For some time it has been stated that the BP5A (aka MazdaSpeed Miata) Intake Cam would gain a few horsepower over the stock intake cam in the 99-00 Miata head in a naturally aspirated platform, but as far as I know no one has ever posted any definitive data to back that up. At least not without other changes being made at the same time which messes with the results. This past weekend at a local Dyno Day I was asked to perform this cam swap on a local forum member's Miata. The car was put onto the rollers for three pulls, I did the cam swap, and then it went back on for three more pulls. Each set of pulls were consistent and we used the highest pull from each set.
The car is a '96 with a complete '00 engine, it has an RPM switch for the VICS, a DDMWorks intake filter w/ heat shield, stock '96 exhaust manifold, high-flow cat, and a 2.25" cat-back exhaust.
The gain we recorded with the BP5A cam was 3.84 hp and 2.85 ft.-lbs. tq.:
So if you have a 99-00 Miata, or a 99-00 head or solid lifters in your earlier 1.8L and you plan on staying n/a, there is some horsepower to be had here without any other required changes. Other improvements such as a better exhaust manifold, intake, etc. will help this power curve go up further.
What I'd like to do next is take the stock 99-00 intake cam and install it into an MSM and see how it performs there, with the necessary before and after dyno pulls.
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