I had two spins at Lime Rock today (nearly identical). I thought some people might find them amusing; and I thought some people might have theories about what I've done wrong.

I *thought* that I was just on the brakes too much while initiating the turn-in, but looking at my data and the g-force traces, I'm not so sure.

The track was pretty hot and greasy... and the Hoosiers I was running have *many* heat cycles.

 

Doesn't sound like you're heel toeing/rev matching and the rears are locking up when you're letting the clutch out.

 

If the gear indicator on the telemetry readout is correct he wasn't downshifting (?). otherwise decent guess.

does the car have adjustable brake bias? anything found out of the ordinary when inspecting the car after either spin?

also was that a sympathy spin someone did into the dirt on your first one?

 

Bingo....Very plain to see in the first, subtle in the second.

Work on yer rev-matching; as you begin to push the car, keeping it happy and balanced at all times becomes more and more important.

 

Did lee also go off in BB on the first spin? Aything on track? Does look a little like locking up rears

 

The first spin was clearly caused by taking your hand off the wheel to give a point-by. Point-by's should be banned. Not sure about the second one.

 

Nice!

 

I think this is the winning answer. Looking at my data this morning, there's a throttle blip right when the spin initiates.


The gear number is "calculated" based on engine speed and RPM - so it must be taken with a grain of salt. It doesn't account for if the clutch is in or out.


Yes, Lee's spin was a "sympathy spin"! He clearly stated, "I was watching you in my mirror, and all of a sudden I was at the edge of the track!"

 

p.s. The green line is RPM, the red is lateral G (turning) and the pink is longitudinal Gs (braking). Where those two G force charts come together, right before 800 on the x axis, that's a full stop.

 

Don’t run the second line except when passing into turn one. It may be a combination of heat cycled tires, not perfect down shift and some trail braking with possible to much rear bias.

 

You clearly need to wave more.

 

Van, How was the car at other parts of the track? Severly worn Hoosiers would have impacted turn in at a few other spots with far more serious ramifications than turn 1.

 

Joe, it was pretty bad with those tires. Turn-in to the left-hander was also dicey. Lots of power oversteer (in a 944!), especially in the esses.

A little wiggly on the downhill. Uphill and west bend weren't too bad.

I need to sell more vinyl to afford fresh tires.

 

From the telemetry on the video, you were hard on the brakes both times at turn in, so looks like a classic case of too much trail braking into the corner.

 

Get a 911 Van...