MR2 Donor?

[Renrut]

It's been a while since I've shown my face on here, my roadster plans fell by the wayside when I got distracted by a cute 21yr old.

After a wonderful 6 month affair, a looming MOT and a bit of investigation has shown the 21yr old to be very very rusty and economically not worth saving - the repair panels alone are worth more than the car.

The 21yr old in question is a 1987 MR2 mk1 1.6. My question is, with a bit of ingenuity could I turn the roadster chassis into a midengine one using the MR2 mechicals?

Are there likely to be any pitfalls in doing this? Would it simply be a case of lengthening the rear end to accomodate the engine? Or would it be better to build something from scratch based on the MR2 wheelbase?

I think fitting the drivetrain into a Roadster would certainly be possible, as you say you'd have to extend the rear of the chassis to take the engine. I'm not familar with the suspension set up on the MR2, does it have a sub frame carrying the engine and suspension?

Cheers

Chris

[Renrut]

The engine and gearbox in the MR2 is mounted transversely as a unit to the monocoque chassis via 4 engine mounts, in the big rectangular box that is the engine bay. If I remember correctly, it's 2 on the engine and 3 on the gearbox. The engine sits forward of the diff so it gives true mid engined positioning.

Suspension on the MR2 is fully camber/caster/toe adjustable mac struts all round, again mounted directly onto the chassis. I'd love to be able to use them to save costs but I imagine that would be quite a task compared to a double wishbone setup. Has anyone tried converting the roadster to use mac struts in some fashion?

Edit to add in picture shamelessly linked from the MR2 online parts catalogue ran by the owners club. The picture shows the mount locations, 2 on the engine high up near the top right, 3 on gearbox low down on left side.
http://opc.mr2oc.com/online_parts_ca...e%20mounts.GIF

[les g]

hi renrut
take a look at the MEV Rocket you you might be able to combine some of that design with some of the roadster
cheers
les g

[Renrut]

Very Ariel Atom but distictive and I think I prefer it. Maybe borrowing the rear end chassis from that MEV Rocket and the front and middle being Roadster based but with variations to take account of the lengthened rear end, e.g. shorter front.

In my hunt for MR2 mk1 based kit cars I came across this: http://www.grabercars.com/

The fully built price is a bit scary ($25K) and the kit isnt even fully designed/written up yet. Lots of credit to the guy though as it looks well thought out. It gives me something to work from but I think the shape of the body is dull.

I'll draw up what I'd like for the body work and post it up so you can see what I'm thinking bodyshell wise although I suspect it would be far too heavy/time consuming/impractical/aerodynamically dangerous to make.

[3GE Components]

At todays exchange rate that's only £12500, not that expensive when you consider a lot of people spend about that building a locost.

Steve spends a lot of time here, www.locostbuilders.co.uk , I think his whole build is detailed on the site. From the amount of track time he's put in i'd say the design is quite well proven.

ATB

John

[Renrut]

Thats still about £10000 more than I was planning to spend on building a roadster

I did originally see his designs on Locostbuilders, I have a lot of respect for the engineering behind the chassis as from what I've seen its well thought out and well executed. I'm just not too hot on the body shape.

But either way £12500 is well out of my price range. I could buy a TVR Cerbera for that. Admittedly not the same kettle of fish but with TVRs spannering is all part of the ownership experience

I could buy the plans for Steve's car which I think we're quoted as $99, which doesnt sound too unreasonable. This would probably same me a lot of ache trying to get the rear end right.

My intention was to use as much of the original MR2 as possible to cut down on costs which would include using the original suspension setup if I can work out a way of doing it without making it far too heavy. Neither Steve's Le Bala or the Roadster makes use of it so I'd be on my own there anyway.

In terms of mounting the engine and gearbox behind the driver in the roadster chassis, initial checks show it would fit without enlarging the rear end too much although the wheels would be mounted further back. The MR2 engine bay is approx 550mm X 1050mm. I could compensate for the extra length by shortening the engine bay area of the Roadster. I think I need to make some measurements on my MR2, in terms of where the suspension fixing points are and compare these to the roadster. The MR2 mounts the fuel tank in what would be the transmission tunnel and I would gain storage space at the front too.

[3GE Components]

The best place to look for suspension ideas using the MR2's suspension would be the Lancia Stratos, or Hawk Cars replica. This might provide the answers you're looking for.

ATB

John

[Renrut]

Looked at the Stratos kits but I can't find any good naked chassis photos.

However I have discovered on stripping down the MR2 some more and having a good look that most of the suspension mounts off subframes bolted to the chassis beams so maybe it wouldn't be so difficult after all. I think I need to spend quite some time with The Book, solidworks, the MR2 chassis and a tape measure.

[3GE Components]

There was a thread on www.locostbuilders.co.uk by a guy called Cymtriks, it was all about how to stiffen up the locost chassis but at the end of it there was a bit about a midi chassis. He has a couple of pictures in his gallery.

http://www.locostbuilders.co.uk/phot...&user=cymtriks

You do need to be a member to view.

ATB

John