I sort of feel that all other factors being equal, a "mid engine" location will work better than a front engine RWD layout. But I wonder if this has ever been proved in the real world. There are some UK manufacturers who are producing 7-type cars with engines in the front and rear. I am wondering if there are records of cars with basically identical engines and similar chassis' but with alternative configuations being run at the same day at track days or races. I guess something like this happened in the early 60's when racing cars were switching to the mid engine layout. But this might have been more significant for single seaters, considering weight and frontal area. So, how does this work out for modern 7dom?

http://www.youtube.com/watch?v=2Tw1PKEHdWo

[Edited on 4/2/10 by Ratman]

Just have a look at nearly every Prototype, formula and many GT cars. They'll be mid engined.
Wether or not you'll notice, or if most other Locosters will notice the difference, is another matter.

The advantage is all to do with polar moments, and the mass of the vehicle being closer to the turning axis (rear wheels).

its probably like a lot of things, where you only really notice when you push it.
in the snow, my dads evo was kinda slidey at slow speeds, we werent overly impressed, however one day he booted it really hard and it was really neat and planted.
probably a crap way of explaining what i mean, but it made sense to me...

A1, I think you might have a good point there. The difference is only going to show at the limit. The closer you go to the limit the more is the benefit of a mid engine layout.

When I watch videos of sevens and locosts on the track they seem to be limited by rear traction. It is not that hard to break the rear end loose. So it would seem more rear weight bias would be in order and I think that is a big advantage of the engine behind the driver.

You also gain under braking, when the weight transfer evens things out a bit instead of overloading the front tires.

Then there is also the availability of so many powerplants from FWD cars, which can simply be moved behind the driver. Here in the states we really don't have so many RWD parts that are suitable...

Hah, a very similar thread's on the LocostUSA forum... where I got flamed about being too positive about my yet-to-be completed middie, called Midlana. It went something like, "We've never seen a privately-built home-made middie that was any faster than a Locost, so pipe down." The funny thing is that this was in their own mid-engine sub-forum, but whatever. Crafty way to win an argument though, ensuring virtually no cars like this exist before saying they're uncompetitive, but I'm over that, lol.

Anyhow, here's what I write in the FAQ in my own forum:

quote:

---

"Is Midlana better than a Locost?"

Depends what "better" means - some people think it only means "faster." Since the primary difference between a Locost and Midlana is engine position, the only way to know would be faster is to run the following test: Two cars, equal weight, equal wheelbase, equal track, equal tires, equal aerodynamics, same exact engine, one mounted front-engine, the other mid-engine. Same driver, same track, same day. Drive 10 laps in each and see what's what - that's it.

Anything else is meaningless because so many factors throw the results off. Realistically, the chances of this test ever happening are slim to none. Of course, the fact that mid-engine cars have won every single F1 race since 1958 should be a strong indicator of what works best on-track. Given the choice, why not start with a superior design right from the start? Phil Hill once said, "It was really astounding how just the placement of the engine [behind the driver] gave comfort to the drivers. The whole feeling of being - at the end of the string - was gone."

So yes, I do feel Midlana is better; not because it may or may not be faster, but because of all the secondary benefits placing the engine behind the seats has - foremost being a much wider choice of engines and the resulting low PMOI.

---

quote:

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Originally posted by Horizenjob
When I watch videos of sevens and locosts on the track they seem to be limited by rear traction. It is not that hard to break the rear end loose. So it would seem more rear weight bias would be in order and I think that is a big advantage of the engine behind the driver.

You also gain under braking, when the weight transfer evens things out a bit instead of overloading the front tires.

Then there is also the availability of so many powerplants from FWD cars, which can simply be moved behind the driver. Here in the states we really don't have so many RWD parts that are suitable...

---

I feel that a properly designed and set up mid engined car will beat a properly designed and set up front engined car of the same weight and power every time.

Of course that doesn't mean that the one will be more fun to drive than the other so unless you are a good enough driver to appreciate and exploit the difference on track don't rush out to change your front engined car for a mid engined one.

Also, I think, for us average drivers a front engined car might generally be easier to pull back from the brink when you have made a mistake and let things get out of hand as a mid engined car tends to give less warning of it's imminent desire to swap ends and needs quicker reactions and better skills to catch once it starts.

