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Discussion Starter · #1 ·
There is a pretty sharp turn in city road near work and it rained a lot in the last day. It wasn't raining this morning, but the road was wet. As I was going through the turn, I added a fair amount of throttle (up to 4-5 rpm) and suddenly the car drifted (back end went to the right on the left turn)... Seems the problem was a wet spot and both rears spinning...ended up almost hitting a metal barrier on the right or the car next to me (2 lane road), but traction control kicked in and I didn't go that far. I never had problems with my other cars with conditions like this. Tires are only 5k miles on them (p zeros) and tread looks fine. It was 60 degrees out. Maybe p zeros are just bad in wet roads?
 

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4-5K of throttle on a wet, sharp turn?
I would guess that any RWD and many FWD vehicles would lose rear traction under those conditions.
 

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There is a pretty sharp turn in city road near work and it rained a lot in the last day. It wasn't raining this morning, but the road was wet. As I was going through the turn, I added a fair amount of throttle (up to 4-5 rpm) and suddenly the car drifted (back end went to the right on the left turn)... Seems the problem was a wet spot and both rears spinning...ended up almost hitting a metal barrier on the right or the car next to me (2 lane road), but traction control kicked in and I didn't go that far. I never had problems with my other cars with conditions like this. Tires are only 5k miles on them (p zeros) and tread looks fine. It was 60 degrees out. Maybe p zeros are just bad in wet roads?
If you spun up the rear wheels it was definitely too much throttle for the conditions.

If you don't have PTV you most likely only spun up one rear wheel. And that makes it worse.

I don't think the P-Zeros impacted you in any way.

I have deliberately done this on P-Zeros with PSM switched off, on a Porsche Driving School course. It can be a lot of fun, but not on public roads.

You can chalk this one up as some experience gained with no resultant damage.

Little less Welly in the wet next time. :hilarious:

:cheers:
 
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Discussion Starter · #4 ·
Yea pushing the throttle was a bad idea thinking about it more. I probably just spun the wheels to lose traction... maybe traction control shouldn't have let me do this. Thing is, I am used to doing this in other cars without a problem...it wasn't even raining or there was no obvious puddle. Suppose I had front or 4WD in other cars and that's better than RWD on wet roads...also the other cars were slower.
 

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With 4 to 5 on the tach the flat six is sitting right on the torque band. It thinks its showtime!!
 

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Yea pushing the throttle was a bad idea thinking about it more. I probably just spun the wheels to lose traction... maybe traction control shouldn't have let me do this. Thing is, I am used to doing this in other cars without a problem...it wasn't even raining or there was no obvious puddle. Suppose I had front or 4WD in other cars and that's better than RWD on wet roads...also the other cars were slower.
Have you got PTV on your car?

It takes a fair bit of throttle if you have PTV to break it loose in the wet. This (below) was on nearly bald P-Zeros I had to change them the next day. You can hear how much throttle I had to give it to break lose and PSM was turned off. So no nannies.

With no PTV the one wheel will spin up very quickly and also add gyroscopic torque to the slide.

I highly recommend that you do a Porsche driving day and learn the limits and abilities of your car. And its a lot of fun in controlled circumstances.


:cheers:
 
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I've done this at very slow speed in near freezing conditions - the P-Zero's can get a bit slidey in the cold. That didn't require much throttle at all.

4-5k on a sharp turn is definitely way too much. Even in the dry, depending on entry speed, gear and tire pressures you could get the back end out. I had a lot of trouble at the recent PCA autocross in 2nd at about 25-30mph taking really tight turns and trying to get on the power, but my tire pressures were mid to high 30's and the surface wasn't that great (but it was dry).
 
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Where you in sport mode?


Sent from my iPhone using Tapatalk
 

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So on a cool, wet morning, you "added a fair amount of throttle" midcorner and because you stated "the other cars were slower" I assume you were driving fast... Stop blaming the equipment and improve your driving skill! Learn how your car handles.

Do at least a season of autocross to learn how to drive smoother and the limits of the car. Just remember that vs street conditions, a track is scrubbed clean and your tires are warm so you'll never have that kind of grip on the street (and you have lots more stuff to hit).
 

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OP: No matter how capable the car, driving too fast for conditions can get you into a "situation." Learning how to handle your car on the track (or autocross course) where the vehicle is at the edge of its performance envelope will better prepare you to handle a simple drift on the street.
 

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Discussion Starter · #12 ·
That video shows what happened perfectly!

I wasn't going fast, but agree the problem was too much throttle. Still learning this car, but my other cars NEVER slid on wet roads doing worse than this. I mean sure the road was wet, but doesn't mean the Porsche needs to suddenly lose control like that.

I'm just surprised that it happened because I didn't feel I was doing anything crazy and the road wasn't THAT wet. Why isn't PTV standard? Is this something I could get from programming? This incident has me a bit worried after seeing how easily the car can get out of control on wet roads. It claws the road and feels 100% stable otherwise and its a slap in the face when this happens and you near wreck the car...

I had been driving 1/2 hour prior on the interstate and the tires were nice and hot.

Researching the p zeros, many say they are bad in the wet too.
 

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Why isn't PTV standard? Is this something I could get from programming?
Just like all the other options, Porsche wants you to pay for each of the options available. The PTV is not something you can get from programming, there is hardware involves.
 

