10" or 11" long is what i want?

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Originally posted by goodall
10" or 11" long is what i want?

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front the front of the engine (at the pullys to the back of the engine (the bell houseing bolt up face)

sorry im not to clear on the technical names

It'll be a small engine!

The bores in a 2litre pinto add up to more than 12" (90mm each x4)... Granted thats an inline 4 pot, but i doubt a v6 would be any shorter than a straight 4 by the time you have the crank/conrod offsets...

David

[Edited on 18/2/07 by flak monkey]

Hmmmm a scale model maybe

My V6 is just under 18" long. A bike V4 might get close to what you want. If i were you I would probably abandon the idea of trying to fit an audi quattro layout in something tiny with no front overhang. The ford system is much more suitable and dead cheap.

Liam

i dont like the ford system for to reasons, 1; its 4WD rather than AWD which is alright but depends on what you want. 2; it uses unequal length drive shafts which causes torque steer.

quote:

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Originally posted by goodall
i dont like the ford system for to reasons, 1; its 4WD rather than AWD which is alright but depends on what you want. 2; it uses unequal length drive shafts which causes torque steer.

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no

4wd is when the power is sent 2 one axle and then another axle is driven but doesnt become fully operational until the main axle has lost traction

awd is were the power is split between the two axle equally in such away that they are both transmitting power

awd helps stop the car losing traction unlike 4wd which helps regain traction

[Edited on 18/2/07 by goodall]

Here's a spec sheet for my V6 Duratec if it helps but 11 inches?? Even the Audi V6 (which is the shortest I've seen) doesn't come close.


[Edited on 18-2-07 by RazMan]

well thats only about 16" from pully to flywheel, id say a V4 will be abit shorter

Dont get too hung up on AWD, 4WD, permanent, part time, etc etc. The terminology is not used consistently between one manafacturer and the next. You're wrong about the ford system (sierra xr4x4/cosworth and escort cosworth). It is a full on permanent 4 wheel drive (or all wheel drive if you prefer) with three mechanical diffs (two of which are LSDs). Whats more power is split 2/3 to the rear which is arguably preferable to a 50:50 split for a sporty vehicle. And of course you dont have to have the engine hung in front of the front axle - i have it a few feet behind in my ford based locost.

Liam

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Originally posted by goodall
well thats only about 16" from pully to flywheel, id say a V4 will be abit shorter

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In marketing speak, awd is a 4wd version of a 2wd car (Subi, Audi), and a 4wd is an off-roader (Landie, Jeep) or soft-roader (RAV4).

Most AWD will be 2wd until electronics detect front wheel slip and transfer up to 50% power to rear wheels.

A real 4wd is permanently coupled, has dual range, manually locking diffs, and 16 feet of ground clearance.

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Originally posted by locost_bryan


A real 4wd is permanently coupled, has dual range, manually locking diffs, and 16 feet of ground clearance.

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damn have just got rid of my saab v4 otherwise i could measure it for you. not that you would want to use one really, would cost alot to get any decent torque aand horsepower out of it.

it would be about 10 inches in length i think

Scuby flat four is 16", well 15" if you don't include the front pulley.

However, for a front mid engined 4x4 sports car, Sierra/cossy 4x4 gearbox has to be the way to go - that is if you want the engine in a sensible place rather than hanging out at the front like a nerd on the school bus.

I suppose Skyline or land rovers are other options, but only if you want millions of ponies and/or more weight "to help it stick to the road".

What d'ya want Audi 'gear for anyway?
Vorsprung durch Ford!

because its more ideal beacuse the front axle line in a mini is just infront of the drivers feet

well audi call it awd and theres is permenant but many 4x4 type jeeps and stuff have no diff between the front and rear axle it just locks the two and thats why most people drive them in 2wd to save tyres and drivetrain. maybe things have moved on since then buts thats the way it use to be

Ford have used a proper system since they introduced it in 1982, MUCH better system than the Audi at the time. The ford system is permanent 4x4, which you don't unlock or any of that rubbish, and it doesn't require ANY electronics to run it.