Some additional points for/against middy's

A middy has the potential to be, maybe, 10kg lighter due to the lack of a prop shaft and less metal required in the bell housing and diff. That can be a big difference (percentage wise) in a light car.

As Ivan indicates the handling of most middys in corners tend to be "grip grip grip spin", rather than "grip, slip, squeal, spin". That bit of extra warning can certainly make the difference in the confidence level of the driver until you get to the top level of drivers.

Mid engined cars have more of their weight concentrated at the centre of the car, front engined cars have more weight towards the ends. This is called polar moment of inertia. Smaller moments of polar inertia are easier to turn (and easier to stop turning). Driven below the limit, a well balanced mid engined car will turn in faster and turn out faster than a front engined car. Above the limit, they spin faster than a front engined car.

Many mid engined cars have the engine right by the rear axle and transversely mounted. F1 cars and the like have the engine nearer the centre of the car with a gearbox separating it from the rear axle. The F1 type layout gives better weight disribution and lowest polar moment. MGFs and Elieses have weight distributions more like rear engined cars which are the most prone to swapping ends when you get it wrong.

quote:

---

Originally posted by kb58
Hah, a very similar thread's on the LocostUSA forum... where I got flamed about being too positive about my yet-to-be completed middie, called Midlana. It went something like, "We've never seen a privately-built home-made middie that was any faster than a Locost, so pipe down." The funny thing is that this was in their own mid-engine sub-forum, but whatever. Crafty way to wind an argument though, ensuring virtually no cars like this exist, at least in the U.S., but I'm over that, lol.

Anyhow, here's what I write in the FAQ in my own forum:

quote:

---

"Is Midlana better than a Locost?"

Depends what "better" means - some people think it only means "faster." Since the primary difference between a Locost and Midlana is engine position, the only way to know would be faster is to run the following test: Two cars, equal weight, equal wheelbase, equal track, equal tires, equal aerodynamics, same exact engine, one mounted front-engine, the other mid-engine. Same driver, same track, same day. Drive 10 laps in each and see what's what - that's it.

Anything else is meaningless because so many factors throw the results off. Realistically, the chances of this test ever happening are slim to none. Of course, the fact that mid-engine cars have won every single F1 race since 1958 should be a strong indicator of what works best on-track. Given the choice, why not start with a superior design right from the start? Phil Hill once said, "It was really astounding how just the placement of the engine [behind the driver] gave comfort to the drivers. The whole feeling of being - at the end of the string - was gone."

So yes, I do feel Midlana is better; not because it may or may not be faster, but because of all the secondary benefits placing the engine behind the seats has - foremost being a much wider choice of engines and the resulting low PMOI.

---

If you guys are open to mid-engine layouts, check out mine at http://www.midlana.com/

[Edit] Oh, and you're right, the low PMOI of a mid-engine layout makes a huge difference on turn-in. My buddy Max (a Brit I might add got a ride on-track in my previous car, a mid-engine Mini, and said he couldn't believe how quickly the car would change directions.

I'm going to mop the floor with any Locost I meet on-track, not that I have a point to prove or anything. Of course, when I do beat them, they'll have some other excuse

[Edited on 2/5/10 by kb58]

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I think it all depends on what kind of engine you're running.

The two biggest lumps of weight in a car, are the driver and the engine. So if you assume the driver weighs 80kgs to 90kgs and the engine weighs much more than this (e.g. American V8, Pinto, Essex), then mid may be better. If you're running a BEC or other light engine where the engine weighs much less than the driver it probaby doesn't make much difference - or front may even be better.

This ignores any packaging benfits you mights get from a mid engined layout to get both driver and engine closer to the centre of the car - and mimimixe the polar moment of inertia.

My understanding of polar monement of inertia, and I've forgotten the maths, is that it's a measure of the force required to get something to change direction. So from a driving perspective it's all about turn-in, not about the speed you can carry through a corner, which is more about grip, centre of gravity and balance.

quote:

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Originally posted by Richard Quinn
This is something that I have experienced on US forums for other sports/hobbies etc in the past. You appear to be in the minority and, while this may be a huge generalisation, we used to refer to one particular forum as "The Flat Earth Society" due to the reluctance to accept something different to the norm. There does seem to be a general blanking out of what does not fit with their paradigm. Any advances are taken as an insult to the current situation.

