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Old 04-06-2009, 08:45 AM   #9 (permalink)
semtex
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Quote:
Originally Posted by kailua View Post
Funny thing, I've had a bunch of 4 cylinder, manual cars (06 STI, 09 Speed3, 09 STI) and never really needed nor wanted the synchro rev match. With the V6, the synchro rev match helps alot, and without it, it is less forgiving when you down shift.
That's due to the heavy dual-mass flywheel. Has nothing to with 6 vs. 4 cylinders. Heavy flywheels have more inertia, which means it takes more energy to change the revs (in either direction). When you downshift, if you don't blip the throttle in advance (either manually or via SRM), the revs will climb as soon as you re-engage the clutch as a lower gear revs higher than the preceding higher one. In other words, as soon as you re-engage the clutch, the clutch will 'grab' the flywheel and force the rpms up. Because a high-mass flywheel has more inertia and it takes more energy for the revs to climb, it's jerkier. This would be true regardless of how many cylinders the engine has. And it's also why they offer lightweight flywheels on the aftermarket (one of the most popular for this car is from Jim Wolf Technology.)
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