Rennolazine

So my Carrera T has about 250 miles on it. I noticed this the last few days and was wondering if it is normal. It seems like the gear ratio between 1 and 2 are pretty far apart and when you are accelerating more briskly in 1st gear its hard to match the revs to the second gear shift (particularly when higher throttle load is applied and shifting around 4k rpm). It seems like the the revs arent matching well, and the transmission is a bit jerky and squats before producing smooth power. Under light throttle this doesnt happen and the the gear changes are actually butter smooth (and have gotten better with increased driving)... except 1-2 which might have actually gotten worse. I havent given the car full beans yet in first gear since I am still in break in.
Sot the question is,... is this just normal behavior for the 7MT under load during break in? Or is this a normal chracteristic for the 1-2 shift in the 7MT? Ive had 3 manual cars in the past and none of shifted this way. Would be interested to know if you think this is operator related (i.e. me not being good at rev matching this shift) or if this will improve as the clutch springs loosen up over time. If you think its the former, what techniques would you recommend to avoid jerkiness on the 1-2 shift under load?

ryoryo

LexVan

It will get better with time. And your muscle memory will improve.

I rarely accelerate very hard out of 1st. Brisk, yes. But not really hard. To me 1st is just to get going.

In the 991.1 in Sport Plus we get a slight blip to help up shifts too. Makes it smoother. Not sure how that is on the .2s.

The manual 7 takes several thousand miles to loosen up. Give it time.

LexVan

Change to a different product? Or just change to "fresh fluid"? I don't think either are necessary. You only have 25K. Maybe at 75 or 100. Only use Porsche 75W90 gear lube. I plan to change mine after 75 but before 100. And I'll do a Blackstone UOA on it.

Rennolazine

I suspect the only way to change smoothly is to short shift at 2-3k rpm or very high revs (speculating). I nailed a couple 1-2 shifts at 5 grand, and the transmission has totally different characteristics in this part of the rev range. Still waiting to go the full 7.5k, but I would imaging this will be like butter once the transmission is broken in.
One thing that helps me is good driving shoes, you can feel everything the clutch and transmission are doing much better.

russdc

I am at 1800 miles on my T, and transmission is getting a lot better . Had the same issues before, now its gone. Smooth as butter.

ryoryo

Rennolazine

Thanks Lex, good to hear! Several T owners also commented on this for the .2. I think the turbo engine is a little more tricky because you are coming off boost between gear changes. What my left foot feels when I get the "bogging" in second gear is that the car is pulling back power while the revs re being matched and it feels like the clutch engagement is electronically controlled to protect the engine. I think in addition to the mechanical break in being important, the TCU does wierd stuff with the syncros and clutch pressure and I fully expect that adaptations will occur that will result in smoother shifting. Im not used to this fly by wire business. I am looking forward to a couple thousand more miles and will make sure to report back...


That is further reassuring. Alex c said the same thing.

911boy

Don't think it will get better. I just hit 35000 kms and 1-2 is still awkward and hasn't changed at all since I got it IMO. Still very difficult to be smooth at high RPM.

Valvefloat991

What is a TCU? Transmissions Control Unit? There's no such thing in the manual. The only electronic intervention I'm aware of in the 991.2 is that the ECU (Engine Control Unit) won't let you rev above 4000-4200 for a clutch drop from rest. That's apparently to preserve the clutch, which can't cope with the combination of the engine's high torque and strong rear traction. That limitation probably hurts the car's 0-60 time by a couple of tenths.

Rennolazine

Good call.. I gotta look into this because it feels like the computer is doing something... maybe its the ECU since its a simple task with the manual. I was just using "TCU" as a generic term for transmission mapping, thanks for catching this

koala

It really is a difficult gear change for whatever reason. I'm ashamed to admit that I've actually ground gears between 1-2, but never with any other gear changes. I've been spoiled by the sublime setup in Honda S2000's, though. This gearbox, while very good, just doesn't come remotely close to that.

It does seem to be smoother/easier if you're just in normal mode and not Sport or Sport+ - could just be placebo effect.

tgavem

I agree, 1-2 can be less than smooth. 3-4k seems more harsh than just above 4k, say 4200rpm.
I'm also getting used to the gear spring, much stronger than it was in the 996GT3, so 6-5 easily becomes 6-3 or 5-6 becomes 5-4.

Rennolazine

I agree completely. Did another 5k shift today and its much, much smootther than 3000-4500. For some reason it doesnt seem to like this...yet (fingers crossed). Good shoes really help and I hope its even easier to feel with gym shoes on with the race pedals I'm getting next week. The rubber pedal covers dampen the clutch/transmission vibrations quite a bit.
One thing that seems to work is moderate throttle in first till about 3k, then crisp shift into second and it has almost a slighshot effect if you have a quick clutch action and dont let the revs fall.
On a side note, downshifting from 6 or 7 is a still an intermittent ****show due to ongoing operator cerebellar plasticity and lever spring tightness. Coming down from 6 or 7 I keep the clutch depressed until I get confirmation Ive selected the right gear (which it only shows you on the tach in sport or sport plus with the rev match on btw). Normal mode doesnt show you what gear you have selected until you fully release the clutch. Dont wanna experience 7 ->4...siiiiike....2nd....boom.

Scorponok

Mine has that 1-2 crunch that I’ve become accustomed to over the years. All my previous Porsche’s had the crunch. At first it was concerning but to be honest I’ve grown to like it and was happy that my T has it (at least for now). Might smooth out after a few more miles. I agree that nailing a perfectly smooth 1-2 shift is a bit challenging but not concerning on my end.