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Power to the SHEEPLE

ba ba baaaah

Why do I need a Mid Engined Car when my weight distribution is 45/55% in my Viento.
Thats as near as perfect as I am likely to get.
Also it changes when that Bat F'Stard of a driver gets in it

45/55 is pretty damn good for the road.
OK on the track when you are competing against others and that 5% swing could make the difference between winning and loosing.
But How Many of you on here are out and out competitive racers where it might make that crucial difference.

Still its Fun to Debate the pro's and cons of a Middy.

I like Both styles.... as the old adage states... If it LOOKS right it usually IS.

Just ask yourself one thing, if Formula cars were faster or handled better with the engine at the front, then they would have them.
Nearly all modern purpose built racecars have a mid/rear engined set up.

i dont know how other peoples engines are positioned but on my roadster my engine is at least 15inches behind the centre line of my front axle.

in my eyes even though the engine is at the front i would still consider the car a mid engine as the driver and engine are in-between the axles.

when you look at most modern fwd cars the engine is usually over or in front of the wheels.

personally i think it all comes down to application the car is intended for. if you are an out and out racer then maybe a midy layout has the advantage but its a hard call unless you have the chance to drive both.

i have seen that riots are pretty good on track but i wouldn't say they are a different league to a 7style layout.

Going back to the PMOI point. Where do peeps think the car turns or pivots during turn in?

It's not the centre of the car but rear axle line and that is where the PMOI are acting about, thus weight distribution isn't too important, it's more about getting the mass as close to the centre of the rear axle as possible.

This doesn't take into account the weight distrobution for steady state cornering and front rear grip though but that's where the compromise comes in.
As a side note when F1 changed back to un groved slicks last year, the FIA didn't change the widths correctly, so there was proportionally more grip on the front than previous years and the weight distrobution moved forward to compensate.

quote:

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Originally posted by ashg
if you are an out and out racer then maybe a midy layout has the advantage but its a hard call unless you have the chance to drive both.

---

My Indy has a 40/60 weight distribution front/rear and uses the same size tyres all round.

Both myself and my mate went on a track day at a very, very wet elvington last year and found that I had a lot more grip that his Lotus 7 which is a bit more 50/50.

I was worried the rear heavy setup would be a bit of a handful, but is seems to do a good job of keeping the traction. Which is just as well, because there is very little I could change on the car to shift the weight forward any further, apart from maybe move the fuel tank to be in front of the engine instead, which may shift too much weight.

It all depends on the application or what the driver wants. This is just what I noticed

For drifting, a front weight biased car tends to be a bit more tail happy and more grip on the front. So you can enjoy sideways driving a whole lot better on windy roads

For good handling, mid rear bias cars tend to weigh down on the the rear wheels and causes more grip and more rear control. The car is less likely to slide out, so its best for good lap times around windy roads.

I think the question should've read:
For what purpose is mid engine really better?

Don't forget that F1 cars have certain aerodynamic issues that road cars don't face. Sticking the engine in the front of a F1 car would create a very wide, tall front and you'ld have to put the driver above the propshaft so the car would be higher. All that drag wouldn't be good at 200mph...

On a road car you generally want to have two people side by side and you can put the prop in between.

I think there's not much to chose between them personally....

Not all of us Americans are resistant to change I also like the fact that this forum tends to help the newcommers instead of insulting them as most typical Americans. Sad really..... anyway....

I'm a big fan of mid-engined cars. The pros and cons have already been hit on pretty thoroughly so I won't continue with that, but I totally agree that its the purpose of the car that determines the best layout. It's hard to make a saloon/sedan for 5 adults when theres a big lump in the middle. Wouldn't leave much room for groceries either.

Well then, since my post was received in a good light, here's my list of benefits gained by going to a mid-engine layout.

- You aren’t forced to pick from a dwindling list of rear-drive engines.

- Using truck parts to build a light sports car increases unsprung weight, giving a harsh ride and a heavier car.

- Mid-engine means the exhaust doesn’t cook your feet, melt brake master cylinders, and foul the steering shaft.

- Not going deaf due to the exhaust being next to your ear.

