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Syncros and Engine speed syncronization

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Old 07-19-2013, 12:53 PM
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rmarks
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Default Syncros and Engine speed syncronization

So we all know that the C7 will have a 7 speed manual and will also have a computer feature to change the engine speed to so there will be a smooth shift. I am waiting on the road tests for this and I am sure it will be good. Smooth upshifts and downshifts I am sure. Cool.

But, think about it. The C7 will require an extra row of gears. How is GM getting the room for them:
1 - bigger transmission case, or
2 - smaller (and possibly weaker gears). or
3 - smaller synchro rings.

I wonder if this auto speed was a necessity to prevent premature wear-out of new and smaller synchro rings?
Old 07-19-2013, 01:11 PM
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Originally Posted by rmarks
So we all know that the C7 will have a 7 speed manual and will also have a computer feature to change the engine speed to so there will be a smooth shift. I am waiting on the road tests for this and I am sure it will be good. Smooth upshifts and downshifts I am sure. Cool. But, think about it. The C7 will require an extra row of gears. How is GM getting the room for them:
1 - bigger transmission case, or
2 - smaller (and possibly weaker gears). or
3 - smaller synchro rings.
I wonder if this auto speed was a necessity to prevent premature wear-out of new and smaller synchro rings?
I am missing something. First, you conclude that there are three options, including a bigger transmission case. Then you decide that of the three options, the one GM choose was smaller synchros, and now you worry about "premature wear-out of the new and smaller synchro rings." What if the other option you suggested was the one GM choose, the larger case and the C7's synchros are neither smaller, nor weaker -- in fact hardened and strengthened.

Maybe we all ought to find out reality first, not worry prematurely about a problem that doesn't yet, and might not ever exist.
Old 07-19-2013, 04:43 PM
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Article about the Tremec TR6070 transmission.
http://www.gmhightechperformance.com..._transmission/

Looks like it's about 40mm longer.

So, I think option #1 was the route they chose, and weaker components was not.

-T
Old 07-19-2013, 05:39 PM
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Racer X
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Originally Posted by Trackaholic
Article about the Tremec TR6070 transmission.
http://www.gmhightechperformance.com..._transmission/

Looks like it's about 40mm longer.

So, I think option #1 was the route they chose, and weaker components was not.

-T
Perhaps is being 42mm longer is part of the reason for extending the wheelbase.
Old 07-19-2013, 07:47 PM
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Seems like the Corvette team learned from the '05 launch and the Z06/ZR1 developments.

Between the twin disc, strengthened diff, halfshafts and built up trans, looks like the car is ready for some hard driving out of the box.
Old 07-19-2013, 08:17 PM
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Originally Posted by rmarks
So we all know that the C7 will have a 7 speed manual and will also have a computer feature to change the engine speed to so there will be a smooth shift. I am waiting on the road tests for this and I am sure it will be good. Smooth upshifts and downshifts I am sure. Cool.

But, think about it. The C7 will require an extra row of gears. How is GM getting the room for them:
1 - bigger transmission case, or
2 - smaller (and possibly weaker gears). or
3 - smaller synchro rings.

I wonder if this auto speed was a necessity to prevent premature wear-out of new and smaller synchro rings?



Let's keep in mind here that rev match will have very little to do with synchro wear and will not really smooth the actual shifting of the transmission as we are not double clutching.
Old 07-19-2013, 11:07 PM
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arghx7
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The Nissan 370Z has had that rev matching feature on manual transmissions since 2009. I've experienced it on that car, and IMO it's gimmicky and pointless. Maybe there are some people who use it every day, but it kind of defeats the purpose of a manual transmission.

You have a manual specifically so that you don't have a computer doing stuff like that for you.
Old 07-20-2013, 04:56 AM
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Originally Posted by arghx7
The Nissan 370Z has had that rev matching feature on manual transmissions since 2009. I've experienced it on that car, and IMO it's gimmicky and pointless. Maybe there are some people who use it every day, but it kind of defeats the purpose of a manual transmission.

You have a manual specifically so that you don't have a computer doing stuff like that for you.
I have not driven it but my thinking was its an attempt to try to substitute for the lack of DCT and make it a bit easier for manual drivers to shift who either aren't good at it or get tired in stop and go conditions.
Old 07-20-2013, 09:40 AM
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Originally Posted by arghx7
The Nissan 370Z has had that rev matching feature on manual transmissions since 2009. I've experienced it on that car, and IMO it's gimmicky and pointless. Maybe there are some people who use it every day, but it kind of defeats the purpose of a manual transmission.

You have a manual specifically so that you don't have a computer doing stuff like that for you.

There will be very little benefit in street driving.

If it is implemented properly it could be very beneficial to those that can't or don't care to heel and toe at the track.

I can hardly wait to try it out. Then add on the elec. diff. and it should be the cat's rear.

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