Cadillac News: Cadillac Unveils New A Twin-Turbo 3.6L V6 For The 2014 CTS

[Robert Hall]

This is clearly targeting the BMW 535i. The V-series will target the M5. Same w/ the equivalent E-class/AMG models, and Audi A6/S6.

Actually, with >400 HP and >400 lb-ft, this new engine is aimed squarely at the 550i (400, 450, 15/22-23 mpg), the E550 (402, 443, 16/26 mpg), and the S6 (420, 406, 17/27). Biggest difference is that the Germans have forced-induction V8s, and the CTS will have a V6TT that pretty much matches everyone in power and FE.

The LLT is still the 535i/E350/A6 3.0T competitor.

I suppose you could look at it that way...and GM went w/ the TT V6 because they don't have a DOHC V8 available.

[Lamar]

This is clearly targeting the BMW 535i. The V-series will target the M5. Same w/ the equivalent E-class/AMG models, and Audi A6/S6.

Actually, with >400 HP and >400 lb-ft, this new engine is aimed squarely at the 550i (400, 450, 15/22-23 mpg), the E550 (402, 443, 16/26 mpg), and the S6 (420, 406, 17/27). Biggest difference is that the Germans have forced-induction V8s, and the CTS will have a V6TT that pretty much matches everyone in power and FE.

The LLT is still the 535i/E350/A6 3.0T competitor.

I suppose you could look at it that way...and GM went w/ the TT V6 because they don't have a DOHC V8 available.

Well, that's how it's gonna be. It wouldn't make much sense comparing a 300/300 engine (535i) with a 420/430 engine (CTS).

True about the DOHC V8... but then we get into the debate about whether to use the LTx instead.

[William Maley]

This is clearly targeting the BMW 535i. The V-series will target the M5. Same w/ the equivalent E-class/AMG models, and Audi A6/S6.

Actually, with >400 HP and >400 lb-ft, this new engine is aimed squarely at the 550i (400, 450, 15/22-23 mpg), the E550 (402, 443, 16/26 mpg), and the S6 (420, 406, 17/27). Biggest difference is that the Germans have forced-induction V8s, and the CTS will have a V6TT that pretty much matches everyone in power and FE.

The LLT is still the 535i/E350/A6 3.0T competitor.

I have something about that coming within the next few hours..

[hyperv6]

Let really take a look at this.

#1 this ain't no economy car.

#2 It is a larger car than the last CTS

#3 They weight may not be that much different since it has grown in size even on the Alpha.

#4 I would not be surprised in the real world numbers will be better. My Turbo is stated as 19 MPG around town and it has never gone below 21 MPG and most year round I see 25 MPG City.

#5 The TT is an option engine. If MPG is a factor there are smaller engines and the ATS.

#6 I am sure there will be a Turbo Diesel here at some point too for the MPG crowd.

I think we should let this play out before we get too worked up. I am sure it will be competitive in class for MPG and as good or better in all other categories.

This engine will feel and drive much like a V8 but with max torque coming in at or fellow 1800 RPM and holding it to well over 5000 RPM.

As for up grades it only takes a couple Map sensors and a computer flash [they have not used chips in years] to pick up 50-100 emissions and warranty approved HP.

This engine and combo should do well for Cadillac and their image. They have stepped out and set themselves apart from the rest of GM with this.

Now I only wonder what GM has set for the Vette now? I saw a dash in a C7 with two boost gauges! Could we be on a verge of a Vette engine and CTS V with a TT V8?.

[Robert Hall]

It is going to be interesting to see if BMW & MB will still have V8s in the next generation of their midsize sedans in non-performance branded (e.g. M or AMG) versions. Audi doesn't have one, nor does Lexus. (though w/ Audi, this output level is comparable to their current S6).

Edited March 18, 2013 by Cubical-aka-Moltar

[regfootball]

the advantage is that Cadillac will be putting an engine in the car people want in cadillac, not one perceived to be a redneck engine or a truck engine.