- No big ugly mufflers on the sides of the car. (A quiet car is becoming a requirement as more and more tracks impose strict sound limits.) Good-looking - but ineffective - Cobra-type side mufflers are often too loud.

- The rear weight bias helps acceleration and braking by increasing rear traction.

- An adult-sized footwell so you don't need special shoes or having to drive barefoot.

- You and your passenger won’t burn the back of your legs on the exhaust while getting out.

- Independent rear suspension gives a smooth ride on the street and excellent camber control at the track.

- No driveshaft down the center of the car means more room for seats.

- No concern about a broken driveshaft hitting fuel lines, the gas tank, brake lines, or you. (The axle can still break of course, but are located behind the drivetrain.)

- Midlana uses the existing FWD transaxle, while Locost builders waste time trying to adapt front-engine, rear-drive transmissions.

- Many potential builders already have a favorite FWD drivetrain that they know well. Midlana allows transfering this knowledge by using the familiar drivetrain, instead of picking an unwanted engine.

- Less weight on the front tires means steering effort is lighter than with a front-engine layout.

- The steering rack is used unmodified - no cutting or welding the rack.

- Mid-engine means the front chassis area is properly triangulated, greatly increasing torsional rigidity.

- A roll-cage is an integral part of the chassis and greatly improves safety and stiffness.

- The side-vents shield the rear fenders from rock damage and autocross cones.

- Midlana uses Miata suspension, steering, gas tank parts, but no drivetrain, so no need to buy an entire donor car.

- Mid-engine means engine torque does not twist the chassis and cause odd handling when on the gas.

- The gas tank is in a much safer location than one in a Locost, where it's used as a crush-structure!

- Side vents bleed off high pressure ahead of the rear fenders, and the engine compartment exit vents help fill the low pressure area behind the engine, both helping to lower drag.

- The oil pan is protected by the chassis, protected from hitting speedbumps, and unlike the Locost arrangment where the pan is the lowest point on the car.

- With the gas tank located at the CG, handling does not change with varying fuel load.

- A portion of the area formerly consumed by the front drivetrain is used as a lockable storage space.

- Room for a real dead-pedal.

- Option for a free heater that uses hot radiator air.

- A large frontal crush structure.

This is all listed on my FAQ at Midlana forum. There's currently a "guess the horsepower" contest and win a book. That's at Book contest though you have to register to see either.

[Edited on 2/5/10 by kb58]

Yeah.....what Kurt said...

My my.. what an International melting pot of a thread is this hey

funny all of us American pro-mid engine chaps are over here...


(although i have had no disputes with the locostusa guys)

My take on it is it's all in how you define "better". Faster around a track, better packaging, easier to source donor components, better ride, better "handling", feel, looks, tradition? Pick your poison, Middies may well have won every F1 race since 1958, but I daresay our cars will face slightly different conditions than your average F1 car.

Kurt has done a good job detailing the advantages of middies above but there are also weird local factors such as the registration laws in Ontario which favour a seven (or any other repli-car) over a self designed scratch-built.

As I've just recently decided to get my finger out and actually get cracking on a car, I'm building pretty faithfully to the Haynes plans, I don't want to innovate myself into a 5-year build

Cheers, Ted

[Edited on 5/2/10 by andkilde]

FYI -
The US LHD Fury Hayabusa's are really "mid engine" but Jeremy's new J15 has obvious benefits.

Chet
Rescued attachment JP-15..jpg

If you confine yourself to "Best" meaning fastest lap times then its a tricky question to answer as so few classes have the rules to make both viable options, as far as I can tell the Panoz LMP was the last serious attempt to build a front engined LMP car to the same rules as the mid engined cars.



this car was not a great success, but reading what the designer had to say about it that cant really be blamed on the engine layout.

http://www.mulsannescorner.com/thorby.html

Interestingly he says: "A front-engined LMP has some advantages (e.g. inherent weight distribution, driver position)" Which is counter intuative to what I would think, but I'm not the one being paid to design cars.

More on the car here:

http://www.mulsannescorner.com/panozlmp07.html

So in think the ultimate case the jury is still out for want of a properly funded front engine effort.

[Edited on 8/2/10 by Doug68]

quote:

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Originally posted by Doug68
Interestingly he says: "A front-engined LMP has some advantages (e.g. inherent weight distribution, driver position)" Which is counter intuative to what I would think, but I'm not the one being paid to design cars.

