 |
PM |  | |
Quote | | |
Reply | | |
Full Topic | |
| Joined: | 03-14-2005 |
| Location: | Atlanta, Georgia USA |
| Posts: | 406 |
| Status: |
Offline
|
Your comparison of ratios confirms the good news we've know for years in that the stock JH 4sp is a fairly close ratio transmission. When combined with h/c pistons and a 'torquey' cam like the E or 107, the stock transmission and rear end provide a great driving experience.
A stock (i.e. non-torquey) JH could easily benefit from a lower 1st gear to help it get moving from dead-stop (much like every 4cyl BMW, where you have to shift to 2nd before you cross the intersection!).
However, stock or modified, the 907 doesn't exactly have a lot of low-end torque or a wide torque-band. Consequently, a wider ratio gearbox could result in a fairly frustrating driving experience around town and definately on the track.
Even with all the flack it receives, the stock JH 4sp transmission (when rebuilt properly) is a regular 'rock-crusher'. It uses the same Borg-Warner style synchros used in the current Corvette, Viper and Mustang transmissions.
Getrag used Porsche-style synchros on the JH 5sp and later tried Moly-style synchros in the 1980s BMW transmissons. http://www.metricmechanic.com lampoons both of these 'innovations' on their website.
In my opinion, the stock 4sp is fantastic with a mildly warmed-over 907 engine. If you want to grab another gear, the W58 Supra transmission has very similar ratios plus an overdrive.
If your budget is unlimited, and if you can find a bellhousing from the early Eclat 2.2, you could use the BMW M3 Getrag 265 transmission modified by http://www.metricmechanic.com into their 'Ultimate Transmission'. Quite possilby the last transmission you'll ever need!
Judson