MelanomaMan

Good thread TD. Looks like you've gotten some good feedback here. Although my setup is a bit different, I've learned to live with a little lift here and there. Part of this driving experience is why I got a 911 honestly, so I could learn how to drive a tail-wagger!

You're doing the right things in checking data, pics, etc. to keep improving which is great. Another thing you could do is bribe one of our RL hot shoes to take it for a spin for their feedback.

Give yourself some credit, I saw lots of good stuff in your vid.

himself

Turn in is fine. No under or over steer (altough I am rolling in most corners (as you know entry speed in this direction is the key to lap times). Even on other tracks it turns in fine, well to me. I haven't had any one else drive it in a while, but the car fits my style without many issues.

Something that has also been bugging me is the amount of the steering input chatter / feedback, specially under braking. I think I need a bigger wing or a new diff. Straightline braking the car is nice and planted. Trailing under heavy G load and the back end is shaking like Shakira.

Over this event, my times didn't vary with / without a passenger. 22s and 23s either way. Which is a good indicator that 21s are possible.

-td

Veloce Raptor

Yeah, your diff may be gone. A better LSD will really stabilize the car under trail braking (if this is in fact the problem).

In my low power BMW, a passenger really makes a difference in lap times.

himself

Nope. Somebody gotta drive!

-td

himself

Passenger makes about a second in my car as well. A little more on the 3.1. Porsche says I have 380 at the crank @ 3400 lbs. With a passenger, I'm at/over 3600. I shook off some cobwebs and made up the weight difference in later sessions.

As for the diff, it's original with 40k miles on it.

One thing about these events is that I really don't get a chance to practice diving. So I keep driving on the same plateau. With a passenger virtually every session, I have to dial it back just a bit and can't push the envelop or work on new things.

When's the next training session? I need some "me" tracktime! Loo

-td

Sean F

if it does anything like the car in this video....take it to the appropriate suspension doctor

Veloce Raptor

Trying to set one up for sometime mid April to early May.

WTF is going on with embedded videos here? they ain't working any more

Streak

The car is junk. Ship it to me. I'll pm my address.

67King

I think the pictures chosen were done so for exaggeration for effect. If you look at the graphs they show, the curves knee rather dramatically when the wheel lifts. Sway bars do some great things, but this is one of their drawbacks. All about striking a balance between too much roll and too much loss of grip (and as I understand it, the increase in grip on the outside tire from the added loaded can't make up for the loss of grip on the inside tire, even before it lifts - thought not by a whole lot). This book is one of the ones I need to pick up that goes into that: .

I would imagine for a lot of cars, it won't matter. But if the throttle has to be modulated to keep it from understeering at track out, it does. When I changed tire sizes on my car, I used to have on throttle understeer entering the esses at Road Atlanta. Beefed up the rear springs, resolved the problem.

I'd certainly defer to Veloce Raptor's opinion on this, but I do have to disagree that you have to lift the tire a bunch for it to negatively impact things.

KaiB

Superb book King and a good choice to add to the library...but a difficult (enjoyably so for those of us so inclined) read and most certainly not THE answer; it adds perspective and highlights the art and guesswork of tire manufacturing.

PedroNole

This thread brings to mind something that we haven't mentioned so far. If there are 1-2 places in the track that this happens due to the unique characteritics of those corners and fixing this takes such drastic set up changes that the car will likely be bad in other places (which, having death with turn 10' and 17 at Sebring for a few years now I know something about), then is it good to chase it?

If the car is good and you are fast, chase something else.... Oh...and physics is a bitch...

Veloce Raptor

Exactly. And that's the way it is at this track...

multi21

At 40k miles the OEM LSD was shot 20k miles ago

Veloce Raptor

That's what I was thinking, too. Those OEM LSD's in the 6GT3's are gargage.

MUSSBERGER

OK how about a pic without the ballast on the right side