Maintenance and gear

Could this Japanese gearbox transform your old British sports car?

by Nik Berg
1 February 2022 3 min read
Could this Japanese gearbox transform your old British sports car?
Photos: Vitesse

In our deepest fantasies of open-topped motoring in a classic British roadster, in which we cruise a coastal road or dash across country while everyone else is still tucked up in bed, there’s one feature that might best be mentally airbrushed out of the picture: the gearbox.

“The Achilles heel of most older cars is the quality of the gear change,” says Tim Henderson of British engineering firm Vitesse.

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Whether it’s a Morgan Plus Four, a Triumph TR4 or an MG of any early alphabet description, the gear selection process is often a challenge to be mastered rather than a delight to be savoured, and Vitesse has an appealing alternative.

It comes in the form of the five-speed manual transmission from the third-generation NC Mazda MX-5 – a car that was designed around the concept of creating a perfect connection between man and machine. Mazda calls this philosophy jinba-ittai (literally translated as “horse and rider as one”) and out of it came one of the sweetest shifts ever crafted. Short, sharp throws require fingertips over force, yet still provide tangible mechanical feedback.

Adding a dash of Japanese genius to an old Brit is transformative, says Henderson.

“We engineered a bellhousing to get the gearbox onto the back of an MGB engine. Prior to that, my wife had a drive in the car and said ‘the gearchange is painful, I’m not enjoying this much.’  We put the new gearbox in and she absolutely delighted in it. She wanted it as a daily driver because it transformed the car. And that’s kind of the feedback we get from our customers. We’re giving these cars a new lease of life to be perfectly drivable in traffic with good acceleration, good cruising and a nice quiet gearbox.”

MG gearbox conversion using Mazda MX-5

Vitesse had previously worked with the likes of Morgan and Caterham to pair the Mazda gearbox with the Ford engines used by both British sports car makers. It was a natural fit with the Duratec engine, and also fettled to fit the smaller Sigma unit. Vitesse even somehow managed to make the Miata gearbox gel with the S&S V-twin motorcycle engine of the Morgan Three-Wheeler.

As Morgan moved to BMW power, so Vitesse sought out new opportunities for its adapted Mazda mechanicals and complete kits are now available for owners of the Triumph TR2, TR3, TR4, TR5, TR6, TR7, and TR 8, along with the MGA and MGB, including V8 versions. Morgan fans are also served with conversions for the 4/4, Plus 4 ,and Plus 8.

The conversion process is “plug and play, with step-by-step instructions,” says Henderson. “If you can change a clutch you can change the gearbox.”

The setup is also completely reversible, and each redesigned ‘box fits snuggly in place of your original, perfectly aligning with existing bolt holes.” Only the MGA requires a small amount of metalwork, with two ears on a crossmember having to be cut. Vitesse supplies replacements that can be welded back on should anyone wish to revert back to the original transmission, “which I honestly doubt very many people will,” says Henderson.

Triumph gearbox conversion Mazda MX-5

Henderson estimates that around 10,000 of Vitesse’s MX-5 gearboxes are now slickly shifting in cars around the world. So far, there is not a single documented failure.

“We’ve got it on the back of 4.6-litre V8s, we’ve got it on the back of supercharged Caterhams,” adds Henderson. “We’ve got it on the V-twin engine, which was breaking 30 mm shafts and belt drives and crank shafts and all sorts, but never broke a gearbox. To date we haven’t had a gearbox fully fail through overloading. Now we don’t want that to be a green flag, because anyone can break anything if they try hard enough, but it is a very durable, very strong gearbox, and it has such a sweet shift.

“The gearbox internals are absolutely 100 per cent unchanged and the casing that was made was done from the master CAD drawings. So strength- and durability-wise it’s exactly the same as Mazda’s original.”

Vitesse is currently shipping 40 units per month to America, where they’re for sale through Moss Motors at around $5000 (£3750). In the UK, that price is from £3198 for an MGB and from £3390 for a Triumph TR5 or 6. Plenty of British sports car fans in America clearly think the transformation in drivability is worth sacrificing matching-numbers components. Will you be one of them?

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