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Does anybody know if the 6t70(e) I'm hearing about will work on a N*? I have a 97 with obd1 and a 98.
 

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it may or may not, depends on if they make a version for more powerful engines. From what I'm reading it tops out at a max torque of 280lbs-ft and 320 Horsepower. The L37/LD8 Northstars pump out 300/295 lbs-ft of torque and 275/300 horsepower. For right now no.
 

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Am I the only one asking why we need so many friggin' gears in a transmission? I REALLY think the OEMs are trying to sell us all a BS line that more is better. It's like, did you ever ask yourself why sportscars with 500HP and 500lb/ft of torque need a 6-speed manual trans? :bonkers:
 

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Katshot said:
Am I the only one asking why we need so many friggin' gears in a transmission? I REALLY think the OEMs are trying to sell us all a BS line that more is better. It's like, did you ever ask yourself why sportscars with 500HP and 500lb/ft of torque need a 6-speed manual trans? :bonkers:
More gears helps with MPG at higher speeds, and in general. There are more oppertuneties for the car to go to a bigger gear thus haveing less RPMs and fuel consumption. Thats why there have always been overdrive transmissions. The theory of getting the bigger gear that might not have passing power but enough to keep speed steady. Bigger gears allow a car to do more with less. Gears these days are more than just getting you in motion.

It kinda lets the engine hold in a fuel efficient range more often. It can help with acceleration keep the car in its power range longer. Now with VVT that story changes, anyway anything over 6 is useless and 5 is pretty good unless you like driving really fast.
 

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In practice, the top gear ratio on these new trannies is pretty much the same on a car with a 4spd as a car with a 6spd. Take a look at the top-gear tranny ratio on the new trannies and compare that with some of the 4-speeds. Bottom line is that MPG in top gear isn't going to be affected by having all those extra gears as the top gear's ratio isn't any lower; engine doesn't spin at a lower RPM.

The advantage with having more gears is improved drivability and some MPG improvement in-town; the engine's operation can be more controlled through the use of more gears when going at non-highway speeds. The gear ratios can be spaced more closely together.

Yes, having an *overdrive* would help with MPG, but that's not these 6- and 7- speed trannies have.

The tranny gear ratios are only half the story. The final drive ratio (the differential) is the other half.

I believe the fourth gear (top gear) ratio in my 2003 STS is .65 (or so) with a final drive ratio of 3.71. Compare this to the new Mercedes 7-speed tranny: 7th gear ratio is .728 with a final drive ratio of 3.45.(http://www.supercarsite.net/ml_63_amg.htm).
 

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The biggest advantage to more gears is tighter ratio spacing, allowing the engine to stay in a more effecient rpm range (power band), thus improving both performance and MPG.:)
 

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Okay, I get all that but;

Have you noticed that most cars haven't any HUGE difference in MPG figures as compared to the technical advancements they've received? I remember my '75 Olds Cutlass getting 20mpg highway and about 15mpg around town with a 350-4bbl and 3-speed, non-overdrive trans. My fleet cars back in the late 80's were full-size Broughams w/Olds 307's w/4bbl carbs and 4-speed overdrive trans, and got about 20mpg highway and 15mpg around town. My '95 Fleetwood gets about the same mpg as the previous examples. So what has been accomplished over the years with respect to fuel economy? Is it REALLY the reason for so many gears in our new transmissions? Does the Viper w/6-speed trans get substantially better mileage figures than and old Chevy big-block Chevelle with a 4-speed? I know these are radically different vehicles in this example but realistically, I think that as engines have gotten much more powerful, and efficient, the need for so many ratios in the trans should be LESS, not more. Especially in the case of modern performance cars. 3000 pound cars with 500lb/ft of torque should not need 6-speeds. My guess is that in the near future, you just might see OEMs starting to admit this fact and start reducing the number of gears in a trans rather than supporting the bigger is better theory (in this case, MORE is better). My guess is that a Z06 Corvette would actually be quicker through the 1/4 with fewer gears, so why not build them that way?
Sorry, rant over.
 

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Randy_W said:
The biggest advantage to more gears is tighter ratio spacing, allowing the engine to stay in a more effecient rpm range (power band), thus improving both performance and MPG.:)
That makes total sense with an engine with a narrow powerband but today's engines with their increased output and use of technologies such as variable displacement, and variable valve timing, shouldn't need so many gears.
 

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Those are some good points, Kevin.. I was thinking the same thing as above - that the more gears you have, the more gas you'd save.. But, you're right.. We aren't saving more gas.. So I wonder what all the fuss is about...
 

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Katshot said:
That makes total sense with an engine with a narrow powerband but today's engines with their increased output and use of technologies such as variable displacement, and variable valve timing, shouldn't need so many gears.
I think GM is gearing up to make a move to more powerful 4 cylinders a la honda. Good gas mileage, but peaky motors.
 

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Those are some good points, Kevin.. I was thinking the same thing as above - that the more gears you have, the more gas you'd save.. But, you're right.. We aren't saving more gas.. So I wonder what all the fuss is about...
Look at a comparison of the tailpipe emissions of those cars of yesterday and today's cars. The difference will blow your mind. Gas mileage savings are secondary to emissions reductions. Most of the innovations and technology since those days of automotive engineering have been aimed at cutting tailpipe emissions. It doesn't matter what kind of mileage you get as long as you aren't dumping massive volumes of CO2, NOx, and hydrocarbons into the air, at least if you ask the EPA. We've also added lots and lots of electronic gadgets to cars since that time, and that's load on the alternator which eats gas. Those electronic gadgets help reduce the emissions and increase the mileage, and they have done wonders for safety and reliability as well as making cars easier and more fun to drive, especially on roads that aren't straight and empty. Not to mention that cars don't have nearly the torque they used to have. They have lots of horsepower, and that's what sells the car, but less torque. They have to work harder, and therefore using more gas, but they burn it in more efficient ways (injection) and ratios (computers and sensors and electronic ignition) to reduce emissions. What's the incentive to increase gas mileage? CAFE? What a joke! There are only disincentives for continuing to dump so much junk out of the tailpipe, and mileage is little more than a political tool.
 