I know myself, I would prefer the twin turbo v6. I would not want a v8 in my CTS.

this engine will go in a bunch of GM stuff also. I'd like to see it in the Corvette and Camaro.

The marketers need the product to have attributes they can market, not to have to sell concepts that are not much in favor in the buying group's minds.

60 degree design, two less expensive pistons, shorter and less expensive crankshaft.........

engine cover is sort of bland.

Let's clarify something: I am not calling for this car to have a V8 - it should not. I am also not calling for more power - it has more than enough.

In all honesty, I am simply calling for better results overall. My thinking here is that this engine has leaned too far to the performance side and ignored fuel economy.

This is V-level performance that should have been toned down in favor of MPG gains.

The V will have to be a lesson in overkill to slot above this engine, and I see that as a mistake.

>Ehh, you young-in's and yur newfangled turbochargers and fuel injection. Back in my day we had carburetors and injections implied a trip to the doctor. We had to crank the engine by hand, none of this motorized starter tomfoolery.

Don't be foolish, the numbers aren't there.

all I know is the 17/25 is much higher than the FE numbers of the non AWD v8 G8 GXP.......for basically similar performance. G8 GXP was like 13/19.......

[hyperv6]

The present CTS comes in at 3800 pounds and so I expect this one to be similar in weight with the added size.

The present Camaro of a similar weight with the LS3 is rated at 16 MPG and 24 MPG.

I find of most of GM's cars of late get the posted MPG or a little better 80 % of the time.

I expect the Chevy SS to get about the same as the Camaro or one MPG less as I saw some place they expect the car to spec out at 3900 pounds since most will be loaded.

But again How many people buy a Twin Turbo for MPG let alone a BMW or Benz. If they do they buy a Diesel

[William Maley]

Okay, here is my comparison piece between the Cadillac TTV6 and Competition V8s.

By The Numbers: Cadillac's TT V6 vs. V8s

[smk4565]

Now Cadillac is in the game, this is the best engine they have had since 1993 when the Northstar came out. They finally have something that can go head to head with the Germans, and the 8-speed transmission is key. The power output is plenty, 0-60 in 4.6 seconds is quite fast for a luxury sedan. On real roads with real traffic you probably won't even be able to use all that engine's power. This gets them on par with the Genesis V8, and sort of splits the difference between the European V6s and V8s. I like this move.

The only complaint would be fuel economy, 17/25 isn't bad, the Jaguar Supercharged V6 is only 1 mpg more and has less power, and the E550 V8 with awd gets 26 mpg, but that is rather high for a V8. Would have been nice if they got another 1-2 mpg out of it.

The turbo 4 needs to be over 30 mpg, and the N/A V6 should be 30 mpg also. The 535i and E350 have 300 hp and 30 mpg, that is sort of expected now in this class. The Germans have more diesels on the way, Cadillac needs one, especially if they want to sell cars outside the USA.

[smk4565]

My guess is this is the ATS-V engine.

I also predict the 3.6TT CTS to be around $60,000+, sort of where the V-series is now, so that will be interesting to see how that plays out.

No idea why this engine will be in a FWD barge like the XTS, didn't they notice that no one bought the MKS Ecoboost because a super power FWD car makes no sense, even with AWD.

[Lamar]

No one's buying the MKS because the Taurus is almost as good for a much lower price. And Ford sells plenty of SHO models.

[ocnblu]

This sounds like an awesome powerplant. People buy European luxury cars all the time with mediocre fuel mileage, I guess Cadillac's just going with the market.

This engine in the XTS, with AWD, should be a sweet combo, too. But the CTS is the one to have. With its '75 Seville taillights.

[Drew Dowdell]

The XTS AWD is a firmer ride and an equal handler to the E-class, so no reason it can't get this engine.... though I expect it to be downrated for FWD duty.