It was a VERY good bit of design work at the time by FF Developments, incidentally set up by irishman Harry Ferguson after he got bored with designing tractors and their hydraulic systems. It was similar in concept to the system he had designed a few years earlier for the Jensen Interceptor, and that fitted to the Boreham Ford MK1 Capri 4x4 rallycross cars in the seventies. Once "productionised" ford (in partnership with GKN) built the transmissions, in a deal which saw FF Developments getting all the competiton parts, like the group A front and rear 9" diffs etc.

The ford, as liam says, used a 66% rear 33% front torque splitting epicylic, viscous coupled limited slip centre diff, with viscous limited slip diff at the rear and an open front diff.

The driveshaft lengths are also as good as equal, where do you get the unequal lengths statement from.

Yes there is a difference of an inch or so on the rear shafts, but the fronts are equal, remember the l/h front shaft is two piece with a support bearing.

For the money you cannot beat the ford system. In its day it was state of the art, and even now it is only surpassed by active centre diffs and variable locking centre diffs, neither of which will fit your budget!!

[Edited on 19/2/07 by NS Dev]

no the front shafts are different lenghts because you have to remember that the shaft thats in the sump is also part of the lefthand front driveshaft. the reason i wouldent use the ford sytem is that its even less useable than the audi system. imgaine were the engine would have to be with the ff system, either pokening between the driver and passenger or in the back seat area to places i dont want it there

errr I think you may need to do some more learning about torque steer!!!!

The it is only the shaft length BETWEEN THE CV's that causes torque steer, hence why every half decent front wheel drive car uses a two piece shaft on the long side to keep the "moving" shafts equal length............. thought that was pretty obvious!!

depends on what sources you believe, because as far as i know its caused by the shaft winding up

Eh? - explain, please

Cheers

Fred W B

In practice torque steer is a bit of a catch-all term for a whole host of reasons claimed to make your fwd car veer all over the road under power. These include scrub radius, driveshaft angle, cv misalignment, what the tyre contact patch is doing, how the diff behaves, suspension movement, etc etc. Most modern fwd cars have all but eliminated torque steer with, among other things, the intermediate lay shaft and equal length driveshafts. So you can be assured that unequal total length (i.e. the diff non-central) shafts isn't a big factor - or all modern fwds would be torque steering all over the place.

Or to put it simply the ford 4x4 front axle doesn't torque steer . Have you driven an XR4x4 or cossie 4x4?

About the mini: With the ford transmission technically the engine can be wherever you want in relation to the front axle if you dont mind modding a sump and the front prop. But the standard position puts the engine right over the front wheels which I would have thought would be ideal for a mini.

Have you had a look at this one?...

4x4 Mini

You obviously want this thing to drive well when it's done or you wouldn't be so concerned about torque steer. In my opinion with something as small and light as a mini you'd suffer from crippling understeer with the weight of the engine hanging out the front and a 50:50 4wd system. I think the ford system is much more suitable for this application.

Liam

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Originally posted by goodall
depends on what sources you believe, because as far as i know its caused by the shaft winding up

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well why do car makers go for split prop shafts?

but i have applied some of my engineering knowledge and i see how different angles would also cause it but i still think its also got something to do with the shaft twisting

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Originally posted by goodall
well why do car makers go for split prop shafts?

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was a rhetorical question that wasnt ment to be answered because we all know the answer and i was thinking maybe some of those reasons also applied to the split half shaft in many modern fwd cars

I'm sorry then.

Non of those reasons apply to a FWD drive shaft as the FWD driveshaft is running at a lot lower speed, is a lot shorter, the diff is much lower than the driveshaft and the CV joints do the job of the sliding section.

The only reason I can see for having split FWD driveshafts is to reduce torque steer.
If your FWD driveshafts are suffering from windup them I must congratulate you on having superb grip. Most torque steer is cause by weight transfer due to poor front geometry or incorrect scrub radius.


I had an Alfa Sprint once.

im not saying the shaft is twisting by a huge amount its just a bit enough to pull one side a greater distance for a short moment causing a turning motion which then exaggerates this effect, you have to remember that steel has a springing coefficient to it and will change shape, some half shafts are very long and even at the lower speed it turns at i could imagine it still causing g forces if it was out off balance by abit. as for the sliding bit i know that done by the cv but remember i said some of the same reasons

anyway this is way of what my question was about i just wanted to know about short V engines nothing more

[Edited on 20/2/07 by goodall]

Assymetric shaft windup is undoubtedly one of the many factors, but the fact that modern fwd cars with this very transmission layout that you're criticising dont torque steer in practise, should tell you it isn't a major factor.

