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    2WD or 4WD

    This is a topic that has been discussed a lot on the forum, but never really got to a fact agreement.
    I chose C4C for added security and had my doubts after my crash (Wet motorway, aquaplanning, thread and pics available back a year in the archives I think)
    The car was quite heavily dammaged. I know you can't do anything against aquaplanning, wether it's C2, C4 its down to the width of the tyres which on a sports car are bound to be large.
    B4 the accident, I always thought, hey I have a C4, I can drive that car on the wet as hard as on the dry!
    Well, not anymore now, I am very cautious in the wet.
    So, sorry but as opposed to what the mags say, the C4 is NOT quite the all weather car I expected.
    But I must admit it feels on "rails" along long bends on dry, don't know how a C2 would feel, but I can feel the front pulling the car in mine. I can accelerate earlier than on a 2WD at the exit of a bend I suppse.
    I remember a thead recently where the conclusion was that the only advantage in terms of performace of the C4 (and Turbo, C4S) is better start from standstill due to 4WD (Better traction) but then the 2WD are better (C2, GT2, etc.)
    That's ok, it actually makes sense.
    But does a C2 really require more concentration to drive?
    With PSM it's just as safe no?
    I'm talking dry conditions here, I'm not really a believer of wet road security after what happened to me.
    Just a thought when the new 997 comes out.
    You get a bigger boot, better traction (standstill start excl.), better fuel consumption, less weight and most of all (well, for me...) an almost Euro 10000 savings which could be converted in nice options or whatever.
    I know it's mostly a matter of taste, but there are certain things I'd like to clear up.
    Like, why is a C4S quicker than a C2 on the Nuburgring?
    Can't be 4WD right? (with the same driver behing the wheel ie Rohrl) So I thought, it can only be the wider track which allows better stability in the bends? Any thoughts?
    In which case, would an eventual C2S be quicker than a C4S?
    Thanks guys,
    Fanch.

    Re: 2WD or 4WD

    Fanch - I think your post is quite accurate. AWD has an advantage in putting the power down to the road in situations where the RWD car might spin its rear tires (standing start, exiting slow tight corners, and poor surface friction caused by rain, snow or gravel). AWD does not have an advantage otherwise. In fact, it does have disadvantages in all other circumstances (weight, smaller trunk, more power losses through the front drivetrain, and a less direct ability to throttle steer the car).

    A C4S is ONE second faster around the 'Ring than a C2. Remember that a C4S has larger brakes and a lower, wider and stiffer suspension than a C2. Despite the fact that one second is totally insignificant on a track that long, the advantages for the C4S come from the brakes and suspension and possibly a better exit speed on some of the hairpins. I think your premise is correct that a C2S would be faster than a C4S, unless the track was wet (yes it does help at low speeds to get underway and pull out of slow corners, but not to prevent sliding at speed). I feel that when the weather is bad, I would rather take a different car from my Porsche and not compromise the purposefulness of my Porsche by adding the AWD. That's why I'm opting for the GT3...

    Re: 2WD or 4WD

    I forgot to mention that the C4S has wider rear wheels and tires to improve its track performance compared to a C2 also.

    Re: 2WD or 4WD

    Thanks Grant,
    I forgot about the sport chassis and the turbo brakes of the C4S, that would then complete the explanation of why it is faster than a C2 round a track.
    Fanch.

    Re: 2WD or 4WD

    Fanch,

    I too aquaplaned last year with my C2.
    I was in a sweeping left hand turn on a highway, and it was raining. I was doing about 120km and was in the outside lane.
    Just before coming out of a turn I hit a puddle, b/c I was still in the turn, the ass end came out hard.

    Thankfully there was no traffice around me, so I just held the wheel straight, and let the car go where it wanted to, with MINIMAL steering adjustments. I let off the gass immediately and didnt touch the break and eventually the ass end righted itself. I knew that as long as i held the steering wheel straight that is with my hands at 9 and 3 o clock that the rear end would right itself. the worst thing I could have done was over steer in that case i would have started the penulum motion and then totalled the car.

