Ecomodding 2015 MX-5 Miata

[serialk11r]

I'm a little surprised on a car as modern as the ND that those canards reduce drag, but I guess they work sort of like the ubiquitous "air curtains" with upward vanes that all German cars now have.

How did you decide on those numbers for toe?

Also sounds like a 10Ah battery, that sounds pretty ambitious with modern car standby power but if you drive it everyday there's obviously nothing to worry about. Have you thought about adding a solar panel to keep the battery topped up?

[Ecky]

Originally Posted by serialk11r

I'm a little surprised on a car as modern as the ND that those canards reduce drag, but I guess they work sort of like the ubiquitous "air curtains" with upward vanes that all German cars now have.

How did you decide on those numbers for toe?

Also sounds like a 10Ah battery, that sounds pretty ambitious with modern car standby power but if you drive it everyday there's obviously nothing to worry about. Have you thought about adding a solar panel to keep the battery topped up?

Although the ND is an improvement over previous generations in terms of drag (particularly with the top down and on the underbody), I expect the design is foremost to look attractive. There are air curtains underneath that direct air over the bottom of the front wheel wells, but my read of the visible body lines is "aesthetic".

The factory alignment specs, per individual wheel, are:

Front:
Caster: 5.5° to 7.5°
Camber: -1.7° to 0.3°
Toe: -1/16" to 1/8"

Rear:
Camber: -2.7° to -0.7°
Toe: -1/32" to 5/32" (ideally 1/8" toe in total)

The middle of the factory toe specs would be 1/16" (0.8mm) per-wheel toe-in on the front, and 1/8" (1.6mm) toe-in in the rear.

Flyin' Miata recommends the following, which they report shows no unusual wear:

Front:
Caster: 8.0°
Camber: -1.8°
Toe in: 1/32" per side / 0.075° / 4.5 arcminutes / 0.8mm

Rear:
Camber: -1.8°
Toe in: 1/32" per side / 0.075° / 4.5 arcminutes / 0.8mm


Essentially, I took the Flyin' Miata specs and dialed all of them back a bit.

~

I don't drive the car every day, so we'll see how the battery holds up. I have another slightly heavier (3kg) 20Ah lithium battery which has lower cranking amps, that I might substitute, with a small supercapacitor assist. Or, I could potentially put the two in parallel. The cranking amps of this new battery appear a bit too high for it to only be 10Ah, but we'll see.

[freebeard]

The canard as a vortex generator is interesting. Much less work than an air curtian.

[Ecky]

New battery!

13.6kg ->2.3kg, or 1/6 the weight of the original group 51 lead acid. It cranks the engine better as well.

[cRiPpLe_rOoStEr]

It does surprise me that switching to a motorcycle battery is not so common where I live, as some older econoboxes have fewer amenities and on-board electronics than your ride.

[MetroMPG]

I'm running a lawnmower/utility battery in mine this summer. Not for the weight savings as much for it's what I had on hand - I got a steal of a deal on a pair of them earlier in the year. (I thought I was going to use a pair to power an old 24v e-bike, but it turned out the bike motor is cooked.)



I've been too lazy to put the larger deep-cycle batt in the car. I like to do some alternator-optional motoring at times - not ideal for a small batt.

[hayden55]

Deka rebrands a lot of their small powersport batterys to lawn and garden for redistribution. Probably slightly lower quality as well. But they have higher and lower quality agms depending on where they are distributed. If I remember correctly the gold series lawn and tractor battery from advance auto parts I had in my mustang was one. Fairly cheap and got the job done.
How do you like zero toe? Typically setting toe too close to zero will make the car try to yank the steering wheel out of your hands in every bump and make the car pretty bad to drive for the average joe.
Also, I tend to need at least -2 to -3 degrees of camber to keep from wearing off the outside shoulders of my tires. I would imagine the miata would need that as well as they are known for HEAVY body roll. -1 to -1.5 degrees in the rear is typically fine for outer tire wear.

[Ecky]

Originally Posted by hayden55

Deka rebrands a lot of their small powersport batterys to lawn and garden for redistribution. Probably slightly lower quality as well. But they have higher and lower quality agms depending on where they are distributed. If I remember correctly the gold series lawn and tractor battery from advance auto parts I had in my mustang was one. Fairly cheap and got the job done.
How do you like zero toe? Typically setting toe too close to zero will make the car try to yank the steering wheel out of your hands in every bump and make the car pretty bad to drive for the average joe.
Also, I tend to need at least -2 to -3 degrees of camber to keep from wearing off the outside shoulders of my tires. I would imagine the miata would need that as well as they are known for HEAVY body roll. -1 to -1.5 degrees in the rear is typically fine for outer tire wear.

As it's aligned now, the rear is a lot more planted. Prior to the alignment I could get the rear of the car out around a corner with careful application of throttle, and now I really have to get on it. The front is very neutral over bumps. If anything, it's a bit less playful overall.

Mine has very little body roll, really. I think it's the lowering springs + lighter weight. The sway bars look OEM, but it doesn't roll at all in hard corners. I've come in too hot on some turns, braking really hard, and lifted the rear wheels off the ground, but even at that speed it's all lateral G's and virtually no roll.

[Ecky]

After replacing the battery, plus adding the hitch to the rear, the front of the car is a finger's width higher than the rear. I'm noodling over cutting off an eighth of a coil on the front springs, to bring it level.

Got the underbody panels installed. Only ~10 hours under the car, drilled into the frame and installing blind rivets. I have to say, I'm a big fan of blind rivets now.










Cut out some space for the receiver:

[ECO-AKJ]

That looks awesome!!!