Conference terri::cars_uk

	Given that most of the weight is at the back, even with the engine
	in front of the rear wheels, power understeer is a characteristic of
	mid-engined cars.  As you accellerate you put weight on the back 
	wheels and lose it from the front, steering, wheels and thus, lose 
	some of your turning ability.  Ease off and get the weight back onto
	the front wheels and they'll start to bite and turn.

	I noticed an understeer, but I wouldn't say that it was dramatic, not
	even with Bill driving.  However, I judge cars relative to the Marlin
	which does understeer in a similar way.  Having a 50/50 weight 
	distribution gives it similar handling features, if you discount the
	MR2's superior chassis, suspension and power (!). 

	As I understand it, and someone will correct me if I don't, most cars
	are designed to understeer, it being thought to be a safe 
	handling characteristic.  The only problem comes when understeer turns
	(no pun intended) into oversteer.  If this transition comes without
	warning, you end up watching scenery rotate.

    
    Yes, especially in slower bends its quite easy with the new MR2 to
    push the nose wide by applying too much power, too soon. As Dave
    said, quite correctly, understeer is 'designed in' to give a safe
    warning to the driver. At this speed, easing the power is all that's
    needed to regain the line.
    
    Be aware though, a car like the MR2 will tighten its line immediately
    that you reduce the power - if you're understeering severely and
    take your foot of the throttle too suddenly the resultant weight transfer
    can lead to oversteer as the rear tyres are suddenly unweighted.
                                 
    Bill.

    
    Thanks,
    
    as I say I was implying any criticism of the car, I was just
    interested.
    
    The Renault doesn't feel anything like the MR 2 and the Marcos
    certainly doesn't understeer anything like as much as the MR2 does.
    
    Does Derek's 23 understeer like this, or is it's purer (?) chassis
    designed to be more neutral?
    
    Bill, you say the new MR2 does this, did the old one do it less?
    
    Mark

	
	re -1.

	I saw this happen in a traffic incident near Valbonne a couple of weeks
	ago where a bloke driving a brand-spanking-new red MR2 16V (or MR as it
	is called in France for linguistic reasons - Would you drive around in
	a Toyota s**tty?:^) entered a bend too fast, lifted off suddenly and
        span. 

	Fortunately no one was coming the other way (he had just overtaken me)
        and he was OK but there wasn't much left of the car.

	From where I was (about 75 metres behind) it all seemed to happen very
	viciously and quickly. Perhaps he was too used to driving hot hatches
	where your right foot does not have to be so skilful to keep the car on
	line? 

    
    I didn't find the handling of the new MR2 that different to the old.
    It felt heavier, maybe not as 'coherent', and just a bit vague due to
    the steering (if it needed power steering, I wish they'ld use it
    rather than make the steering slower - that's one aspect where the
    new car suffers by comparison to the old). That said, it probably has
    higher limits than the old MR2.
                                                                      
    I don't think what you've seen can be classed a criticism. Planting
    your foot early in the bend pushed the nose wide, simply because of
    the available power. For what its worth, I'd expect the 23 to do the
    same, allbeit at higher limits.
    
    For example, compare a 1 litre Renault and a GTT. In a second gear,
    20 mph bend, floor the throttle. The 5GTT will understeer (if its on
    boost ;-) etc... The base model will pootle round. This doesn't mean
    the base model handles better...  
    
    The old MR2 is less powerful, but you can still push the nose wide
    if you are too heavy with the throttle (especially in the wet).
    
    Cars like the MR2 reward good technique - enter the bend under gentle
    acceleration, and use the power progressively as the road straightens.
    This doesn't mean you can't corner quickly, you can (as Dave implied!).
    Its just means that the car will do what you tell it, and not compensate
    as much for 'sloppy' driving (no criticism intended).
    
    Bill.

    
    You're undoubtedly right Bill, the MR2 is very different to drive
    to the Renault in corners (and not so quick in a straight line :^)).
    
    The reason I put this in a seperate note was that I suspected that
    the handling was a trait of mid-engined cars rather than any inherent
    fault in the MR2's design.
    
    I agree with you about the steering (although it was a lot better than
    the Celicas!) being a little vague, but the car still seemed easy to
    place through corners.
    
    One thing you must all remember about Renault 5 GTT drivers is that
    we are used to flooring the throttle just BEFORE the apex of a corner,
    otherwise we end up with irate XR2 driver's up our tails! :^) So please
    make a little allowance for our 'sloppy' driving.
    
    Mark

	I don't think the MR2 qualifies as a 'mid' engined car. Just
	because the engine happens to be in front of the rear wheels
	doesn't make it any more mid engined than a front engined car
	where the engine is behind the front wheels. It's mostly just
	hype. It's rear engined.

