Guard Transmission Cup Car gearsets
10-14-2011, 09:38 AM
#1
Rennlist Member
Thread Starter
Join Date: Feb 2006
Location: Wishing I Was At The Track
Posts: 13,618
Received 1,853 Likes
on
960 Posts
Guard Transmission Cup Car gearsets
I was pinging with Matt regarding their new Cup Car gearsets. Don't think anything has been posted on Rennlist on this stuff yet and figure others might find his comments interesting so here goes.
Nizer
"Guard Transmission is now making replacement gearsets and certain service parts for the 997 Cup Car sequential gearbox.
What I have available is as follows:
1st gear with mainshaft 3.167
2nd gear 2.133
3rd gear 1.722
4th gear 1.400
5th gear 1.153
5th gear 1.130
6th gear 0.964
6th gear 0.931
Replacement dog teeth, sliders/claw collars, and drivers/hubs.
The ratios are the two standard 2008 and 2010 homologation ratios as the cars were delivered from Porsche. The gears are all the latest revision to 2010 spec with the shorter slip fit dog teeth. They are legal for Grand Am, PCA, and Pirelli Drivers Cup. Sorry ALMS guys, PMNA has banned us from the series on your sealed gearboxes. But we take that as a compliment.
More ratios will be available by the 24 Hours of Daytona.
There's a number of things that are different about our stuff versus Porsche/Holinger gearsets and components.
The biggest and most pronounced difference is our toothprofile. They are still using a generic off the shelf tooth profile that's been in use for the better part of two decades. It's a somewhat course design and the problem with it is that the tip of the gear tooth hits the root and eventually "chops down the tree" when it wears through the hardening.
Our gears,in direct contrast, use a tooth profile that was developed in F1 racing. The gear cutting hobs to make them are custom to our specification and cost 10 times the cost of an off the shelf hob like Porsche uses. Here's a picture of two gears side by side:
While these gears are helical, they make the point. See how our gear, on the right, is crowned and has a slight change in angle out at the tip? Our teeth don't contact at the root. Furthermore, the pressure angles of them are such that the contact patch is basically an instantaneous contact of 80% of the tooth face at once. Porsche's gears roll through the teeth in a pitter patter motion, which doesn't equalize the load on the tooth as well. This is part of why a number of Cup gearteeth snap off, even on gears with low miles that haven't worn out at the root.
Also, our toothprofile has less friction. There's actually less HP loss to the driveline with our parts. It's somewhere in the neighborhood of 3-5hp on a 400hp car.
Beyond that, our metalurgy is different. We use a higher quality gear steel that is stronger and carries an AMGA rating of 11. We've never tested Holingers gears, but I've been told that they're something like a 7. Porsche's gears are heat treated to 45/1000th of an inch. Ours are treated to 55/1000th. This makes for a gear and parts that's both stronger and more durable. Last year Brumos rans our components in their car at the 24 Hours. They held up so well that after the race was over, they opened up the box, put in a shorter 6th gear, and resealed it without changing things to go run Homestead.
Lastly is the price. Our gears are $1500. That's almost $1000 cheaper than a Porsche gear. For something that's stronger, and more durable, you pay less because it doesn't carry a Porsche logo."
Nizer
"Guard Transmission is now making replacement gearsets and certain service parts for the 997 Cup Car sequential gearbox.
What I have available is as follows:
1st gear with mainshaft 3.167
2nd gear 2.133
3rd gear 1.722
4th gear 1.400
5th gear 1.153
5th gear 1.130
6th gear 0.964
6th gear 0.931
Replacement dog teeth, sliders/claw collars, and drivers/hubs.
The ratios are the two standard 2008 and 2010 homologation ratios as the cars were delivered from Porsche. The gears are all the latest revision to 2010 spec with the shorter slip fit dog teeth. They are legal for Grand Am, PCA, and Pirelli Drivers Cup. Sorry ALMS guys, PMNA has banned us from the series on your sealed gearboxes. But we take that as a compliment.
More ratios will be available by the 24 Hours of Daytona.
There's a number of things that are different about our stuff versus Porsche/Holinger gearsets and components.
The biggest and most pronounced difference is our toothprofile. They are still using a generic off the shelf tooth profile that's been in use for the better part of two decades. It's a somewhat course design and the problem with it is that the tip of the gear tooth hits the root and eventually "chops down the tree" when it wears through the hardening.
Our gears,in direct contrast, use a tooth profile that was developed in F1 racing. The gear cutting hobs to make them are custom to our specification and cost 10 times the cost of an off the shelf hob like Porsche uses. Here's a picture of two gears side by side:
While these gears are helical, they make the point. See how our gear, on the right, is crowned and has a slight change in angle out at the tip? Our teeth don't contact at the root. Furthermore, the pressure angles of them are such that the contact patch is basically an instantaneous contact of 80% of the tooth face at once. Porsche's gears roll through the teeth in a pitter patter motion, which doesn't equalize the load on the tooth as well. This is part of why a number of Cup gearteeth snap off, even on gears with low miles that haven't worn out at the root.
Also, our toothprofile has less friction. There's actually less HP loss to the driveline with our parts. It's somewhere in the neighborhood of 3-5hp on a 400hp car.
Beyond that, our metalurgy is different. We use a higher quality gear steel that is stronger and carries an AMGA rating of 11. We've never tested Holingers gears, but I've been told that they're something like a 7. Porsche's gears are heat treated to 45/1000th of an inch. Ours are treated to 55/1000th. This makes for a gear and parts that's both stronger and more durable. Last year Brumos rans our components in their car at the 24 Hours. They held up so well that after the race was over, they opened up the box, put in a shorter 6th gear, and resealed it without changing things to go run Homestead.
Lastly is the price. Our gears are $1500. That's almost $1000 cheaper than a Porsche gear. For something that's stronger, and more durable, you pay less because it doesn't carry a Porsche logo."
10-14-2011, 11:23 AM
#4
Rennlist Member
Thread Starter
Join Date: Feb 2006
Location: Wishing I Was At The Track
Posts: 13,618
Received 1,853 Likes
on
960 Posts
10-14-2011, 11:47 AM
#5
Former Vendor
10-14-2011, 01:18 PM
#6
Drifting
Don't know. I'd ping Matt: gtgears@yahoo.com
Thanks Matt!
Trending Topics
10-17-2011, 09:02 PM
#9
+1,000
Matt is a class act and has the products to back it up.
Very rare now a days to have a company with both great products and customer service to back it up.
Nothing but Matt's products will go into my porsche car's from now on.
Loving my Guard LSD in my race car
Matt is a class act and has the products to back it up.
Very rare now a days to have a company with both great products and customer service to back it up.
Nothing but Matt's products will go into my porsche car's from now on.
Loving my Guard LSD in my race car