    Re: 2WD or 4WD

    Well, you were definitly more experienced than me!
    I was on a straight! the car hit a patch of water (it was raining) doing about 150kmh, and then aquaplanned.
    It all happened so fast, I can't remember if I hit the braked (which is a huge mistake) but I did remember spinning AT LEAST 5 times!!! (7 I think). It was real tarmac surfing
    Then the car hit the protection wall on the left, I thank France for that, very very effective! tha car JUMPED on it!!! Yes! just the front, and then back on the motorway to a full stop, facing the traffic
    No traffic during the accident thank god.
    No injuries whatsoever, this is impressive from Porsche, the chassis takes all (had a crash in a Boxster as well quite bad, and nothing happened to me either nor my passengers in both cases).
    There must be a pic back in the archive quite a while ago.
    Another thing, the gendarmes were extremely efficient as well and nice too! The guys were on the spot 10 minutes after my call and the car was moved from the motorway in 30 minutes.
    Anyway, I'm extra careful on the wet now.
    Fanch.

    Aquaplaning

    have nothing to do with 4WD or 2WD. Its has to do with the tread of the tires, depth of the water surface and speed.

    Unlike power induced drift, aquaplaning can't be recover by counter lock... you have basically no traction until the tires surface touched the ground again.

    Re: Aquaplaning

    Yes you're right which is why it's so bloody scary because basically, the best thing to do when you start aquaplanning is... DO NOTHING!
    Or actually yes, you can go in neutral and start praying
    Which is why I don't think that wet hanling should be an argument when you chose 4WD over 2WD but other stuff like corner grip, better traction, etc.
    Or maybe wet handling but only when the road is a little bit wet, not when it's raining heavily, in the latter case, the best place for a sports car is the garage
    Unless your name is Senna or Shumacher
    Fanch.

    My opinon on 4WD vs 2WD

    4WD is a very useful system for sport car especially for people who crave conering grip and speed. A beginner can drive a 4WD very fast around corners and apply traction more efficently than a 2WD. Throttle input for the 4WD is not as tricky as 2WD. Full throttle and the car glue to the ground which is not the case for 2WD.

    In retrospect, most people will not come near 90% of the car potential. In which case, 2WD is more entaining to drive when you are at 60% of the car potential, more driving skill involve as the result more satiflying to drive. Some people choose car that is fun rather than fast. 2WD in my opinon is the way to go for weekend track car. Full potential of a 2WD can be as quick or even quicker than a 4WD car if driven correctly. More room to play with the turn-in direction and most importanly, it is lighter...

    Track/fun car- 2WD
    Everyday super car- 4WD

    Sailing along

    A 5-turn spin is pretty impressive Fanch.

    Actually, aquaplaning is down to simply tyre pressure and speed. There is a mathematical calculation which will tell you when a tyre will aquaplane. Higher tyre pressures are better and lower speeds are better.

    Of course, we all know that the width of the tyre and the tread depth make a difference. But I believe this is down to the ability to remove the water. Remove the water and obviously you won't aquaplane.

    I'm very cautious in the rain. With new tyres I'll probably drop to below 180 km/h. With worn tyres below 160 km/h. If it really starts bucketing down then you have to slow even more.

    I'm not sure I agree with the advice that there is nothing you can do and you should do nothing.

    First, a good driver is always looking ahead. You should see the problems before you arrive. It shouldn't be a suprise. Not getting yourself into a mess is the best way to get out of it.

    Second, I don't agree about aquaplaning being sort of an all or nothing thing. I can often feel (and see in my rear view mirror) that part of the tyre is not making contact but that part of it is. If you've got a little traction then the PSM can work a bit and you might be able to countersteer. Ditto if the back wheels are aquaplaning and not the front. And ditto if only one front wheel is aquaplaning. Each situation is different and you have to be able to read it.