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I guess Porsche has a valid reason to put the 4,200 RPM "break in period" in their owners manual!

I did this on my Ducati a long time ago. Rear slid out as I squeezed the throttle in a turn. Except, when you're on two wheels and the rear wheel regains traction you get high sided and thrown off the saddle in a violent fashion. Lesson learned the hard way.

So be glad it happened to you while you were on four wheels and you were able to make a relatively easy recovery.
 

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Suppose I had front or 4WD in other cars and that's better than RWD on wet roads...also the other cars were slower.
THIS is your answer. RWD with mid engine has VERY different dynamics compared to a front engine, FWD or AWD car. I had and still have Audi's. On a wet street you can pull out from a side street under heavy throttle with very little slippage and if there is any, the front will push out as much or more than the rear. Our Caymans are different. The throttle must be SQUEEZED rather than floored under these conditions. The up side is that at speed on a track--- (3rd gear and higher) this is not a big factor and is not a hinderance. It is actually helpful in getting the car to rotate in a turn and thus not understeer wide as is the case with the FWD or AWD cars. Practice "feeling" for the traction limits in wet conditions. After a while it will become instinctive.
 

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The Porsche PSM is less intrusive than other cars and it will let you slide a little, a little more in Sport, and a little more yet in Sport+ and it's a GOOD thing.

If you drive the same corner in something like a Lexus you probably will go slower, and the VSC would go on much sooner and intervene at the earliest hint of skid, ...

So it's not the tires nor the car but it's the driver doesn't quite know the car well enough and perhaps a little refresher in driving a high performance RWD car is in order.
 

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Yea pushing the throttle was a bad idea thinking about it more. I probably just spun the wheels to lose traction... maybe traction control shouldn't have let me do this. Thing is, I am used to doing this in other cars without a problem...it wasn't even raining or there was no obvious puddle. Suppose I had front or 4WD in other cars and that's better than RWD on wet roads...also the other cars were slower.
One thing you must understand about traction control is that it is a reactive feature. It has no idea that your tires are about to lose traction until they actually do, then it's a matter of forcing some brake to slow down the spinning wheel. In a straight line, that means almost nothing but in a corner with even .5 Gs pulling the car left or right, the loss of traction for even a brief moment will cause the rear of the car to kick out. In a front drive car this same action will just cause it to push momentarily and might not even be perceptible. PSM isn't a fortune teller. Glad no wreck or injury.
 

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There is a pretty sharp turn in city road near work and it rained a lot in the last day. It wasn't raining this morning, but the road was wet. As I was going through the turn, I added a fair amount of throttle (up to 4-5 rpm) and suddenly the car drifted (back end went to the right on the left turn)... Seems the problem was a wet spot and both rears spinning...ended up almost hitting a metal barrier on the right or the car next to me (2 lane road), but traction control kicked in and I didn't go that far. I never had problems with my other cars with conditions like this. Tires are only 5k miles on them (p zeros) and tread looks fine. It was 60 degrees out. Maybe p zeros are just bad in wet roads?

Menthral:

What was the temperature? P Zeros are SUMMER tires, NOT all-season tires. When weather gets to 40F or below, the rubber compound starts to not work as well. You have to be careful with cold tires.

All this talk about vehicle dynamics is great, but everyone needs to be aware of the dangers of cold summer tires. I've got quite a few hair-raising stories about this in my logbook. Had an M3 out for a winter ride on a cold day with summer tires. I did a full sideways slide in downtown Batavia, IL on a crowded street. The back just came right out. I nearly hit a couple parked cars and was pulled over by a cop. He saw that I was not an 18 year old hooligan and, lucky me, he got a call for something more serious. Told me the charge would have been reckless driving or something nearly as serious if he'd continued. I honestly was at a loss at the time as to why I lost control. Was trying to catch a light and went just a little faster than usual through the left turn. Temp then was quite cold though. The colder it gets, the worse summer tires get, even on DRY pavement, especially when you first start out. Below zero, they have been known to crack, so either get winters or A/S or park it when it's very cold. I used to like going for an hour's drive on very cold days because the roads were dry then. I don't do that anymore.

I just put my winter tires on yesterday. It's snowing now. I'm ready!

Winter tires rock! They stick so much better even on dry roads in the cold. Their chemistry is made for cold temps, tread is made for light snow, slush and dry roads. If you have Winter Sport tires, they sacrifice a little deep snow and ice traction for good handling on dry, cold highways etc. Worth it for me. I like the sportiest versions of Pirelli Sottozero and Michelin Alpin.

I bought lightly used Pirelli winters and put them on Boxster S take-off wheels I bought from a dealer on the classifieds here. Used them for 4 winters and just got a new used set.

I once had Bilzzak snow and ice tires on a Mazda. They're no fun...They get you though anything but they make all cars feel like old Toyotas.

:cheers:
 

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What you're describing is exactly what you'd expect to happen in a rear drive car. That's why I've been very careful with the throttle in corners, until I can work out exactly how the car does behave in these circumstances. Last weekend was the first time I got to play with this, it was the first time I got to autocross the Cayman. Its a very handy way of getting around tight corners in a hurry.

On the street, with limited run off area, I'd be more careful.
 
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