alexb76

I've reported in the past that I've had some issues with shifting in/out of 2nd. It has been much worse on track and during my last track day of the season, I kinda narrowed it down.

After 2nd session when the car was hot and track dried a bit (was a very wet day), I had major issues downshifting into 2nd on a hard braking zone, with sharp right turn, on a down hill. It was either very hard to get into it (proper brake, heel/toe, downshift), or a couple of times I actually could NOT get into 2nd at all, and had to slow down and get into 3rd...

Then on the last few sessions of the day I realized WHY! The point of engagement into 2nd was SHIFTED to the right!!! So, basically it was not at the far left bottom of the gear, but somewhere between typical 2nd and 4th slots! So, over the last few laps I basically re-adjusted where I put it into 2nd, and it was fine.

After track day was over and driving back on street, the shifting is fine, just at the same engagement point as before?!

What could cause this? Anyone has encountered the same?

My first suspects are:
(1) Linkage needs adjustment, or it's loose,
(2) Engine mounts either have issues or just not solid enough for track use, hence the movement of engine on a downhill, SHIFTS the engagement point.
(3) Synchros might have issues?

Thanks!

PS. GREAT trackday at Pacific Raceway, was my first time going there and it was amazing, incredibly wet at the beginining and I almost completely lost the car on turn 1, at 120 Mph, but I saved it.

cvazquez

On my Boxster the factory forgot to install the transmission mounting screw, so recommend you check that first.

simsgw

I imagine most people have when we get up towards 8 or 9/10's as racers say it. I've had it happen every time I get down close to my fast time of the day. My diagnosis is simpler. The linkage has lock-out springs that keep us out of the detente that is where reverse gear lives. Picture how you pull the lever hard left to get into reverse and then push forward. Those are the lockout springs you're working against, and normally they keep us from hitting reverse when we wanted first.

Now we're on the track and shifting down from third to second so we pull the shift toward the near corner. Except we are ... pumped is probably the best word. I know that coming into corners at that extra twenty feet per second that constitute 8/10's jacks up my adrenalin levels at first. They're naturally a little higher than when I'm just motoring around the track. At that point, the force levels I apply grow higher, and the lock-out springs might as well not be there. So I end up inside the detente, but pulling back toward myself, not pushing forward. That zone is limbo. No gear lives there. As you noticed.

The answer is to mentally picture the entry for second being a little to the right as you did, or remind yourself to do as Bob Bondurant always recommended: handle the gear shift like an egg is in your hand. This never happens to me at 9/10's. Probably for one of three reasons:

1. I can't get to nine-tenths until I have the adrenalin under control, so by then I'm back to the egg business. (Which everybody teaches. Bondurant just found the colorful metaphor we all remember now. I think it was Bondurant. I always remember the egg.)
2. I don't drive this car at nine-tenths because I have health problems that make that ill-advised. So the chances to have it happen at that rate of speed are an empty set for me. And my previous road cars that I did race had reverse over to the right and back. The cynics can choose this one. I prefer to think I control my adrenalin by the time I'm driving that fast.
3. Cars prepared for racing usually have supplemental ways to keep you out of that detente zone. Most visually memorable is the Ferrari trick of using a chrome plate with the gear entries carved away. Then they put a little flip-up piece of steel that closes off the entry for the area where reverse lives. You have to flip up the blocking piece and move the lever at the same time. That would look cheap and/or Rube Goldberg-ish if anybody else did it, but this is Ferrari, so of course it looks cool instead. Another trick is to add a sequential shifter that transfers your fore-and-aft movements into the correct gear entry. Not practical for road cars of course. I haven't looked to see if they do anything special for the GT2 and GT3, but if not, I'm sure the detente lock-out springs are a little stronger than on other Carreras.

Formula cars just omit the reverse gear in the box unless regulations require it be present, in which case they put a completely separate lever or button or cable that must be pulled, pushed, or otherwise manipulated to reach reverse. And even then, it rarely works outside tech inspection with the mechanic who installed it doing the almost-secret manipulation. To back up a real race car, the usual technique is simpler. Just wave your hands at somebody nearby until they get the point and push you back.

