George D

I posted this on the GTS light post. A few wanted to know which Audi Diesel gears I'm using for my 968. Figured since shared on that post, I'd provide the neat Excel spread sheet created. Once opened, you can change all fields to see RPM drop, speed in each gear at a set RPM, etc. You can download this to your desktop. I've sent the Excel transmission spread sheet as an editable document for fellow Rennlisters, feel free to share. Cool tool - better than anything I've found on internet sites.

COPY/PASTE:

Haven't been on here in a while. The attached Excel spread sheet, once downloaded is editable. Very cool doc built so I could see the changes from gearing changes on any vehicle with a manual type transmission. This will allow you to enter whatever gearing you'd like to see with RPM drop etc. The Audi gears I'm using is under the Audi 3.6 second down. Scott Dewitt sourced these gears for me and he's building the box. Shaft and gears are being micro polished and hardened. These gears are hard to source in the US as these 8 series Diesel manuals weren't imported here. You likely have to buy a used box from Europe and have it shipped. Scott Dewitt at: http://advancedautomotion.com/shop/ is the best source for these gears in the US. A well known shop "specializing" in Porsche transmissions didn't know you could use these Audi gears - actually wanted me to give them the ratios and they'd get back to me with pricing. Sorry guys, but I won't do their job. One call to Scott, and my box was on it's way to Texas.

Understand clearly I would not have changed the stock gearing if this was a track only car. I drive it to San Diego, my place in Greer, AZ, sometimes when going to Phoenix for biz, and a few times a week to work. The stock gearing, in my opinion for my use is too short. Those that have done this share the taller gearing is awesome. One of the V8 conversion 968's actually used taller Audi gears than my setup with no acceleration difference - "His Statement". This setup "sort of" allows sixth gear to become basically a "cruising" gear. Track events, time trials, drivers education, etc. I'll have basically a taller 5 speed than the stock 951. I haven't entered the 951 five speed ratios, but I will now.

The stock G50 968 boxes you HAVE to use the stock 1st and 2nd gears as they're part of the shaft design.

This motor at the wheels has over 400wt below 4K, and will likely move lower once we finish tuning with the Snow Performance Meth setup. Notice we got fairly close to the factory 968 Turbo RS ratios.

I've driven high powered cars with an installed WaveTrac using the CF material. Smoothest LSD I've ever used. You can change the lockup using different friction materials for a track only setup. State of art LSD's with no clutch plates to wear out.

http://www.wavetrac.net/

George D

Just entered the ratios using the 944 Turbo 5 speed. Impressed that my 968 now has very similar gearing to the Turbo in the first 5 gears. Weird I never entered the 944 Turbo ratios to compare. Very happy with the results!

azbanks

Thanks for the info George!

333pg333

Thanks for the post George.
I would like to get a shorter 6th cog. Don't think there's one out there though.

FHM

I thought Albin makes a shorter 6th.

333pg333

Yes, they probably do, but they won't do a 1 off. Nobody else would want one. Need to do a batch of at least 10.

bumflick

Awesome. Thanks for posting this. I have a 968 open box in the basement. I'll save my pennies for one of those boxes from a diesel Audi 8 series. Did you swap over 3rd, 4th, 5th and 6th from the Audi box? Agree, 1-5 are pretty close to stock 951 box.

George D

Yes - the gear ratios are in the Excel doc created you can edit.

G

George D

Hey Patrick,

Sorry my friend, the shortest G50 6th gear from any Audi box is what I installed .60 - There are actually taller gears available - makes sense in a high TQ/HP Turbo Diesel. My Duramax will pull a building down with the TQ at 38psi - stage 5 on controller - but the programmed Allison still shifts around 3500RPM. Tall gears make complete sense in a manual luxury Audi A8 with a manual six. Close to 300hp and 500tq BELOW 3K with decent top speed - Jolly Green Giant tall gearing madness running these motors at speed.

George D

With 10 - still in the 3+K range - plus the six month wait - always add three months from estimated delivery - then start the unfortunate "badgering" calls simply asking for what was promised.

333pg333

Thanks George. I don't have gear charts in front of me. Are you saying that the .60 is shorter than a stock 6th gear? Doesn't sound like it. I know we can fit G50 LSD's into our 'boxes but I don't believe we can use their gearing which is a shame.

azbanks

I emailed Scott. He says he can not get gears for a 5 speed 944 T box. I didn't realize there was that big a difference between a 968 and a 951 box as far as the gears go. Won't the Audi .6 gear you are using fit in a 951 box, George? Is the shaft different or is it something else?

FHM

The 944T boxes are Audi 016 based vs the 968 is a G50 based. The shafts and gears are different in dimensions. None of the parts are interchangeable.

scottmandu

Actually the 968 box is 01E based, however it does have similar diff dimensions as the G50.

There is a shorter 6th gear (.87) available from Audi.

FHM

I believe you are correct but the Audi 01E and 968 gearbox seems not to have much interchangeable components.