Dennis Gentner

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MirageJHU

I don't know the track, but this doesn't appear to be lift throttle over steer because you're braking for a corner and turning in.

Without seeing brake pressures it's hard for me to tell - but I'd check to see if you're locking up rear tires...or you're just trail braking too much into the corner?

The 'g' read-out on the top of the video makes me think there's too much weight on the front as you're bending the car in and so the ***-end of the car wants to lead...

Veloce Raptor

I agree
Too hard too late on brake and probably locking inside rear wheel

CRex

You need to look at your brake pressure trace. The 991 brakes need *better* modulation (as in quicker release) than what you're used to in the 997.

From your dash lights (it isn't immediately clear tho) it appears you did not lock rears. You had a minor momentary lock on the front right (that single red light at 00:09) which wouldn't have caused your problem. Without data, I'm guessing your issue isn't wheel lock, but how much weight you had on the front.

You probably would've caught the slide if not for your right wheels getting jacked up by the black/yellow speed ramps.

If you don't mind me saying, from the video you're at a stage where a pro coach will do you a lot of good. That coaching will be a much better investment than another set of new tires. I've been there and am working on climbing the curve too

BBMGT3

car has ABS. So no real lockup

But, you can't stand on the brakes and turn like that. 991 doesn't work like that. 997 you could.

CRex

^ Exactly my point. Seems to be an issue of weight management

Dennis Gentner

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CRex

If you got ABS, brake bias issues will only reduce your efficiency but not cause spins per se.

The "50:50" is a calculated output of the IPD. What's your raw bias value?

Dennis Gentner

Now idea of the RAW Value.

50:50 is that what my display shows me...

Veloce Raptor

Move a couple clicks to the front and see if it works better.

Then try a couple of clicks of rear bias.

C.J. Ichiban

Personally I don't like the way the car reacts at 50/50 bias. I like the feeling of the big rear tires holding the rear of the car down.

Without seeing a clean passage to judge against - were you not slowing down enough or how far in advance of the corner you need to slow.

fleadh

IMO, You need faster hands. Also, it looks like too much rear brake bias, but it's hard to tell without seeing data. Take a screen shot of a zoomed in view of your throttle/brake/steering/speed traces and post it here. Even if you have ABS, your brake bias is critical for corner entry.

How are you checking the brake bias? Make sure you're using the proper pedal pressure otherwise the value doesn't matter. Regardless of the %, adjust it until it feels correct. Also, your brake bias bar on the master cyl's might be incorrect which has a big effect on the bias migration -- as you're coming off the brake pedal, which has big effect on trail braking, which is where you lost it.

Have you checked your differential lately? The 991 Cup's are very sensitive to the diff as it goes through it's life cycle (and opens as it wears, which translates to instability on corner entry). How is the balance in other types of corners?

-mike

analogmike

This. You barely counter-steered.

SDGT3

I am going to guess rear Bias is an issue. Cannot tell from data on screen but 50/50 seems fairly strong toward the rear. Under braking and weight transfer, the rear lockup will definitely bring the *** around to say hello! Look at the data and check wheel speed for lockup. that can confirm your bias issue.

Steve113

Looks like you loose it at turn in . Have you checked alignment? Big rear toe out ?