Try picturing Bondurant's Egg or have a stronger detente spring installed. It will be a pain in normal driving, but it will help overcome the force levels we generate with the sudden rise in adrenalin. Then remember the egg anyway. Fastest way around a track is learning gentle control movements. It's like flying an airplane on instruments: every control is moved as gently as the resistance permits. It does move, and without question, because my force levels ramp up automatically to ensure that. But I guess the difference is I don't yank on controls that don't compel me to react that way. That's how you want to control a race car: as gentle as she will permit.

Just be glad we don't need first gear on tracks.

Gary

zanwar

I'd agree it was probably red mist. You could try installing the OEM short-shift kit. If you don't have a harness, lock your seat belt. Find a good pair of driving gloves. All of these things will reduce your stress level and help you concentrate. Ultimately you need to slow down your shift to 2nd to give yourself time to get it right. You have until the apex to get the car back into gear, so there's no need to rush it.

simsgw

+1.

G

MTB

Thats sound like T3a, a solid engine mount will definitely help. Or try down shift just before turn in.

simsgw

For anyone researching this question, here's the answer with more information as I just posted it in the GT3 forum.

Gary

alexb76

Interesting idea... it could very well be the case that at the heat of the moment, or downshift forces in speed has caused me getting into reverse locking mechanism... I however disagree with your drawing of gears, for my car, 2nd is RIGHT under 1st, not slightly to the right as you described.

I still suspect something is not right for getting into this situation, something loose, worn, or needing adjustment. The reason for that suspicion is that this phenomena never happened last year when I first acquired the car and drove it on track a cpl of times! I was even less experienced with the car and would have definitely made more mistakes then than now... so between those track sessions and more miles something has caused the shifting to become less precise, potentially making it easier to get the shifting wrong.

simsgw

No, you're right. Second is right under first. But first is not on the leftmost side of the linkage pattern. That position is reverse. I know it doesn't seem this way in ordinary road driving, but when we get in a hurry it is very easy to overcome the detente force.

When we first got our Carrera, it was stalling occasionally at traffic lights. (The new HPFP fixed that.) I would restart it and then grab first. Or try to. In a rush, since I very much wanted to avoid being run over by the car behind, and being used to cars with the lock-out on the right, most recently our lamented NSX, I would forcefully push the lever into that left forward corner. The trouble is, first on a Porsche does not live there. I got reverse several times until I rewired my subconscious with the linkage pattern for this car.

As I said in the GT3 forum, the linkage has four columns: reverse, first, third, and fifth in the forward positions. Four columns, not three. Since second is indeed right under first, that puts it one column over from the leftmost position in the bottom row: <empty>, second, fourth, sixth.

I wasn't joking about being glad we don't need first in track work. If I ran low-speed autocross, I'd find some way to put a mechanical lock-out on reverse. Just to keep from embarrassing myself by grinding coffee for the onlookers. Or, God forbid, actually stuffing it into reverse at twenty mph.

Gary

alexb76

Thanks Gary. I think your explanation is most valid... I wish I could try it, but track season is pretty much over (unless down in South CA), so can't really test it.

I still will inspect to ensure everything else is right, including transmission mounts, linkage, cables, etc... to ensure nothing's a miss. I might also flush the fluid, just in case.

If anyone else has fixed this issue by any other means than shifting technique, love to hear about it!

simsgw

That's a good idea anytime, Alex. And the change to other engine mounts (discussed in the GT3 forum) is never harmful either unless you're hauling around someone sensitive to vibration between track days.

Gary

alexb76

Quick question on that... would upgrading motor mounts cause *significant* more vibration on street? This is my DD, so I like to keep it as streetable as possible.

GTgears

See my comments in the GT3 forum about changing the gear oil. I didn't realize there were two threads or I would have just posted it here since it's 997 Aisin gearbox specific. GT3 gearbox stuff doesn't really apply that much to your car...

alexb76

Thanks for your help, I think I definitely need to change fluid... posted back there wondering which fluid would be best for me.

BTW, reason I cross-posted is that GT3 folks track a lot more and might have more experience with shifting issues.

Cheers!

JFERR

Use to happen to me all the time. Learned to hold the shifter gently. Instead of grapping and pulling/pushing, don't grap, push/pull gently. Never happened again.