v8kid
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| posted on 17/2/05 at 08:44 AM |
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Why Bother?
As I see it there's not a very good case, if at all, for most mid engined road cars - so why bother?
The Locost concept works very well for lightweight medium powered (say 200 hp) cars, there is loads of operating experience out there to draw on and
specialists abound - so why mid engined?
I agree it is different when engine power rises above 300hp, with current tyre technology the main consideration is then to get as much weight above
the driven wheels and fit the widest rubber available.
But this solution has a big drawback the moment of inertia drops - great for responsiveness in turn in but the ride quality is a pile of mince and the
handling's twitchy.
If you doubt me compare driving a MGF to a MX5. Which would you prefer to travel a couple of hundred miles in?
So as I see it there's no place for mid engined road cars particularaly those based on mid powered front engined drive trains. Slightly
different if we are considering track day/sprint/hillclimbers but most on this forum 'aint.
Anyone think differently?
Cheers
David
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shortie
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| posted on 17/2/05 at 09:03 AM |
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Yep, I think different, my Elise was great fun to drive on the road and track.
Personal choice I guess.
I'd drive the MGF everytime, MX5 is for hairdressers only! 
Rich.
[Edited on 17/2/05 by shortie]
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smudgersmb
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| posted on 17/2/05 at 12:39 PM |
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Whilst I agree with some points, I think mid-engined is a lot of fun, I have the best of both worlds, fantastic steering due to Mini rack etc and
power/weight on the rear wheels giving me better traction.
Proud Mosquito Owner (1 of 10)
Smudger
 
Rescued attachment Green 2.JPG
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Alan B
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| posted on 17/2/05 at 01:06 PM |
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Ok I'll bite, although I can't believe this is a serious question........
Why bother building your own car at all?.......makes no sense at all when you look at it logically.
So, if you aren't particularly logical and want to do it anyway, then why not a middy?
Then the practical side of things.....over here in the US there isn't an obvious equivalent to the Escort/Cortina/Sierra....yes there are some
suitable donors, but a hell of a lot more FWD donors.....
So they are my reasons....but of course I don't need to justify my decision.
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ned
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| posted on 17/2/05 at 01:13 PM |
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I recently bought a peugeot 205 1.9gti which is rather fast, handles well, why bother building a locost when the above car only cost me £500?
It's a hobby, it's fun, you can do what you like, to your own design or otherwise, satisfying, learn/develop/hone
engineering/manufacturing skills, learn about mechanics etc etc
need i go on?
mid engine is better weight distribution for better balance in a car, maybe only shown on track, but i bet a lot of finished cars onhere have/will go
on a track at some point, so the benefits will be realised.
Ned.
beware, I've got yellow skin
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sgraber
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| posted on 17/2/05 at 02:49 PM |
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Believe it or not your choice in engine placement all relates to your preference in women. Some men prefer a buxom woman, with the weight all up
front, and some prefer a woman with a nice derriere, with, you guessed it the weight at the back. Of course almost everyone likes a well balanced
woman, with some weight transfer to the front when pushed hard... But I find that a woman with a small, powerful engine placed in the back offers more
performance potential in the curves...
Ok, I'll stop there! But I think my argument has more validity than the first post! 
Steve Graber
http://www.grabercars.com/
"Quickness through lightness"
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wheelsinsteadofhooves
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| posted on 17/2/05 at 03:48 PM |
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hear hear graber!!!
is this for real? ever driven a middie in anger? if well designed/set up it knocks ANY fwd car for six. why do you think all serious race cars have
the motor round the back? and if you cant appreciate handling finesse even at non-racing speeds, youve got the sensitivity of a potato.
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kb58
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| posted on 17/2/05 at 03:56 PM |
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The Locost concept works very well for lightweight medium powered (say 200 hp) cars, there is loads of operating experience out there to draw on
and specialists abound - so why mid engined?
I live in the U.S. Where do we locate an easy-to-find 200hp 4-cylinder engine driving the back tires?
I agree it is different when engine power rises above 300hp, with current tyre technology the main consideration is then to get as much weight
above the driven wheels and fit the widest rubber available.
With 60% weight on the rear wheels, a mid-engine car will stop much faster then the equivalent front-engine version (case in point, Porsche). Light
front-engine cars of even modest power easily spin their rear wheels in lower gears, mid-engine cars do not.
But this solution has a big drawback the moment of inertia drops - great for responsiveness in turn in but the ride quality is a pile of mince and
the handling's twitchy.
What does moment of inertia have to do with ride quality? That's shock damping, spring rates, roll-bar stiffness, and wheelbase. If anything
it'll be better because the seating position is closer to the CG giving less pitch. Handling depends on lots of things including all the above
+ steering sensitivity.
So as I see it there's no place for mid engined road cars particularaly those based on mid powered front engined drive trains.