    Actually, the biggest problem I find in the wet is tramlining. the Water will collect in the ruts in the road. The wheel will aquaplane on that water. But the edge of the tyre can still be directed by the top of the ridge. The end result is that the ridge can drive the wheel left or right of centre and there is no traction to oppose that force. This can feel just like a tail slide but instead of correcting for it you probably want to get the wheel up out of the valley on to the ridge where you will have traction. Counter steering is the opposite of what you want.

    Those are my two cents worth.

    Stephen

    agree very much

    "First, a good driver is always looking ahead. You should see the problems before you arrive. It shouldn't be a suprise. Not getting yourself into a mess is the best way to get out of it"

    In my opinon, looking ahead and predict the problems is more important skills than any racetrack driving skill. You can easily tell a good driver from a bad driver simply from this.

    Re: Sailing along

    I enjoy rain driving. It is a great way to improve your driving skills. As FixedWing says, vision is the most important thing. It is important both to avoid incidents as well as to recover from them. Once a slide begins, don't look at what you think you are going to hit. Instead, look down the road where you want to go. This is extremely difficult to do, it takes some practice - but it is a key. A couple of other hints:

    Use winter tires,
    Add tire pressure,
    Use softer sway-bar and damper settings,
    Use higher than normal gears,
    Drive off-line, stay away from the apexes,
    Look for drier, more abrasive asphault,
    Cornering traction is reduced more than braking traction,
    Drive smoother,
    Don't hit a puddle with one side of the car.

    Re: agree very much

    Guys,
    I agree with the looking ahead advice, and thanks Fixed for the physics behind it too. But, honestly, and I'm sure I'm not the only one, I don't concentrate always 100% on the road, especially on the way I was driving that day. Ok, it was raining, but I was doing 150kmh which is not even 3500 rpm in 6th, and chatting with my passenger, listening to music, having a fag, etc.
    You know what I mean: Dull straight motorway driving.
    Theory is good and maybe it would have helped but it really happens fast!!! But I suppose I learned the hard way. Now on rainy days, I looks for water patches etc.
    But I can't concentrate ALL the time on the road! Especially on motorway, now that the french police nails you when you speed, I don't even drive over 160kmh Sad, I know. But you'll understand that one can get bored at that sort of speed on straight endless tarmac.
    Thanks for the advices anyway. I'll remember now.
    Fixed, what does Tramiling mean exactly?
    Fanch.

    Re: 2WD or 4WD

    Aquaplanning is one thing, grip in wet conditions is another thing, I think we are getting them mixed up and buched up together. If you are aquaplanning, you have lost all contact with the road surface and you are hovering over a thin film of water and it doesn't matter if its RWD or AWD or FWD and is dependant on the ability of the tires to evacuate the water puddled on the surface (thread pattern and depth, shape of contact patch, width of tires, etc) not the number of wheels with traction.

    But another thing is drifting, sliding, oversteering, etc in wet conditions in which you have contact with the surface just like in dry, its just that there is less friction than dry. Thats when the AWD is superior that FWD and RWD because it has greater grip due to the fact that the tractive force is shared over a greater contact patch (all four tires) and hence the Slip Angle is reduced (its the same mechanism why it also has greater grip in straight line launches). So the AWD with have greater cornering grip in all surfaces but specially in slippery ones like wet, making them safer and faster in slippery conditions, hence in the slippery roads of the World Rally Championships the cars are AWD.

    So in terms of aquaplanning it makes no difference AWD or not, but thats not the only thing that can happen to cause an accident or slow you down, just like in dry, gravel, snow, etc you can loose grip and crash without aquaplanning and for that the AWD is superior.

    With this I'm not saying that the AWD are always superior, I depends on what you want, needs, location, etc. The AWD are also heavier so if you like in Arizona, the AWD may not be as important than in Seattle. Also there is some power loss to the wheels from greater frictional components, they are also less "tossable" that the RDW so a profesional driver in a dry track will be handicapped by the AWD while a non-profesional driver will be helped by the AWD since its more controlable, thats why the more powerfull and all purpose street intended TT come AWD standard and the track minded GT2 is RWD. So its a personal choice, but in terms of wet, aside from aquaplanning, the AWD is always superior (faster and safer).