You know what might be hot though? SRX-V anyone?

[smk4565]

XTS and SRX carry a lot of weight over the front axle horsepower doesn't fix bad weight distribution, it makes it worse.

I did read that on the XTS it will have 370 lb-ft and a 6-speed automatic. They could do that with the SRX also, but what's the point. It is like making a 400 hp Lexus RX, the people that buy those don't want power or RWD handling, they want the feeling of driving wallpaper paste.

I think the XTS is about to get really irrelevant in a hurry when this new CTS arrives. The CTS will probably have a better interior and it wouldn't surprise me if it had more interior room since the XTS wheelbase isn't very long. Combine that with RWD superiority and more potent engines, and game over XTS.

[G. David Felt]

XTS has a place and there are still plenty of baby boomers and livery that will want the XTS.

With the TT V6, stretch an XTS into a Limo and you have a solid power plant as long as it is reliable.

[Robert Hall]

XTS has a place and there are still plenty of baby boomers and livery that will want the XTS.

With the TT V6, stretch an XTS into a Limo and you have a solid power plant as long as it is reliable.

[Drew Dowdell]

XTS and SRX carry a lot of weight over the front axle horsepower doesn't fix bad weight distribution, it makes it worse.

Still better than the Audi's weight distribution for AWD models.

[smk4565]

The XTS AWD has a 58/42 weight distribution, with a heavier turbo engine and beefed up front end that will probably be 60/40. The Audi A6 has a 55/45 weight distribution. Either way, those cars aren't 50/50 and Benz and BMW outsell Audi by a large margin.

The 2014 CTS on powertrains already shows promise, 25 mpg from a V6 is nothing great but buyers in this segment don't care too much about fuel economy anyway. I do think they need the turbo 4 and V6 around 30 mpg though, since all the other guys are there.

[smk4565]

XTS has a place and there are still plenty of baby boomers and livery that will want the XTS.

With the TT V6, stretch an XTS into a Limo and you have a solid power plant as long as it is reliable.

The Livery market does not want or need a 400 hp car, they want fuel economy and low cost of operation. Hearses rarely top 30 mph, and Limos can't do sporty driving because you can't make the people in the back sick or roll out of their seat. A turbo 4 (which I know is coming) or a turbo diesel 4 with big low end torque makes more sense than a twin turbo V6. As far as the 65+ crowd buying the XTS (or Lexus ES) they don't care about speed either.

[Drew Dowdell]

The 2.0T isn't slated for the XTS for the US.... officially.... yet....

[balthazar]

That XTS hearse is SWEET!

[William Maley]

I kind of want that XTS hearse

[Drew Dowdell]

Who needs a Transit Connect when you can ride in Cadillac Cadillac Cadillac style?!

[Blake Noble]

Am I the only one that's a little irked that we're just now seeing an eight-speed automatic from Cadillac?

[Intrepidation]

Better late than never.

[G. David Felt]

Am I the only one that's a little irked that we're just now seeing an eight-speed automatic from Cadillac?

Naw, most people do not care or really understand the tranny. Marketing has always pushed HP which is a bogus thing also unless you have the proper Torque.

Torques moves everything.

[dwightlooi]

I hope they don't put this in the ATS-V. It's essentially inferior in every measure compared to the LT1. It costs more, weighs more, takes up more room, has more things to break, is more maintenance intensive, while making less power, less torque and is less desirable to a performance oriented driver (presence of turbo lag). The fuel economy advantage is either non-existent or minimal (0~1 mpg). For forced induction to be worthwhile you need to do way better than 116 bhp/L

The engine will essentially appeal to those who blindly worship alphabet soup. But such individuals are likely to buy that Bi-turbo six BMW M3 anyway unless they perceive the Cadillac brand differently. And, the only way to change their minds is not to do what BMW does but do what BMW does not do and kick their butts for a couple of generations of models. Short of that matching alphabet soup won't do you any good because they'll believe that "BMW DOHC Bi-turbo" is naturally better than "GM DOHC Bi-turbo".