Apparently a lot of people think differently; consider the Lotus Elise.
"Anyone think differently?"
An odd thing to ask considering where you are. You're making the assumption people on the mid-engine list know about as much as Locost builders
when it comes to vehicle design. No - Locost builders don't design anything, they just follow instructions in a book. The people here are
self-taught chassis and suspension designers who at least have a clue.
Your ball.
BTW, are you, as your avatar claims, building a Midi? Regardless of the answer, you're either misrepresenting yourself, or very unhappy with
what you're building!
[Edited on 2/17/05 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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kreb
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| posted on 17/2/05 at 04:04 PM |
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I think that the V8 kid is yanking our chains. Note that he says that he's building a middy. Wither he's having a bit of fun at our
expense, or he's realized that he's over his head and wants to... well I dunno, want's something.
(opening the envelope) The best response goes to....... Graber (Although I tend towwards the top heavy in my taste in women )
[Edited on 17/2/05 by kreb]
https://www.supercars.net/blog/wp-content/uploads/2016/04/1966_FiatAbarth_1000SP1.jpg
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kb58
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| posted on 17/2/05 at 04:52 PM |
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Yeah if you look at the threads he's in, it's mid-engine V8 stuff... go figure.
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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chunkielad
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| posted on 17/2/05 at 04:59 PM |
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I think he wants to build a Middy and has the right to ask the question to see if everyone else agrees - nothing like a good debate!!!
Well, here's y tuppence worth.
I'm building a middy cos I can!! No really - a custom bodied car will usually look better if it's a middy. With a Bike engined Middy,
(like mine) the weight on the rear will be very usefull considering how light the car is going to be and the porwe rgoing throught he rear wheels.
I haven't designed a chassis as such just modifying the LOCOST one and building around it. I don't have the knowledge just yet to design a
whole new chassis at the mo. Driving it is going to be better than anything I've driven before HOW EVER I DO IT!!!!
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kb58
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| posted on 17/2/05 at 05:48 PM |
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quote:
Originally posted by chunkielad
I think he wants to build a Middy and has the right to ask the question to see if everyone else agrees
He must not want to build one very badly if he's decided there's no point.
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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Geoff011
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| posted on 17/2/05 at 10:45 PM |
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He posted 6 weeks too early - should have been April 1!
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robinbastd
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| posted on 17/2/05 at 11:01 PM |
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Following Steve Grabers train of thought....I'm building a middy AND my wife has a great arse. Consequently I am a happy bunny.
Only a dead fish swims with the tide.
http://smuttygifts.com/
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cymtriks
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| posted on 18/2/05 at 12:00 AM |
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You are partly right.
For a mass produced road car it's mainly an issue of whats in the corporate parts bin and what the market will buy.
When faced with a parts bin full of transverse engines and a market that hasn't spotted the fact that no serious race car has a transverse
engine then that's what you build. As soon as the budget grows car makers usually ditch transverse layouts for middy cars and go
longitudinal.
For us Locosters we're faced with a rapidly diminishing supply of front engined rwd donors and a rapidly growing supply of transverse engined
donors. So a big slice of the future is transverse engined middy for us.
As regards driving, acceleration, agility and braking in a straight line are better with a rear weight bias. However other aspects of handling may be
worse. Middys have a reputation for being more easy to spin for example. Ride quality does suffer when polar moment of inertia goes down, that's
one of the reasons why luxury cars are big!
I reckon it's still the case that a front engined home build is easier to sort out than a middy from a handling point of view. I'd be
surprised if a transverse engined middy ever seriously challenged a Caterham in this respect.
Oddly, if you work through the maths of the issue front wheel drive with a rear facing longitudinal engine, as in the Citroen Traction Avant or Miller
race cars of the 20s have the absolute highest cornering speeds. However they have zero adjustability at that point of maximum cornering speed so one
twitch and you're off. Other layouts have lower ultimate cornering capability but much bigger (its relative!) margins at the limit so they
actually go faster on a real road.
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Dale
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| posted on 18/2/05 at 12:35 AM |
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I myself am building a front engined kind of Frankenseven--long wheelbase late 1930s ish thing. I have only driven one mid or rear engined car - if
you dont count the beetle. The fiero gt was a fun car to drive responsive but a bit twitchy-- but thats what made it fun. I started out in this
nonscence by going to go and buy a porsche 914-- but luckily I was too big to be able to drive it. I think the choice of the front engined sevenish
car is the open wheeled roadster more than anything else.
Dale
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Fred W B
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| posted on 18/2/05 at 06:04 AM |
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What Cymtricks said.........
When I first started talking to people about my project, several people assumed I would be doing it with a tranverse engine, and we have a race class
out here that is like that. But looking at them, where does a decent length rear upper wishbone go?
