traffic-inducing smog factories during rush-hour commuting to a dedicated mode of transport for enthusiastic drives designed for nothing more than enjoyment. Because if you want to lose to an EV with 800+ horsepower, all-wheel drive, and unassailable handling characteristics, you want to have fun doing it, right?

Joking aside, darn near any manual swap is doable with metric tons of money and labor. And hours of homework before starting anything! On the Supra, have a look at the photo above, as you will need a Euro-spec BMW Z4 2.0i for parts. If the 2.0-liter-only, six-speed manual is too weak for a 3.0-liter mill, you might be forced to only grab the pedal assembly, shifter/linkages, NVH parts (i.e. things like rubber boots), and console trim from a donor Euro Z4. The trim parts will be challenging, but fusing Toyota and BMW plastics together will likely create the finished product you so desire. And perhaps the 2.0 transmission can be upgraded internally to handle the 3.0’s torque output. Or perhaps it’s fine as-is?

Let’s assume the 2.0’s manual can handle a 3.0 Supra, but no matter what, you’ll need a computer re-flash to get the car talking to the new gearbox. And that’s another expert you’ll seek online for counsel.

Or perhaps give the folks at EAG a wheelbarrow full of money and let them make it happen on your Supra? Whatever works for you!

The C8 will be far more difficult, as there’s no platform-mate with a manual to borrow things like a bolt-in pedal assembly. But since they use a LS/LT small block Chevy motor, odds are the fine folks at Ultima Sports Ltd. already found a way to adapt a Porsche transaxle to the C8’s engine. Will cubic money be involved in getting them to share their trade secrets? Yes.

Then again, maybe someone like Weddle Industries can make this happen with less pain. Once the bellhousing adapter is sorted, spending the time and money to fabricate a functional set of pedals, a shifter/cable subsystem, powertrain mounts, and ECU tuning will net amazing results. Perhaps someone can scan the C8’s console trim plate, then engineer/3-D print a new one that incorporates a manual transmission shifter/boot. Odds are the wiring harness for all the switchgear will need a bit of work too, but that’s what extra plugs and lengthening wires are for. Oh, and any holes drilled to get shift linkages and/or wires back to the transaxle will likely need reinforcement to ensure the C8’s integrity remains intact. You know, easy stuff like that. 

Sigh, this is getting far too complex for most of us. But who knows, when done this can be replicated as a kit, one that others will pay big money for. I see a nice little revenue stream for the forseeable future for anyone crazy bold enough to make this happen for C8 owners. There’s a pretty good chance that General Motors will never offer a stick shift again, so you’ll have no competition. Well, until someone comes out with their own kit by ripping yours off, and offshoring the production on a scale most folks can’t fathom. But hey, ’twas better to have loved and lost than never loved at all, right?

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