Yorkshire Lad wrote: ↑Fri Apr 19, 2024 7:37 pm
So, a quick question for all you seasoned F Type owners. I have had the car for a couple of weeks and have just returned from a few days in North Yorkshire.
Everything was great until the point where I nearly finished up in a ditch at the side of the A169 which is the road over the moors from Whitby towards Pickering.
If anybody knows the road, there is a fairly sharp right hand kink at the bottom of a hill just after the road that goes to Goathland. The road was wet and I was in Dynamic mode. After going around the tight bend, the road opens up going uphill with a fairly gentle left hand bend. I was accelerating up the hill, probably doing 35 to 40 and then, on the bend, the back end just let go and I managed to eventually catch it before we ended up off the road,
My car has 4 wheel drive and I think it was the fact that the front wheels regained the traction that prevented any more drama. I don't mind admitting, it scared the sh*t out of myself and my wife. It just seemed so out of character for the car to just start to swing around at such a relatively low speed. The only other thing that may have contributed to the incident was that I noticed when we climbed the hill out of the village called Sleights, I could see what looked like oil or diesel mixing with the rain on the road surface but this incident happened a good 3 miles after this so I am at a bit of a loss as to what may have caused this. So going back to the title of the post, what effect, if any, does Dynamic mode have on the traction control etc. and could this have been part of the reason that the back end just let go so suddenly. The tyres all have good tread and the pressures are correct so was I just unlucky or has this type of thing happened to anybody else at such a relatively slow speed?
Your thoughts and opinions would be very welcome.
Thanks
I know the road well, and also ride it on two wheels now and then...
I am fairly certain you've been caught out by spilled diesel which hasn't washed away. (possibly, too, some marbles/gravel which have been washed out from the road sides?). There's a darned good chance that just ahead of you was an old truck/transit van with an overfilled fuel tank, all captured by the rag stuffed into the filler cap.
Personally, I wouldn't get too hung up on the tyre types/makes; the Pirellis are decent and have done me well for near 65,000 miles on a couple of different vehicles I've owned. I had a similar 'moment' going around the York ring road many years ago in my XKR where the A1237 joins the A64 just after the traffic lights/roundabout. The surface was poorly-maintained with patches of worn chippings, on the curve as you accelerate. A bit of diesel was probably just sufficient to help break traction, but thankfully caught it in a bit of a weave and kept it in lane. The XKR was a bit of a loper and not as dynamically advanced as the F-Type, with its shorter wheelbase; also, the electronic aids were unlikely to have been as advanced as the current F.
I'm pleased I wasn't on two wheels, but always believe that tyre technology far exceeds my abilities, whether two-, or four wheels are involved.
As for the description of the tech - the Jaguar manual describes (weakly, IMHO) the abilities of each of the modes but, the following copied and pasted from Robert Pepper's Australian site, seems to do justice better than the Jaguar manual....
Dynamic Stability Control If only manufacturers could agree on the same name for exactly the same thing. Jaguar calls it DSC, or Dynamic Stability Control, but it’s the usual electronic stability control (ESC) which detects understeer (when the front of your car pushes wide in a corner) and oversteer (or when the back of the car tries to overtake the front). The on-board computers figure out what’s happening by monitoring individual wheel speeds, steering wheel angle, throttle position, yaw and pretty much anything else it can get a reading on, and it all happens in milliseconds. If the computer brain decides things are heading for a what in the trade is known as a “moment” then it then takes corrective action by braking individual wheels and if necessary, restricting throttle opening. That is standard ESC…
The Jaguar F-Type’s DSC is a little bit different because it has three modes, and it’s not alone here with BMW’s M3 also running various stability control modes, like most proper sportscars. The Jaguar’s modes are DSC On, Dynamic Mode and Track Mode.
DSC On is what you’d use for normal driving, and as soon as the car steps out of line the computers are in like Flynn, sorting the car out for you. It is a well-tuned system like most modern designs, subtly correcting as opposed to slapping the driver into next week – all ESCs are far from equal, and the real sportscar manufacturers put a lot more time into their systems those who make lesser vehicles.
Dynamic Mode is ‘kind of’ a racetrack mode. This allows a little bit more latitude before the computers get involved to keep you pointing in the right direction, and this is important. When a car is driven even sedately there is what is called “slip” – the drive wheels are always, microscopically, wheelspinning and every corner you take you are, almost imperceptibly, sliding the tyres, yes, even Grandpa in his Camry. I know it doesn’t feel like it, but you are. Now, as you drive faster, those slip angles increase, so there’s a fraction more wheelspin, a fraction more sliding around the corners. It’s not a full-on opposite lock powerslide or anything, it’s just creeping up to the limit of adhesion because losing tyre grip isn’t binary, it’s gradual, kind of like pulling Blu-Tack off a wall.
Dynamic Mode is about allowing a bit more slip than usual road driving. It means the driver has the freedom to get to that on or near limit grip level in a way which the DSC On mode doesn’t permit. In our family, it’d be like Dad watching the kids on the playground as opposed to Mum, different level of risk tolerance.
Now if the grip level is truly exceeded Dynamic Mode will come in and help, in the same way Dad would stop the kids from trying handstands on top of the swings. What you’re looking for in a good ESC mode of this nature is the ability to marginally overstep the limit with the driver able to make a quick correction before the computers get excited.
Finally, there is Track Mode. This is where ESC (sorry, DSC) is completely switched off. That is what you want for the ultimate thrills, and if you are going to try your hand at drifting – and why else did you buy a 400kW rear-wheel drive car (but only on a race track, of course). If you exceed the traction limits here the computers will just sit there, arms folded, laughing as you experience that horrible moment in time between the loss of control and the impact with the armco. However, ABS remains active even in Off mode. It is not clear whether torque vectoring stays on as that relies on the same basic system – I would hazard at guess at the answer being no as torque vectoring is a kind of stability control, but I suspect the EAD (active differential) remains working. Again, the fact the F-Type has a completely Off system is good, another mark of a true sportscar. In normal cars the Off switch is actually more akin to Dynamic Mode, not really off, just turned down a bit.
I very much doubt anyone outside of Jaguar's engineering and development centre would be able to define precisely what the specific limits are, which would have been reached during miles and miles of testing over different surface types, climates, road conditions, and terrain but I think they'll envelope the vast majority which we mere mortals experience.
It's interesting to note when I managed a track day once, the instructor suggested keeping the TracDSC engaged..... and the car still blew everything else into the weeds.
SVR Coupe in Ammonite.
does it not make your bum clench each time you rewatch it? The road surfaces seem to be so poor at the moment, I spend most of my time looking out for and avoiding the huge potholes that seem to be multiplying.
P340 R-Dynamic RWD Coupe, Caldera Red on 19˝ Centrifuge wheels. Pzero. Mods: Reverse camera, interior/puddle lights and tinted windows.