BTW, I stand by my prediction from 1.5 years ago for the ATS-V --

• Pushrod 6.2 V8 (LT1)
• 470 bhp / 450 lb-ft (SAE)
• 8-speed Automatic
• 17/25+ mpg

[ocnblu]

That XTS hearse is the sexiest last ride I've seen. It would certainly be the funeral car to have if I were in the market.

[Robert Hall]

I kind of want that XTS hearse

With extra windows and a reconfigured interior it would make a sweet wagon...

[Lamar]

I hope they don't put this in the ATS-V. It's essentially inferior in every measure compared to the LT1. It costs more, weighs more, takes up more room, has more things to break, is more maintenance intensive, while making less power, less torque and is less desirable to a performance oriented driver (presence of turbo lag). The fuel economy advantage is either non-existent or minimal (0~1 mpg). For forced induction to be worthwhile you need to do way better than 116 bhp/L

The engine will essentially appeal to those who blindly worship alphabet soup. But such individuals are likely to buy that Bi-turbo six BMW M3 anyway unless they perceive the Cadillac brand differently. And, the only way to change their minds is not to do what BMW does but do what BMW does not do and kick their butts for a couple of generations of models. Short of that matching alphabet soup won't do you any good because they'll believe that "BMW DOHC Bi-turbo" is naturally better than "GM DOHC Bi-turbo".

BTW, I stand by my prediction from 1.5 years ago for the ATS-V --

• Pushrod 6.2 V8 (LT1)
• 470 bhp / 450 lb-ft (SAE)
• 8-speed Automatic
• 17/25+ mpg

You and Camino should talk.

[Blake Noble]

Better late than never.

meanwhile at chrysler ...

[Intrepidation]

The next 200 is supposed to get a 9-speed, and several existing models already have the ZF 8-speed.

[regfootball]

CTS will for sure outshadow the XTS but I still think they will put this engine in the XTS. XTS biggest problem is the Epsilon disease, too narrow, also the roof is too low and too little visibility out a claustrophobic cabin. Mainly the older set DTS type fans who want it large inside and very open and roomy feel are a bit put off by the XTS in width and openness.

[Camino LS6]

Omega

[hyperv6]

If you do not like the XTS here then it is doing it's job. That car is to appeal to the older owners and fleet and not take people away from the CTS and ATS. If we loved the XTS and CTS then Cadillac did something wrong.

The XTS will do its thing and the rest of Cadillac will do its thing.

Omega is coming the only question is who and how will it be leveraged out over the rest of GM. Will it become a Buick Riviera and a new Holden too?

The whole gear thing once you get to 8 starts to get silly but if it sells cars so be it. It is kind of like wheels as once you get so large you start to pay the price in un-sprung weight for the sake of styling. But again if it sells cars so be it.

[smk4565]

The XTS isn't too low, it is the crazy high belt line that is the problem. Likewise with the LaCrosse, there is hardly any side window glass in those cars and it isn't due to a low overall height.

[hyperv6]

Most cars today have high belt lines to meet crash standards. GM and Chrysler tend too keep the low roof and smaller windows where Ford lifted the roof on the Taurus and look like a SUV or Checker.

[dwightlooi]

If you do not like the XTS here then it is doing it's job. That car is to appeal to the older owners and fleet and not take people away from the CTS and ATS. If we loved the XTS and CTS then Cadillac did something wrong.

The XTS will do its thing and the rest of Cadillac will do its thing.

Omega is coming the only question is who and how will it be leveraged out over the rest of GM. Will it become a Buick Riviera and a new Holden too?

The whole gear thing once you get to 8 starts to get silly but if it sells cars so be it. It is kind of like wheels as once you get so large you start to pay the price in un-sprung weight for the sake of styling. But again if it sells cars so be it.

