MG's J3 racer actually shrank its engine below the standard J2's — down to 746cc — purely to legally compete in the fiercely contested 750cc racing class, leaning on a supercharger to make up the difference.
Median 41 hp across 11 similar cars
Lead trim: J4 746 supercharged four (72 bhp)
MG J-Type J3/J4 supercharged racersJ3-J4 · 1932–1933
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Nobody in Burbles has spotted a MG J-Type J3/J4 supercharged racers yet. See one on the street, point the app at it, and the first card is yours — with your @handle permanently credited on this page.
FactMG's J3 racer actually shrank its engine below the standard J2's — down to 746cc — purely to legally compete in the fiercely contested 750cc racing class, leaning on a supercharger to make up the difference.
The J3 (1932–1933, 22 made) was a racing version with the engine capacity cut to 746 cc by shortening the stroke from 83 to 73 mm (to compete in 750 cc class racing) and fitted with a Powerplus supercharger and the larger brakes of the L-type; the J4 (1932–1933, 9 made) was a pure racing version with lightweight bodywork and the J3 engine but more supercharger boost to obtain 72 bhp. Wheelbase 86 in. The page gives no figure for the J3.
Collectors Spotted in the MG J-Type Lineage
No member has published a public street spot of the MG J-Type yet — the First · Worldwide stamp is wide open.
Trims & Figures
2 published trims in the catalogue. A blank is a figure not recorded, not zero.
| Trim | Years | Engine | Power | Torque | 0–60 | Drive | Gearbox | MSRP |
|---|---|---|---|---|---|---|---|---|
| J3 746 supercharged four | 1932–1933 | 0.7 L Inline-4 | — | — | — | RWD | — | — |
| J4 746 supercharged four (72 bhp) | 1932–1933 | 0.7 L Inline-4 | 72 hp | — | — | RWD | — | — |
Owning one
We don’t estimate running costs for a car like this. What it costs depends on its condition, its specialist and how it is driven, and an average would mislead.
Owners’ builds
Nobody has claimed one yet.
MG's J3 racer actually shrank its engine below the standard J2's — down to 746cc — purely to legally compete in the fiercely contested 750cc racing class, leaning on a supercharger to make up the difference.
The J2's overhead-cam drive had a nasty quirk: any oil leak from the cambox could drip straight into the dynamo's brushgear — turning a routine seal failure into a fire hazard.
Rivals
Same body, same money, other badges — tap any card to flip.
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