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POWER AND TORQUE
>
> Wide open throttle power and torque curves were run after adjusting
> the mixture correction table and the timing. Mixture setting was
> approximately for maximum power. Data was initially gathered up to
> about 6000 RPM, but looking at the data showed that the torque curve
> was still flat, and hp increasing, so subsequent runs were made to
> 7000 RPM. Still no break in the hp curve. Given that the 2.17 redrive
> ratio limits engine RPM to about 6300 (Prop @ 2900), there was no
> point in pushing things further.
>
> The torque curve is distinguished by it's flatness; varying only by 10
> ft-lbs from 210 ft-lbs at 4000 rpm to a peak of 220 ft-lbs at 5000 -
> nearly constant from 4800 to 6800. The 220 ft-lbs is not
> extraordinary, and could be improved by 9.7 compression rotors vs the
> stock 9.0 rotors that are in the engine. Mazda's data indicates about
> a 4% increase in power with 9.7 vs 9.0 at 5000 rpm. It may also
> improve some as the engine wears in - this is an engine with only a
> couple of hours of running since overhaul.
>
> I won't argue the case for/against the longer so-called 'tuned'
> induction runners, but I conclude that performance benefits are
> minimal. Tuning for a given range may give slightly higher power in
> that range, but I'll have to see the dyno results to believe it. If
> you're looking for a flat torque curve (great for a car) this setup
> achieves it. The manifold is 4 ½" flange to flange, engine to
> throttle body, and the throttle body barrels are about 5".
>
> Al
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