Any chance of Dyno sheet overlays of the '19 vs a '17 or '18?
Does the 2019 Mazda MX-5 Miata ND2 really make more power than before? Time to find out.
While we had one in our hands, we visited Rob Fuller at Z Car Garage in San Jose, California. Did you notice the BRE Datsun 240Z on the cover of the latest issue of Classic Motorsports? He maintains it. And the 1971 Skyline that won the all-Nissan race at Speedfest at the Classic Motorsports Mitty? He preps that one, too.
Plus he has his own personal collection, including the turbo 510 that graced the May 1985 issue of Auto-X. That’s the magazine that became Grassroots Motorsports.
Rob also has a Dynojet chassis dynamometer.
We can’t yet share any driving impressions of the new MX-5 due to a media embargo, but we did gather some more facts and figures.
The first pull was made using sixth gear. The other two were made in fifth. Fifth gear delivered the best numbers: 168 horsepower at the wheels along with 149 lb.-ft. of torque. (And, yes, we rounded to the nearest number.)
Here’s the sixth gear pull:
And here’s the fifth gear pull:
Mazda’s official numbers are 181 horsepower and 151 lb.-ft. of torque, which works out to about a 7% decrease in horsepower due to driveline loss. Calculating actual driveline loss is a notoriously inaccurate science, but for a rear-wheel-drive car, we’re tempted to say that Mazda’s rated power output might even be pessimistic.
What does this mean in the real world? Read our full technical discussion here.
Read the full 2019 Mazda MX-5 Miata Details here.
Any chance of Dyno sheet overlays of the '19 vs a '17 or '18?
How does this 168hp and 149lb-ft compare to ND1 dyno numbers?
We're working on that story right now.
Calculating actual driveline loss is a notoriously inaccurate science
My job here is.. totally precluded. 
I've recently had Toyota 2zz's on my mind since acquiring a couple of real basketcases. Those were rated 180crank and dyno'd ~160whp through FWD drivelines that have a lot less spinning weight than RWD drivelines. I'd say your underrated comment is a fair guess!
That's a 50-60 whp increase over a fairly healthy NB in stock form. Not gonna lie, I'm a bit envious. Nevermind the torque...
te72 said:That's a 50-60 whp increase over a fairly healthy NB in stock form. Not gonna lie, I'm a bit envious. Nevermind the torque...
FWIW, I'll be driving an NB in STR at Solo Nats. :)
The first pull was made using sixth gear. The other two were made in fifth.
Why did you make the dyno runs in both 5th and 6th gear?
Wouldn't the 6th-gear results be most accurate because of the 1:1 transmission ratio?
-- Pete
Technically as long as the dyno is directly measuring the engine speed (it always knows the drum speed) it is always going to calculate the gear ratio and you're still going to come up with basically the same power result. You can choose a gear either because you think it incurs the least 'loss' or because the gear isn't going to result in tire speeds on the roller where a tire failure would kill everyone close to the car. lol
Vigo said:Technically as long as the dyno is directly measuring the engine speed (it always knows the drum speed) it is always going to calculate the gear ratio and you're still going to come up with basically the same power result. You can choose a gear either because you think it incurs the least 'loss' or because the gear isn't going to result in tire speeds on the roller where a tire failure would kill everyone close to the car. lol
Generally speaking, the 1:1 gear will have the least drivetrain loss because it's usually just directly coupling in the input and output shafts in the transmission, with no gears involved in changing speeds. It's also usually the strongest gear, for the same reason.
In reply to codrus :
Hearty "it depends". If it is an inertial dyno, testing in top gear may make the pull take so long that the engine heat soaks and loses power. This is not as much a problem when you have a 100mph headwind.
I always tested my RX-7 in 3rd gear for this reason.
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