Heavy Spray.

[Banwell]

I had the misfortune of travelling down the M1 on Monday night, through some very heavy rain and lots of spray. Normally I'd press on regardless and put my faith in the quattro system/ESP, but the highway warning speeds were indicating 50mph max & potential skids.

At speeds approaching 100 if you lift the throttle when hitting large sheets of standing water the car jerks left then right. I was concerned because at these speeds any sudden movement could potentially send you into a skid. Plus the sudden movement is unwelcome when overtaking ar-tics! /ubbthreads/images/graemlins/crazy.gif


If you keep the throttle open when hitting the standing water there seems to be less movement - is this right?

I experimented with ESP on and off and this had no noticable effect on reducing the sudden left-right jerk. But decided it was best on.

 

[mramage]

Lee, your a nutter!

As I recall, the best thing is to not make any changes if you hit standing water.

Maybe someone who's been on a proper driving course can tell us though!

 

[edwin98]

I have no ESP (i think) on my S3, and yesterday i was driving through very heavy rain. My car was also pulling hard from left to right, and there is a very loud noise coming out from under the middle of my car???? The rain stopped, the road was normal wet and the problems went away!

I wanted to go to my garage this weekend, but maybe you know what this could be?

I had the problem before but thought it was nothing, but it was coming back yesterday. But only on a very very wet road with loads of water.

 

[Mo-S3]

Edwin, thats a common problem on the S3. Apparently the exhaust bracket near the engine carrier is too close and when it suddenly cools from rain water hitting it causes this knocking noise.
I had the same problem on mine and was replaced by the dealer as a known fault, although he did say that its not a recall and u have to ask them specifically about it.

RE the spray i have felt it too and think its normal for the car to this unless u are driving a 3 ton beast. Must be the car just aqua-planing slightly. Just caount urselves lucky we r driving quattro cars and not crappy 2wd fiestas or similar that would not fair so well under the same circumstances

 

[graemedunn]

what you are experiencing is the tyres attempting to clear a large volume of standing water and as someone else said, the car is beginning to aquaplane.Unfortunately it doesn't matter whether you have 4 or 2 wheel drive as it is the tyres ability to disperse the water that is important and not the fact that 4 wheels are being driven - this is irrelevant.

 

[Mo-S3]

Everything is 'relevent' my dear watson !! /ubbthreads/images/graemlins/fuck_you.gif

 

[LYRAC]

Oh dear here I go again!! /ubbthreads/images/graemlins/wink.gif

With the S3 and many Performance cars like the Ford RS Turbo /ubbthreads/images/graemlins/blush.gif (sorry I didn't mean to swear)the front differential has a Viscous differential coupling, allowing the transfer of power to the wheel with the most adhesion. /ubbthreads/images/graemlins/smile.gif Yes it also has on in the rear but that is not as noticeable.
What happens is as the wheel that has the grip it automatically tries to turn the car in that direction and then vice-versa. In the snow or wet grass it is even easier to realise what is happening. From a standing start accelerate fairly hard provoking wheel spin (No not like a Bansi HOOLIGAN) and you will feel the steering being tugged in opposite directions snatching from one to the other. All that one has to do is NOT TO FIGHT IT just (try) to remain calm, don’t correct the pull, hold the steering wheel straight and as long as you are on a flat surface (or the camber will provoke it more)the differential will sort it out for you. It is a little un-nerving at first but it works.

Now remember "take care 'cause we care!"
Lyrac

 

[AL_B]

Not experienced any alarming left-right movements going through standing water myself, but this is what the Roadcraft (Police drivers handbook) says about aquaplaning...


Aquaplaning

One of the most frigtening experiences a driver can encounter is aquaplaning. This is where a wedge of water builds up between the front tyres and the road surface, often because of inadequate depth of tyre tread. Whether you brake or steer, the vehicle will not respond. The safest solution is to remove pressure from the accelerator or to declutch, allowing the vehicle to lose speed and the tyres to regain their grip. Do not turn the steering wheel while aquaplaning because the vehicle will lurch whichever way the wheels are pointing when the tyres regain grip.

AL