Mx-5 Donor - SSC
 

Fellow forum members may remember that Saturn was putting together a Roadster based on the Mazda Rx-8 Rotary Wankel engine, well that car was just about a rolling chassis but over the xmas break i had a chance to have a good think about what is best for the Haynes Roadster and fellow builders. As a result of this i have decided that the Rotary Wankel based car was a bit of a fantasy, although it will happen at some point, it was not the best way forward for Saturn and the Roadster as a whole. To cut it short the way onward is a Mazda MX-5 based roadster, which we are well on the way to now having a rolling chassis. The donor car has been acquired, stripped and parts waiting to all go in.

The car will be based on an Mx-5 used as the sole donor with all similar parts used as with the Sierra, the only exception being the Rear Uprights which can also be used from the Mx-5. The build will be blogged on the Saturn Site, along with the build for the 2 Saturn Roadsters, in conjunction with TeamTrain Ltd in Newcastle, which will be raced on the Northern Race Series Cup first race being in April at Croft - transfer of all running gear from Ginetta G20 to Roadster starts this weekend with a lot of help and work from Flyerncle / Paul.

The body work will be re-worked for the Mx-5 build with the wider and longer scooped bonnet, similar to the Westfield V8 bonnet mentioned a couple of days ago. This will allow the engine to be raised slightly which will allow the sump to be un-modified. Once a rolling chassis is built the full build, in a similar format to the Chris Gibbs's, will be put up in pdf format on the Saturn site so that other builders may use to build their own chassis, wishbones, chassis plates and also a build guide to accompany it. The pdf's will contain all measurements and plans for amateur build as the Haynes book.

Of course, the full Saturn range will be extended to include all relevant parts for the roadster based on the Mx-5 donor, as will the pre-cut chassis packs be available from HandyAndy. Although builders will have full access to plans in order to build their own from scratch should they wish. Hopefully this will keep the full self build concept alive following the slow demise of the Sierra as a donor. I know that some other builders have started or are having thoughts about the Mx5 donor route but it is mainly intended to be a way of standardising the roadster with a change of donor while making available all the build info to other builders to make the transition as smooth as possible and help with the longevity of a fantastic car.

All the Best....Andrew

That sounds good Andy,

Widening the donor base is going to be key for the survival of the self/kit car industry in general but especially sierra based cars .

I have had a sly look at one or two mx's on ebay now and again whilst thinking about future ideas.

TT

thats bloody great news Andy.
now for next trick can you do the same again with a BMW donor
many thanx les g

Excellent news, I've been trying to decide whether to go the tried and trusted Sierra route, or somehow bodge an MX5 in myself, and this may well tip the balance in the MX5's favour :D

He,s not stripping my Beemer down to use as the test bed :D

Indeed it is a fantastic step forward to widen the Donor base for the Roadster,
I,ve seen the work & hours Andy ( Spud) has put into this new project & its looking great, Nice one Andy :cool:

cheers
andy

That's a fantastic idea, using an MX5 donor; why hasn't anyone thought of that before!

M

Fantastic news as it'll save me doing the donkey work now:D


BV.:)

Excellent news Andy. Trouble is I know where there is a K plate MX and its probably going to be cheap, hmmmmm:rolleyes: .

D.

There are thousands of Mx-5's available, a quick search on E-Bay shows this and at a good price. When you strip down the car its quite amazing how many similarities there are between that and the roadster. Probably why the Mx-5 gets so much praise for its superior handling. It's the obvious donor choice.

Andrew

I think this is pure genius:) I had a look on ebay and saw there were about 2 suitable Sierra donors and hundreds of MX5's. I understand they have great engines and boxes in them so if it can be made to work then this absolutely has to be a winner. Given the quality of Andy's stuff this has to be good news for the roadster. I wish you the very best with this venture which I am sure will be up to your usual high standards and sure as hell makes sense from a commercial point of view.
Bloody good stuff, I say:)
Dave.

Nice one Andy, pulled another blinder.
I'm now expecting you to design a car that costs 50 quid to build, runs on tap water, and looks like something designed in Italy. Turns from a single seater, to a 2 seater, to a 4 seater at the touch of a button. Oh yeah, and it flies, literally. At Mach 2.
I'll log on in a fortnight to download the plans! :)

I second that as 50 quid would be well spent:D
Only problem here is mx5 go for silly money no matter how old and regs state that for building a clubman the engine has to be '99 or newer:eek:

Blimey for all that surely it has to be worth £55 you tight beggar...;)

Any pics yet Andy?

There are some pics Fabby but i'm still not happy with the rear suspension, so until revision 5, at least, there wont be any pics - wont be long though then i can cad the chassis.

Don't want much do you Alan......:eek: If the chemists get their fingers out and split water into its elements, cheaply, we'll all be running on tap water. I reckon they already can but the Arabs and Texans have put a hold on it until they've sold all the oil.....;)

Cheers...Andrew

Yeah but knowing where there is one (less than 200 yds away as we speak) and that you are sorting a design to use the MX5 its sorely tempting to go and buy it. Trouble is I really can't afford it and I already have way too many projects on the go anyway. i suppose I could always get it and if its MOTable I could run it for a while as a company car:D then when everything else is completed (somewhere around 2028 at my present work rate) I could just write the MX off (financially speaking) and build a Saturn MX Roadster;) .

