Originally Posted by GTgears

Top is ours, bottom is the Holinger 997 Sequential gearbox (called the PCS). If you look closely at the two, there is one major difference. The Holinger is still essentially an H-pattern gearbox inside. While it now uses a small little shifting drum (with the blue nipple) to initiate the shifts, it still maintains a shift rod for each shift fork/gear pair.

A traditional H-pattern gearbox alternates the fixed gears and loose idler gears, back and forth between the input shaft and output shaft (pinion on a Porsche transaxle). While it works fine for a street car, there's a lot of wasted motion and extra weight there for a race box. And the complex mix of rods is part of why the 997 Cup sequential went through 4 redesigns before it was replaced with the all new box in 991. The box came into production in 2003 and didn't get "perfected" until 2012. The big problem in the first generation was accidentally engaging 2 gears at the same time. On a true sequential that's impossible.

So if you look at my gearbox, there is a single full length rod that the forks float on. They aren't bolted to it. The forks are actuated by a full length shift drum that rotates on a cam and pawl mechanism bolted to the bearing plate. Also, the single shift rod is simultaneously the oil squirting spray bar. In the Holinger box it is that funky bent brass colored bar in their diagram. All our fixed gears are on the input shaft and all idler gears are on the pinion. It's substantially lighter and it has fewer moving parts. The best of everything really.

As for the clutch? Use it if you want or don't use it. On upshifts there is clearly no need. On the downshift, if you have a blipper in place, you can skip it as well. But if you want that involvement that everyone talks about it, by all means use it.

The main bell housing, differential and ring and pinion set are stock street car parts. We are actually casting a new tail cover to make everything fit inside. But the beauty of this is we can convert ANY 987 6spd or 981 gearbox. The architecture inside these boxes is all the same. Once you cross out of the differential area there is no difference from gearbox to gearbox. There is machine work, and people would need to provide a core gearbox for the conversion. Obviously you would most likely want to buy one on the used market and keep your stock gearbox complete in a corner for a rainy day.
Any questions?

Originally Posted by GTgears

OK, I've hit the end of my workday and have some time. Bolded answers within your quote.

Originally Posted by GTgears

OK, I've hit the end of my workday and have some time. Bolded answers within your quote.

Originally Posted by sportscentury

Yep. If the 4RS is PDK only or PDK-rigged MT, I'll just keep the GT4. Simple.

Originally Posted by BGB Motorsports

I do want to go on record in saying that the Getrag gearbox on the 981/987.2 platform is the single most reliable OE Porsche gearbox we ever encountered in street stock racing. The carbon lined syncros are robust, the trans can take serious abuse and it comes from a diesel Audi in Europe which satisfied all my torque limit concerns when it came time to decide whether or not it would last 24 hours. The 997 Aisin box was way better than the 996 Getrag box but this gearbox reigns supreme in my humble opinion. You can service it, put new parts in it and and run it til the cows come home.