Mondeo 4x4 Power Limit

So the front and rear differentials are open, but an LSD is fitted between them?

I've known about the Quaife LSD and planned on getting one when I got around to a trans swap. With the Mondeo's setup I assume would it be possible to change the front and maybe rear diffs to LSD's?
 
I can't imagine why you'd need them, and infact it would probably just encourage more tyre scrub than all-wheel-drive tends to give. You'd need an awful lot of torque deployed very aggressively to find yourself "cross axling" a 4x4. It should, in theory, be possible though with the Mondeo 4x4 set up.
 
Okay. I'm pretty ignorant with AWD systems so this is all new to me. What exactly is "tyre scrub"? I can guess that is has something to do with tire's traction, but I'm not familiar with the phrase.

Since there's an LSD between the front and rear diffs I understand it would keep the power distributed between the two. In a case where either loses traction it would stop all the power from going to that set of wheels. What if a single wheel loses traction though? If a front axle was to 'break' then with the open diff all the power in the front would just be sent towards the broken axle and only the rear would be getting power. That's a bit extreme and I know there are more normal examples, but that one came to mind. Is it just to be assumed that in the event of one set of wheels slipping the other set will still have traction?
 
All cars with LSDs on an axle are hostile to tight corners as the LSD resists the difference in wheel RPM due to the difference in turn radius between inner and outer wheel. Most 4x4 cars tend to do this too to a small extent as there's a lot of mechanical drag. At best it means that 4x4s and LSD equipped cars in general munch their tyres a bit quicker in general urban driving where tight steering lock is used. At worst, LSDs can actively encourage understeer as the inside wheel is less inclined to match it's RPM to the roadspeed as the LSD tends to enforce the outside wheel's (which is heavier loaded and on a longer turn radius) ideal RPM onto it.

The worst case scenario for the Mondeo 4x4 is a launch from standing start. The weight shift is rearwards as with any car, which unloads the front wheels (which is why FWD is fundamentally flawed and has no place on any performance car). Even with the 58% bias though, the front wheels only need to distribute 58% of the total roadwheel (not flywheel) torque between them to stay non-slip. Even if one does slip, the limited slip transfer 'box will lock up the diff and turn it into RWD for a few moments. If one of the rears spins too then you're goosed, but the rear axle weight increases when you apply power, increasing available friction from the rear tyres. That and it still takes some torque to spin that rogue front wheel so the rears still wont need to do all of the work.

In short - unless it's some monstrous long-stroke blown V8 you're fitting, or ice you're racing on, you won't be wanting for traction with just the limited slip transfer diff.

An open transfer diff - now that's another story, and it might as well be FWD for all the use that would be...
 
Well that makes more sense now. There's no room in here for some sort of V8 and I'm not one of the guys that has a deluded notion that it's even possible, lol. I also don't plan to do any sort of racing on ice so that's not a concern. Given that it's an AWD system though I hope it would improve handling at least some on snow or ice. Then again by the time I had the money to fit this I imagine I would be able to buy a winter beater truck and wouldn't have to worry about the Cougar in snow.
 
Well the good news is that if does work on ice. From what the guys here say, it works better on ice than the Jag set up does, because the torque split almost exactly matches the weight distribution. On the Jag it's the inverse of the weight distribution, and as I said, the X-Type can mimic my S-Type pretty well in the snow, with the exception than the steering is blunted just enough that you can't feel what's going on at the front end with the X-Type as well as you can in the S-Type. Still, I've never had the X-Type stuck (famous last words :LOL:)
 
I thought the power was split roughly 60/40 with bias to the rear? How's it equally distributed when the majority of the car's weight is toward the front? Of course I'm thinking of curb weight. Do you mean when accelerating since the force is toward the rear?
 
