
Traum 90mm Forged Pistons — J-Series (J32 / J35 / J37)
Traum 90mm Forged Pistons — J-Series (J32 / J35 / J37)
Traum forged piston set for J-series engines, forged from 2618 aluminum alloy — one of the strongest piston materials available and the race-grade standard for high-horsepower, forced-induction, and high-RPM builds.
Each set includes: pistons, rings, wrist pins, and clips.
Bore size: 90mm — the stock bore for J37 engines, and a +1.0mm overbore for J32 and J35 blocks bored to 90mm.
Estimated compression ratios (based on matching crankshaft & rods):
| Piston Top | J32 Crank & Rods | J35 Crank & Rods | J37 Crank & Rods |
|---|---|---|---|
| Dish | 9.0 | 9.65 | 10.05 |
| Flat | 9.7 | 10.4 | 10.75 |
| Dome | 10.6 | 11.55 | 11.8 |
| Tall Dome | 11.3 | 12.2 | 12.5 |
Choosing your top: As a general guide, the lower-compression dish and flat tops are the usual pick for boosted and nitrous builds, while the higher-compression dome and tall dome tops are geared toward naturally aspirated power on race fuel or E85. Not sure which top and ratio fits your combo? Reach out and we’ll help you spec it.