How to Get 40 Miles per Gallon out of an NA Miata

David S.
By David S. Wallens
Mar 20, 2020 | Mazda | Posted in Features | From the Oct. 2016 issue | Never miss an article

[Editor's Note: This article originally ran in the October 2016 issue of Grassroots Motorsports, some information may be different today]

We have seen many Miatas built to go faster, but how about one modified for improved fuel economy? Meet Jim Dowd’s 1994 model. Power now comes from a 1.3-liter engine originally fitted to a Ford Festiva, and Jim reports 40–45 mpg.

The SOHC Festiva engine bolts right up to the Miata transmission, and the Miata motor mounts bolt up to the Festiva block,” his GRM build thread reports. “I mixed and matched Miata parts and Festiva parts, and this is almost a bolt-together swap.” A taller fifth gear from a Mazda RX-7 and a custom ignition setup also help economy.

This car can keep up with a stock Miata up to 5000 rpm,” he reports. “Then it falls on its face. The beauty of this swap is the car behaves exactly like a normal Miata during the daily commute, making this a stealth economy car. Given the choice, I would rather drive a detuned Miata than a Toyota Prius.”

Want to read up on how this car was built? You can read the original thread, but an updated thread is also available.

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Comments
ClutchMeister
ClutchMeister
8/27/16 11:45 p.m.

Wait so your saying that this car is only good for fuel economy? other then that even a stock miata takes it on all angles... if thats the case then its a worthless swap!

Driven5
Driven5 Dork
8/28/16 1:47 a.m.
ClutchMeister wrote: Wait so your saying that this car is only good for fuel economy? other then that even a stock miata takes it on all angles... if thats the case then its a worthless swap!

Trading power for efficiency is no less "worthless" than trading efficiency for power...Not that this suddenly negates any of the other great aspect to owning and driving a Miata either. I say kudos!

alfadriver
alfadriver MegaDork
8/28/16 7:42 a.m.
ClutchMeister wrote: Wait so your saying that this car is only good for fuel economy? other then that even a stock miata takes it on all angles... if thats the case then its a worthless swap!

To you, perhaps. I'd love to get a big jump in fuel economy for my Miata.

Knurled
Knurled GRM+ Memberand MegaDork
8/28/16 10:20 p.m.

OMG THIS POST IS BOLD

I have always wondered if a 16 valve B6 head's valves would clear a B3's bores. A 16v 1.3l sounds kinky enough to try. Sure it might still only make 110-115hp but that is pretty well strung for only 1.3l so it should be a riot to drive.

WildScotsRacing
WildScotsRacing HalfDork
8/28/16 10:31 p.m.

In reply to ClutchMeister:

You will learn quickly (if you choose to notice) that around here, stating a purely preferential opinion as if it were undisputed fact will gain you neither friends nor respect. Especially regarding someone else's preferences for modding their car.

Dietcoke
Dietcoke Reader
8/28/16 10:49 p.m.

nothing like making an anemic car slower.

Doc Brown
Doc Brown Dork
8/31/16 6:55 a.m.

Awesome, my oddball Miata got a full page in GRM! Obviously the car is not meant to be driven on the track, however the performance on the street will surprise a lot of folks.

Anyway, this just made my day!

alfadriver
alfadriver MegaDork
8/31/16 7:20 a.m.
Dietcoke wrote: nothing like making an anemic car slower.

Just as good as car people being judgmental of other car people.

Wall-e
Wall-e GRM+ Memberand MegaDork
8/31/16 7:25 a.m.

Why is everyone using such big letters? OMG my letters are big too!

alfadriver
alfadriver MegaDork
8/31/16 7:34 a.m.
Wall-e wrote: Why is everyone using such big letters? OMG my letters are big too!

David left an extra b in his post. I'm sure that didn't fix it. again.

IT DID!!!

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