Those we are building, how long have you manged to get the rear upper link, or what else have you done regarding rear suspension layout (if not
retaing a McPh strut, Stratos style)
Cheers
Fred WB
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TheGecko
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| posted on 18/2/05 at 07:25 AM |
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When I first saw v8kid's message I wasn't going to reply as I thought he was just taking the piss. But, given the number of responses
(although, notably, none from David himself), I'll throw in one of my own.
I think David's remarks suggest a somewhat narrow view of the sports car world perhaps coupled with limited actual driving experiences.
My reasons for building mid-engined are many, most of which have already been mentioned by others. The primary one is the desire for a compact,
nimble car, optimised for Sunday runs in the mountains. The second was the neccesity of using a recent drivetrain to meet emissions requirements here
in Oz. The third was the "because it's different" factor - something we all should be familiar with
Re Fred's question about rear suspension. When I started out I went to-and-fro for a VERY long time about rear suspension options. As you
know, true wishbones don't fit; multi-link is not much better; de Dion is a possibility; or I could retain the struts. Re-using the struts is
attractive to me for a lot of reasons:
- it's cheap! Alloy sleeves to convert my struts to coil-overs cost < AU$40 each.
- it's compact. Simple packaging means simpler build.
- it's simple - in the sense of adjustments, of which there are less. Not as few as a de Dion, but less parts.
- it's cheap! (did I mention that already )
Seriously though, Lancia made it work well on the Stratos, Lamborghini made it work on the Urraco, and Toyota definitely made it work on three
generations of MR2. I should be able to get tolerable behaviour for my purposes.
Dominic
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v8kid
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| posted on 18/2/05 at 09:12 AM |
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Thanks for all your replies chaps I assure you I am Serious if a little frivolous to get the debate running.
I guess we are all in this because as Ned says it's our hobby/fun/learning/developing/hone skills - can't put it better myself.
The internet in general and forums like this specifically are fantastic ways to achieve these aims but the trouble is there are a lot of myths
circulating which simply 'aint true.
It's so easy to get involved in the detail of "how to" in a project that we, or at least I, forget to look at what we want to
achieve.
Some of those myths or partial myths are - better weight distribution, lower MOI, better traction, quicker turn in and so on.
I sprint, hillclimb and weekend drive a 25 year old v8 front engine car with 50/50 weight distribution but quite a high MOI - never used to have a
problem with traction modern tyre technology and engine management systems take care of that and all the chaps I compete against have front
engines/rear drive. None of them suffer these alleged problems.
The trouble is I got a new engine going from 3.6 to 5 liters and a bit wilder tuning. Now I have a serious traction problem to the extent that
I'm running the old engine. - hence the midi interest.
You could say my sole interest was traction but at what price? Some tracks are bumpy, certainly here most roads are I don't want my car to be
undrivable on the limit 'cos it pitches all over the place ('fraid low MOI does cause this) and if i adjust it out with dampers/springs
the wheel rates will go to pot.
Also I admit I'm no Schue I need some stability at high speed another problem with midi's
At the end of the day I've no option but to go mid engined but I'd rather do it with my eyes open and I just can't see the logical
case below 200- 300 hp (lightweights excepted).
Logical reasons I said, there are better reasons as others eloquently pointed out, preference for women or just 'cos you can seem like MUCH
better reasons than stuffy logical reasions to me - the bugger is they dont make you go faster.
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chunkielad
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| posted on 18/2/05 at 12:45 PM |
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Ferrari and porsche make midis and they are designed to be very fast. Can't be that bad an idea.
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Fred W B
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| posted on 18/2/05 at 02:17 PM |
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Most Porsches are rear, not midengined (being pedantic)
Cheers Fred WB
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Alan B
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| posted on 18/2/05 at 02:34 PM |
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quote:
Originally posted by Fred W B
.......Those we are building, how long have you manged to get the rear upper link, or what else have you done regarding rear suspension layout (if not
retaing a McPh strut, Stratos style)
Cheers
Fred WB
Fred check out my site if you like.
http://www.desicodesign.com/meerkat/index.html
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kb58
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| posted on 18/2/05 at 03:36 PM |
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And you can see my approach here:
http://www.kimini.com/Diaries/2004Winter/rear%20suspension.JPG
http://www.kimini.com/Diaries/2004Winter/rear%20suspension2.JPG
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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Alan B
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| posted on 18/2/05 at 04:02 PM |
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Interesting how we both end up with 3 brackets down each side of a vee.
Re. your second pic.
http://www.desicodesign.com/meerkat/images/020202_rear_bracing.jpg
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kb58
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| posted on 18/2/05 at 04:46 PM |
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Well huh, I hadn't seen that picture before. Doing it again I'd use a different mounting style on the lower arms. While what I have
works, it's a real bitch to get at.
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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