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Old 02-20-2009, 10:25 PM   #31
Matt Monson
Scooby Guru
 
Member#: 832
Join Date: Jan 2000
Chapter/Region: RMIC
Location: Teh Ghetto Garage, CO
Vehicle:
99 2.5RS, '85 911
'73 914 and 2012 BRZ

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Quote:
Originally Posted by FuJi K View Post
I just found out that the '08 WRX uses the LGT gears and runs a 4.111FD. I wonder if it is the same tranny.... more likely.
Same exact part numbers for the mainshaft, 1st and 2nd gear idlers. I know because we just installed them in a box today. Though I've always thought it was a misnomer that people call this the LGT swap. These are the same ratios that were in the v4-v6 JDM STi's and WRX sedans. They aren't new ratios, though they are new to the US market, and of course we get them with a different FD ratio than the 4.44 they see in Japan. There's a certain US vendor who has been selling these for years as a complete 5 spd kit calling it v5/v6 STi. Though, they force you to buy all 5 gears in that kit, and you end up with an additional 0.738 5th gear, which you've already got if you drive a USDM WRX. Now, with these in US cars, you are free to just buy the 3-4 gears that you need. We're building a bunch of these boxes.

However, there is one difference with the '08 WRX gears. It's a shorter 5th. They've tightened it up to a 0.780 like were used on the GC chassis 2.5RS and first generation of Outbacks.

Also, there's just a couple of minor errors in your ratio charts. The ratios you attribute to 96-99 WRX-RA/ Type RA/ 22B etc are actually 97-2000 ratios. Also, same for the WRX/STi reference directly under that in the list. Those ratios, which are the ones we are discussing above were for 97-2000 as well. Just a one year shift off of what you've got listed.

Otherwise fabulous thread. When I have more time I'll come give some of my personal input on choosing ratios and applications. Even now with all this new stuff, Subarus are still pretty restricted on what we can do with these boxes. On the Porsche gears I am making we average 12-20 different ratios for each individual gear position. At the same time, on Porsches you are generally only working with 2 final drive ratio options instead of the 3 we have with Subarus. That reduces the number of gear ratios you need to have to reach the same end. Though there's a tradeoff there and if you adjust a final drive it forces you to move all ratios the same percentage at the same time. A shorter R/P ratio that might make your 2-3-4 better might take your 1st and make in pretty much worthless.
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