Pros and Cons of 4 wheel drive

[martine]

Having never driven a 4wd would anyone like to summarise the advantages and disadvantages?

[ScoobyChris]

I've owned both performance 4wd's and off-road 4wd's but here are some of my thoughts....

Cons
1. Cost a fortune in fuel and road tax (both my Scooby and Disco (diesel) did 25mpg) as well as tyres which may wear out quicker
2. Expensive to repair if they go wrong (allegedly - neither of mine did)
3. Prone to lift off oversteer (that could be a pro too )

Pros
1. Phenomenal off road and you can really feel the power being shifted around if you put some of the wheels on a lower grip surface
2. The Scooby had seemingly endless levels of grip in all conditions and could be very easily adjusted on the throttle (might be as a result of the rear LSD)
3. Something to wind up the environmentalists with

For most every day driving situations, you'd be hard pushed to know it was 4wd...

Chris

[dibbs]

I agree with the slight increase in cost to run and fix. Transfer Boxes/ Tyres etc.

Lift off oversteer is well within manageable limits as you can put the power down again and it sorts itself out.

Roundabouts are tricky as you find yourself getting to the other side quicker than anyone expects well within comfort levels and people tend to seem to pull out on you as they don't expect a car to make it round so quick so look out for that!

Slow starts of junctions unless you want to melt your diffs and transfer box because the clutch will give out long before you lose grip in the dry.

Wet weather is a joy as everyone else struggles for grip!

[ScoobyChris]

Lift off oversteer is well within manageable limits as you can put the power down again and it sorts itself out.

Agree with this, but if you've misread a situation (as an inexperienced young man did once ) putting more power down as you're fast approaching a hazard is counter intuitive and takes some practice before you realise it is actually the right thing to do!

Obviously much easier not to get into that situation in the first place, but I digress!

Chris

[martine]

Thanks guys for the opinions.

So does 4wd let you go around corners quicker and if so, why? Does it follow that all true high-performance cars ought to be 4wd? Would a fwd 911 be quicker on corners than rwd (like for like)? I'm not talking off-road or in the wet...simple dry tarmac.

[jont]

I'll wait for the Stressed one to chip in, but in the meantime you can see what Don Palmer says about various drive characteristics here:
http://www.drivinghandbook.co.uk/part3.htm#frontwheel

[Mr Cholmondeley-Warner]

Too many variables:

Most high performance cars are not 4wd because the systems are complicated to make, expensive to maintain, increase weight (both sprung and unsprung), suffer high transmission losses, and only give benefits where grip is running out - hence their popularity in rally circles but not in most forms of tarmac racing. Also a lot of 4wd systems fitted to street cars are not permanent, but usually fwd with the ability to engage the rear wheels when necessary.

A fwd 911 would no longer be a 911, not just because of tradition, but because its weight distribution would change, along with torque forces on the steering wheels, giving a car with different characteristics, i.e. not "like for like".

The Carrera 4 is a nice car, but most enthusiasts agree it's a pretty pointless one. It's slower than a 2wd Carrera, and not better enough at keeping traction to make it a "better" car overall.

[martine]

Too many variables:

OK perhaps I was wrong to give an example but I'm interested to know if in principle 4wd provides faster cornering.

What does the theory say?

Or does anyone know of a race series where 2wd and 4wd are allowed to compete side by side? BTCC? Would an ultimate F1 car be 4wd if it were allowed (which it isn't)?

Sure 4wd is more complicated and expensive and loses a little power but I'm only asking about which is best at cornering.

[dibbs]

Normal driving conditions- Fwd will be quickest as anyone can plow into a corner and drag themselves out of it

Rwd will be quickest in the hands of a pro slowing for the corner powering through the apex and pushing themselves out of the bend

4wd will be quickest when it has the torque to match. Plow into a corner, pull yourself round, push yourself out.

Techincally 4wd will be quicker given a good amount of torque in a car that is more powerful than its 2wd counterpart.

Generally (as has been said) 4wd is just a normal car with all the extra bits mechano'd on so it loses in power to extra weight.

4wd may be faster but it isn't as fine or fun as Rwd because it takes less skill to balance and set the car to get the best out of it.

IMHO

But in the wet...

[Mr Cholmondeley-Warner]

I'll wait for the Stressed one to chip in, but in the meantime you can see what Don Palmer says about various drive characteristics here:
http://www.drivinghandbook.co.uk/part3.htm#frontwheel

And in a more lighthearted vein ...

http://www.donpalmer.co.uk/news/newspt01.htm

[jont]

And in a more lighthearted vein ...
http://www.donpalmer.co.uk/news/newspt01.htm

Doh. That's the article I was looking for originally. I knew I'd seen it on his site somewhere...!

[Prelude]

You know one is behind you while driving in the dark - their headlights shine/blind you through every mirror. On the motorway it is even more disconcerting if following close behind you!

[ScoobyChris]

You know one is behind you while driving in the dark - their headlights shine/blind you through every mirror. On the motorway it is even more disconcerting if following close behind you!

Surely that's only the off-road ones? The sports ones will be in front of you

Chris