Datsun Works engine horsepower progression

I note two things from this chart:
* Two main ways to increase HP: more CCs, or more RPM
* 6 hp increases were made at each step. Every little bit helps when racing in a size-limited class (in this case 1300cc).


1. A12 100ps @ 7600rpm with stock 73mm pistons
2. A12 112ps @ 7600rpm with 1.5mm overbore
3. A12 118ps @ 8400rpm with 2.5mm overbore
4. 1300 124ps @ 8000rpm (TS1300 = A12 with 76.8mm pistons)
5. 1300 136ps @ 8200rpm
6. 1300 142ps @ 8400rpm
7. 1300 152ps @ 8600rpm
8. 1300 155ps @ 8800rpm
9. 1300 161ps @ 8800rpm

upper lines: horsepower in PS (DIN rating)
lower lines: Torque in kg/m

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Dave what would be interesting would be to also see the compression ratio during each step................Dave Patten (I think) got 156 RWHP out of their A15 powered GT-Lite race car.

Of course there is a precedent on RPM's = more power, Honda's mid sixties GP bikes like RC148 or 149 5 cyl 125cc GP bikes making 34HP at 21K RPM's

Yes the little bores can really zing.

I assumed that for each jump in RPM, they changed the cam profiles, the manifolds and other parts to support the higher RPM. The compression ratios might be in the article, it's all in Japanese, but the pictures are often easy to figure out.