I have always said that what's needed isn't more gears per say but a wider ratio spread -- the lowest gear divided by the tallest. The 7-speed and 8-speed boxes tend to have a wider spread, and this is where the overwhelming majority (like 95%) of the fuel economy advantage comes from. However, more speeds doesn't automatically translate to wider spread. For example:-

• The current GM 6L80 6-spds auto = 6.05 ratio spread (This is about as good as 6-speed conventional automatics get)
• ZF's 8HP 8-speed auto (used by BMW) = 7.04 ratio spread
• Aisin's TL80SN (used by Lexus) = 6.71 ratio spread
• GM's latest 8-speed to be put into the CTS 3.6 Bi-turbo = 6.71 ratio spread (I suspect it's the same Aisin sourced box as Lexus')
• Mercedes' 7G-tronic 7-speed auto = 8.86 (best in the world at the moment)

Hypothetically, if you are to create a 6-speed transmission with a ratio spread of 7.05:1 it'll accelerate just as fast as the 8-speed ZF in 1st and be just as economical on the freeway in top gear. Acceleration performance through the gears is arguable. An 8-speed allows for closer ratios in between gears and keeps the engine in a slightly more optimal powerband. Yet, having 8-speeds and closer ratios means that you shift more often and in the fraction of a second when the shift occurs, engine power is temporarily interrupted. So, it is hard to say which will be faster. In a V8 or bi-turbo V6 engine with meaty and flat power curves, less gears may actually be faster. In a small displacement engine making peak power high up and in a narrow rpm range (like a Honda S2000 engine for instance) more speeds is probably faster.

Edited March 20, 2013 by dwightlooi

[Drew Dowdell]

Is the ZF 8-speed setup the same in the Chryslers?

[dwightlooi]

Is the ZF 8-speed setup the same in the Chryslers?

Short answer is, yes!

ZF8-45 is the same transmission as the Chrsyler-Fiat 845RE. There are some differences such as the choice of clutch pack friction material and the oil pan under the tranny. But even the ZF8-45 varies from application to application in this regard. It's the same exact design and architecture.

Chryslet-Fiat license builds the 845RE in their Kokomo, IN, tranny plant. But Chrysler is also takes delivery of 845RE from ZF's Greenville, SC facility -- or at least has signed a letter of intent to do so.

[Blake Noble]

Is the ZF 8-speed setup the same in the Chryslers?

There are a few different versions of the ZF 8HP 8-Speed that I know of, each designed to handle different torque ratings. Chrysler uses the ZF 8HP45 with the 3.6 liter Pentastar V6 — or, to be more specific, the 845RE, which is a Chrysler-specific version of the 8HP45 with revised internals and a larger oil pan. The 845RE is designed to handle somewhere in the neighborhood of 400 lb-ft. of torque, and the 8HP45 handles up to 450 lb-ft. As the Hemi-equipped Chrysler Group models ditch the old W5A580/NAG1 five-speed auto and the 65RFE six-speed automatic, those models will recieve the ZF 8HP70, which can handle torque ratings in the ball park of 700 lb-ft. The Hemi-powered 2013 Rams and 2014 Grand Cherokee already have the 8HP70; the Challenger will have it (as well as the 845RE for 3.6 liter models) when it is redesigned on its new LA platform for 2015, and the Charger and 300 will have it when they are refreshed in the very near future. The 8HP70 is also essentially the same transmission used in the new Land Rover Range Rover and BMW 7-Series.

Considering the new TT GM 3.6 liter V6 is producing 430 lb-ft. of torque, the ZF transmission used here may either be the ZF 8HP45 similar to what Chrysler uses, or the ZF 8HP55 as seen in various Audis. Just my guess.

