Here is a quick 4 corners of oversteer at Sebring. I am trying my *** off to go faster through all the corners and am encountering oversteer on many occasions. How do you assess if the car is handling poor or if one is actually at the limit of adhesion? Just to be fair the first clip is turn one and its a bad downshift which puts the car sideways. But it put my heart in my throat!

Some other facts, Hoosier R6 245(f) & 315(r), fastest lap 2:25.0




Or is it impossible to tell anything from this video?

 

Somewhat tough to tell. That is a bit bumpy there, and your rear sway may be a bit too stiff. By the same token, it sounded as if you are a bit late (and hard) to throttle there, although that could just be the sound quality on the video. Perhaps you are just surprising the car? Does it happen anywhere else.....like 17?





Professional Racing and Driving Coach

 

Like VR says, it's hard to tell, but it seems like you are not committing to the gas. You are feathering it, which doesn't allow the weight to shift to the rear and get the back to hook up. I assume that it is a cup car, which has really stiff springs and requires that. Or your car could be over-damped; too much rebound in the shocks and you are losing grip over the bumps.

 

Far from being an expert, listen to the engine noise just beyond mid-corner. Larry is on to something for sure.

Are the bumps causing your go pedal foot to change position rapidly?

 

I agree with Larry 100% , committ to the throttle sooner and more for the weight transfer and you will be good. Also agree on the 2nd part of being over dampened but I feel the first big threshold you have is the throttle. - If you have data you should be able to clearly see this.

 

Love the nose and wing on the Boxster btw !

 

Its not the throttle, it appears he's late unwinding the wheel....
I agree it's really impossible to know without driving the car, but with all that HP the bars should be setup stiff up front, soft rear with reasonably soft springs like maybe 500 front/600 rear to allow the car to transfer weight front to rear....

 

bingo


looks like you need to be unwinding the wheel a bit sooner combined with a little sooner on the gas but more smoothly. try either turning in earlier and *driving* the car harder through the corner or apexing a little later, carrying more speed in, and then waiting a little longer to get on the throttle until after you have started to unwind the wheel a little more.

 

I do not qualify to critique and I am no racer or anything, but I do not see anything wrong with your driving..

Maybe a softer sway bar rear? Maybe your tires starting to let go in the rear from trying to hard?

I run 2:24's on Toyo's..
I hate the feeling of an understeering car and I had my car with the rear sway bar tight, it felt fast, but as soon as the rear tires give up, it slows me down a lot. Like so:

http://www.youtube.com/watch?v=r1yk1fMMoiE

I've been softening up the rear bar and stiffening the front bar more and more. I don't like the feeling too much, but the car is much easier to drive, the rear much more relaxed and planted. It feels slower, but actually same laptimes so far with the Traqmate and if I learn to drive the understeer, I think actuallly faster..

 

Yup, that's sort of what I suggested above as well--you can "hear" the bumps in the rapid (and unwanted) throttle modulation over the bumps.





Professional Racing and Driving Coach

 

Thanks guys, I know looking at a couple of grainy videos is hard to diagnose but I thought it would be interesting.

I will make it a goal to get back to throttle sooner and unwind the wheel sooner next time I'm there. Turn 10 is very bumpy and that is the noise your hearing as the car loads and unloads over the bumps.

JR, I have a question. You state that the front bars should be stiff while the rear bars should be soft. I understood the swaybar adjustments to be as follows, the softer the front the better turn in. The harder the rears the more free/loose the rear will be (overstreer). So knowing that the Boxster understeers I have set up the front to be full soft for max turn in grip. I have set the rear to be full stiff to impart a free back end to help rotate the car at turn in. The video might be proof that this dynamic is working. The car is loose in Turn 5, 10, Tower, 15b, & 16.

I'm running 500 # springs in rear. It might be time to soften the rear one position. Do I have my swaybar adjustment understanding correct?

 

I would change your sway bars closer to what JR is saying

 

Not JR....and not always true...






Professional Racing and Driving Coach

 

Captin Slow reporting; in T-10 how far left are you tracking out after apexing it seems that you could unwind more which would place you slightly closer the gatorbacks and not forcing the rear of the car to be so tight.

That being said I run 4:17s so I'm not sure how helpful that is and for what its worth the only time I can get overstear is when my coolant (water & water-wetter) dunps on my rear tires. That's being corrected next week.

 

Agreed and I knew I was opening a can of worms hence my preface about "impossible to know without driving the car"....