RWD with LSD vs 4WD ?

[developer]

Maybe it`s my sub - conscious that thinks that RWD cars are ALL tail happy.... I need to prove myself wrong.

I can tell you that an LSD won't prevent your car from being tail happy, though traction control does help to keep it in check somewhat.

 

[Mr Kripling]

Your arguments are based on costs, which we're not talking about, not engineering

Which goes back to what what you meant by "an engineering point of view". Most automotive engineers that I know consider cost and efficiency to be some of the most crucial aspects of car design.

As I've already said, in pure performance terms RWD is better. What irritates me is when people dismiss F/AWD cars outright without being able to put forward any sensible reasons beyond "They're cheap and they understeer".

 

[Deleted member 37751]

Most automotive engineers that I know consider cost and efficiency to be some of the most crucial aspects of car design.

Yes, when costs are at the forefront of the brief...I doubt very much the engineers at Ferrari are wondering how they can squeeze two more mpg out of the Enzo...

 

[Deleted member 37751]

What irritates me is when people dismiss F/AWD cars outright without being able to put forward any sensible reasons beyond "They're cheap and they understeer".

Ok, and I genuinely mean this, I'm looking for a weekend toy at the minute so give me some suggestions and what you'd recommend to buy with a £10k budget.

I don't mind having a bash at a car, I did by this woeful X5 after all, so I'm all ears.

 

[Mr Kripling]

Well, I'm guessing you meant to say something with FWD so how about this?

 

[grober]

Perhaps it should be pointed out that the WRC has been dominated by 4WD vehicles for many years. If RWD was the dynamicaly superior setup one imagines this would not be the case?
https://en.wikipedia.org/wiki/World_Rally_Car

 

[Charles Morgan]

Ok, and I genuinely mean this, I'm looking for a weekend toy at the minute so give me some suggestions and what you'd recommend to buy with a £10k budget.

I don't mind having a bash at a car, I did by this woeful X5 after all, so I'm all ears.

Alpina B10 3.3 manual, 95000 miles Individual Velvet blue, lots of work done, new PS2s all round and reasonable change from your budget. Oh and RWD, none of that FWD malarkey.

 

[renault12ts]

Perhaps it should be pointed out that the WRC has been dominated by 4WD vehicles for many years. If RWD was the dynamicaly superior setup one imagines this would not be the case?
https://en.wikipedia.org/wiki/World_Rally_Car

But...if Formula 1 rules allowed 4 wheel drive...would it happen?

 

[grober]

Don't know but since it was banned in 1983?? along with 6 wheeled cars who knows. Formula 1 cars are so far removed from ordinary motoring that I am usure of their relevance to the argument. Suffice it to say that any major precipitation of rain normally reduces them to very expensive surfboards with wheels attached .

 

[gasman2]

all i can say you can throw and impreza all over the place and wld have to be a seriously bad driver to loose control
i wouldnt attempt the same thing in a rwd car no way

 

[kid-jensen]

WRC may well be all 4WD, but we're talking about driving enjoyment here..

All that matters in motorsport is winning. The car may be a pig to drive (I'm sure they are) but the primadonna drivers are paid those huge sums to get around that and give the teams a win.They wouldn't need to be as fit as an Olympic athlete if the cars were easy to drive..

Much like a fast road car and a track car. they're horses for courses. If you have a car that's both, you've arrived at car-heaven..

 

[grober]

Given that for the majority of car owners the purpose of the vehicle is to transport the driver ,passengers and possibly luggage from A to B under all circumstances then 4WD wins every time simply because its more efficient at translating motive power into forward movement. If on the other hand you regard the vehicle as merely a source of entertainment then other criteria take precedence and how the car drives becomes more important. Often in exchange for more driver feedback and what is termed entertaining handling vehicle stability has to be sacrificed to an extent. This places greater demands on driver skill and also may restrict both the condition and nature of the roads the car can cope with. A car that can achieve both is indeed a rarity to be treasured and if such cars exist then their quality of handling might be appreciated by more owners if their handling was not compromised by manufacturers continuing to fit unfeasably wide low profile tyres as standard fitment as mere fashion statements rather than for any handling reasons.

