interestedparty
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| posted on 16/11/02 at 07:57 PM |
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One nice thing about transverse MEC's
The transverse engined layout has one major advantage over longitudinal engined cars (both front and mid), and that is that there is less power loss
from engine to wheels. Not having to turn the drive through 90 degrees saves quite a bit of power, bevel gears of course being the culprit.
Just thought I would share that thought with you guys.
John
[Edited on 16/11/02 by interestedparty]
As some day it may happen that a victim must be found,
I've got a little list-- I've got a little list
Of society offenders who might well be underground,
And who never would be missed-- who never would be missed!
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Alan B
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| posted on 16/11/02 at 09:16 PM |
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John,
Good point.
To me the sheer availability is a big plus, and fact they are a nice compact package.
Seen any Coram pics yet? 
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interestedparty
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| posted on 16/11/02 at 09:25 PM |
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Coram? I thought that was a DuPont product for making kitchen worktops out of.
Seriously though, I think by the time the photos are ready I will have lost interest, talk about hype!
There was a posting today on the pistonheads site about it from the guy that runs it saying the photos are on the site, so I clicked on the link and
it's still the artist's impression
John
As some day it may happen that a victim must be found,
I've got a little list-- I've got a little list
Of society offenders who might well be underground,
And who never would be missed-- who never would be missed!
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theconrodkid
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| posted on 16/11/02 at 10:33 PM |
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it is one of the nicest artists impressions i have seen and i hope it makes it but i have my doubts.
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ProjectSRP
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| posted on 17/11/02 at 12:05 AM |
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Yea I think these guys started hyping their product way before they had anything substantial. They also failed to make their first official launch
which doesn't reflect well. Gives the impression they are a bit desperate.
[Edited on 11/17/02 by ProjectSRP]
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interestedparty
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| posted on 21/11/02 at 03:42 PM |
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Another good thing about transverse mid engined cars is that they don't suffer the ground clearance problem inherent with longitudinal MEC's.
Next time you see the Ultima display, have a look at the engine and gearbox which accompanies it. Look at the relationship of the gearbox output
shafts (driveshafts) to the sump. Because the drive has to pass into the gearbox UNDER the differential it means that the whole engine has to
be mounted lower than is ideal.
No such problems with transverse engines, and no power-sapping bevel gears either
John
As some day it may happen that a victim must be found,
I've got a little list-- I've got a little list
Of society offenders who might well be underground,
And who never would be missed-- who never would be missed!
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garethpowys
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| posted on 21/11/02 at 10:32 PM |
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quote:
Originally posted by interestedparty
Another good thing about transverse mid engined cars is that they don't suffer the ground clearance problem inherent with longitudinal MEC's.
Next time you see the Ultima display, have a look at the engine and gearbox which accompanies it. Look at the relationship of the gearbox output
shafts (driveshafts) to the sump. Because the drive has to pass into the gearbox UNDER the differential it means that the whole engine has to
be mounted lower than is ideal.
No such problems with transverse engines, and no power-sapping bevel gears either
John
I never really considered ground clearance to be much of an issue in a sports car. Unless you're planning to use it through city centres over big
traffic humps? The Noble gets over the sleeping policemen round here OK (just). The ground clearance on that is next to nothing.
Low engine, low CofG. Which is more important low CofG or off road ability? ;-)
Transverse engined MECs also carry the weight a bit too far back, meaning you have to keep the whole thing very short to keep the weight balance
right. They also have a tendency to load up the outside rear wheel more in corners, particularly when accelerating. This tends to make the breakaway
more sudden. In my experience Exige just goes bang (although you have to push hard) whereas Noble gives plenty of warning that it's going. I know
which I prefer.
In an ideal world I wouldn't be building a transverse engined MEC.
Gareth
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Spyderman
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| posted on 21/11/02 at 11:42 PM |
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quote:
Originally posted by garethpowys
I never really considered ground clearance to be much of an issue in a sports car. Unless you're planning to use it through city centres over big
traffic humps? The Noble gets over the sleeping policemen round here OK (just). The ground clearance on that is next to nothing.
Low engine, low CofG. Which is more important low CofG or off road ability? ;-)
Transverse engined MECs also carry the weight a bit too far back, meaning you have to keep the whole thing very short to keep the weight balance
right. They also have a tendency to load up the outside rear wheel more in corners, particularly when accelerating. This tends to make the breakaway
more sudden. In my experience Exige just goes bang (although you have to push hard) whereas Noble gives plenty of warning that it's going. I know
which I prefer.
In an ideal world I wouldn't be building a transverse engined MEC.
Gareth
I would have thought that in general any reference here would be about a car that would be used in city streets. Just to get off my housing estate
you have to go over at least 12 speed humps. So yes it could be an issue.
