Guinness
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| posted on 19/8/06 at 12:07 PM |
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Mid Engine Conversion
Can anyone help me out with a few questions:-
There was a company exhibiting at the Harrogate show who specialised in rear / mid engine conversions for supermini's (Saxo Punto Corsa etc).
Can anyone remember their name or contact details?
If you put an engine in the back of a supermini like that does it have to be sva'd or can you just get it MOT'd and put it back on the
road?
Can I keep the original supermini front hubs? Can you cap off the hole for the drive shafts or do you have to use RWD front hubs off a cortina /
sierra?
Is there anyway of getting a 4wd drive train like the old Group B 205 Rally cars without spending mega money?
Finally, if I wanted to use a post '95 3lt V6 with fuel injection would I have to use the donor catalytic convertors to pass the emissions
tests?
Cheers
Mike
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iank
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| posted on 19/8/06 at 01:17 PM |
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JMA is the name of the company
Web site here -> link
If the chassis is chopped around that much I believe SVA is required. Though it's probably easier to 'get away with it' than an
obvious kitcar. JMA SVA their cars.
You can just cap off mini front hubs - been done like that for years on mini midi kitcars (GTM etc), but I don't know about generally on FWD
cars. Probably depends on how the bearings are retained.
Don't think you need the donor cat's specifically, but you will need a cat of some kind.
[Edited on 19/8/06 by iank]
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Guinness
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| posted on 19/8/06 at 02:00 PM |
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Thanks Iank
Mike
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froggy
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| posted on 19/8/06 at 06:07 PM |
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i really wanted to build an rs200 replica but the cost was out of my league  i lookes around for a donor to build a 4wd middie but came up blank so
converted a rover v8 bellhousing to mt75 4x4 box and used xr4x4 front uprights on my indy chassis much the same way as dax do their quaddra kit
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rav
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 posted on 20/8/06 at 01:14 PM |
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Just logged on to see what peoples opinions are on suspension design for middys, especially roll centres and how much caster is needed on the front
uprights??
It sort of related to this thread - I'm putting a 3L Alfa V6 into the back of a Fiat cinquecento. Its nearly at rolling chassis stage and has
been relatively simple so far...
I used all the mechanical bits from the front of an alfa 164 which means all I had to do to the cinq shell was cut the back out and make 4 mounting
points for the 164 (front) subframe and strut tower tops. These "strong" points then get linked together by the cage, with lots of
triangulation!
This means the track width is the same as a 164, which is about a foot wider than the cinq - perfact for a group B style car!
I then wanted to widen the front track to the same as the back. I decided cinq front struts n springs would probably be too stiff given how light
the car will be at the front and opted for MR2 mk1 struts complete with uprights, hubs and brakes. Longer fabricted tubular wishbones link these to
the original wishbone mounts on the shell (which happen to be in about the right place and of quite a good design), with new strut tower tops grafted
into the shell. Being a fair bit wider, the strut tops are now half in the front wings, but no worries as the cage will extend forward to them.
One big advantage of the 164 v6 is that its engine wiring loom is seperate to the main one for the car. Getting the engine running only involves
connecting about 4 wires to positive and giving it some fuel!
So far so good, it should be quite a quick car (192bhp, loads of torque and rounghly 800kg) and cheap (so far £600, aiming to stay under £1000
completed) and loads of fun on trackdays!!
Have been wondering about road legality myself, probably best to go for an SVA I suppose to be on the safe side as far as the law is concerned...?
As far as 4x4 mid engined hatchbacks go, I reckon the ultimate (both from a performance and cost POV) way would be to mount an engine and box
longitudinally, but facing the opposite way to normal, eg gearbox infront of the engine. Then find/make a simple transfer case (eg two gears in a
box) which drives off the end of the greabox and steps the drive sideways linking to two prop shafts, one running forwars, one back to the front n
rear diffs. Sorry its hard to explain without a drawing/picture!
V similar to am RS200 except thay had the engine and box seperated by a long "prop" shaft, I presume so the weight of the box could be
right up at the front.
Anyway, I've rambled on for long enough, if anyonw has any thoughts on what sort of F/R roll centres I should aim for or how much caster is
needed to get nicely weighted steering on a middy with axle weights of about 500kg R and 300kg F I'd love to hear from you...
Mark
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Guinness
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| posted on 20/8/06 at 04:17 PM |
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Hi Mark
Welcome to the forum. I think I saw your V6 under a tarp on a trailer at Geoff's house a while back. Certainly sounds an interesting
project.
Can't help on roll centres or castor I'm afraid.
Mike
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kb58
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| posted on 20/8/06 at 06:48 PM |
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It very much depends what you're doing. Casual cruising means it doesn't matter. Drag racing, you'd want them at ground level
(though with a live axle it's harder to place.) Road racing? It depends on your CG height and how much the car is expected to lean.
The roll-center placement depends on the centroid axis, at least that's how I calculated mine. To answer your question requires knowing the CG
locations of all major components. Anyhow, for my mid-engine Mini I choose a 2" front and a 4" rear. Is that correct? I don't
know, but I do know the car has a very balanced feel.
About caster, it's a very subjective and personal thing. How much of a "return to center" feel do you want? For your car I'd
guess around 7 degrees or so... but that's just my opinion.
Mid-engine Locost - http://www.midlana.com
And the book - http://www.lulu.com/shop/kurt-bilinski/midlana/paperback/product-21330662.html
Kimini - a tube-frame, carbon shell, Honda Prelude VTEC mid-engine Mini: http://www.kimini.com
And its book -
http://www.lulu.com/shop/kurt-bilinski/kimini-how-to-design-and-build-a-mid-engine-sports-car-from-scratch/paperback/product-4858803.html
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v8kid
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| posted on 22/8/06 at 12:04 PM |
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I'd go with KB the important thing is to get the front roll center lower than the rear as this adds nice safe understeer characteristics at the
limit.
I found that 7 degrees negative was too much for my car and the straight line braking suffered. I ended up with 3 degrees determined by tyre
temperatures over a number of different courses. Interestingly I should set different cambers each side depending on the course - can't be arsed
though its too much hastle with all the other stuff going on at the same time.
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kb58
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| posted on 22/8/06 at 01:37 PM |
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FWIW, I run 5deg caster and (for me) it's a bit light. The amount by the way very much depends how much weight is on the steered wheels. The
lighter the car the more you need.
About the RC locations, in general you want it higher at the end with the higher CG, and of course lower at the end with the lower CG.
[Edited on 8/22/06 by kb58]
Mid-engine Locost - http://www.midlana.com
And the book - http://www.lulu.com/shop/kurt-bilinski/midlana/paperback/product-21330662.html
Kimini - a tube-frame, carbon shell, Honda Prelude VTEC mid-engine Mini: http://www.kimini.com
And its book -
http://www.lulu.com/shop/kurt-bilinski/kimini-how-to-design-and-build-a-mid-engine-sports-car-from-scratch/paperback/product-4858803.html
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