Edited March 20, 2013 by black-knight

[Blake Noble]

Considering the new TT GM 3.6 liter V6 is producing 430 lb-ft. of torque, if a ZF transmission is used here it may either be the ZF 8HP45 similar to what Chrysler uses, or the ZF 8HP55 as seen in various Audis. Just my guess.

Just for the record, that's how that last bit should've read. I don't know if GM's 8-speed box is from ZF or Alsin, although considering what dwight posted about the ratio spread, he's probably right about it being from Alsin.

[hyperv6]

If you do not like the XTS here then it is doing it's job. That car is to appeal to the older owners and fleet and not take people away from the CTS and ATS. If we loved the XTS and CTS then Cadillac did something wrong.

The XTS will do its thing and the rest of Cadillac will do its thing.

Omega is coming the only question is who and how will it be leveraged out over the rest of GM. Will it become a Buick Riviera and a new Holden too?

The whole gear thing once you get to 8 starts to get silly but if it sells cars so be it. It is kind of like wheels as once you get so large you start to pay the price in un-sprung weight for the sake of styling. But again if it sells cars so be it.

I have always said that what's needed isn't more gears per say but a wider ratio spread -- the lowest gear divided by the tallest. The 7-speed and 8-speed boxes tend to have a wider spread, and this is where the overwhelming majority (like 95%) of the fuel economy advantage comes from. However, more speeds doesn't automatically translate to wider spread. For example:-

• The current GM 6L80 6-spds auto = 6.05 ratio spread (This is about as good as 6-speed conventional automatics get)
• ZF's 8HP 8-speed auto (used by BMW) = 7.04 ratio spread
• Aisin's TL80SN (used by Lexus) = 6.71 ratio spread
• GM's latest 8-speed to be put into the CTS 3.6 Bi-turbo = 6.71 ratio spread (I suspect it's the same Aisin sourced box as Lexus')
• Mercedes' 7G-tronic 7-speed auto = 8.86 (best in the world at the moment)

Hypothetically, if you are to create a 6-speed transmission with a ratio spread of 7.05:1 it'll accelerate just as fast as the 8-speed ZF in 1st and be just as economical on the freeway in top gear. Acceleration performance through the gears is arguable. An 8-speed allows for closer ratios in between gears and keeps the engine in a slightly more optimal powerband. Yet, having 8-speeds and closer ratios means that you shift more often and in the fraction of a second when the shift occurs, engine power is temporarily interrupted. So, it is hard to say which will be faster. In a V8 or bi-turbo V6 engine with meaty and flat power curves, less gears may actually be faster. In a small displacement engine making peak power high up and in a narrow rpm range (like a Honda S2000 engine for instance) more speeds is probably faster.

That is my point. The greatest need will be with larger engines to keep the RPM down on the highway in various gears with overdrive and to a lesser extent the smaller engines. I think the 8 speeds will be the general tranny on the market as it will handle the needs of nearly every engine out there. A few engines may still be a little high strung or a larger engine and need a gear or two but most will do just fine with 8.

Also it was noted by someone who really knows this topic that the added weight is also a added consideration to these larger transmissions. I can not recall but he stated the pounds added per gear on average and this is at a time when most companies are removing all the weight they can. Also you have to factor in the weigh of cars too as they get lighter it will change the parameters of need too.

[G. David Felt]

If you do not like the XTS here then it is doing it's job. That car is to appeal to the older owners and fleet and not take people away from the CTS and ATS. If we loved the XTS and CTS then Cadillac did something wrong.

The XTS will do its thing and the rest of Cadillac will do its thing.

Omega is coming the only question is who and how will it be leveraged out over the rest of GM. Will it become a Buick Riviera and a new Holden too?

The whole gear thing once you get to 8 starts to get silly but if it sells cars so be it. It is kind of like wheels as once you get so large you start to pay the price in un-sprung weight for the sake of styling. But again if it sells cars so be it.