---

Sam, now can you explain for my feeble brain, why all the top running cars at LeMans, the FIA GT's, and USA LM series, are the opposite configuration to what you'd recommend?

Cheers,
Nev.

quote:

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Originally posted by Neville Jones
Sam, now can you explain for my feeble brain, why all the top running cars at LeMans, the FIA GT's, and USA LM series, are the opposite configuration to what you'd recommend?

Cheers,
Nev.

---

quote:

---

Originally posted by Neville Jones
Sam, now can you explain for my feeble brain, why all the top running cars at LeMans, the FIA GT's, and USA LM series, are the opposite configuration to what you'd recommend?

Cheers,
Nev.

---

I've built a lot of cars for a lot of years and its how you do it not where things are (wihin reason) and the old rule of the thumb "as long as you get the major mass inbetween the wheels and low" still works because physics hasn't changed.

In huge favor of what we are refering to as mid engined, ie FWD unit behind the seats is mostly the exhaust - exhausts are the biggest pain in the ass and very few people design them in early. obviously the whole unit with gearbox and driveshafts being very common and cheap make it a nice choice too.

In favor of 'front' mid engine (the engine behind the front axle but still up front) is things happening slowly and more drivers can stay near the limit for a longer time which, yes, possibly are lower than a middy.

At the end of the day it still comes down to good tyres and springs and shocks to match the tyres and if you dont believe that go to a Historic race meeting and see how fast 60's or 70's sedans go with their front engines and antique suspension layouts but with good tyres/shocks.

Weight distribution numbers such as 50/50 are nonsense and dont tell where the masses are, you could have 2 Chev V8's 1 meter out each end and honestly tell me "I have 50/50" - but how does it handle? Ask Audi and their rally car with 50/50 but a huge 5 cylinder engine, hanging mostly in front of the front axle, how they handle.

I am tired of reading/hearing F1 nonsense relating to road cars especially suspension ideas that are based on huge ground effects but find there way to street cars/kit cars more and more - yeah right, good luck with that.

Kurt I didn't see that stuff, I find the Locost USA forum ok but then maybe saying people were using truck parts in their cars wouldn't help lol!!

[Edited on 16/2/10 by cheapracer]

quote:

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Originally posted by Doug68
[

Did the Panoz fail because it was front engined or because the engine wasn't up to it or for a lack of testing or funds?

No one out there has the balls - cash to find out do they?

---

quote:

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Originally posted by cheapracer

quote:

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Originally posted by Doug68
[

Did the Panoz fail because it was front engined or because the engine wasn't up to it or for a lack of testing or funds?

No one out there has the balls - cash to find out do they?

---

They were a bit short of funds and i believe 2 things influenced the Front engine desision and they were gearbox at huge reduction in price and diffuser size could be increased. theyw ere easier to drive according to the drivers and were reasonably successful but you cant beat the money that was up against them.

---

quote:

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...Weight distribution numbers such as 50/50 are nonsense and dont tell where the masses are...

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quote:

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Kurt I didn't see that stuff, I find the Locost USA forum ok but then maybe saying people were using truck parts in their cars wouldn't help lol!!

---

Overall mid-engine is better.

Generally lighter and better polar moments.

In most road applications a mid engine isn't there for the handling.

The real reason for their popularity is not handling but availability. The number of mass produced front engined RWD drivelines has shrunk to virtually nothing over the last few decades. Anyone who wishes to design a middy to be sold in any significant numbers has to dip into the the parts bins of front drive hatchbacks. They have no choice. That is all that's available.

All this stuff about how race cars all have mid engines is just missing the point. They are purpose designed to make use of the advantages of the layout. They are not restricted to the limits of hatchback design.

So why does the origin of the engine matter so much? Because of modern car design, that's why. No transverse hatchback engine is ever designed with mid mounting in mind. They are designed for crush zones and emissions. That normally forces a tall package to fit the stuff in around the block. This raises the centre of gravity.

Now a low polar moment of inertia is a good thing but conversely a high centre of gravity is a bad thing. So using a modern transverse package as a straight transplant is never going to give the full advantage of a mid engined layout.

However it is possible to design a modern front engined car with the engine set well back and fit it with a low sump to keep the centre of gravity low.

