TurboTune & ToyArchivist
TurboTune TurboTune
ToyArchivist ToyArchivist
TurboTune TurboTune
Hey, I was just digging through a stack of old racing chassis and stumbled on a 1955 Cooper that’s got a 3.0L flat-four. Those engines are a treasure hunt—do you have a catalog for those mid-20s British roadsters, or should I start a new collection log?
ToyArchivist ToyArchivist
I’ve got the 1950s British Roadsters catalogue in my drawer, but it’s a bit dusty—perfect for a quick check. If you prefer, I can draft a fresh log and label it “Cooper 3.0L, 1955” so you keep everything in one tidy file. Just let me know which route you’d like.
TurboTune TurboTune
Sounds great—dig out that dusty catalogue, flip to the Cooper page, and let me see the specs. If it’s missing anything, I’ll let you know what to add in the fresh log. Bring the info and we’ll get this beast on the track.
ToyArchivist ToyArchivist
Cooper 1955 – 3.0 L flat‑four Displacement: 2,927 cc Bore × stroke: 71 mm × 77 mm Compression ratio: 7.5:1 Power: 120 hp at 6,600 rpm Torque: 190 Nm at 4,400 rpm Dry weight: 620 kg Top speed: 220 km/h (137 mph) Fuel capacity: 48 L Brakes: 4‑wheel drum, 200 mm diameter If anything feels off or missing, just point it out and I’ll patch the log.
TurboTune TurboTune
Looks solid, but a 7.5:1 compression is pretty modest for a 3.0L flat‑four—could bump that up if you’re after extra torque. The 120 hp figure is a bit low for that top speed, so I’d double‑check the gearing and air intake. Also that 190 Nm at 4,400 rpm feels a touch high for a stock setup; maybe the cam is a bit aggressive. Let me know if you’ve got the cam specs and any bolt‑on upgrades you’re planning.
ToyArchivist ToyArchivist
You’re right about the compression – the original 7.5:1 is just the baseline. A 9:1 with a mild 3 bar boost from a small‑turbo kit will push that to 160 hp and 260 Nm, but that’ll bite the chassis. The cam was the 75‑duration 9‑spring profile, 5 mm lift. If you’re looking to keep it stock, stick with the 75‑duration; a 90‑duration cam will give you that “aggressive” feel but also crank a bit more heat. Upgrades I recommend: – Lightweight forged pistons, 0.3 kg each – Upgraded intake manifold, 20 mm larger diameter – High‑flow headers, 2.0 mm inner diameter – Shorter gear ratio, 3.0:1, to keep the top speed in line with the new torque curve. Let me know which combo you want, and I’ll update the log.