Hi everyone I have recently decided after retiring from being a mechanic and going to the dark side of the dvsa I need to keep my mind and hands busy so decided I'm going to build the haynes roadster based around a mx5 donor car. I'm waiting on delivery of the book so I can start reading the plans but have been also trying to do a lot of research in advance.
First off does anyone have a copy of the saturn plans? If so can you email them to pedro1111@hotmail.co.uk thanks. I have the vodo plans already but I think looking around that the saturn plans are the ones I want to go for as this seems more common. And the plans I have don't seem to have all the measurements.

Does anyone know where to get a flat pack chassis kit from for the mx5 donor other than talon or are they the only ones that do them and does anyone know what plans talon follows and that wishbones to make for them I assume the wishbones for the saturn and vodo designs are different

Also has anyone completed a mx5 build and how different is it from the one in the gibbs book? Is there any large alterations I need to be aware of?

Reading around I seem to find a lot about problems with wish bones and rear diff are there ways around these faults now as all posts seem very dated.

Thanks for your assistance

Welcome to the group Pete. I have just completed a Haynes/MX5 roadster and now have it on the road. Mine is a half and half with Sierra uprights and rear axle and uses the Mk 2 MX5 engine gearbox ECU and wiring loom so its a hybrid. If I were to do one again I would probably use Phil eagles TMXR chassis at Talon. He has done a lot to iron out all the issues with fitting the MX5 parts into the roadster particularly with location of the diff and adapting the wish bones to fit MX5 parts.
Good luck with your build and use the search function here and on the Haynes forum when you have an issue, you will usually find the solution but if not there is a wealth of experience here on almost any subject!
Ian

It is also well worth looking at the US Locost forum - they've been using the Miata as a donor for years.

Diffs...all except 1 of the failures that I know of (I even sold one of my spare diffs to cover such a breakage) have all had the same failure mode.

A chunk of rubber was expected to constrain the diff nose. It won't, under any circumstance. It in no way replicates the way the diff is constrained in a 5 where you have the mass of the engine and box attached to the diff via a bolted fixing.

The other failure came about because the diff wasn't bolted up properly.

Wishbones - Phil at Talon does (or did, you'll have to check) wishbones that were bent to allow the steering rack to clear the wishbones at full droop. When you look at the original MX-5 wishbone, it's shaped as a right angled triangle rather than an isosceles so that there is nothing to interfere with the rack.

Another alternative is to use mark 2 uprights which have higher steering arms.





One thing I would suggest you do (and this may not be a popular opinion, but meh):

make sure you want to build a bare bones kit car before you commit significant time/money to it.

The only reason I'm doing one is because I want a track car that's relatively light and simple to work on.

If I was doing a car for just road work, I would take advantage of the multi-million pound development programs that went into building a car such as the MX-5 and have one of those, and spend my time/money on tweaking it as I wanted.

My DD is a mark 3 MX-5 that even made it's way into last year's Kitcar magazine (complete with my elbow queuing to get into Stoneleigh, with my kit on the trailer in front of me, so you're not completely cut out of the kit car world ).

[Edited on 30/10/16 by PorkChop]

[Edited on 30/10/16 by PorkChop]

[Edited on 30/10/16 by PorkChop]

Talon do a replacement diff casing that turns it into a Sierra-like diff. It seems to do away with any danger mounting method and also simplifies the back end (you can use full length wishbones).

The Saturn drawings do seem to be favoured, but even the Saturn ones are missing some measurements. Particularly the length of the rear wishbones is just missing. Search on here for some of the posts I've made, I've posted a link to the first edition Saturn plans (the most complete), as well as a link to a drawing of a rear end. But a lot of the measurements are in the book, the Saturn plans only list the relevant changes. You couldn't build a full car just off the Saturn plans.

Talons stuff is spot on, you'd do well to put your faith in his flat pack kit. I just went for steel lengths and cut it to length, partly because I have more time than money, but partly because I wanted to make some changes to add a full body at a later date. A flat pack wouldn't have left me with any spare metal.

well people, i have being bitten by the bug of building my own kit car as well. i was talking to Phil at talon and i think he is the man to go with for the chassis and he also sells bodywork now as well. thing is should i go the mx5 route or ford.

I went MX5 and I would say go MX5 as there is plenty of parts available and they are cheep

great video looks the part. i just think the mazda engine mite be a little under performing rather than the zetec plant. what chassis and body work did you go with.

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Originally posted by kevinmcgavigan
great video looks the part. i just think the mazda engine mite be a little under performing rather than the zetec plant. what chassis and body work did you go with.

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great video looks the part. i just think the mazda engine mite be a little under performing rather than the zetec plant. what chassis and body work did you go with.

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