	Personally I prefer cars that understeer, they're easier and
	more forgiving to drive.

	-John

    Front engined = engine in front of driver
    Mid engined   = engine behind driver, centre of mass of engine in front
                    of rear axle
    Rear engined  = centre of mass of engine behind rear axle
    
    I believe there is a big difference in handling between mid and rear
    engined cars, which is why the distinction is made...
    
    Scott

    
    Scott's definitions match my understanding. Another point is that
    in the MR2, the engine isn't right at the back (it is in the 911),
    but in front of the boot.
    
    Oddly, they termed the BMW Z1 front-mid engined... 
    
    Bill.

    What does front-mid engined mean?
    
    In front of the driver, but behind the front wheels?
    
    Mark

>>    Oddly, they termed the BMW Z1 front-mid engined... 

isn't something like the 7 front-mid too (i've seen magazine descriptions
of it as such)

the engine isn't over the line of the front wheels (as is it in most front
drive cars)



...art?

    
    What's all this theory about under/overstear then, Derek? :-)

	By way of illustration consider these three cars -

	Lotus Europa  - Mid engined sportscar with very good handling.
	Lotus Elan    - Front engined sportscar with exceptional handling.
	Renault 16    - Front engined saloon with no handling at all.

	The interesting thing being that the Renault 16 and Europa both
	use the same engine gearbox arrangement, just that in the Europa
	it's pointing the other way. This I suppose means that the 16
	is front mid engined.

	'Mid' engined cars inevitably have an arrangement whereby the
	gearbox/final drive unit is attached to the end/underside of the
	engine and straddles the wheel line.

	Now in the Elan the engine sits well behind the line of the front 
	wheels and has it's gearbox poked well down the tunnel in the
	centre of the car, where it truly is in the middle. Hence the
	Elan is far more mid engined than the Europa.

	Rear engined cars can often be recognised by the fact that the
	rear tyres are wider than the front, a true mid engined car would
	have same all round.

	As a term mid-engined may be well known but literally it has no
	meaning. Can anyone think of a true mid engined car?.

	-John

    Sounds like a perfect case of oversteer! :^)
    
    Mark
    (Who spent most of Sunday TRYING to get his R5GTT to understeer anything
     like as much as an MR2. Now I SEE what an MR2 can do that a Renault 5GTT
     can't or is it just that MR2 drivers never go fast enough to experience 
     the real vices of their car? :^))
        

    
    I don't know, next you'll be trying to get an MR2 to torque steer...
    
    Bill.

    
    Re .18
    
    I could only get it to do that in reverse!
    
    Mark

    If you want to experience *real* spinning, try it in a glider!
    
    Jeff :-)

    Ooops, sorry - should have looked more closely at the title!  But
    try one, and you'll never want an engine again, mid or anywhere :-)
    
    Jeff.

                   <<< Note 1225.21 by NEARLY::GOODENOUGH >>>

>    If you want to experience *real* spinning, try it in a glider!
    

but at least a spin in a glider sorts its self out!

(its been a long time.. but I seem to remember the glider
instructor saying that as long as you have it trimed correctly
if you get into a spin (with enough height!) if you dont
know what to do then just let go of the controls.. and it
will sort its self out (ie get out of the spin) on its
own)

    
    Its sudden, noisy, and a bit embarrassing. You know the warnings
    were there, and you know you messed up. The tyres howl, just to
    advertise  your mistake. Inside, with standard seat belts and seats,
    it can be uncomfortable.
    
    The brakes don't have ABS, so you can lock them to spin in a straight
    line (useful point to remember, and practice, if you drive competitively).
    Its amazing how quickly the car does stop...
    
    Oddly, its also addictive. You need to try it again, and again...
    Not because spinning is fun, it isn't really; but the moments before you
    push yourself a bit too far, when the car seems balanced by the
    throttle alone and any steering corrections are subconscious, are
    memorable.
    
    Bill.

    Hello Derek,
    
    What's this about fitting a front spoiler to reduce understeer?
    The Golf should have had a 'deep front spoiler', but a previous owner
    has obviously kerbed it when parking and it's nowhere to be found!
    
    I did at one point inquire about the cost of replacing it, to make the
    car more complete.  I had also read that front spoilers improve
    'high speed' handling.  Wonder what speed this is?  I hardley ever go
    above 80mph on the motorway anyway.
    
    The cost would have been about �45 for it, so I decided against it.
    (BTW has anyone else noticed a new Escort rear spoiler being advertised in
    the VTX Engineering Noticeboard for �<mumble>)?
    