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What's the incentive to increase gas mileage? CAFE? What a joke! There are only disincentives for continuing to dump so much junk out of the tailpipe, and mileage is little more than a political tool.
Another form of marketing, and trying to track the shift in public want (staying ahead of the curve). Look at the Prius. When gas spiked to nearly $3, there were shortages. They were selling above sticker price. Gas is only expected to go higher.... This is exactly the same reason you see SUVs rusting away at used car lots, nobody wants them.
 

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mcowden said:
Look at a comparison of the tailpipe emissions of those cars of yesterday and today's cars. The difference will blow your mind. Gas mileage savings are secondary to emissions reductions. Most of the innovations and technology since those days of automotive engineering have been aimed at cutting tailpipe emissions. It doesn't matter what kind of mileage you get as long as you aren't dumping massive volumes of CO2, NOx, and hydrocarbons into the air, at least if you ask the EPA. We've also added lots and lots of electronic gadgets to cars since that time, and that's load on the alternator which eats gas. Those electronic gadgets help reduce the emissions and increase the mileage, and they have done wonders for safety and reliability as well as making cars easier and more fun to drive, especially on roads that aren't straight and empty. Not to mention that cars don't have nearly the torque they used to have. They have lots of horsepower, and that's what sells the car, but less torque. They have to work harder, and therefore using more gas, but they burn it in more efficient ways (injection) and ratios (computers and sensors and electronic ignition) to reduce emissions. What's the incentive to increase gas mileage? CAFE? What a joke! There are only disincentives for continuing to dump so much junk out of the tailpipe, and mileage is little more than a political tool.
I get all that but it has nothing to do with the topic of the number of gears in the transmission. I agree the engines are far "greener" then they used to be, but that's due to better engine management and better fuels.
I'm telling you, I really feel the number of gears in the trans is more for marketing than anything. I mean hell, even my new '05 Jeep Wrangler now has a 6-speed! Talk about over-kill.
 

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Katshot said:
I mean hell, even my new '05 Jeep Wrangler now has a 6-speed! Talk about over-kill.
better than a 2 speed :nyanya:

If it's a manual, then yes that would be terrible. If it's an auto, then who's counting? :p

Speaking of the new 6 speed auto, it will be 8% more efficient, and I've heard it may be smaller than most other 4 speeds. Our land boat 4t80e's lose 25% to heat, friction, and those stupid pumps inside. That is a LOT!!! For the VIN 9 guys, that's 75HP!! That's like a honda! :crying:

So, long story short... more gears... "meh"... more power to the wheels... "yay!!"... more fuel economy... "yay!!"... more marketing power... "yay!!"... less weight (better acceleration, more fuel economy)... "yay!!"
 

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Absolutely it's a manual. And with the bottom-end torque of the 4.0 I6 in it, the LAST thing it needs is more gears IMO.

As for your take on the new 6-speed trans, it all sounds good but the REAL key to it is effecient design not the number of gears, right? So why not make it with fewer gears and in that way reduce weight, rotating mass, and complexity. Should even be able to reduce the cost and parasitic loss too.
 

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Well the best thing for all would be CVT and it's coming to a big powerful car near you soon! The problem with CVt has been packaging, the old Subaru CVT sucked because it wasn't even strong enough for 80 h.p.. Ford has had better luck and GM is working on one for the next gen RWD cars and for trucks in about 2-3 years. That along with a proper torque convertor would keep your engine at a stable rpm through the whole acceleration process. You could in theory mash your Caddy to the floor and stay at 6500 rpm from 0-170mph!
 

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Katshot said:
Absolutely it's a manual. And with the bottom-end torque of the 4.0 I6 in it, the LAST thing it needs is more gears IMO.

As for your take on the new 6-speed trans, it all sounds good but the REAL key to it is effecient design not the number of gears, right? So why not make it with fewer gears and in that way reduce weight, rotating mass, and complexity. Should even be able to reduce the cost and parasitic loss too.
Well from what I understand about the new 6t70, it's really like a manual. They have direct acting clutchpacks that eliminate a lot of moving parts. If you look at it, it is hard to tell it apart from a manual. It even "looks cool". I believe that's where the new efficiency comes from (not the cool looks, the new clutches and their integrated 32 bit controller!). By going to a 4 speed, they would reduce some weight and cost, but that's about it. IMHO it's about as efficient in losses and weight as it's going to get. I have heard rumors that it weighs half as much as the 4t80e, which is like removing a dead body from the trunk of your caddy. It WILL be noticeable. The 6t70 should handle the N* torque just fine, but I haven't read the specs on the maximum gearbox torque, so I don't know if they'll be putting them in caddies anytime soon....
 

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The new M-B S500 has a 7-speed automatic. That better be a pretty smooth shifter, otherwise it would be pretty annoying driving around town. The thing would be shifting constantly! Maybe it only hits 6th and 7th if you're flying down the autobahn.
 

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I hear Mercedes Benz is making an 8 Speed Automatic!!!!!!
Is there anything the germans can't do??:bulb:
 

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Just wait until CVTs make the mainstream market... It'll be interesting flooring the car from a stop, and just having the tach hang at 6000rpm or where ever peak hp is.
 
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