1994 Mazda MX-5 Miata: Baseline Dyno Test
April 19, 2010
As I was wrapping up Project Miata's baseline dyno test session, the dyno owner -- Mark DiBella -- hollered from across the shop.
Mark: "Hey, so how'd it go? Let me guess. 98 horsepower, right?
Dang, he's good. Hit the jump for the dyno chart.
It seems stock 1st-gen Miatas are predictable things, and this car's results -- 96 lb-ft of torque at 4,900 rpm and 97 horsepower at 5,700 rpm (1% weather correction; Dynojet 248 chassis dyno) -- are right in the realm of normalcy. When new, its 1.8-liter engine was rated at 128 hp and 110 lb-ft at the crank.
This is not an engine that begs to be wrung out to the rev-limiter, both subjectively and in terms of actual power production. While Honda engines of this car's day are comparatively smooth and free to rev, Mazda's BP is a thrashy, trucky thing. It sounds strained under load and feels like it has a lot of rotational inertia.
You'd think this was a pushrod engine with the way torque rolls off after the peak. Mazda clearly biased the powerband to lower revs, as the torque curve is quite flat up to 5000 rpm. This suggests that they were more interested in tractability and providing the impression of snappiness, which would also explain the super-short gearing.
Still, considering it has 174,500 miles on the odo and numerous signs of utter neglect, it's to the engine designers' credit that this car still manages to make normal numbers. Inherent robustness has its advantages.
Jason Kavanagh, Engineering Editor @ 174,500 miles.