"MPGiata" modding thread: aiming for 50 MPG with a 1990 Miata. Update: success, 55 MPG!

[freebeard]

Mercedes-Benz have a windshield header spoiler converging duct that would let you keep the top down later. Theirs is electric, one could fabricobble a removable version.

It would look like an odd sun visor.

[Gasoline Fumes]

Could the oil rings just be stuck? Maybe pouring some solvent in the cylinders would help?

[freebeard]

Here's an Aircap test but skip to youtu.be/U1g3U1rkXDc?t=239



I think the perforated infill is important.

[wdb]

Good point! Oil control rings can get gunked up, typically due to infrequent oil changes but sometimes due to carbon blowing through due to the compression rings being bad. An attempt at cleaning them out is not a bad idea.

A compression/leakdown test would tell the tale of the compression rings. You could also find someone with a cylinder scope (a tiny camera on the end of a flexible stick) to look at the cylinder walls. If the car has sufficient power, and you can avoid the oil consumption, and you are happy with your MPGs, I don't know how much more I would "worry" about it. Come to think of it a nice loose engine might be just the thing for hypermiling.

[classicalgas]

This bumper cover would get you half way to your rear skirt/fairing, in fiberglass...can't post link, it's a carid rear skirt for a NA


Tucking the rear bumper underside rather than the common trim, does a lot to reduce rear "parachute" drag.

Panels for under the nose(your originals are probably missing or damaged) are available off the shelf, not too hard to fab from coroplast, and they do reduce drag(though less with your deep air dam than on a stock nose.

Your boot cover will do more for drag if you fit some curved battens to bulge it up and keep it from flapping.

[classicalgas]

Originally Posted by AdrianD

There are drain holes on each side of the jacking points on the rocker seam. Too bad everybody closes them, then the rockers rust from the inside out

They just fill up with debris, a thin wire will open them up. I managed to collect over 2 gallons of water from the rockers one of my miatas. You will want to check the drain tubes behind the seats, the drains in the doors, and pull the rugs..the fiber matting under the rugs can hold ten pounds of water, easily.

[MetroMPG]

Welcome to the forum, classicalgas!

Are you referring to this rear bumper treatment? It's what I got when I searched:

the fiber matting under the rugs can hold ten pounds of water, easily.

YES! Frequently wet carpets caused the floor in this car to rust out:




(From thread: https://ecomodder.com/forum/showthre...tml#post546477 )



I didn't re-install the fiber matting under the carpet after welding in the patch panels.

[MetroMPG]

Originally Posted by wdb

If the car has sufficient power, and you can avoid the oil consumption, and you are happy with your MPGs, I don't know how much more I would "worry" about it. Come to think of it a nice loose engine might be just the thing for hypermiling.

Check, check and check!



The car has plenty of power, as far as I can tell. However that assessment may be influenced by the fact that my other 2 cars have ~50 hp and ~72 hp respectively.

I'm very happy with the MPG's: this was my 4th summer driving the car, and it delivered the best annual average MPG so far.

I still want more, though. I'm thinking next year's first mod will be installing a 1000w coolant heater. The car is very cold-blooded and it sure runs rich when cold. (I know I should also check the thermostat, but I don't think it's faulty - the car always reaches a consistent, stable operating temp; it just seems to get there really, really slowly. Even with a ~90% grille block. )

[Piotrsko]

Not to be obtuse: have you checked the gauge system for accuracy? Might not be cold blooded at all, just a bit chilly

[MetroMPG]

Checked? Not really - only to the extent that the temp gauge needle matches heater output. So I don't think the needle's off.