    BTW the fact that the C4S is not more than 1 sec faster than the C2 from is because its also 220lbs heavier! and that, in the fast power track of the ring makes a big hadicap. And in a dry day, in good track surface, and driven by a professional, the AWD is a handicap too, for the reasons I mentioned before. So thats why with wider track, Turbo brakes and sport suspension its only 1 sec faster: its 220lbs heavier and AWD. As a matter of fact that one sec slower 8:17 lap time of the C2 is of the 3.4l 300HP pre-2002 C2, and official laptimes of the new 320HP C2 are slower!! suspicious ain't it? (Porsche probably didn't want the cheaper C2 non-"S" C2 to be faster around the ring than the C4"S". so non-official laptimes of the 2002 C2 are probably already faster than the C4S in the ring (only in the dry of course ;) )

    Personnally the advantages of AWD of the C4S, in my situation/circumstances, is not as worth while than a same priced C2 with RoWM030, X-51 powerkit and 18" wheels. Whereas the C4 (not sold in US) is a C2 with just the AWD added which is worthwhile for the smaller price difference.

    Wheels

    Don't forget though Carlos that there are four wheels on a car. If all wheels are aquaplaning then you're totally correct. But often it is only the backs or only the right side or some combination. Then you've still got some control.

    Stephen

    Tramlining

    No need to worry Franch, we're not critisising. If you had crashed my car you might have some explaining to do but it was your car and no one was hurt. So a valuable education.

    Tramlining comes from when there were tramlines in the cities. Cars had narrow tyres as did bikes. It was very easy to have the tyre try to follow the tramline.

    It still happens today with wide tyred cars such as ours and especially when the tyres are bald. You'll be driving along and the edge of the tyre will try to follow an expansion joint or rut in the road. When it happens at the back it can be really disconcerting as it feels just as it the back is sliding. But it isn't and instinctively correcting for it will tend to keep the tyre in the groove. I've had it so bad sometimes that I initially thought it was a mechanical failure.

    As for paying attention, when I'm driving in the rain ever hair on my body is standing on end. These cars are no fun at all in heavy rain. They can be driven quick but you've got to have hair-trigger responses. It is really draining to go fast in heavy rain.

    If you want to smoke, daydream or play with your girlfriend then better to get a VW Golf for such occasions. The narrower tyres make it much better for rain driving. In fact, in the rain ordinary cars can be very quick. It is the one time that a well driven [oops]-box can take on a sports car and maybe win.

    Stephen

    Re: Wheels

    Thanks Carlos for the info!
    Stephen, I understand your point but I still think it all happens too quickly for the normal driver to do anything (ie, me )
    Did you learn how to control your car on the open roads under wet conditions? If yes, how? Empty car parks, etc.
    I'm planning on doing a course but safety orientated, I don't know if some of them specialise in wet driving? Suggestions (in France if possible)
    Thanks,
    Fanch.

    Re: Tramlining

    Yes you're right about rain conditions, the only time where a Polo GTI can humble a Murcialego .
    As for right car in the rain, I agree too, but this was the occasionnal week end with great weather on sat and terrible on sun. I'm sure you know what I mean, not much you can do, you have to go bak to work on monday .
    And I only daydream, listen to music, chat in my car, I don't play with my gilrfriend!!! Anyway, it's a manual gearbox, so it'd be quite tricky anyway
    F.