    Do you think there would be a dramatic reduction in understeer?
    Rob.
    
    p.s. Mr. Mod, please feel free to move this into a Spoiler topic if 
    	 many replies appear. 

    Front spoilers (on road cars) basically stop air getting under the 
    front of the car and lifting it.
    
    If the front lifts, the grip is reduced and you get understeer (as
    described in the case of the mid-engined car) the problem is that
    if you get understeer in a corner at 80 mph then it's more likely to
    be a serious problem than at 20 mph in a mid-engined car. Of course
    mid-engined cars are lighter at the front and therfore EVEN more 
    prone to front end lift.
    
    Mark

    
    Re.31
    
    Isn't that what I said?
    
    Mark

    Thankyou to you Derek, for explaining that understeer is not a problem
    on the motorway. 8-)
    
    Rob.

Wasn't it CAR mag which slated the MR2 for it's difficult handling ? Precisely
what the noter from France observed. I think the cover had some pretty graphic
illustrations of the point they made...

What I would expect from a competant car is initial understeer (message is 
"you're cornering now idiot"), followed by as near neutral handling as possible 
with understeer preferred but not lots of it. Buttoning off mid corner should
tighten the line, put weight to the outside of the car, right rear - make the
car squat a little. Terminal oversteer should very, very rarely happen.

French cars often seem to get it right (for me anyway).

    
    But WSC (World Sports Cars)  gave it their car of the year award.
    
    Mind you the version they tested was the least powerful
    
    Nigel
    

    If anyone is still intersted in the original topic :-)
    
    A friend of mine bought a MR2 (old version) a few months ago.
    
    Several days later she found herself spinning whilst taking a bend on a
    dual cariageway (couldn't have been too tight a bend). It had rained
    recently after a dry spell so the road could have been slippy.
    
    MR2s are not sold as being 'suitable only for experienced race or
    advanced drivers'. I suspect that they MAY have a serious safety
    problem in the hands of joe public.
    
    Any comments?
    
    	
    Peter

    
    .0 referred to the New MR2, not the old one.  The stick in the
    motoring press has also been towards the new MR2 and not the old.
    
    I'm a bit surprised about spinning on a dual carriageway.  I suspect
    that there must be more to this than meets the eye.
    
    Nigel
    
    

    
    While I was on holiday I read a copy of Fast Lane magazine.
    
    It had a number of articles on mid-engined cars and an editorial on 
    the mid-engined concept. Basically the gist was, yes M.E. gives you
    rapid response to steering input, but it also gives you a dramatic and
    sudden switch from understeer to oversteer, which front engined RWD
    cars do not and which can (they claimed) be made to handle just as well
    as M.E. cars, but within much greater safety margins.
    
    The suggestion was made that maybe the WSPC could be restricted to cars
    with front engine in an attempt to remove the artificial impression
    that only M.E. cars could be made to handle well. In theory, F.E. WSPC
    cars would be able to return a great deal of technical advancements in 
    the areas of passenger car aerodynamics and handling to mainstream car
    production which is seems M.E. cars will never be able to do due to the
    inherent disadvantages in the design (lack of space for passengers and
    luggage).
    
    Any comments from the pro or anti Mid-Engined lobbies?
    
    Mark

    
    The point they were seemingly making is that the regulations favour a 
    form of car design which has little practical application in the 'real
    world' and that forcing manufacturers into using a FE design would
    force them to research in that direction rather than ME. Obviously,
    no-one would race in a series dominated by ME cars and expect to be
    competitive with a FE car, but if they all had to be FE then the
    designers would have to find a way to gain advantages in such a design.
    
    Personally, I suspect many manufacturers would consider WSPC too
    expensive to produce FE cars for, but Saloon car racing does not allow
    much scope for devising new approaches to FE designs, whereas a FE
    WSPC would.
    
    Mark

    
    Yes, there are M.E. cars in production but they only form a TINY
    portion of the total of cars produced.
    
    Taking your points in turn as to things which can be applied to
    production cars with F.E.s :-
    
    Aerodynamics - No. Putting an engine in front makes the front of a car 
    very different.
    
    Suspension - Maybe.
    
    Tub design - This doesn't have a lot to do with ANY MASS production
    car.
    
    Gearbox and engine derivatives - I'll give you that.
    
    Rallying provides only as much development as Group A racing, which is
    not a lot. Front engined development effectively stopped when Group B
    cars were banned, but even then the manufacturer had to build 200 cars,
    which didn't make it a great basis for new ideas.
    
    Mark

    
    Re .47
    
    You're right, I was thinking of the original Group 4/B Audis, but
    everything after that was M.E., again because the rules favoured them.
    