However this restricts you to the parts bins of Mazda and BMW.

For anyone else a mid engine is forced on the designer, not because it is better because it may not be better at all with a higher CoG, but because they have no choice.

quote:

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Originally posted by cymtriks
They are purpose designed to make use of the advantages of the layout.

---

Cymtrics has raised a vital point about keeping the COG low and the problems with modern FWD drive engines where COG plays a secondary consideration in design - so if you go transverse mid engine and handling is a priority of yours find the lightest all aluminium engine you can that provides the power you need or go for a flat four longitudinal layout.

I think an inch downwards in COG will have a significant impact on handling.

If I recall the BT front engined cars angled the engines significantly, I presume largely for COG reasons and if your middy design allowed that it might be worthwhile pursuing.

I guess the same could apply to front mid engined cars as well.

[Edited on 10/3/10 by Ivan]

quote:

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Originally posted by Ivan
Cymtrics has raised a vital point about keeping the COG low and the problems with modern FWD drive engines where COG plays a secondary consideration in design

---

Don't really have to explain it because it is compromised compared to what it would be with a lower COG.

It's only as good as it is because they knew what they where doing and designed for the compromises made.

Indeed it's a very complex trade off. A transverse middy will (for the same number of seats) have a much shorter wheelbase than an inline middy. A shorter wheelbase will tend (all other things being equal) to make the car more agile at the expense of high speed stability.

On angling the engine, the Onyx Mongoose had it's mid engined K series tilted over a very long way, to the level where they had to make some modifications to the oil system to avoid it blowing out of the exhaust by the pint iirc (their description is long gone from their site sadly*).

* Just found it's been archived by the wayback machine for those that are interested.
http://web.archive.org/web/20080110065409/www.onyxsportscars.f9.co.uk/id20.htm


[Edited on 10/3/10 by iank]

I used a FWD Honda H22A1 in my last build, and am using a FWD Honda K24A2 in my latest build, both mounted transversely in a mid-engine arrangment behind the seats.

In both cases, the bottom of the oil pan and transaxle limit how low it sits - no different than a front-engine setup. There is 4" ground clearance below the pan and transmission, exactly what I wanted. So, while FWD engines may not be designed for mid-engine applications, that in itself doesn't mean they won't work great. For me, the Honda K-series works very well.

Regarding shortening the sump, besides inducing oil supply issues, doing so doesn't allow the drivetrain to be lowered due to the transaxle case hanging down just as far as the pan did. But since it can be set as low as the bottom chassis rails, there's no need to change anything.

So I don't see how a FWD setup in a mid-engine arrangment is any different from a CG point of view than a front-engine layout - at least for modern FWD drivetrains. Perhaps you guys are refering to other FWD setups, maybe ones with the transaxle under the engine - that would certainly raise the CG.

As was said, the transverse layout works great for shorter cars. In my mid-engine Mini it was a natural. For Midlana, a Sevenesque car, it keeps the engine bay short, retaining some of the Seven look.

[Edited on 3/10/10 by kb58]

quote:

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Originally posted by Doug68

quote:

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Originally posted by Ivan
Cymtrics has raised a vital point about keeping the COG low and the problems with modern FWD drive engines where COG plays a secondary consideration in design

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This arguement is good in theory, but then you need to explain the Lotus Elise.

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Referring to Kurts post...

Looking at the picture below, it the flywheel size thats setting where the bottom of the engine is (just like a front engined car).
And clearly the motor is not on top of the transmission.

I think the idea that transverse fitments have a higher cog compared to inline comes from the typical engines that are used.
i.e. 4 pot engine has a higher cog than a V8 more so for DOHC 4 pots compared to OHV V8s.

quote:

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Originally posted by Doug68
Looking at the picture below, it the flywheel size thats setting where the bottom of the engine is (just like a front engined car). And clearly the motor is not on top of the transmission.