I have always said that what's needed isn't more gears per say but a wider ratio spread -- the lowest gear divided by the tallest. The 7-speed and 8-speed boxes tend to have a wider spread, and this is where the overwhelming majority (like 95%) of the fuel economy advantage comes from. However, more speeds doesn't automatically translate to wider spread. For example:-

• The current GM 6L80 6-spds auto = 6.05 ratio spread (This is about as good as 6-speed conventional automatics get)
• ZF's 8HP 8-speed auto (used by BMW) = 7.04 ratio spread
• Aisin's TL80SN (used by Lexus) = 6.71 ratio spread
• GM's latest 8-speed to be put into the CTS 3.6 Bi-turbo = 6.71 ratio spread (I suspect it's the same Aisin sourced box as Lexus')
• Mercedes' 7G-tronic 7-speed auto = 8.86 (best in the world at the moment)

Hypothetically, if you are to create a 6-speed transmission with a ratio spread of 7.05:1 it'll accelerate just as fast as the 8-speed ZF in 1st and be just as economical on the freeway in top gear. Acceleration performance through the gears is arguable. An 8-speed allows for closer ratios in between gears and keeps the engine in a slightly more optimal powerband. Yet, having 8-speeds and closer ratios means that you shift more often and in the fraction of a second when the shift occurs, engine power is temporarily interrupted. So, it is hard to say which will be faster. In a V8 or bi-turbo V6 engine with meaty and flat power curves, less gears may actually be faster. In a small displacement engine making peak power high up and in a narrow rpm range (like a Honda S2000 engine for instance) more speeds is probably faster.

Hi Dwight,

If the auto companies then properly program the tranny, you should get great performance from an 8 or 9 speed tranny equal to what you would get out of a 4 or 5 speed. The logic would go that under normal driving to improve MPG they move through the gears as needed to optimize shift points to get every mile out of each squirt of fuel.

Under hard acceleration, the tranny should then move into performance mode and do a 1,3,5,7 or 8 shift or in the case of the 9 speed, 1,3,5,7,9 as it holds each gear longer and then shifts to the next gear based on RPM and throttle.

Is this what I gather from your great info?

[Drew Dowdell]

How come they mostly don't make taller top gears for highway cruising.... especially when mated to these torquey engines?

Edit: The 300C Hemi + 8-speed should be a whole new level of good.....

[dwightlooi]

dfelt, on 20 Mar 2013 - 21:43, said:

Hi Dwight,

If the auto companies then properly program the tranny, you should get great performance from an 8 or 9 speed tranny equal to what you would get out of a 4 or 5 speed. The logic would go that under normal driving to improve MPG they move through the gears as needed to optimize shift points to get every mile out of each squirt of fuel.

Under hard acceleration, the tranny should then move into performance mode and do a 1,3,5,7 or 8 shift or in the case of the 9 speed, 1,3,5,7,9 as it holds each gear longer and then shifts to the next gear based on RPM and throttle.

Is this what I gather from your great info?

You can always use a taller ratio to reduce the engine RPM at cruise for better fuel economy. The problem with that, of course, is that you can only push it so far. Make the ratio too tall and the car becomes really slow accelerating from a standstill. If you have a 505 hp engine with 470 lb-ft of twist -- like the Z06 -- you can use a tall enough ratio that 62 mph arrives in 1st gear and the car turns over at 1400 rpm at 65 mph in 6th. This is in part why that 7.0 liter engined Z06 turns in 25 MPG on the freeway. Try that on a Honda Civic and you'll probably get off the line at a stop light with the acceleration of a caterpillar.

Most 7 and 8-speed transmissions do in fact skip gears. However, they generally do that in during gentle acceleration. Many in fact even start in 2nd gear unless you put them in "sport" mode or the equivalent. At full throttle, they generally don't skip. For engines powerfull enough and having a wide enough torque band, a taller final drive (axle ratio) is typically used so the 1st is taller and fewer shifts are needed to reach a given speed (eg. 62 mph). This allows the 8th gear to be taller and provide better fuel economy. You generally do not use a shorter axle ratio then skip through gears so you have fewer shifts during full acceleration -- that defeats the entire purpose of the 8-speed transmission.

