GTgears

No. The 991 is an Aisin 7spd gearbox and the GT4 is a 6spd Getrag. This has also been discussed earlier in this thread.

bhk1004

Cheaper to revert back to stock and also don't need an entire transmission build. Unless I am missing something about the install. Also probably easier go sell if you plan to do so and and easier vs having to sell random gears if you revert to stock. Also if the actual gear ratios don't need to be individually changed I'm hoping the computer can compensate and not need a reflash to work the auto rev match.

GTgears

Installing a ring and pinion is about twice the labor of installing gesrsets. You are thinking of it like a rear end on a bmw. On a Porsche the whole gearbox comes apart to install a ring and pinion.

And you guys just think in terms of your cost. I said not cheaper to manufacture. Like a $100-150k investment for someone to manufacture. And the actual design and development is more difficult too. I put 18 months and $50k into the ring and pinion project before pulling the plug on it. Guys talk like these things are simple and straight forward. They aren't.

Phokaioglaukos

I'm learning a LOT from you. Don't be discouraged that the same pointS come up several times--it's inevitable when there is no faq here and people just get their cars.

One way or another I'll spend a lot of money (for me) with you and BGB.

GTgears

I Only get frustrated when people don't read the whole thread. ;-) you can't expect everyone to know all the previous info from the 2 or 3 other threads.

supercup

It will be interesting to learn more about the auto blip feature and how to synch that up with the revised gearing. That will be a key feature to maintain with the upgrades to the gearbox.

The offer by GT to put in the time to do the R&D and develop a new mainshaft (1st & 2nd) and many choices for 3-6 is awesome and will allow us to maximize the potential of our GT4's! With respect to pricing you get what you pay for and while not an inexpensive venture, you will dramitcally improve your car's performance, not to mention the smileage quotient it will provide!

bhk1004

Didn't realize the cost was getting into 150k territory. Thought 25-50k would be a good neighborhood. Thanks for the info. Maybe you posted it above and I missed it.

GTgears

The lower number is for the mainshafts. I own the means of production and control minimums for the mainshafts/gears. Ring and pinions require a different $1.5 million machine which we don't own.

When I made R/P sets for the GT3 Cup cars I worked with Ricardo, who does own that machine. Ricardo made the Ford GT gearbox, Koenigsegg's gearboxes, and most recently the 991 Cup gearbox. They are a top engineering and manufacturing firm. I won't go into the details of trying to work with them on the Cayman r/p and why it didn't work out. But the bigger number is because someone like them requires much higher minimum production on units than what I use internally. And there's the development cost. The $50k I already wrote off is what I spent trying to make a ring and pinion with Ricardo. Every time I did a run of GT3 r/ps is cost me six figures. And as I told earlier in the thread, selling that many units took years (plural).

I came up with the group buy idea for the mainshaft because John and Pete and others kept telling me they really think people will buy it. So, without investing my own money, I've come up with a way to see if that is the case. Organizing this thing is on you guys, the car owners. If you can pool together enough cash deposits then I'll make the product for you guys.

Jenner

Sounds like a perfect fit for kickstarter

GTgears

There's a difference between lacking capital and considering a product a poor ROI. As I've said elsewhere I'm putting my money into a full sequential conversion gearbox for Cayman.

supercup

Now that sound very interesting for the track!

Phokaioglaukos

Sorry if you have said this elsewhere too, but what would that be like? Like a 997.2 cup box with electronic autoblipper? Like the box in the GT4 Clubsport (and just what is that?)?

GTgears

I think I previously posted a picture of the internals, but I'm on my phone (as I usually am here). When I get to a computer sometime in the next few days I will dig out something for "show and tell".

Short answer, is NO, not like a 997 Cup gearbox. The Holinger sequential is a hybrid conversion. It's still internally very much like an H-pattern gearbox in how it functions. It has a sequential shifting drum but still alternates shafts back and forth in pairs. A proper sequential doesn't do that.

And not like a GT4 Clubsport either. That's a PDK gearbox.

I will explain further when I'm at my desk.

Spyder Man

I am interested in a 4.1 or even 4.4 final drive for my Spyder.

If you developed this final drive I am sure a lot of the GT4/Spyder owners would be interested. Also think about the 981 BS/CS owners.

Most of my driving will be on the street and I really want to be able to redline in 2nd without losing my license.

s2ktaxi

the final drive would need to be a 20% reduction