PzKpfw_III said:
I thought the power was split roughly 60/40 with bias to the rear? How's it equally distributed when the majority of the car's weight is toward the front? Of course I'm thinking of curb weight. Do you mean when accelerating since the force is toward the rear?
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If you're talking about the Mondeo 4x4 setup, power is biased towards the front (y)
 
PzKpfw_III said:
Well that makes more sense now. There's no room in here for some sort of V8 and I'm not one of the guys that has a deluded notion that it's even possible, lol. I also don't plan to do any sort of racing on ice so that's not a concern. Given that it's an AWD system though I hope it would improve handling at least some on snow or ice. Then again by the time I had the money to fit this I imagine I would be able to buy a winter beater truck and wouldn't have to worry about the Cougar in snow.
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This is not delusional mate, there are 4 that i know of in america that have the boss302 V8 engine fitted. I had planned on putting a sbc in my cougar, requires changing the floorplan and modifying the engine bay layout, have binned the idea after loosing my job though, worked out will cost me £26,000 to do the conversion.

I still think using the subaru impreza awd system is the best idea as it is proven to be more or less bullit proof (y)
 
Procomm said:
This is not delusional mate, there are 4 that i know of in america that have the boss302 V8 engine fitted. I had planned on putting a sbc in my cougar, requires changing the floorplan and modifying the engine bay layout, have binned the idea after loosing my job though, worked out will cost me £26,000 to do the conversion.

I still think using the subaru impreza awd system is the best idea as it is proven to be more or less bullit proof (y)
Click to expand...

No I know that it's "possible" and have seen the pictures. It is, however, entirely impractical given how much modification is needed. In the end the only Cougar bit left is the shell. What I meant by what I said was that a V8 won't just pop in like a Duratec does or even with minor modification, but basically requires a complete redesign. So while it is "possible", over here the notion is generally treated as daft. Only the new guys give it any serious thought before a more experienced member has to bring them back to reality.
 
I tend to agree. There are far better platforms to start with if you want a V8 engined coupe, and ones which will work well as a package - i.e. it'll handle properly without trying a dozen suspension setups to find something that isn't plain dangerous; the interior quality will be in line with the rest of the car, all the dashboard parts will look like they belong together and all the electronics will work properly. Even an aftermarket alarm is a MASSIVE turn off to most people - they just want one key fob which does everything with no butchered wiring looms and nasty aftermarket bits showing inside.

You could get a great example of most V8 coupes for what it would cost to produce a first attempt at such a conversion, and any of them will wipe the V8 Cougar off the road in every single respect other than that the Cougar is unique - and virtually worthless because nobody ever wants to buy a drastically modified car because there's no way of knowing it's been done right or even what parts you need to buy to service the damned thing, let alone the prospect of insuring it.
 
The future's bright, the future's XKR!

Jaguar-XKR_Coupe_2005_1024x768_wallpaper_02.jpg
 
I've very slowly gone from not really liking the 'old shape' XK to falling absolutely in lust with it. I know the new one is lighter, better built and is in probably every way a much better car, but I just adore these.

To keep this post vaguely on topic, do we think an XKR could be 'fourby'd'?
 
I've driven a 2005 4.2 XKR Rich, and it's got the reverse Tardis feel, but in a good way. It's heavier than the X150 for sure (and I've been passenger in the 5.0 2011 XKR - Wow! It pulls harder through 100mph than my lowly S-Type does in 2nd gear. It's literally that savage) but it feels smaller than it looks, and it is tight, well balanced and agile. Those Brembo brakes feel great under the pedal too. I spun the rear wheels on the 4.2 kicking down at 50mph - and it was booted with the proper OEM 275mm wide Pirellis on the back.

The 4.2 is a big improvement on the 4.0 (improved power, reliability, better seats and dumped the 5spd Mercedes gearbox in favour of the 6spd ZF which improved performance, driveability and fuel consumption even though the engine got 200cc bigger and gained 30bhp).

Add it to the "must have" list.

I drove a 1996 4.0 XK8 too. Not stellar performance by any means, but still a nice car in it's own right. Nearly bought it, actually.
 
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