1, 3, 5 's Shifting.

**curtis265** · 25-10-2010 10:29 PM

Originally Posted by migoreng

Sometimes you have just redlined 1st from the lights, gave a bit of a squirt in second and already hit the speed limit say ,80kph...
What do you do?
-Shift to 3rd for half a second, then 4th for another second then 5th?
-I could clutch in , move the shift to 5th, wait for the revs to drop enough then release the clutch.

i'd doublt clutch letting the revs drop completely in N, and then go into 5th

**migoreng** · 29-10-2010 07:44 PM

So why is skipping a gear bad?

I could go 2 > 4...
What if the 3rd gear ratio was the same as 4th?
I would shift 2>3 (revs would drop more because of the wider ratios) but what would the difference be?

**VeYzZii** · 30-10-2010 06:36 PM

Originally Posted by -Tom

From reading the S2Ki post, shifting to 3rd takes off some of the force the engine exerts on the gearbox which, if you shift straight from 2nd to 4th, may 'mushroom' the gear because 4th gear can't handle the extra force.

Where not flat shifting skipping.. Why would the 'force' have any effect if your speed is in range of the gear? As in, if the speed is right for the gear.. Is the real issue actually the shifting bit, or is the issue the fact that you shouldnt use taller gear at lower speeds..? I still dont get why selecting a taller gear, and shifting will stuff up synchros. Synchros are engaged while pushing in the gear.. Right? And what does your theory say about eg. Going engage clutch in 1st,accelerate, then 2nd engage clutch accelerate, then holding clutch while shifting to 3rd stil holding clutch, not engaging it in 3rd, then moving from 3rd to 4th and then engaging clutch in 4th to accelerate...?

**euromandeluxe** · 30-10-2010 10:00 PM

You guys should go to the first page of this thread, click the s2ki link and have a good read. everything's explained there pretty clearly.

it's not the gear teeth that get mushroomed, it's the synchro dogs that do because they have to absorb a greater force (greater spinning speed difference) when skipping gears.

migoreng, the if 3rd had the same ratio as 4th it's dog would get mushroomed too. that's kinda why it has the shorter ratio.

in any case, this problem seems to hit the 5th and 6th gear synchros the worst.

double clutching for skipped upshifts will allow the falling engine speed to slow the input shaft to the right speed for the gear you're skipping to, but you'll need to shift into it with the correct timing.

rowing through the gears as veyzzii said will distribute the speed matching load among all the synchros, which means no individual synchro will take the brunt of the force, but if you do this at normal shifting pace it's likely the engine speed will have fallen all the way to idle during the time the clutch was pressed in.

in all honesty I don't get it - if it's known skip shifting can cause accelerated synchro wear on the S, then regardless of the questionable synchro design, why do it? the car has a peaky powerband and a close ratio box with a dream shift action, it was made for shifting gears. it's not like it's a huge amount of extra effort anyway.

my 2c.

**VeYzZii** · 30-10-2010 10:55 PM

Originally Posted by euromandeluxe

Y
in all honesty I don't get it - if it's known skip shifting can cause accelerated synchro wear on the S, then regardless of the questionable synchro design, why do it? the car has a peaky powerband and a close ratio box with a dream shift action, it was made for shifting gears. it's not like it's a huge amount of extra effort anyway.

Yea. Thanks. Now starting to make sense abit more. No i agree with you. If it is shown that it does accelerate wear or encourages it, then obviously it shouldnt be done. Thats the reason i posted the thread. All input is much appreciated. Thanks guys !!