Ecomodding 2015 MX-5 Miata

[freebeard]

Any blowback from hiding you tail lights?

[MetroMPG]

Arm signals. Easy to see from a convertible.

[MetroMPG]

PS:

regardless, I had 3 tanks at 4.8 L/100km (49mpg), 4.9L/100km (48mpg), and 5.0L/100km (47mpg).

Driving conditions were approximately 50-50 top up and top down, with air conditioning running when the top was up. The drive was probably 60% at 100kph (60mph), 20% at 110kph (68mph) and 20% at 80kph (50mph).

That is really impressive at those speeds. Shows just how much more efficient the new model is vs gen 1.


PPS: stunningly beautiful photos of the coast, a couple of posts back.

[Ecky]

Originally Posted by freebeard

Any blowback from hiding you tail lights?

It isn't ideal. I wouldn't do it on longer trips, but this was just across town on (mostly) side streets.

Originally Posted by MetroMPG

PS: That is really impressive at those speeds. Shows just how much more efficient the new model is vs gen 1.

PPS: stunningly beautiful photos of the coast, a couple of posts back.

These Skyactiv Atkinson Cycle engines are funny. Digging into the go pedal even at low RPM absolutely ruins fuel economy. They're very polar - drive gently, and they're phenomenally economical. Drive hard, and they're exceptionally thirsty. In some ways it makes for an engaging eco-drive.

What many say when they come to NZ is, "I didn't expect you could just point a camera anywhere and see this". There are beautiful places in North America and Europe, but you often have to hunt for the shot there.

[Ecky]

Not exactly an update, but I'm planning some lawn edging side skirts, and to possible extend the wind deflectors around the front and rear tires.

After reading Phase's thread about smaller wheels vs highway economy, I also thought I'd place what my wheel research has come up with. While others may not use the same size, the relative weights of different wheels ought to remain close. Some of these options become lighter than others at 15" or 17", but they don't drastically change in their rankings. It's worth noting that higher offsets (pulling the wheel's inward) are lighter, in addition to narrower wheels. Forged wheels typically have thinner barrels because the materials are stronger, so the weight savings in forged wheels are in the best place.

In the 16" size:

TWS T66-F 16”x6.5+45 10.54lbs
Mugen MF10 16x7 +43 11.00lbs
Racing Hart CP-035 16x7 11.2lbs
Sparco Viper R 16x7 11.2lbs
BuddyClub P-1 Racing QF 16x7 +45 11.33lbs (non QF are heavier)
Rays TE37 OG 16x7 11.2lbs
-Note SONIC are newer and stronger, with a higher weight rating, +37 Face 2 recommended
Rays TE37 SONIC SL 16x6.5+38 wheels 11.55lbs (?)
+42 are 11.40lbs - REV9 sells these for $3300 + 350 shipping
Rays CE28N 16"x7+42 11.64lbs (one version 11.22lbs?)
Motegi Traklite 16x6.5 +42 12.00lbs
SSR Type-C 16x7 +42 12.10lbs
SSR Type-F 16x7 +42 12.30lbs
SE37 16x8 12.5lbs
Spoon SW388 16x7.5 12.56lbs
Enkei RPF1 16x7 +43 13.70lbs

The stock 16x6.5 +45 on my car are supposedly 14.3lbs, which is already considered very light. Typical steel wheels in that size are 20-24lbs. Of the lightest wheels on the list, only TWS, Rays, and Eknei are currently in production. The rest are older lightweight 90's and early 2000's wheels.

Supposedly certain 15" wheels can fit on my car. 15's will fit over the base model ND with 1.5L engine which has smaller brakes (258mm), but the brakes on my car are 280mm (11 inches), making fitment with 15" very hit and miss.