    I'm not trying to make a case against M.E. cars here, they obviously
    have their advantages, but they do not, and probably never will, be a 
    practical form of car for the majority of uses, therefore there is a 
    lot to be said for having a form of racing which encourages advancement
    in the area of F.E. designs, which there doesn't seem to be at present.
    
    Mark

    Mark, the concept of trying to improve the FE cars behaviour sounds
    excellent to me. There's certainly space for a LOT of improvement.

	Sounds like Colin Chapman, he prefered front engined cars, he just
	couldn't win races with them...

	As for rules, you don't mean to say that sets of rules are made up
	to support/deter particular configurations/manufacturers?  Gosh,  
	you'll be telling me next that we live in a democracy...

	Dave

    In principle (!) a car like the new Lotus Elan (or maybe the BMW Z1)
    could be made to handle very efficiently. Engine (weight) is located
    just over (Lotus) or just behind (Z1) the front axle. All you need is
    some mechanism to make the rear end turn easily into the corner (rear
    wheel steering ?).

    
    The Z1 was classified front-mid engined, I think. Personally, I
    think its all a matter of preference.
    
    On the circuit, people should be able to use the configuration
    that works best (is front engined actually not allowed in the WSPC
    rule book?). Mid engined does seem popular. 
    
    
    On the road, people buy sporty cars according to their means, practical
    requirements etc. There are only a handful of affordable mid engined
    road cars available; a few years back, somebody in my position wouldn't
    have had the chance to own one. But, front engined cars are getting
    better all the time - the Peugeot 205, 309, the VW Corrado, the Lotus
    Elan and Excel and the Porsche 944 have all had rave reviews (now look
    at the list again, 4 of them are FWD!). 
    
    Conclusions aren't easy. For myself, I really enjoy mid engined cars.
    I also enjoy front engined cars and rear engined cars. And FWD, RWD
    and 4WD cars. The configuration isn't what counts, its the way the
    car 'feels' on the road, and the amount of involvement and feedback
    the driver gets that is important. Thats why I can't decide between
    a 205, MX5, NSX or 911!
            
    William.

    
    William (My, we are formal today - Did you enjoy your skiing?),
    
    The Group C rules do NOT exclude front-engined cars, it's just that
    they are not competitive with mid-engined cars (I never said that
    mid-engined cars didn't make better race cars, any idiot can see that
    that is true, even me and Colin Chapman! :^)).
    
    I agree there are good and (probably) bad cars made in all
    configurations (FE/FWD, FE/4WD, FE/RWD, ME/RWD, ME/4WD, RE/RWD, 
    RE/4WD), and each should be judged on it's merit rather than on any
    biased preconception. The trouble is, as in most things, everyone has
    their own preferences and it is hard to overcome those (can you see
    Derek buying a Z1?).
    
    Mark
    
    PS You're letting your prejudice show again. What about the car that
    one of the rags described as 'the best handling FWD car, Elan
    included'? :^)

    In model car racing there is almost a standard regarding engine
    possition:
    
    4wd Mid Engine/Motor 
    
    2wd (rear) Rear Engine/Motor
    
    2wd (Front) is not favoured because of the lack of weight over the
    wheels.
    
    The reason for this is fairly clear.  Rear (or Front) engine/motor cars have
    a weight distribution similar to a dumbell.  Try spinning a dumbell,
    hard to get moving and hard to stop (large moment of something-or-other
    inertia).  The practical implication of this is the car has good
    straight line stability, but once it spins it keeps going!
    
    Mid engine/motor cars are more like a ball, easy to spin and easy to
    stop. Result is a car that has no great desire to keep going in a
    straight line but has front wheel drive to pull it out of any
    instability but lots of manouverability.  The rear wheel drive helps to
    get the power down.  It is normal to arrange for the front wheels to
    free-wheel overrun, so they only deliver power when they rotate slower
    than the average of the rears, ie when the back is spinning or car is
    cornering.  
    
    With electric cars the main weight is the batteries and these are
    arranged to support the above weight distribution. The motor is the
    next heaviest item.  
    
    Regards,
    
    Rob

�    PS You're letting your prejudice show again. What about the car that
�    one of the rags described as 'the best handling FWD car, Elan
�    included'? :^)
    
    What cars this then ?
    
    	Rik whos-waiting-for-his-Elan-to-arrive-latter-in-the-year :-)

    
    Shouldn't that be a ZR-1?
    
    Mark
    

    
    I haven't followed the press recently, but I guess the Renault must
    have done well. I haven't driven one on the circuit (no real desire
    to, either), but having driven the Peugeot I'd count it as a good-un.
    As I say, its down to preference and prejudice. I don't like the
    5 turbo, and I can't see my opinion changing.
    