Certainly not a main criteria for choosing one donor transmission over another, or a good reason for choosing a tranny that gives you such packaging problems.

Liam

but both transmissions would cause packing problems

I'll leave this topic alone then because I don't know of any V4 engines that have been fitted to a car in the last 30 years, and I can't see the point in having a AWD/ 4WD performance car with a thirty year old engine with 80bhp and no tuning potential because it gives you equal length driveshafts at the end with the least foward grip.

quote:

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Originally posted by goodall
but both transmissions would cause packing problems

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id be going for the audi transmission with a torsen mid diff for sure, i took a look at that web site and it does look good alright, iv never seen a ford 4x4 gearbox in real life so i dont know what they are like as for weight up front that is a concern but neither transmission really gets away from that problem.

maybe its just not worth while doing this idea

Back to the original topic. Why not use a bike V twin. Very short front to back. 2CV engines are also short but you'll need several of them. What about the VW beetle flat 4? The later brazilian imports had EFI (f you can find one) and were said to be very good engines due to the 50 years of development they had.

bike twins are short but you are still looking at 400mm ish for my Aprilia twins

PS current road car is an XR4x4 and i can categorically say the only time you know the front wheels have drive is on ice and snow or gravel, where you can feel some slight pull at the wheel.

On tarmac, wet or dry, the rear bias of the drive plus the equal length shafts mean you just get grip, and lots of it, together with an excellent rwd type steering feel.

footnote, my 4x4 is a workhorse, not a preened toy car, and I only like em cos they are totally bulletproof!

Just a thought - if fitting and transmission (Audi or Ford or whatever else) & engine in the front of a mini is troublesome, why put it there?

Theres far more space in the back!
No hassle of working around a tiny engine bay or modifying the scuttle. Then you can choose from all sorts of pokey engines & boxes and as long as the engine sits right behind the seats it will be mid-engined, probably with a slight rear weight bias. Which means potentially much better handling than the front heavy sardine tin approach.

If it has to be 4x4 and thats putting you off, I'm pretty sure the Lancia Delta S4/ RS200 style transmission layout is do-able, even on a locost budget.

Any longitudinal engine and RWD box combo (as long as the box is narrow since its a mini and it has to fit between the seats, or rather the seats have to fit beside it!) facing the opposite way, a transfer box mounted down near your feet somewhere sending drive front and rear via propshafts on the passenger side, into a couple of suitable diffs.

All those bits are available, then its just a case of mounting them all and making some propshafts and possibly driveshafts.

It would mean adding a structural framework to carry all those bits, but then if you're going to be driving it hard you'd probably want a cage anyway....

A type 9 box is 6" wide, as long as that could fit centrally between the seats I think it would be possible.

Alternatively, bike engine mounted behind the seats, chain driving a centre diff. Engine would be on the passenger side, assuming you didn't flip the diffs, so it would be nicely balanced with the driver on board. Someone must have done that before?

Mark

nah i to keep it as a four seater so mid engine is a no

Is there something special about the number 4?!

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Originally posted by goodall

maybe its just not worth while doing this idea

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sounds like a nice idea haveing it sticking out of the boot but i want to shock people a little less than that

nah i want it to be a mini for the design its just a little british classic

no the number 4 just happens to be the number of people you can carry in a standard mini

just i was thinking if i could get a 1.3 V4 that give out about 150 bhp at the most i could use two mini subframes and hopefully have more than 8 points (dont have to do a sva) and then just insure it as a standard 1.3 mini and claim to the insurance company if i crash i got the car like that and since the engine size is right i might just still be insured, unlikely i know but worth a try, anyway im not planing on crashing since i built it (not that very many people plan on crashing their car anyway)

[Edited on 22/2/07 by goodall]

Anybody mentioned the Honda 116bhp VF1000 V4? Or the 125bhp Pan European ST1300?

but can you mount them to a normal gearbox with ease?