I'm buying* Canada's cheapest, roadworthy**, 50 mpg*** Mazda Miata MX-5

[MetroMPG]

45.1 MPG US = 5.2 L/100 km

From just under the 1/2 mark, clicked off until I could see fuel in the neck, like last time.

More mods!

Previously done: 50 PSI; AC/PS belt delete; partial grille block; passenger mirror delete; front license plate relocated.

More mods added during the last tank: MPGuino; full front air dam; LRR Dunlop Enasaves on front wheels; driver's side mirror delete; synth 5w30 oil change.

Coming soon: timing advance; wheel discs; test rolling resistance of Enasaves vs. the tires it came with before changing the rears.

I swear I'm going to start a mods thread.

Driving style: same as last tank. Weather got cooler though.

MPGuino fail: I couldn't calibrate the MPGuino -- it keeps randomly freezing/resetting and losing the tank data. It's still extremely useful to have onboard for trip-by-trip numbers though.

And based on trip numbers vs. this tank result, it's dialled in reasonably closely.

THANKS, AntiochOG for sending me your Miata MPGuino settings.

[gone-ot]

Maybe you could log MPG vs. TEMP data throughout the year to see what "curve" you get?

[Stubby79]

Can you adjust the timing? There's no distributor to rotate...

[MetroMPG]

Yes! The Camshaft Angle Sensor angle controls timing.

See: https://www.miata.net/garage/ignition.html#timing

[MetroMPG]

Last night: so I couldn't for the life of me locate the timing mark on my crank pulley -- it's a TINY engraving, and the accompanying paint mark disappeared long ago.

So instead I changed my gearing...



That's a 15 inch Civic rim that my neighbour had laying around. Tire size is 185/65R15, the same width but larger diameter than the factory 185/60R14 tires. I've got them on the rear axle only.

RPM difference @ 80 km/h (50 mph):

• OEM: 2587 RPM
• NEW: 2404 RPM

Difference in rolling resistance? Unknown!

Difference in aero drag? Unknown! (It raised the rear of the car by about 3/4 inch).

Difference in rotational weight? Unknown!

---

Back to timing... I did end up finding the wee timing mark this morning using the "find TDC with a screwdriver through the spark plug hole resting on top of the #1 piston" method. So I'll get to advancing the timing soon enough.

[MetroMPG]

Difference in aero drag? Still unknown... but improved!

Re-used the 15 inch wheel discs I saved from my 2007 Honda Civic former winter beater, and which also spent some time on my 2004 Prius winter beater.

I need to make up a pair to cover the factory 14 inch wheels on the front.

I swear I'm going to start a mods thread some time.

---

If the fuel gauge and the odometer can be trusted, the car is on its best tank yet: 46+ ?? More mods than last tank, plus the weather turned warm again. We'll know soon.

[Stubby79]

You're crazy.

In a good way.

[jimhs]

Rwd and ecomoding..my ideal automotive lust..
I had a great time with my lightweight BMW,having a blast on the twisty roads and ecodriving everywhere else.
Averaging 36 mpg and a pair of rear tyres every 6 months...
Enjoy it!

[Baltothewolf]

I would love to see what you could do with a 3.63 rear end.

5-speed with your current gear (I'm assuming a 4.3) = 2404 at 50.

5-speed with 3.63 = 2000 at 50.

Of course the cost would never outweigh the gains. It's 1200 for an assembled 3.63.

[MetroMPG]

$1200! That's more than I have in the car. I do know a guy with the next-gen Miata from mine, and he autocrosses it. His has a slightly taller rear end, so I suggested we swap. But his is a LSD and he didn't think mine was. So, no go. Sad.

Originally Posted by jimhs

having a blast on the twisty roads and ecodriving everywhere else.

I'm definitely enjoying driving without brakes MUCH more than in my Firefly.