    As for the skiing, I go on Friday. We've got an AX GT, a 944 and
    a 635 going so it should be fun (As another HPC member and I are
    driving the AX, it should be fun seeing if the others keep up!).
    On the way back we'll be doing the Nurburgring - can't wait!!
    
    Bill.

    
    In that case,
    
    Have a good time.
    
    Mark

�           <<< Note 1225.7 by HAMPS::LINCOLN_J "Where sheep dare" >>>
�                              -< Mid engined ??? >-
    
�	I don't think the MR2 qualifies as a 'mid' engined car. Just
�	because the engine happens to be in front of the rear wheels
�	doesn't make it any more mid engined than a front engined car
�	where the engine is behind the front wheels. It's mostly just
�	hype. It's rear engined.
    
    
    Re.  Derek's suggestion - using this topic
    
    I haven't read all the replies to this one, but I don't think that
    this is the correct description.
    
    Can you please explain why you feel the MR2 is NOT mid-engined.
    
    I didn't think the engine was *behind* the rear wheels, so in my mind
    it can be classed as mid-engined.
    
    Would you say that *mid* is only a correct term if the engine
    is ahead of the axle/gearbox, but behind the driver ?
    
    What about the Bugatti ?  Would you call that mid- or rear- engined,
    since it has the gearbox alongside the engine (actually built-in to
    the crankcase).
    
    Could you perhaps provide a list of cars which you class rear-engined,
    against some which you would call mid-engined.  Then maybe you can
    give your reasons for any of those with which people disagree on your
    classifications.
    
    J.R.

    
    As I understand the conventional thinking on what is what is that :-
    
    Front engined = Engine in front of driver (regardless of actual
    		    location in chassis!)
    
    Mid engined = Engine behind driver, but in front of rear wheels.
    
    Rear engined = Engine behind rear wheels.
    
    I think John is arguing that the position of the engine relative to 
    the midpoint of the chassis or wheelbase SHOULD actually influence
    what is classified as what. Certainly a car with the driver sitting 
    right on the rear axle with the engine a long way back from the front
    wheels is going to handle better than a car with the engine behind the
    driver, but near the back of the car (By better, I mean more
    neutrally).
    
    Mark
    
    PS I generally bow to conventional terminology.

    
    Derek, if you'll excuse the comment, C*bblers! :^)
    
    Ride isn't a factor of where the driver sits. It has a lot more to do
    with springs, dampers, suspension travel, etc.
    
    Mark
    
    PS What does mid-engined win? I'd assume you mean races. If so, why
    are Westfield 11s so successful in the Group K series?
    

    
    Right, so we'll all agree that the nimbleness of a mid-engined car
    (in front of rear axle, behind driver) makes it a winner on the track
    (of course factors such as aerodynamics also dictate that the engine
    behind the driver makes a better racing solution, not just handling),
    but away from the relative smoothness of the race track and in the
    hands of mere mortals are mid-engined cars better than front?
    
    Ok, in the extremes a M/E car has superior capabilities, but a good
    F/E car will have limits beyond those that any sane driver would reach
    on the road (even you, Derek! :^)) and a more predictable and forgiving
    nature. 
    
    Just a thought.
    
    Mark
    
    PS I was just playing devil's advocate about Group K, BTW, but I'm
    not convinced on you theory about ride. Not many sportscars have the
    driver sitting OVER the rear axle!

�    not convinced on you theory about ride. Not many sportscars have the
�    driver sitting OVER the rear axle!
    
    I'm not too sure about Derek's argument, but I would agree that if
    the driver is sitting over the axle, then he/she will experience
    a worse ride.  This is certainly the case with the 7's, isn't it ?
    
    J.R.

Re: several previous 

I'm sure that plenty of people in this conference regularly drive 
their cars on the limit. Most likely not on quicker roads but most 
likely turning into parking lots and around slow corners. It's easy to
push a car to it's limit at 15-20 mph without too much danger. When I
was over there I particulary enjoyed your roundabouts :-)

There are several reasons why mid-engined cars are used exclusively in 
purpose built race cars.

	. better aerodynamically than front engined cars
	. easier to achieve good balance in front to rear weight
	. lower poler moment of inertia (maybe the most important)


Imagine taking a bar with a weight on one end (a heavy hammer) hold it 
by the lite end and swing it back and forth quickly. Now hold the
weighted end in your hand and swing the lite end back and forth. This
will be much easier to control. In a car you will have better control
at the limit with the weight near the center. The car will have better
break away characteristics.