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Anyone here done a Mazda MX 5 powered locost?
carnut1100 - 10/1/04 at 03:04 PM

Has anyone here done a MX5 powered locost?
I am about to start building a friend's locost (I can't afford my own yet) and it will be powered by a current model 1.8 MX 5 engine and gearbox. It will be hooked up to a Australian Cortina diff (from an Australian six cylinder Cortina, so it can cop the power) which is a Borg Warner axle and has bigger brakes than the UK Cortina. It will have Cortina front hubs with the six cylinder vented discs.

Are there any problems associated with an MX5 setup? Any tips?
Driving impressions?

Findlay234 - 11/1/04 at 08:37 PM

Wouldnt have guessed there were many in the uk, when i started research for my build i looked into the mazda maita (thats what its called in australia isnt it?) But no cheap examples found here, that was a good year ago so things might have changed. Youll find guys on the yahoo oz list thatll have used that engine.

Mx 5 setup would be good because you can use the engine gearbox, propshaft, axle, etc, mite even be able to use the front uprights.

Bob C - 12/1/04 at 10:21 AM

The mx5 engine is solid but pretty heavy. Early 1.6s had a known problem with the crank pulley & its associated woodruff key - this scraps the crank & will account for many of the engines you find in scrappers.
Gearbox mounting - there aint one - the 5 has a girder down the tranny tunnel called the PPF (power plant frame) which acts as rear gearbox mount & takes diff torque reaction. You can't use this in a 7, it takes a 10" wide transmission tunnel! But it would be easy to fab up a mounting to bolt onto the PPF holes.
I am going to use mx5 uprights front and rea5 and mx5 wheels - I reckon these are the lightest around. I'm always horrified by the unsprung weight of 17" alloys, big discs, mudguards etc that folk bung on a 1/2 weight car... I can't give chapter & verse of balljoints etc. yet but I'm confident it's all soluble!
Bob C

carnut1100 - 12/1/04 at 01:20 PM

No, the MX5 was called MX5 here, and I believe it was called Miata only in America.

We are using Cortina uprights and diff, and only buying the motor or gearbox or possibly a front cut from the Japanese Import wreckers. MX5s cannot be imported to Australia unless as a private import with previous ownership time so many of the ex-Japan ones are cut in half and shipped here as parts.
We will be using a B8 motor.

We have secured a set of Peugeot 405 Mi16 15" alloys with good tyres. Are there any problems tu using these?

stephen_gusterson - 13/1/04 at 01:10 AM

in japan its called the eunos

you see some imports in uk

take a look on yahoo

search for locost

there is an aussie group



TheGecko - 13/1/04 at 07:02 AM


Here's a few links to MX5 based builds in Australia. These were found just by putting "locost MX5" into a Google search.
Simon Gigney, Gumby, Ben Chapman. I'm sure there are others but they may not be on the web.

And for Stephen G - The MX5 is called the Eunos Roadster in Japan. Eunos is a brand with the same relationship to Mazda as Lexus to Toyota, Acura to Honda, or Infiniti to Nissan.


[Edited on 13/1/2004 by TheGecko]

JAG - 13/1/04 at 04:29 PM

I'm building a Stuart Taylor Locost car with an MX5/Eunos engine and gearbox. I have an Escort rear axle and Cortina front uprights.

I have shortened the sump to lower the engine by 30mm but will probably still need a bonnet bulge of approx 30mm to get over the cam cover/plenum chamber.

I manufactured a gearbox mounting and bolted it into the PPF mounting holes in the underside of the gearbox. Biggest issue with the gearbox was cutting off the large Aluminium block cast onto the side for the two llllooooooonnnnngggg bolts that also hold the PPF. Without this mod the gearbox would not fit into the transmission tunnel - even now it's tight (less than 10mm in places).

Only other major issue was finding a wiring diagram and wiring loom for the fuel injection/ECU/sensors in the engine. I found this;

This guy has fitted the Mazda B6 engine in another saloon and created his own wiring loom! He also responds to email pretty well. This diagram works for my engine/ECU/sensors etc... which came from a Jap import Eunos (1993 1.6 Mk1).

Good luck with the build.

If you want to send me U2U we can discuss this off the forum.