 

[def90cars]

Perhaps it should be pointed out that the WRC has been dominated by 4WD vehicles for many years. If RWD was the dynamicaly superior setup one imagines this would not be the case?
https://en.wikipedia.org/wiki/World_Rally_Car

that it is compulsory to be 4WD

• Open to cars complying with the new class RC1 technical regulations.
• 1.6-litre, fuel injection, turbocharged, four cylinder engines fitted with a 33mm air intake restrictor.
• Power output restricted to about 300bhp.
• Cylinder block and head based on those in the standard road car.
• Modifications allowed to crankshafts, con rods, pistons, cylinder linings, valves and camshafts.
• Permanent four-wheel drive transmission and sequential gearboxes.
• Mechanical front and rear differentials.
• 0-100kph in less than 4sec.
• Top speed exceeding 200kph.
• 7 x 15inch wheels for gravel, 8 x 18inch wheels for asphalt.
• 300mm brakes for gravel, 355mm brakes for asphalt.

 

[grober]

Correct -4wd is compulsory----NOW ----but the formula evolved from a time where there were few restrictions as to power or transmission and in that "free for all" period 4WD was generally found superior to RWD starting perhaps with the legendary Audi Quattro. Hence the adoption of 4WD as todays "standard" as defined by regulation.

 

[markjay]

The theory (from 30 years ago....) was that RWD has an advantage when cornering because the tail going out means the front wheels can remain alligned with the direction of travel, especially when coming out of the corner, allowing quicker acceleration into the straight stretch that follows it.

The power waste at the corner was deemed irrelevant because you can't use full engine power through the corner anyway.

AWD has other advantages and is overall better but still not at that particular point i.e. accelerating when coming out of a corner.

Things may have moved on though.....

 

[grober]

I think the key here is that in order for the rear of the car to move sideways the traction/grip of the rear tyres to the road has to be broken- this is loss of drive, tyre wear and probably the most important loss of stability- possibly momentarily- but on a road with limited grip- possibly permanent leading to loss of control and the car spinning. Often the criteria for this to happen are governed by the engine torque available at any given rpm, the width of the tyre transmitting the power, and the condition of the road surface. While wider rear tyres may convey more grip in dry conditions the opposite may apply in the wet. Perhaps more important than the absolute limits to rear end grip is that period of transition where grip is lost. A car that gives ample feed back of this happening and whose transition to oversteer is gradual may not ultimately corner so fast but will remain entertaining to drive. The car that maintains grip to higher levels but then lets go suddenly may require driver skill levels beyond the average driver to avoid loss of control. Hence my comment on wider tyres.

 

[R1NGA]

...... If on the other hand you regard the vehicle as merely a source of entertainment then other criteria take precedence and how the car drives becomes more important. Often in exchange for more driver feedback and what is termed entertaining handling vehicle stability has to be sacrificed to an extent.......

Which is why 1WD and my Morgan 3-Wheeler is way more fun in terms of pure entertainment than the SLK55, but also way slower too, which may be why I've never got on very well with rallying in the tricycle......

 

[DuncS3]

I've had many 4wd cars in the past, still have an old quattro but I prefer RWD - more fun - reminds me of the old BMX days, doing skids and so on

If the C63 had a 4wd option, I would still buy RWD - although the 4wd would be much more useable.

 

[moonloops]

Ok, and I genuinely mean this, I'm looking for a weekend toy at the minute so give me some suggestions and what you'd recommend to buy with a £10k budget.

I don't mind having a bash at a car, I did by this woeful X5 after all, so I'm all ears.

You can buy my back burner project - MK3 MR2 that has Audi S8 V8 engine in the back. Another £2k to finish the project and all in it will be half of your £10k budget. 0 to 60 in 3.4 seconds.. if it doesn't kill you first....

 

[Mr Kripling]

The theory (from 30 years ago....) was that RWD has an advantage when cornering because the tail going out means the front wheels can remain alligned with the direction of travel, especially when coming out of the corner, allowing quicker acceleration into the straight stretch that follows it.

It's more a case that the front wheels can use all of their available grip for steering rather than steering AND accelerating (hence you can start accelerating out of a corner sooner).