Vince964T

Hi

What's your experience with the 997 CUP gearbox life expectancy when equiped with paddles ?

Still needs rebuild after 6000 miles or so ? And still as expensive to rebuild ?

Looking at a 2011 with paddles, c.a. 5000miles since rebuild.

Also is it possible to downshift to soon and over rev or are the aftermarket systems around intelligent enough to override early downshifts ?

Thx

dogger15

I think the rebuilds are based on time vs mileage. My tranny got rebuilt every 35 hours with a bump shifter and mechanical blipper. I'm planning to stretch that interval a bit with a paddle shift since it's supposed to be a little easier on the gearbox.

As far as over-rev protection, I don't know if all the systems have it, but I do know the Holinger and Mega Line have it as part of the included software.

Vince964T

Thanks

Cost for the rebuild ?
Heard horror stories... 25/30k USD, that's before autoblip and paddles. I guess these extras should not change the cost and frequency, just reduce the flat spots and risk of missed heel&toe.

dogger15

Horror stories are true. Pretty expensive for a rebuild with all Porsche parts. Cost of rebuild goes down after gearbox doesn't need to be rebuilt by PMNA and sealed per series rules. Gearboxes can be rebuilt by a good shop using aftermarket parts for a much lower price. Prices vary so
it's a good idea to shop around.

As far as extending the interval, maybe someone who has had enough time and experience with a 997 with paddle shifters can chime in with their new rebuild interval.

Keep in mind that nearly every moving part on the car is on the clock.

smf32s

I have been doing about 45 hours before open and refresh with KMP paddles in a 997.2 Cup. Trans was in great shape and only needed one dog and one bearing. Not too expensive. Paddles save the over revs too. Not a single over rev since I installed my paddles. Love them.

Stu

FLA997

Paddles or not, the life of your gear$ does not change, especially 3rd gear that takes a beating.

Matt (GT Gears) posted a thorough synopsis on this subject a while back.

My Cup box was opened up by the shop that rebuilt it at 40ish hours of paddle use and they were amazed at how good things spec'd out and virtually no wear. Note: the box was rebuilt at the same time as paddles were installed. At the time, the paddle systems just came out there was no verifiable data...so we were curious to see the results. For reduced wear -- big thumbs up on paddles, but you still have to time out the gears or you are asking for that big repair bill you mentioned.

__________________
2014 997 GT3-R
2010 997 Cup Car
1989 911 3.2 Coupe

93 FireHawk 968

I have an estimated 55 hours on my 997.1 gearbox and upon recent inspection it was pristine. I have a blipper and use the clutch on all downshifts which may improve longevity.

Vince964T

That is great feedback thanks a lot
I come from a 996CUP, then took a break back into road legal porsches but the appeal of a the cup is strong !

dogger15

Agreed. I did a little digging around in my tech manuals and discovered Porsche specified rebuilds every 20 hours for sprint races and 30 hours for endurance races. I know these are overly conservative, but 40+ hours is more than double that specification. I have to admit I like the idea of extending the rebuild interval, but at 35 hrs I'm already extended and I guess I'm too chicken to extend it further. I've had my share of DNFs due to gearbox failures. I think I'll either tighten up or stick with my existing schedule. Besides, with the cost of a rebuild down considerably, it's worth it just for the peace of mind.

That certainly is an extended interval. One key problem I discovered when rebuilding racing gearboxes is many times the dogs, gears, shafts all looked and specced pristine right up until something let go. The problem was metal fatigue and it's very difficult to detect even using advanced NDI techniques. Porsche's approach to that problem is to time out the components - replace before fatigue occurs. Be careful.

FLA997

3rd gear should be considered a paperweight at 40+ hours...sure it may go longer (and probably will), but then you are playing with fire and may be looking for not only all internals, but a case also.

I think the Porsche Motorsports intervals are conservative as well. With the exception of the 4.0L 2 Ring Engine (good idea to stick to the manual recc. rebuild hours on that one), I think I've pushed the limits way beyond what the manual says on every other part in the past...but I don't make a practice of doing that any longer.

GTgears

What fla997 said. If a shop put a 55 hour 3rd gear back in I would pray before every session.

93 FireHawk 968

Points well taken, going to get the refresh before season starts.

Rob S

Outside of PMNA, can anyone recommend shops or practitioners who rebuild of these sequential transmissions properly and reasonably?

John H

Brian Copans. He's in or just outside of Athens, Ohio would be my suggestion.

FLA997

On the East Coast:

1) Orbit Racing (has done my box twice)
2) Autometrics




__________________
2014 997 GT3-R
2010 997 Cup Car
1989 911 3.2 Coupe