More solid engine mounts helped with my street BMW M3 going into T3 CW at TWS. There is a hump in the track in the braking zone and I would always crunch the 4-3 downshift there if I wasn't exactly perfect. When from stock mounts to fake BMW Group Ns and problem went completely away. The Group Ns are a tad softer than poly mounts.

-Mike

 

SBRS was and is correct. YOU are correct.

 

Yes, when I say "max brake pressure", I mean max brake pressure for that speed and traction situation, not max pressure overall.

 

+1...

 

Point 1: it works on the street but not the track...so something in your use of it at the track is at least magnifying the issue

Point 2: we seem to have terminology confusion here...when I asked if you were at max pressure, that means exactly that: your maximum braking for that corner. If you are already fading out of brakes by the time you are trying to go to 2nd gear, you are NOT at max braking...

 

THIS is true. Purple pressure is good!

 

That's why I used the term threshold braking.

 

As I said, terminology confusion. Back on page 1 I asked if you were at maximum braking and what you meant by threshold braking. Your answer prompted my comments that followed. But you didn't mean maximum and the two terms are not synonyms.

Anyway...moving on... I am still surprised it works fine on the street but totally balks on track.

 

OMG.

Now you are just trying to sneak your way out of your mistake.

When people are threshold braking it means they are using the max brake pressure allowed for the situation...even as it changes and the actual required pressure on the pedal changes. That is "max braking".

You wrote:

Why are you downshifting while "threshhold braking"?

So no, you were not talking about "maximum pressure". Threshold braking is not a specific "pressure" on the pedal.

 

I mean threshold braking in it's literal sense. The max vehicle deceleration rate as a function of brake pedal force and vehicle velocity at a given point in time. I wasn't confused.

Edit: Right what winders said.

 

Yep. It's broke. Something's moving that shouldn't. Cable, mounts, something.

 

Why are you being an ***? What mistake?
Sorry Scott but when I look at data with clients and we look at max braking in a particular brake zone, it means just that: max brake pressure . For example 700 psi. That is why I asked the OP the specific question I did and also asked how he was defining threshold.

To the OP, thanks, now I understand what you meant.

 

This would be easier if it were very obvious (maybe this is obvious to some). But again, I'm no expert. So, I'll take it to the guys who are. Either way, I would never have considered the synchros before starting this thread so thanks to all for chiming in. I'll do some test drives and edit a YT video to post here this weekend (if my wife doesn't pop.. due date tomorrow). Stay tuned.

 

+1

 

Pretty serious and interesting side discussion here.
I have a 996 and had trouble w/ the 3-2 shift where 2nd wouldn't be ready on clutch out
as if it were in neutral. Retry would be fine. Annoying, but rare enough, not like the consistency
you describe. I switched to the 997 GT3 shifter (a bit shorter) and haven't had problems
at all. There is an alignment tool you use to center the stick so you can adjust the cables.
But I tilted the stick more towards me, and then set the cables.
I still have a 2-3 shift annoyance and have put in Turbo motor mounts and the occasional
problem occurs when powering out of a turn. Synchros take a beating on the 2nd try. Now
I suspect THAT is technique by being in too big a hurry.
Just a longshot...