From a technical standpoint, it is the small engines and lower end cars -- like the Cruze -- that benefits most from 7 or 8 speeds. A corvette really does not, nor does an ATS-V powered by a powerful engine. The problem of course is that cheap cars are less likely to receive expensive transmissions even if they need them the most, whereas expensive (and powerful) cars get them while the benefits are marginal. Regardless, if the ATS-V gets the 8-speed Aisin box, look for 65 mph cruising at something like 1200~1300 rpm!

Edited March 20, 2013 by dwightlooi

[hyperv6]

Most cars today will Cruise at 1600-1900 RPM as anything lower tends to be too low.

Taller gears are counter productive for the most part the companies like to gear the cars with a gear that will get them to accelerate at a good pace or even better in a performance car but they still really on he upper gears for the Overdrive to bail them out.

Todays cars are doing two things here. One is to gain MPG while the other is to lower emissions with these trannys. CO2 laws could be a major issue and with the lower RPM you are putting out less emission and CO2.

Yes I agree that the new trannys can and do jump gears as I see it in the Malibu and the Terrain. The other thing I note is while the Malibu when shifted to manual mode will go to what ever gear you are in with the paddle shifters while the Terrain will automatically go to 4 gear if you are in 5-6. It is no longer a one tranny tune for all vehicles anymore as each are tailored so much for the vehicle and drive line package.

The Tranny in my Terrain V6 works less than a 2.4 Terrain. GM has really worked hard to get the most out of the 2.4 Eco in such a heavy vehicle,

The Corvette team stated they chose the transmissions they are using in the C7 because of the performance is optimum and the weight is good. They claimed anything more did not return any better MPG or performance for the engine they are using. Now if they were using a DOHC non turbo they may be better off with more gears to keep the RPM up when needed.

But take any new car today and most will be 1600-1900 RPM in top gear with light throttle on level ground. We will not see much change on this. Also with the drop cylinders engines they need so much RPM to remain smooth.

The key is the move to so many Turbo engines are to deliver the low end Torque and get the cars moving to get up to speed faster. Once up to speed you can get off the gas more and longer and with Direct Injection this adds much to the MPG. Now shifting into neutral and coasting does not do the same thing but leave it in gear get off the gas and the MPGs roll up fast.

If you learn how to drive a DI engine to take advantage of this you can still have great performance and still get good MPG.

[smk4565]

I seem to remember BMW saying the 8-speed they switched to a couple years ago weighed less than the ZF 6-speed they had been using. The new 8-speed was something like 25 lbs lighter than what they had been using and had fewer moving parts as well.

Mercedes 7G transmission starts in 2nd gear for forward and reverse unless it is in sport mode.

I read only the twin turbo CTS will get the 8-speed, which is sort of sad since even a Hyundai Genesis Coupe 4-cylinder has an 8-speed transmission. I see no reason as to why every Cadillac doesn't have a standard 8-speed on everything, at least on their rear drive vehicles.

[hyperv6]

I am sure they all will get 8 speeds in time as they ramp up production. Even the Malibu has the 4 cylinders on the 4 speed till they got production to the point to support all.

[smk4565]

I am sure they all will get 8 speeds in time as they ramp up production. Even the Malibu has the 4 cylinders on the 4 speed till they got production to the point to support all.

They don't have much time, Lexus had an 8-speed transmission in 2007, Hyundai even has their own in house built 8-speed. When Cadillac first got 5-speed autos in the CTS and STS the other guys went to 6, when Cadillac got 6-speeds, Mercedes, Infiniti, Lexus, BMW starting using 7 or 8. If the ATS gets an 8-speed on the 2017 refresh, BMW will probably be on a 10-speed by then.