In an ideal world we could all use what we considered the optimum layout.
The benefit of transverse MEC is that you can make them very short.
Having a longitude mounted MEC forces you to make car longer in wheel base, so the arguement goes both ways.
Surely under "acceleration" loading up the outside rear wheel is what you want. With the weight being virtually over the rear axle it is the best
place for drive wheel traction.
Also non transverse MEC are heavier by mere necessity!
Each to their own though I suppose!
Terry
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garethpowys
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| posted on 23/11/02 at 10:37 AM |
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quote:
Originally posted by Bull
I would have thought that in general any reference here would be about a car that would be used in city streets. Just to get off my housing estate
you have to go over at least 12 speed humps. So yes it could be an issue.
In an ideal world we could all use what we considered the optimum layout.
The benefit of transverse MEC is that you can make them very short.
Having a longitude mounted MEC forces you to make car longer in wheel base, so the arguement goes both ways.
Surely under "acceleration" loading up the outside rear wheel is what you want. With the weight being virtually over the rear axle it is the best
place for drive wheel traction.
Also non transverse MEC are heavier by mere necessity!
Each to their own though I suppose!
Terry
Taking the points in order:
Sports cars are by definition cars for the open road, I can't understand why you seem to think that "any reference here would be about a car that
would be used in city streets". Anyway as I said the Noble can get over the humps round here (if you're careful) and if that can, anything can, same
designer as the Ultima too.
Cant disagree with the next point though 
IMHO having a very short wheelbase is not such a great thing. A shorter wheelbase means you have less scope for adjusting weight distribution,
there's less room to move things around. Long legs? You'll need a long cabin, stretching the car and biasing the weight distribution to the rear.
Then theres the weight transfer problems, to get good grip you need to keep the tyres loaded, under braking particularly very short cars can lose the
rear with very little provocation, if the mass of the car is biased toward the rear it will make any spin even harder to save.
What I actually said was under acceleration in a corner. Just like too little load, too much load will unstick a tyre. Also loading up one corner
unloads the others, so you may well need an LSD. As eny fule kno the be all and end all of driving any given car fast is corner exit speed, get a 1mph
advantage on the exit of a corner and you carry that advantage all the way to the next corner. Higher corner speed in itself means very little if you
can't get the power down on the exit.
It would be a very boring world if we all did it the same!
To close I'll ask the question: How many mid engined race cars (where rules allow either layout) have transverse rear engines as opposed to
longitudinal?
Gareth
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interestedparty
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| posted on 23/11/02 at 11:18 AM |
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quote:
Originally posted by garethpowys
Sports cars are by definition cars for the open road, I can't understand why you seem to think that "any reference here would be about a car that
would be used in city streets".
I'm going to have to say that I disagree with that statement. I think a more common definition of sports car would be- two seater, low-slung,
probably convertible car designed primarily for good performance.
Even if the car were to be trailered from where the owner lived out to the 'open road' there would still be a problem if the open roads were
anything like they are around here
"Just like too little load, too much load will unstick a tyre. "
That's a new one on me, any proof? I don't think so. Formula one cars would be in great difficulty if that were true
John
As some day it may happen that a victim must be found,
I've got a little list-- I've got a little list
Of society offenders who might well be underground,
And who never would be missed-- who never would be missed!
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garethpowys
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| posted on 24/11/02 at 12:46 PM |
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quote:
Originally posted by interestedparty
I'm going to have to say that I disagree with that statement. I think a more common definition of sports car would be- two seater, low-slung,
probably convertible car designed primarily for good performance.
Even if the car were to be trailered from where the owner lived out to the 'open road' there would still be a problem if the open roads were
anything like they are around here
"Just like too little load, too much load will unstick a tyre. "
That's a new one on me, any proof? I don't think so. Formula one cars would be in great difficulty if that were true
I agree about the "performance" bit, or better yet "performance driving". I also think fun has to come into it somewhere. However I don't see why
a sports car needs to be low slung, two seater or convertible. By your definition something like an FQ300 isn't a sports car, sure it's relatively
tall, seats five and has a tin top, but it's ridiculously quick, corners like a Scalextric car with magnets and is loads of fun to drive. In my book
that makes it a sports car.
As I said before a Noble M12GTO can make it over all the speed bumps round here, and I know of one that get's used for occasional commuting into
Ealing. It *is* way out of it's element there, however that doesn't mean you couldn't live in a city centre and drive your Noble (or whatever) out
to the countryside to have some fun.
As for the grip thing I think we're talking at cross purposes here. When I talk about loading up a tyre in a corner, what I mean is weight transfer.
What I think you're talking about is downforce. Doewnforce is good because the force is acting directly downwards through the tyre's contact patch.
