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, Mon, 23 Jul 2007 21:16:51
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First, shift quality can be strongly influenced by the fluid. It is the fluid film between the synchro parts that actually does the work, and if the fluid is too "slippery" then the synchro's don't work well. But you can't use sand and gravel b/c that's hard on the gears and bearings ;-).
Anyway, once you've optimized the fluid, you can still ease downshifting by "double clutching". This will be infinitely easier (one you get used to it) on both you and your 1st gear synchros than "bumping first", and will accomplish the same thing.
The issue is when downshifting, if you are just shifting "normally", the synchros need to "speed up" the input gears. This "speeding up" is done in opposition to whatever drag there might be, and if the synchros are "weak" they just won't be up to the task. When you are upshifting (from 1st to 2nd, for example) you are "slowing down" the input gears, which is something they want to do anyway, so with a light touch even a failing synchro will work ok by just preventing you from moving the lever all the way until the gears are ready.
When you "bump" first, you are *really* speeding up the input gear train, so now the shift into second is, for purposes of synchronizing, the same as an upshift. Now for "double clutching", you shift from 3rd to neutral, let out the clutch, blip the throttle, push in the clutch, then shift from neutral to 2nd. The throttle blip in neutral speeds the input gears, and if you hit it "just right" then everything is already in synch when you go for the gear.
You can do this while braking too, using the so-called "heel and toe" approach. You don't use your heel, you brake with the ball of your right foot and turn your ankle so you can blip the throttle with your instep. Saab's pedals are well set up for this, and the relatively soft brake feel makes it easier too.
Unfortunately Trionic 7 interferes a lot in this process by slowing throttle response. Trionic 8 (on 9-3 SS models) and Trionic 5 (on 9000, NG 900, and 1999 OG 9-3s) are a lot better suited.
posted by 24.33.227...
, Mon, 23 Jul 2007 08:53:27, Mon, 23 Jul 2007 17:53:24, Mon, 23 Jul 2007 21:16:51, Tue, 24 Jul 2007 14:33:20
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