View Single Post
Old 01-10-2005, 11:24 PM   #47
Tool Pants
Registered User
 
Join Date: May 2002
Location: San Jose
Posts: 1,889
I am not going to read all the messages.

When I started Boxstering almost 6 years ago the S did not exist. When it came out there were questions about why it had the same gear ratios as the 996 which has the same basic transmission and ratios but more torque. Another S in S is merely repeating what others have questioned long before he started Boxstering.

I have put in at least 30 B&Ms over the years, and before the B&M came out it was the EVO short shift. It is about even between the base Boxster and the S. I test drive the cars to make sure it shifts properly. The B&M does the exact same thing on the base as on the S - shortens the shift throws. It does not improve anything other than that.

The 986 S transmission is made by Getrag. It is said the 987 S transmission is made by Aisin, as is the 997 and 997 S transmissions. The Aisin transmission shifts differently and has a shorter throw because it is not a Getrag and the standard shift lever has changed.

I have the tech intro booklets for the 997/997 S with the gear ratios. My mechanic friend went to 987 school last week and I asked him to get me the 987 tech intro booklet if they had it. If he was able to get me a copy I will compare the ratios.

The 997/997 S has a 15% reduction in the shift throws because the pivot point of the shift lever has been raised - this is exactly how a B&M works. Having shorter shift throws can increase the syncro wear. The Aisin transmission compensates for this. The Getrag has a single syncro on each gear. The Aisin has 3 on 1st and 2nd, 2 on 3rd, and 1 on 4th-6th. Syncros usually wear out faster in the lower gears, so it makes sense what Aisin did.

The gear ratios on the 997/997 S Aisin have changed from the Getrag due to the simple fact the diameter of the tires have been increased by 5%.
Tool Pants is offline   Reply With Quote