masseyis
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| posted on 20/6/08 at 10:18 AM |
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General Midi Q's afore I start thinking
Hi,
I'm just starting to plan a Locost build, but I think I will be deviating from the books quite a bit for budget, availability and design choice
reasons. I think I'd like to make it a mid-engined build, which I'll design thoroughly before starting (former Aero student with Pro-eng).
I wonder if anyone can help with my general midi questions, before I get too far down the thought/design processes. I'd probably like to make
something very similar looking to the locost, but use a Renault 5 GT turbo engine transverse mounted behind the driver. If I do this:
Presumably, I'll need to turn the transaxle upside down unless I want to go backwards? Is this safe/workable?
Is it sensible to move the radiator and fuel tank to the front and extend all the plumbing?
Will I still need to find a RWD drive donor to get the front steering assemblies?
Is there any reason the Haynes style rear suspension won't work fine?
Am I wasting my time not simply following the book?
Thanks in advance for any help - I'm sure all this is answered elsewhere, but I can't find it 
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Hammerhead
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| posted on 20/6/08 at 10:27 AM |
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take a look at mk engineering website, he is making a midi that looks a bit like a 7. Might inspire you.
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Ivan
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| posted on 20/6/08 at 10:37 AM |
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Not sure why the transaxle will have to be turned upside down - most fwd engines work just fine when moved to the back in a middy configuration.
Unless the motor and gearbox you envision using is from a rear engine design. In which case why complicate your life when there are so many more
suitable engine choices to choose from?
Have a look at other kit cars that have already done what you intend for inspiration - the Riot springs to mind.
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masseyis
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| posted on 20/6/08 at 10:52 AM |
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Yes, the MK engineering build is pretty much exactly what I was thinking of. Thanks.
I was planning on taking engine, gearbox and transaxle straight out of the FF Renault 5 and spinning it round to the back, but surely that would now
go backwards, so I presume something must be reversed or upside down to go forwards? Or am I being dumb?!
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Fred W B
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| posted on 20/6/08 at 11:13 AM |
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You just move the drive train backwards. leave the left wheel as the left wheel etc etc. You just sit in front of the engine instead of behind it.
some thoughts in this thread
http://www.locostbuilders.co.uk/viewthread.php?tid=76650
Welcome
Regards
Fred W b
[Edited on 20/6/08 by Fred W B]
You can do it quickly. You can do it cheap. You can do it right. – Pick any two.
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masseyis
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| posted on 20/6/08 at 11:28 AM |
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Ah. I see. I just found the engine/drive train assembly pic for the Mojo (now that looks good!) and I see what they've done - it becomes RR,
rather than MR. The engine continues to sit straight over the axle. Would this make it pretty rear heavy in corners? Probably actually makes the
power/drive assmably much easier even than the Champion Locost, I guess.
The Sylva cars still use Sierra fronts - I take it there's no way around having to find a RW car for the front?
Thanks - you guys are QUICK on the responses!
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Alan B
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| posted on 20/6/08 at 11:39 AM |
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These are my answers for you....
Q- Presumably, I'll need to turn the transaxle upside down unless I want to go backwards? Is this safe/workable?
A - As the others have said...if the engine is already ahead of the front axle line it then be ahead of the rear axle line..perfect
Q- Is it sensible to move the radiator and fuel tank to the front and extend all the plumbing?
A - If necessary that is perfectly acceptable
Q - Will I still need to find a RWD drive donor to get the front steering assemblies?
A - Not necessarily....custom made or modified FWD parts will work too.
Q- Is there any reason the Haynes style rear suspension won't work fine?
A - With appropriate geometry, no reason at all.
Q - Am I wasting my time not simply following the book?
A - You will inevitably delay completion, no question. However, you will end up with what YOU want.....just be prepared for a lot of work.
HTH
Alan
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TheGecko
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| posted on 20/6/08 at 11:55 AM |
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As others have said, a FWD engine is not generally behind the axle line. Here's a photo of the 20-valve Corolla drivetrain I was
originally going to use in my middy. Long story about why I'm now using something else but the basic layout is common to the vast majority of
modern transverse FWD cars.
[img][/img]
As you can see, the axle line is on the left (three lobed inner CV joint visible). The front of the whole package is to the right of picture i.e.
almost all of the engine is forward of the axle line except the alternator and some of the plenum.
With regard to RWD suspension - as Alan says, you can use FWD assemblies with some work. There are usually RWD donors that suit - you just need to
think about what your drivetrain donor is. The Mojo uses Sierra because its a) common and b) same 4x108 PCD as all of its Ford brothers (including
the Fiesta). My donor drivetrain has a 4x100 pattern (very common in small to medium FWD) and two readily available front suspension donors are
Chevette (Holden Gemini here in Australia) and Mazda MX5 (NA & NB series). Start with your donor drivetrain PCD then look around at possible
front suspension donors.
I'll echo the other replies too - be prepared for a fair bit of "two steps forward, one step back" as you strike out into new territory
Good luck,
Dominic
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John Bonnett
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| posted on 20/6/08 at 02:47 PM |
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Hi, I've done a similar thing using a Peugeot 205 engine and box. You do not need to turn it round and it will operate in exactly the same way
as it did in the front. Even the gear lever operates in the same way. I took the easy way and kept the engine on the subframe and used the McPherson
struts as well. I needed to find calipers with the handrake facility and Citroen BX filled the bill as their handbrake is on the front wheels.
On the front, I used "Book Suspension" with Cortina uprights. I fell into the classic trap of using the Peugeot steering rack and when you
turned the steering wheel to the right, the car turned left. A left hand drive rack turned upside down sorted that out.
Best of luck with your build
John
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kb58
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| posted on 21/6/08 at 03:49 PM |
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Here's my scratch-built carbon-shell, Honda-powered mid-engine Mini, http://www.kimini.com
And here's the next car currently in design, very much as you're describing, www.midlana.com
<self-promo alert> I sell a book that explains how to make it all work, in sig.
[Edited on 6/21/08 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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masseyis
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| posted on 23/6/08 at 01:13 PM |
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Ah. Handbrake! That's a good gotcha that had slipped my mind.
I plan on buying the Kimini book, actually. I thought it looked like it would have a lot of answers to the questions I have. I'm going to get
that book and read it and start looking for a donor car, then design the thing based around the dimensions of the engine from the donor.
Thanks for all your help
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