In no particular order:

Desmond Regamaster 15x6.5 - 8.6lbs
Enkei RP-F1 15x7 - 9.1lbs
Modex Ks-Ce 15 x 6.5 Forged - 9.2
SSF 15 x 6.5 - 8.6
SSF 15 x 7 - 9.4
Racing Sparco Viper R (Japan Only) 15 x 6.5 Forged and Spun - 9
SSR Type-C (called Competitions in US) - 10.4
15 x 6.5 SSF - 8.6
15 x 7 SSF - 9.2
Volk CE28N 15 x 7 Forged - 9.1
Volk TE37 15 x 6 Forged - 8.8
Volk TE37 15x7 - 10.34
Volk TE37 Sonic 15x7 - 11
TWS T66-F 15 x 7 Forged - 9.8

More modern wheels, like the TE37 Sonic and TWS T66-F, which are stronger than older wheels, don't seem to save as much weight going smaller in diameter.

Many of these superlight wheels are not very aerodynamic. Styling trends tend to want concave faces, and spokes with sharp edges or lots of open space for showing off brakes.

The two I favor (in terms of weight and availability) are the TE37's and TWS. Here are some sample pictures of what they look like:

[Ecky]

Small update:

I installed some window wind deflectors which reduce buffeting significantly when the windows are down, or partway down. They also noticeably drop wind noise when the top is up, suggesting to me a drag reduction.




I took a road trip to New Plymouth and back for work. On the way up I had the top down, and targeted 100kph (62mph). My average was (adjusting for tire size, +1.7%) 21.1km/L, or 49.8mpg.

On the way back I filled with 100 octane and had the top and windows up, and averaged 24.8km/L, or 58.3mpg, also driving at 100kph.

On the return trip, it was cloudy, with some very light rain at times, and the temperature was between 20 and 24° C.

[freebeard]

I installed some window wind deflectors which reduce buffeting significantly when the windows are down, or partway down. They also noticeably drop wind noise when the top is up, suggesting to me a drag reduction.

Commercial product or home brewed?

Tuft testing might tell whether it's a simple A-pillar wickerbill, or there is interaction with the mirrors.

[Ecky]

Originally Posted by freebeard

Commercial product or home brewed?

Tuft testing might tell whether it's a simple A-pillar wickerbill, or there is interaction with the mirrors.

Somewhere in the middle. He has them made in low volumes, from a model he made. He then paints them himself. I'd be interested in doing some tuft testing.

[Ecky]

Update:

I put new shoes on the car yesterday - Continental Ultra Contact 7 in 195/50R16 (down from 205/50r16). These are a Grand Touring tire which have lower rolling resistance, longer lifespan and much lower noise, but still maintain high levels of grip. I'd have liked to put Michelin Primacy 4+ on, but none were available in the exact size. Next time around I might try the Primacy in a size up, and see how they do.

Initial impressions - these tires are still very sticky, but they're not so sticky that rocks stick in the face of the rubber, as they did on the Pilot Sports. Most of all, they're quiet, which is something I've been favoring lately. It makes long drives far more pleasant. Visually, I don't think they look as nice.

First test - I filled the tires to 39psi, got the car warmed up and drove around for about an hour. I then reset the counter and continued another hour on a long seaside drive, basically ~50kph with the top and windows down and very little braking. At the end, the mpgmeter had crept up to 26.5km/L, or 62.3mpg. I might have gotten another ~1-2mpg out of it at that speed, but that's pretty close to the real world maximum the car is capable of at 50kph.

I then reset the meter and took the highway home. Top down, windows up I averaged 21.8L/100km, or 51.3mpg, traveling around 15 minutes at 100kph.

I don't have an apples to apples comparison with the old tires. The Pilot Sports were best in class rolling resistance, and were basically bald. The new tires aren't broken in yet and have full tread. Highway fuel economy is at least similar.

[Piotrsko]

Yup they're sticky, which is why they are on the golf which is a different animal than your miata. Havent noticed a mileage increase after + 20,000 possibly because diesel fuel is getting modified to be less polluting and therefore less fuel efficient. Still getting 46 no warm up In city only driving. Running 40 front, 36 rear which is heat gun saying the contact patch is even along with depth gauge agreement. Enjoy them.