Weight transfer loading comes through the contact patch at an angle. What tends to happen is that the contact patch grips well, but the tyre distorts
and rolls over so that part of the contact patch lifts as the outside edge of the tyre rolls onto the sidewall, resulting in a major loss of grip.
Also race tyres have very strong sidewalls, road tyres have quite flexible sidewalls because roads are much rougher than race circuits.
Gareth
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Spyderman
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| posted on 24/11/02 at 01:28 PM |
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quote:
Originally posted by garethpowys
Taking the points in order:
Sports cars are by definition cars for the open road, I can't understand why you seem to think that "any reference here would be about a car that
would be used in city streets". Anyway as I said the Noble can get over the humps round here (if you're careful) and if that can, anything can, same
designer as the Ultima too.
Cant disagree with the next point though
IMHO having a very short wheelbase is not such a great thing. A shorter wheelbase means you have less scope for adjusting weight distribution,
there's less room to move things around. Long legs? You'll need a long cabin, stretching the car and biasing the weight distribution to the rear.
Then theres the weight transfer problems, to get good grip you need to keep the tyres loaded, under braking particularly very short cars can lose the
rear with very little provocation, if the mass of the car is biased toward the rear it will make any spin even harder to save.
What I actually said was under acceleration in a corner. Just like too little load, too much load will unstick a tyre. Also loading up one corner
unloads the others, so you may well need an LSD. As eny fule kno the be all and end all of driving any given car fast is corner exit speed, get a 1mph
advantage on the exit of a corner and you carry that advantage all the way to the next corner. Higher corner speed in itself means very little if you
can't get the power down on the exit.
It would be a very boring world if we all did it the same!
To close I'll ask the question: How many mid engined race cars (where rules allow either layout) have transverse rear engines as opposed to
longitudinal?
Gareth
Gareth,
The reason for the first statment is to make things clear as you seem to be mixing racing cars with sports cars.
Just to make sure we are talking about the same things!
We are not buying designer cars we are making our own. Why does everything have to compare to a Noble or Ultima?
You contradict yourself with the shorter wheelbase arguement though!
Having a shorter wheelbase means that any adjustments will have a greater effect on balance. Just by moving the battery forward from rear to front
will have a far larger effect on weight balance than on a longer vehicle.
Having a longer cabin in a longer vehicle will have same effect, but to a lesser degree agreed, but then just because you have long legs shouldn't
mean you have to put up with a long wheelbase vehicle.
Your arguements about braking and spinning out don't hold true as there is no direct comparison between the layouts and their characteristics. We
have no standard by which to compare.
Also it would be possible for either style of layout to exibit such properties depending on various other variables like suspension type, wheels and
tyres, height of CofG, etc.
Agreed a large mass such as engine is centred nearer to the rear axle. This is why tranverse MEC favour smaller lighter engines. The engine is not all
of the weight and as such should not be treated as so. The driver contributes a great deal to a sports cars weight.
If you continue to argue with Ultima's as the example then yes a heavy small block Chevy engine mounted transversely would be a pig to handle.
The larger the engine mass, the further forward it has to be moved.
Strongly disagree about putting the power down on exiting a corner though. You do not accelerate through a corner, but out of it. The greater the
loading on the drive wheels means the sooner you can get full power on and hence maximum acceleration. Ever wondered why Porsche's are so good at
racing?
Going into the corner other better balanced cars have the advantage, but coming out it is a different story.
Quote "it will make any spin even harder to save". Do you know how to stop a spin once started? What is the secret? I'm sure many proffesionals
would like to know that one!
Arguement for LSD holds for both layout styles.
Getting the maximum cornering speed in any style of car means you will be loading up the outside tyres and unloading the inside.
Your last question seems misplaced as again I remind you, we are talking about road cars. Anyway it would depend on your meaning of race car. Do you
include GT cars in that question or do you mean fomula 1?
In my opinion the most interesting racing is done by road car derived classes.
Interesting discusion this, let's all keep it friendly!
Terry
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interestedparty
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| posted on 24/11/02 at 02:03 PM |
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quote:
Originally posted by garethpowys
However I don't see why a sports car needs to be low slung, two seater or convertible. By your definition something like an FQ300 isn't a sports
car, sure it's relatively tall, seats five and has a tin top, but it's ridiculously quick, corners like a Scalextric car with magnets and is loads
of fun to drive. In my book that makes it a sports car.
The definition I offered is not MY definition, just one that I am certain most people would accept. The Concise Oxford Dictionary gives "of low built
fast type". The car you are referring to is a performance car, NOT a sports car.
The loading on the outside tyre of a fast cornering car is always going to be at an angle, wherever you put the engine.
John
[Edited on 24/11/02 by interestedparty]
As some day it may happen that a victim must be found,
I've got a little list-- I've got a little list
Of society offenders who might well be underground,
And who never would be missed-- who never would be missed!
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