Setting Fuel Economy Records in August - 2016 Mazda MX-5 Miata Convertible Long-Term Road Test

Edmunds.com

Setting Fuel Economy Records in August - 2016 Mazda MX-5 Miata Convertible Long-Term Road Test

Edmunds conducts a long-term test of a 2016 Mazda MX-5 Miata and reports on its fuel economy for the month of August.

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banhugh

Speaking of MPGs, is there an established, reliable power upgrade for the ND engine yet? A supercharger maybe? Flying Miata has nothing

longtimelurker

SkyActiv? Really. I bet you could put the 1.5T from the Civic or the 1.8T from a Golf in there and get the same mpg and better performance.

The. Car. Weighs. Only. 2,400. Pounds. And the aerodynamic cross-section is negligible. ANY modern four-cylinder from anyone, in that car, will do the same.

The Civic weighs 700 pounds more and has more power. It's getting almost 3 mpg better than the Miata. However can it do that without SkyActiv? Hmmm...

tlangness

1: The Civic motor probably wouldn't fit in the Miata. 2: Not so sure about that golf estimate of yours. The last Golf we tested didn't even meet its city EPA estimate during it's time with us:

http://www.edmunds.com/volkswagen/golf/2016/hatchback/rating/

3: Just because cars like the Civic use technology that allows for impressive performance and fuel economy at the same time, doesn't mean the Miata can't also posses such virtues.

You keep harping that the Miata only weighs 2,400 pounds as if that's some kind of cheating mechanism or something that negates it as a good car. I see it the other way around. It's lightweight and good. They aren't mutually exclusive.

slyons89

banhugh, if you check out Miata.net there are several offerings for engine tuning. A simple tune with no other modifications can add at least 15 HP and 15 ft/lbs torque. Tuning with a more open exhaust adds more. The biggest upgrade package right now is from Goodwin Racing where with a header, exhaust, and tune, making over 180 HP and torques. That's a pretty decent upgrade without having to add a turbo and all the related tubing, wiring, and engine management headaches. Although the package isn't cheap.

csubowtie

longtimelurker said:

SkyActiv? Really. I bet you could put the 1.5T from the Civic or the 1.8T from a Golf in there and get the same mpg and better performance.

Except that the 1.5T from a Civic or Golf could only better the mpg OR provide better performance. Not both simultaneously. That's the problem with all these small turbo engines. They get good mpg when you stay out of the boost, or they give decent performance on boost, but then suck fuel. Turbo engines tend to be EPA champs and real world losers.

And yeah, the car only weighs 2400 lbs. So what's the new Civics excuse? Wasn't that one of the reasons civics were the main car of the import craze of the 1990s? IIRC those hatchbacks only weighed about 2400 lbs too.

And no, I don't think any 4 cyl could do that. Look at the Fiat 124. It's got a turbo 4. It's got more power. It's also heavier, slower, and gets worse mpg.

longtimelurker

"Except that the 1.5T from a Civic or Golf could only better the mpg OR provide better performance. Not both simultaneously. That's the problem with all these small turbo engines. They get good mpg when you stay out of the boost, or they give decent performance on boost, but then suck fuel. Turbo engines tend to be EPA champs and real world losers."

Except that in real-world use, with drivers asking for both fuel economy and performance at various times, over almost 14,000 miles, the Civic is getting almost 3 mpg better fuel economy than the Miata. You miss that?

The Fiasler 1.4T is a crappy engine.

longtimelurker

tlangness said:

1: The Civic motor probably wouldn't fit in the Miata. 2: Not so sure about that golf estimate of yours. The last Golf we tested didn't even meet its city EPA estimate during it's time with us:

http://www.edmunds.com/volkswagen/golf/2016/hatchback/rating/

3: Just because cars like the Civic use technology that allows for impressive performance and fuel economy at the same time, doesn't mean the Miata can't also posses such virtues.

You keep harping that the Miata only weighs 2,400 pounds as if that's some kind of cheating mechanism or something that negates it as a good car. I see it the other way around. It's lightweight and good. They aren't mutually exclusive.

Look, you're trying to tell us that the reason the Miata gets such good fuel economy is due to SkyActiv. I'm saying it's more due to low weight than anything. It's not cheating...but it's not a trick powertrain that is enabling a car of this size to get OK fuel economy. And really...it's just OK for this size and weight and power. Your Kia is getting almost the same fuel economy and it's got quite a bit more power and weighs almost a thousand pounds more than this Miata.

slyons89

The MX-5 also does 0-60 in 6.3 seconds vs 7.7 in the Kia, (a 1.5 sec difference is huge) and gets better gas mileage. And doesn't need an expensive and potentially maintenance intensive turbo and 7 speed dual clutch transmission to do it. So at the very least this shows that weight advantages pay off BIG.

But especially when compared against the last generation MX-5, which only weighed ~150 lbs more. This ND gets significantly better MPG and faster 0-60. And what makes that big difference, you ask? Not just the 150 lbs, it's the direct injection, higher compression, more aggressive engine timing and management, and lower internal friction. That's what Skyactive is to Mazda. So yeah, fuel economy and performance improves can absolutely be attributed to their Skyactive branded improvements.

jdmskier

The Civic weights 2900 lbs, so it's 500 lbs more. EG Civic hatch (92-95) weighted under 2100 lbs.

Also, gearing/transmission plays a big role. A Civic with a CVT tuned for fuel economy is rated 35 mpg combined (31/42 EPA). Same car with a manual gets is rated 31 mpg combined (27/40).

The Mazda 3 with essentially the same engine as the Miata and a manual is rated 33 combined (29/41) and 34 combined (30/41) with an auto. The Miata is rated 30 combined (27/34). The 3 is also 200 lbs heavier than a Civic.

Clearly, if you put the Civic 1.5T engine in a Miata with a performance oriented tune and a manual transmission (+ stickier tires, rwd drivetrain loss, etc), it will probably get the same mileage as the SkyActive. Many 4 cylinder cannot match it. If you want an apples to apples comparison, compare the same engine in similar cars. Sports cars are not tuned for efficiency as the primary goal, just look at the fuel economy on a pre-SkyActive Miata for example...21//28. That is actually something to complain about.

zman49

A side question, can someone explain to me why the Miata requires premium whereas the Mazda 3 with essentially the same engine and identical HP only requires regular?

slyons89

The Miata's engine is tuned for better throttle response, meaning the ignition timing is tuned to be more aggressive. If you run 87 octane in the Miata, the engine will have similar characteristics to the 2.0 Mazda 3 because the knock sensor will retard the timing to the levels that the Mazda 3 engine usually runs at. The folks at Mazda figured that Miata owners would prefer to pay a little more at the pump for improved throttle response. It's easy enough to achieve the same throttle response on the Mazda 3 with an aftermarket engine tune for 91+ octane, but when marketing a compact economy car like the Mazda 3, it's more important for them to put 'recommended regular fuel' on the marketing material rather than 'recommended premium fuel' but you get better throttle response.

zman49

Thanks, that makes sense.

vipermoon64

Actually, all MX-5s are always 13:1 compression, guys. This is due to not enough space for a full-sized 4-2-1 exhaust manifold. It still technically has a 4-2-1 in its more compact version, but the "2" is extremely brief. The other Skyactiv applications are 14:1 in Europe.

ducky10

My 16 GTI with performance pack gets the same mileage, carries more people/stuff, and is a hoot to drive.