D.

I can fully understand the need for a new donor and why the mx5 is suitable but my daft head is finding it hard to fathom why you would break a sports car only to make another one? If Mx5's are cheap why not just strip it out fit a cage and run it as it is as no IVA to pay for....:confused:

Unless it's a smacked car but then surely chances of things being poggered are high?

Mainly because we want our own self build roadster on the road which is even better performing, half the weight, 540kg v 1080kg, twice the bhp / ton, and the Mk1 Mx5 is notorious for rotten front and rear wings which are a factory item and expensive to replace.

And we are all daft.....Andrew

Well that's fair enough......good to know I'm not alone in being daft :D

Well done Saturn
 

A huge well done to you Andy.

The MX5 donor option is a huge step forward in the development of the Haynes Roadster :cool:

Even more delighted that you are willing to share all of the development work with us mere mortals :D

Having watched Saturn go from strength to strength, I have nothing but admiration for all that has been achieved in such a short time.

Customer service and promoting the Roadster as a self build concept, as allways, first & foremost.
Passion for the brand ahead of just making a quick buck .... What more can you say :)

Look forward to following your progress :cool:

That's great news! I love Japanese cars :) MX-5 was inspired by the classic British roadsters, and is a faithful modern tribute to them, their direct descendant.

However, pragmatically, I'd be more enthusiastic about a BMW donor. MX-5's are quite rare around here. On one used car ads board there are 37 Sierras and 5 MX-5's, the cheapest one having the asking price of 3500 quid, and over a thousand E36 Bimmers.

Sorry Albert but you cant please everybody. on the up side there are plenty of mx5 parts available and maybe you could put together of the 2, its mainly the suspension areas that are the awkward part of the crossover.

Regards....Andrew

Andy,
Do bmw builders a deal....say you will do the mods if they have a nice shade of pink for the bodywork:cool:

Interesting, very interesting :D

Any pictures yet Andy?:)

there'll be some tomorrow Mark ;)

Okey dokey :)

There you go Mark,

Started a build blog with pics on FlickR. Any constructive comments appreciated.....:)

Cheers....Andrew

http://www.flickr.com/photos/saturns...7625932340212/

Just had a wee nosey and looking good so far, of course I asked a few daft questions and left some ideas/thoughts for you:)

Looking good !;)

I like the way the rear suspention is mounted to the upper wishbone but i carnt see how you can change the camber adjustment!
Do you plan have no rear adjustment. (just a thought)

Hello Mick,

I did put it in the comments but i'm going to put the adjustment on the lower wishbones now i've decided on the uppers. Tranny tunnel needs widening at the rear slightly then the front to be done.

Cheers....Andrew

Sorry andy missed that one diden't read all the posts just looked at pics mate!
I had to make new rear lower wishbones for my car the mx5 wishbones were no good. The power of the bike engine totaly destroyed the rubber bush ended up having to make heavy duty wishbones with a nylon bush.
Good luck with the design its looking well.

It's looking good Andy. However I do have 1 comment about the proposed rear camber adjuster. You say there will be 2 threaded inserts on each side of the wishbone, so if i understand it correctly you will have 4 camber adjusters for the rear of the car, 2 each side?

If so then I'm not entirely sure as to how good of an idea this would be, as it would mean that it could be quite easy to add some toe-in or toe-out to the rear wheels, meaning that you could end up in the situation of scrubbing the rear tyres, or even with the rear wheels being set at an angle so that the car will have a tendency to turn around the rear wheels even when trying to drive in a straight line.

I'd say it's the other way around: you have an easy way to zero the toe on the rear.

Mx-5 Donor - SSC
 

As you are most likely aware there are quite a few Mx-5 builds in the states on the LocostUSA site. Check out Scotts 1999 Miata on the completed builds section . He machined neat brackets that use the stock eccentrics for the rear camber and toe adjustment. His car ultilizes stock a-arms but i am using the same setup with Haynes a-arms on my Miata based build that is still in the design stage.

Cheers Mick,

Yes i'm not too keen on the rubber bushes either.

The rear lower arm adjusters will be 2 on each arm Tatey, you will have to screw them in and at in unison. But as Alga says you will be able to make small amounts of toe adjustment with them. I also plan to have the same setup on the front lower wishbones to allow castor adjustment to front uprights.

Thanks ffoyd, found the LocostUSA site but cannot find a link to Scotts page if you have one.

Many Thanks.....Andrew

still stuck on the pink bodywork idea are we mark. :D

Pink and black...........:D

Added a new set of pics for the G20 strip down and fitting into roadster:

http://www.flickr.com/photos/saturns...7625812138411/

Regards....Andrew

Here is a link to Scott's 1999 Miata build .The adusters allow for 10mm of toe or camber change. I might still use use the Haynes setup on the upper a-arm for major camber changes.
http://www.locostusa.com/forums/down...5513&mode=view