ian996gt3

I recently purchased a 997.1 Cup after driving a track prepped 996 GT3 for the past three years. Saturday was my first day in the car at Lime Rock Park. The car was truly amazing. Handling was superb, and the motor felt very strong.

However, I had some trouble adjusting to the gearbox (sequential with auto-blipper). Upshifts were a breeze, but downshifting was more difficult. I missed a few shifts from 4th to 3rd going into Big Bend. And when we ran the Chicane later in the afternoon instead of the normal Uphill, I missed a few shifts from 3rd to 2nd.

While upshifts seemed to be an easy pull of the shifter, I felt like I really had to slam the shifter forward on downshifts. I have watched several in-car videos of other drivers shifting 997 Cups, and to my uneducated eye, it doesn’t appear as though they are working as hard on the downshifts as I found myself. The transmission is relatively new, with about 8 hours on it.

Overall, I managed to turn decent times for my first day in the car (on scrub tires). It ran consistent low 56s with one 55.9 lap. But I definitely felt as though my downshifts were costing me time & effort.

Is this a normal experience given that I have never used a sequential transmission before? Is the downshifting just something I need to get used to? Or does my description make you guys think something could be wrong with the gearbox and/or autoblipper?

Thanks in advance for your thoughts/comments/suggestions/advice.

Best,
Ian

Yannick-HST

How much throttle-% is the Blipper adjusted to?

A video of your driving would be helpful.

MirageJHU

I am not a mechanic, nor a tech, nor super knowledgeable but I had a similar issue in my 997.2

Turned out to be a throwout bearing (assuming you're clutching for downshifts right?)

We were bleeding the clutch every 2nd or 3rd session because of this issue and when we had a long break between events they went into check the clutch and voila...new throwout bearing did the trick.

Obviously YMMV, but my symptoms seemed eerily similar to what you are describing...

93 FireHawk 968

If all mechanical issues are eventually ruled out plan be should include making sure all shifts are truly deliberate and engage the clutch a second before the down shift. My experience with missed down shifts is I was too soft with the shifter and/or engaged the clutch too late. Watch some of the in-car video of pro drivers and you'll be shocked at the speed and force of their activating the shifter.

analogmike

The in-car videos you see don't relay how hard we are hitting the shifter, in both up and downshifts. Never "pull" or "push" it like a normal shifter, treat it like a woman.

Polarporsche

I had the same issues on my 2009 Cup, I was struggling with my downshift, I though it was my inexperience with the Sequential box. I decided to get the gearbox rebuilt at 21 hours since I was grinding the downshift, way to often. Bill Rader said the box looked great and only required a normal refresh for a 21 hour gearbox. Since the tranny was out I had my shop replaced the pressure plate, clutch, and release bearing, this fixed the downshift issues, I'm no longer fighting with it on downshifts.

claykos

Simplest thing to check is that the clutch pedal stop is properly adjusted so it is fully releasing.

BBMGT3

Difficult downshift could be mistiming on the clutch and/or not smacking the shifter hard enough. Driving a 997 is a workout

Up shift is easier than downshift.

A bad clutch could explain some problems but I would think that you would notice other issues too

Sequential takes time to get used to. I love it but it does slow you down a bit

coryf

A lot of good advice so far. You don't have to be forceful. Don't jam, hit, slap, punch ect.. the shifter. Just a solid deliberate push on the downshifts and a quick and snappy pull on the upshifts. The dogs sometime line up just wrong and it will not complete a shift in either direction. Release the pressure on the shifter and then try again. You can down shift without a clutch with these boxes but it is normally easier on the components to use the clutch on downshifts. An indicator the clutch isn't completely disengaging is if it grinds/scrapes going into reverse or first.

tedean

As noted above, check the clutch peddle length to disingagement and the clutch release bearing (throwout). This is exactly what happened to me. It is also important to do asap because if the bearing goes out in the release bearing, it will not spin properly and damage the pressure plate.

wagongotya

typical to have difficulties downshifting initially. best advice is to be deliberate with your shifts...don't hang your hand on the shifter preparing to shift, take your hand off the steering wheel and click it forward and release immediately. if you need to run a couple gears, repeat, each time releasing the shifter. also remember these transmissions shift much better in the higher rpm bands so time your shifts accordingly and keep them smooth and rhythmic as you decelerate. practice makes perfect.

BBMGT3

+1

Joes911

Made the same transition months back. Up shifts require acceleration and can be botched at part throttle. Full throttle, high RPM, no clutch the up shift is borderline magic.

Some great tips above. Practice and deliberation seem the prominent themes.

I have worked to refine downshifts and find two areas improve the smoothness: fast in and out with the clutch, most important with autoblipper do NOT hang on to shifter. Forward crisply and right back out. On mine 997.1 the autoblip is a throttle cable and the longer you hold it the higher it revs. Probably less of xmission issue but a poor driving tech to engage clutch with revs well in excess of target.

Had my lube changed after each of 5 weekends by Goldcrest thus far and they tell me no unusual metal wear. I really hope for a longer rebuild cycle than 20 hrs

Safe driving to all Cup drivers! Js

ian996gt3

Thanks everyone for their input. As usual, Rennlist is a valuable resource.

My primary takeaway is that I need more seat time to practice downshifting and ensure that my movements are deliberate and crisp. I have three days at Watkins Glen coming up, so hopefully I can focus on working out the kinks shortly.

After the Glen I will definitely have my shop take a look at the throwout bearing and make sure my clutch pedal stop is adjusted to the correct position.

One more question… should I be releasing the clutch pedal in between every gear? Or can I do two gears at once? i.e 5th to 3rd with only one clutch movement?

Very happy to have made the jump to the Cup… and I am sure I will have more questions for the group in the future.

Thanks.

BBMGT3

I wouldn't skip gears...