    Re: Wheels

    </font><blockquote><font class="small">Quote:</font><hr />
    Don't forget though Carlos that there are four wheels on a car. If all wheels are aquaplaning then you're totally correct. But often it is only the backs or only the right side or some combination. Then you've still got some control.
    Stephen

    <hr /></blockquote><font class="post">

    Absolutely <img src="http://www.rennteam.com/w3timages/graemlins/smile.gif" alt="" /> but in that case its ussually easy to avoid the accident since loss of contac is small or short (usually the front then ther rear - I get plenty of those) otherwise all fours would be aquaplanning, just don't make any inputs to the car (wheel, gas, brakes) until you regain contact unless you are in a bend, in which case you have to point the front wheels ahead before you regain contact. Also not always is the AWD going to give you greater grip in wet, if you are throttle oversteering because you suddently let off the gas while at WOT in middle of a turn in the wet then it doesn't matter if its AWD (done that <img src="http://www.rennteam.com/w3timages/graemlins/blush.gif" alt="" /> ), we are talking about general situations.

    My best recommnedation against aquaplanning is getting a set of S0'3 tires which are the best in wet conditions I have tired I have tried. I have significantly reduced aquaplanning situations with the S02's and now the S03's (I do a lot of very high speed highway miles and it rains quite a bit here in winter). They ussually last me 15,000kms (9,000miles) before I replace all four at the same time. Aquaplanning is very little for a tire so wide, does anyone remember the MXX3's? <img src="http://www.rennteam.com/w3timages/graemlins/tongue.gif" alt="" /> they were horrible in aquaplanning I was force to slow down so much it was ridiculous.

    Re: agree very much

    Quote:

    now that the french police nails you when you speed, I don't even drive over 160kmh Fanch.



    Fanch, have you considered an european radar detector? It does wonders in terms of being able to drive relaxed at highspeeds in the highway. I don't have to worry so much about the cops and concentrate more about the road. The Bel 966R Vector Europa work the best in Europe, gets the european K (fixed - Gatso), Ka (fixed and movile famous "French made" Multanova radars used in the highways) and the Ku (mini-Gatso). Don't worry about being illegal (exept UK), its a stealth version. The antena is hidden behind/inside the front bumper. You can order them by the www from the Bel UK site.

    Re: Wheels

    Quote:

    I'm planning on doing a course but safety orientated, I don't know if some of them specialise in wet driving? Suggestions (in France if possible)
    Thanks,
    Fanch.



    Look for Autocross events with dry and artificial wet conditions, I learnt a lot on how to react on wet conditions to understeer, oversteer, braking-steering, etc.

    Re: Sailing along

    Stephen, I like your Avatar...how do you like mine?

    Avatar

    Thank you RC! Colourful isn't it?

    I usually get a different response -- especially on another unnamed board where it caused something of a virtual riot.

    Yes, I like your avatar very much! Photo of a future suiside bomber, right??

    Stephen

    Re: Avatar

    Quote:
    Thank you RC! Colourful isn't it?

    I usually get a different response -- especially on another unnamed board where it caused something of a virtual riot.

    Yes, I like your avatar very much! Photo of a future suiside bomber, right??

    Stephen



    Well, then I guess all Germans, French, Japanese, South Korean, Taiwanese, Italians, etc. became suicide bombers, right?
    C'mon Stephen, this is a car board and you knew that such an Avatar would provoke people.
    I don't see any connection between the Avatar and cars.
    If you want to discuss politics, I can set up a free forum without registration and we can discuss about god and the world until we all drop dead of boredom. But again: this is a car forum and unless you want to discuss the reliability of the Humvee in the Iraq theater of action or a future Cayenne military version in the Cayenne Forum, politics should be kept out. I didn't make these rules, the boss did.

    You show me yours and I'll show you mine.

    Well actually RC, I didn't discuss politics here. It is simply an avatar. Just like your avatar is simply an avatar. You're the one that brought up the topic.

    But anyway, I'll happily make a deal with you. You delete your avatar and I'll delete mine.

    Sounds fair.

    Stephen

    Re: You show me yours and I'll show you mine.

    Quote:
    But anyway, I'll happily make a deal with you. You delete your avatar and I'll delete mine.

    Sounds fair.

    Stephen



    Very fair, indeed. And very fair to all users of this forum.
    Go ahead, guys.

     
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