t4orce

Frustrating situation today, I feel like sharing with the CL community.

I used to do autokhana events in AWD cars such as Subaru WRX and Mazda 6MPS. I have a fair bit of skill in getting those cars around an autokhana course quickly. Today I did a tuning day in my F and it was woeful.

I struggled to get a nice clean fast lap. I had all aids off, sports button on and manual mode engaged. I found the car easily unsettled and hard to control. Quite often when I thought I had traction to power out the car would kick into a slide and spin me around. I was gentle with the throttle and steering inputs as well. The last time round I did a 360 into the grass verge and caused the seal of my tyre to give. I need to reset the tyre. .

I wonder if I should have left vdc on. Tyres are in good condition albeit OEM size.

How much easier is a proper diff ISF to control at pace? I fail at driving this car. More practice needed.

Juanca

iTrader: (5)

All your experience goes to the trash when swtiching from AWD to RWD, you have to go into re-learn mode.

Murph145

yup awd cars are way easier to drive that rwd only.... makes most people feel confident when driving awd.... basically like stated above you just have to re learn the car and get used to driving a rwd it reacts totally different

Valkirk

Personally would leave the VDIM on, worth noting that the record breaking LFA Nürburgring lap was done with it switched on, running faster than the Pro race driver could do with it switched off for the previous laps. Different cars I know but the philosophy for the LFA and the ISF are both performance orientated.

ISFSteve

I agree, I would have left them on at this point.

Autobacs

iTrader: (1)

Same as the others. Your driving instincts are geared are for AWD.

Continue practicing, learning, and it will take time but you'll pick it up.

I would leave it off while you're learning so you can probe the limits.

lobuxracer

iTrader: (2)

You can't turn VDIM off. You can modify (Sport mode) or eliminate VSC, but you'll can't turn off VDIM. Comments about a particular pro driver going faster with VSC on vs. VSC off don't mean a lot. VSC will let you do some really bad things and can lead to cooking your front brakes at a track day and total brake failure from overheating (AMHIK) . I also have video of a friend who tested his Corvette both with and without the stability controls. He went faster without. So, saying "leave it on because it's better" is not solid advice. IMHO and IME, turn it off, learn the limits of the car, THEN if you want to use it as a safety net, run it in Sport mode after you know what the car can and cannot do by itself.

Valkirk

As I said "Personally" meaning just in my opinion, he said he was having issues getting the most out of the car. Interestingly your reaction is portrayed in the Lexus article I read talking about it:

“There is an accepted theory on how to drive a sports car,” Iida says. “But I thought I could not break the record if I followed it. I had an idea, and I asked Mr. Tanahashi to let me try it.”

Iida’s plan: activate Vehicle Dynamics Integrated Management (VDIM) on his test run. This was a bold move. Conventional wisdom holds that VDIM, while excellent for normal driving, is an impediment to maximizing a car’s performance on a motor racing circuit. For this reason, enthusiasts typically disable it when driving on a track. But Iida’s plan was to use the system to his advantage.

His reasoning was sound, though—the LFA’s VDIM is the most sophisticated Lexus has ever developed. And after all, the Nürburgring is essentially a collection of streets and highways—precisely what the technology was made for.

And, as the auto world now knows, Iida’s gamble worked. The LFA lapped the Nordshleife in a blistering 7:14, shaving six seconds off the previous mark.

It's a good read: https://secure.drivers.lexus.com/lex...ecord-Breakers

Again as I said it's talking about the LFA so not strictly relevant but I reckon a lot of the know how was shared between the cars.

F4Fast

Awd>rwd when it comes to traction. Ive had a fwd, rwd and awd cars. Nothing was more fun than the awd car. Lauches were damn near perfect, slides and controls easily. 4 tires gripping over 2 is alot more control. Ive been able to push my car once, but now with better and wider tires, more power and more experience with the car, i cant wait next time i hit the track.

t4orce

Thanks for all your advice. There were times that I felt that I knew the limit of traction and I think at other times I just pushed it a bit too hard. As most of you said it's a matter of learning the car which I did. I have a new respect for electronic aids on the road during the daily grind.

A pic for your enjoyment when I managed to get the car to drift around a hairpin and another of me coming back into the pits.

Valkirk

Lovely pics! The drifting one is a superb action shot!

lobuxracer

iTrader: (2)

I have no trouble understanding how someone with detailed knowledge of how the car handles could exploit VDIM to make the car faster with less effort. But you won't get there without developing that knowledge first. You'll just have all the nannies popping in with heavy handed corrections and overstressing the brakes. If you're already close and know clearly where close is, you can use it as a safety net to go slightly past close and fully explore the limits without worrying about touring the tulips.

From the description, it seemed our OP needed some time with the car unfettered to get a feel for where the limits are before trying to manhandle it with VDIM taking up the slack. I know what he's talking about because I wasn't especially impressed with the amount of understeer Lexus designed into the car, but with some track time, it's possible to rein the understeer in, and get the car to drive pretty nicely. It just doesn't tolerate hamfisted piloting all day long, it will throw in the towel at some point, again AMHIK.

06isDriver

yeah, the understeer plagues the entire IS line

t4orce

I noticed the understeer as well but to balance it all with throttle inputs and trying to be smooth with the steering was a bit of a challenge for me. I'm sure more time behind the wheel would have sorted it out.

The other thing I struggled with which in reality should make things easier was the paddle shift. It felt somewhat strange the first few times especially being used to manual trannys and heel and toe.