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It seems just about every car out there comes with 6-spd manual transmission, how come the RL with a powerful engine didn't?
 

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The T56 is extremely heavy (for a manual transmission) so I imagine until they design a new lightweight and strong 6 speed that has computer controls they're just going to use the 5 speed they have in it now. I just hope it's stronger than the piece of tinfoil T5 they used back in the 80s F-body. I know once a 6 speed becomes available I'll be buying one to swap in. I'm going to miss 6th gear very much.
 

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hey guys.
I do think 5 speed is fine, of course I hear the neayh about 2-3 ratio, but with everything considered i do think it is fine. I can see say HONDA s2k got to have 6th since it got verry narrow power band, say gto, or last gen camaro with tremmick 6 speed, well 6th gear was just for fuel economy and as much TQ as those had it was fun.
Regarding on Borg Warner T56 IT IS NOT THAT MUCH HEVIER! it is a great tranny, but I don't think we really need it, sure if I would be given an option of 6speed I would go for it, but 5 speed should do!
Being a turbo car I definatly can see myself using 3rd gear a lot, so tall gear for me would be a plus, the only thing that I would bitch is a freaking 6300 redline...WTH?! I mean my big block can rev higher!
ilber
 

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... the only thing that I would bitch is a freaking 6300 redline...WTH?! I mean my big block can rev higher!
ilber
ECM reflash should take care of raising rpm some. I understand reg Sky was raised 200 more rpm... don't know what the possible limit with be with turbo..:thumbs:
 

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Being an i4 engine car having a 6-speed tranny is not necessarily a goo thing. Look at all the MX5 race cars, they all come with the smaller 5-speed and not the 6-speed because the 6-speed is supposedly pretty crappy for racing. Big engine cars end up with 6-speeds more often to help fight with fuel economy issues too. The LNF engine has the propensity to get better fuel economy then the current base LE5 due to it's smaller displacement.
 

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It seems just about every car out there comes with 6-spd manual transmission, how come the RL with a powerful engine didn't?
Because the SKY isn't just every other car???:cool:
 

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"THIS one goes to eleven..."


:lol:

The gains of having multiple gears begins to diminish above 5 speeds. That's why you have seen many uncontested claims that 4-speeds are better than 3-speeds (they are), 5-speeds are better than 4-speeds (they mostly are), but then it starts getting muddy.

Is a 6 speed better than having a PROPERLY spaced 5-speed for the application? It depends - how big is your torque band?

On the Honda S2000, the torque band is like from 6800-7800 RPMs, so the decent working range is prolly 6200 (peak torque minus 500-700 RPMs) to redline minus about 200 RPMs. That's a pretty small working range - so to range properly, you prolly need 6 speeds. This motor's peak torque is not huge either, meaning the power comes from engine speed.

On the MX-5, similar ranges, peak torque 5000 peak power 6700 RPMs, working range about 5500-6800. It MAY or MAY NOT be an advantage to have a 6-speed, and is prolly application (read here: track) dependent. On an autocross course, sometimes shifting the gearbox around is not worth the x-tra torque.


Now, if you have more torque, and/or a larger working band to work with, you can take advantage of this and reduce time lost by shifting and eliminate the extra gears.

Base SKY has peak torque ~4800, pk power ~6600, but very strong torque at peak torque. The working range for this motor is prolly around 4000 - 6700 RPMs. Questionable whether adding another speed in the mix will be an advantage, ASSUMING the gears that are there are spaced properly. In 2006, 3rd gear was too far away from 2nd gear, and almost too close to 4th. This is supposed to be changed for 2007 model year for all manual trannys. :thumbs:


Now, the SKY RL has peak torque at ~2500 and produces this torque all the way to 5300 RPMs :eek:. I would expect this still pulls some past the peak power at 5300, so the working range is prolly 2100 (when the boost starts to come up) to maybe 5500. I doubt that adding an extra gear will do much for the RedLine, except giving you something to mess up your track times... :lol:


Of course, there will be someone who begs to differ, and that's fine too. This is just my technical interpretation based on what I've learned over the years.


Another thing to consider is that the extra gear adds weight, too. That's why you don't see many 8-speed manual trannys out there - the added weight and complexity aren't worth any "supposed" gains.

It all boils down to this: the transmission/RER/tire size system's purpose is all to keep the engine operating in the maximum range of torque and power. The "distance" in the rpm curve from the max torque to max power is important to consider.
 

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trans

I will put in my 2C. I cant tell you how many times when downshifting I mis shifted with a 6 speed. Too many gears for the street. Going from 5 to 3 and grabbing first is a real eye opener and there is nothng to prevent that. 5speeds are just a good idea. JMO...
 

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vs Miata

There was a link to a video posted here awhile back - some japanese guys - comparing a Miata to a Kappa (cannot recall for sure but I think it was a Solstice). One thing they mentioned was that the get around the track the Kappa required less frequent shifting which they thought might have actually resulted in about a 1 second slower lap time for the Miata. they also had video of the feet/pedal area for both - and the Miata had to be shifted up and down between 2nd, 3rd, and 4th to keep it in the power band - the Kappa could be left in 3rd and still put power on the road.

When I test drove a Miata I had to keep reminding myself I had a 6th gear available.

On some cars - GTO, Corvette, etc - the top gear would only really be for highway crusing to lower overall gas milage I think.
 

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A world class T5 could easily hold the power of a redline and the T56 would be complete overkill.
 

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Auto 6speed

People are talking about missed shifts and fuel economy with manual trans. Automatic is computer controled a six speed could have closer gears and flawless updown shifting where you would go mad shifting manual up and down in traffic. the Cadilac STS has a 6speed auto and isnt that where we get are rearends from? On a less expensive car so people don't post that is a option on a 50-60k car, we have the Ford Fusion that has a 6 speed automatic and that car stats under 20k and tops mid 20s. I would guess a properly set up 6speed auto would result in greater performance and economy than six speed manual where human error is a factor. Just my opinion.
 

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gm only has the 6l80e auto trans right now as an auto 6 speed. it is heavy and it is overkill. they are developing a 6l50e that would be be the right size for this application, as well as any other application they currently have a the 4l60/4l65/4l70e in. currently the 4 speeds are being fazed out, as well as the current 5l40/5l50 trans.

manual wise they do wave the t56, but it is rather large, though not that heavy (75lbs maybe). they are also using the as6 aisin 6 spped in the cts now, however i doubt they have a bellhousing for the ecotec made up.

i'd expect by 2009MY both a 6speed manual and 6speed auto will be available.
 
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