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I guess, when I started this thread, I had hoped that someone would have some actual hard evidence comparing like with like. In UK I think there are some kit manufacturers who make both front engine and midi versions of cars that are designed and built with very similar concepts and perhaps with identical engines. Then (this is stretching things a bit) maybe they have tested them at track days on the same track and can pass on their experiences. My own experience is pretty much just one short wheelbase (2100mm) midi with 66% weight on the rear wheels. This gives a real advantage off the line and very responsive handling, but it is twitchy and spins do happen. Building again I think I would make the wheelbase longer, and if you are doing this, then it must be six of one and half a dozen of the other for front or mid engine. As soon as the straights get to be a decent length then the biggest difference is probably aerodynamics, and a midi can generally be built lower because the driver doesn't need to be able to look over the engine. I think this is really what caused the shift in the early sixties with F1. All up, I think mid engine is more entertaining, and that's what it is all about..
Here's one of my spins.. What I think happens is that although the midi tends to more likely to spin, it is more likely to stay on the road when it does it. Watching Porsche races on TV, the same seems to happen with them.

http://www.youtube.com/watch?v=UkKSIFUctPc

I think that video demonstrates why reverse is now required for IVA. Nose first into a cliff on a blind bend wouldn't be a good place with other traffic around.

Back on subject, I think I probably agree with the aerodynamic argument for single seaters, which seems pretty logical with 20:20 hindsight. Also running a propshaft to the back past the driver requires a wider car in that environment.

quote:

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Originally posted by Alan B

quote:

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Originally posted by Doug68

quote:

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Originally posted by Ivan
Cymtrics has raised a vital point about keeping the COG low and the problems with modern FWD drive engines where COG plays a secondary consideration in design

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This arguement is good in theory, but then you need to explain the Lotus Elise.

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Beat me to it Doug....I'd forgotten just how s**t the Elise was..........could it be better with lower CoG...sure, but we are taking road cars and the Elise aint too shabby......

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quote:

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Originally posted by cymtriks
FWD driveline with the typical higher CoG

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Rescued attachment Box.jpg

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Originally posted by Doug68
Examples please.

I've looked at Toyota's and a few others and I'm not finding engines on top of transmission's they're next to them as per this Mitsubishi one...

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Ok so how about we clear this up with some dimensions?

Using the bottom of the chassis for reference so to take ride height out of the equation.

For my longitudinally mounted V8 I get the following dimensions from underside of chassis to...

1. CL Crank height. 225mm
2. Top of cam cover height. 595mm

Also the fuel tank is typically 40kg of weight or more and compared to a 7 it seams to be very easy to get the fuel tank in a middy in a better location so from underside of chassis to...

3. Underside of fuel tank 28mm
4. Rough fore aft distance of CG of tank to CG of car. 0mm the CG of the car is inside the fuel tank.

So what do other peoples cars measure and how do the number above compare with a 7?

(CG measurements taken from my CAD model which has proven accurate to date)

[Edited on 21/3/10 by Doug68]

I'm not sure how useful this'll be because it depends if the builder is fine with the oil pan hanging down below the frame rails. I'm not, so I'll come up with one number, but if another builder's fine with 75mm ground clearance, he'll get a much "better" number. Never mind the pan may get removed by a speedbump.

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Originally posted by Doug68

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Originally posted by cymtriks
FWD driveline with the typical higher CoG

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Examples please.

I've looked at Toyota's and a few others and I'm not finding engines on top of transmission's they're next to them as per this Mitsubishi one...

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Originally posted by cymtriks
On a typical FWD the engine crank is a bit forwards and a bit upwards from the axle line.

Now look at a purpose designed transaxle. Often they are inverted (axle above engine input) which, with a small bell housing and low sump, can put the CoG much lower. There are also transverse gearboxes available for longitudinal engines (as on the McLaren F1) which also put the CoG lower.

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Mine uses a renault Transaxle, which has aproximately 30 degree angle of the driveshafts. It was fixed to a renault engine which was in line (as per the original car) and is soon to have the cosworth engine mounted the same way.

Personally, i think the car is very well balanced, and the paperwork at SVA (at the time it was done) said that the weight distribution was 55% to the rear from memory - Almost a perfect balance.

The car is noisy, as the exhausts and the engine are only about 6" from the back of your head, behind a flimsy firewall. I like it, its like russian roulette with pistons rather than bullets!

If this post is out of context, its because i got bored with some of the detail of the above, and thought id post anyway!!

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Originally posted by cymtriks
Now look at a purpose designed transaxle. Often they are inverted (axle above engine input) which, with a small bell housing and low sump

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