Black Sea RD

Rule of thumb is a 5 speed TT has three, while automatics have two.

BUT, my automatic 1986.5 TT had three! Also many 928s out there have had replacement TTs by now and depending on where they came from, who knows what's inside.

One thing to consider, we made different bearing units, one made of steel and one of aluminum. Most street driven 928s with normal HP/TQ engines will do very well with two steel bearing units, both the autos and 5 speeds. The heavier steel bearing units dampen TT vibrations and were desigend to take away the need to replace the OE TT dampner. These OE vibration dampners are now coming apart due to age and start slamming up and down the TT moving around the bearings. This was found in our own 1986.5 TT.

The lightweight aluminum bearings can be used in 928 TTs for racing applications as well as the middle third bearing for street driven 928s which are boosted and need a more robust TT as Dave did in his excellent write up. Or as piece of mind for all owners who want a very robust TT for their 928s.

HTH,
Constantine

EDIT: I responded to Mr. Howell before seeing Ryan's nice picture of the two different TTs side by side and explanation.

Black Sea RD

After more consideration and conversations with a few Rennlisters, I have decided to also order the 28mm bearing inserts for the new TT bearing units currently in production. This change only affects those with 87 and later 928 automatics which should have the newer, thicker, 28mm drive shafts installed by the factory. I emphasized should since most 928s are at the age that TT changes have been done to many and there is a possibility some 87 and later 928s have the earlier 25mm constant diameter now installed.

This change is being done to let the 928 owners have as many options available to them whenever they need to consider rebuilding their TTs. Also due to the age of many of the 25mm drive shafts out there, there are no gaurantees that any of those drive shafts will not shear sometime in the future as we have found out in our research.

We will still offer the new automatic 25mm drive shafts we are having made.

I'm confident that 928 owners will understand the issues concerning drive shaft shearing possibilities and will make the appropiate choices which will fit their needs and pocket books.

Thank you,
Constantine

IndyMatt

Constantine, I am very interested in this product. Do you happen to know when these will be available for sale?

Black Sea RD

Hi Indymatt,

Probably sometime in late March or early April.

Cheers,
Constantine

checkmate1996

keep us posted....my car will be sitting all apart for a while at that rate!!

IndyMatt

Ok thanks I will be on the lookout since I will be dropping the tranny to have it rebuilt this spring. I will be replacing or replacing the bearing on the torque tube, replacing the TC and bearings, and R&R the LSD as well. So basically I will be replacing/repairing the entire drivetrain.

Black Sea RD

Hi Indymatt,

Okay, sounds like a lot going on and it will be a great time to do the TT rebuild. Will make the announcement when the parts get in.

Cheers,
Constantine

LS1Porch

Visiting here from the 944 side of things, but any thoughts on producing something similar for us '44 guys? I don't know the specs offhand, except that our TT uses a 6006 ZZ C4 bearing which is no longer made.

Black Sea RD

Hi LS1Porsch,

First off I understand your 951 conversion and my friend at work and I have discussed this type of conversion at length. Take the Porsche well designed body and suspension and then put in one of the sweetest power plants on this earth in terms of HP/TQ and simplicity and you can't argue with the result. Bet you are having a ton of fun! Ever track it?

A far as the 944 torque tube bearing rebuild kits, yes we are right now in the middle of finishing the first prototypes for the 944/968 platform. They will have the upgraded 2008 C4 series bearings just like our 928 versions, which is a much better solution than using 2006 C3 bearings that many are using presently. We expect to have the prototypes ready within a month for testing. However given the R&D we put into the 928 versions we really do not expect the R&D curve to be as long.

When do you need to rebuild your TT? Feel like being a tester?

Cheers,
Constantine

LS1Porch

That's great news, Constantine!

Yes, the car is a blast! I've put in some limited track time, but the car is down now for the next round of upgrades

As of right now, i have my TT out and ready to be rebuilt! I am absolutely willing to be a tester for you! It was actually my search for some "pucks" that led me to your posts (with thanks to Brian Broderick):

https://rennlist.com/forums/944-turb...-carriers.html

I'll send you a PM with my email address, and we can work from there!
Thanks again, this is exciting news!
~Chris

Black Sea RD

PM and email sent!

Cheers,
Constantine

Jadz928

Just read this interesting thread. Good Q&A.

Constantine,
I understand why you may not want to set an expectation on price yet. In kind, I will not set a expectation to purchase but will say I'm interested. Once you offer them for sale, please send me a PM.

Thanks Constantine and Dave for putting this together.

jetrainor

Just noticed this thread....Constantine, as you may remember i have installed on my 87 auto one of your excellent flexplate clamps....if the quality of the TT bearing assembly is the same, this is a no brainer. I'm curious whether i have the 25 or 28 mm shaft....is that step down visible at the flex plate end of the shaft?.
John T

Black Sea RD

Hi Jim,

Yes we are still trying to price the different set ups that can be done with these units. I believe that we can offer them at very good pricing points that will be affordable for most. Package deals with our 928 Super Clamp are also being worked up.

We will make a formal announcement soon. Thank you for the interest!

Kind regards,
Constantine

Black Sea RD

Hi John,

Good to hear from you! Yes I do remember you and our good conversation when you bought one of the first clamps!

To answer your question the 28mm drive shaft neck down is visible at the front flexplate area and can easily be seen when you remove the cover.

We did decide to offer the 28mm bearing inserts to allow the owner to make the decision to change the drive shaft to a 25mm or keep the 28mm. The 28mm has shown more of a propensity to shear than the 25mm, although many people report having them with no issues. But let's face it, all these drive shafts are getting to the age where failures will probably be a bit more common for either.

Hope all is well and thanks for the kind words on the clamp,
Constantine