It's the 9-Speed Automatics

[dwightlooi]

Since the launch of the XT4 with the rather anemic (if more refined) LSY engine, many (including myself) had questioned why GM does not offer the Tripower 310 bhp / 348 lb-ft (L3B) 2.7T 4-cylinder in the XT4 (at least) as an option. To a lesser extent some have also questioned why the LSY is putting out a mere 237bhp / 258 lb-ft whereas the outgoing LTG engine is good for 265~272 bhp / 295 lb-ft. Is it just so that it can have 258 lb-ft arrive @ 1,500 rpm? Now, we have the answer...

It's the 9-speed Automatics.

Adopting the 9-speed automatics is deemed a priority for refinement and fuel economy. The new GM-Ford 9TXX transmissions, jointly developed with Ford promises better fuel economy and better shift quality. There are currently two versions of this transmission:-

• 9T50   -- 258 lb-ft
• 9T65   -- 280 lb-ft

The need to pack 9-speeds into a very slim transmission case meant that they have to use an ovoid cross section torque converter, a tension chain coupling and abandon the high torque capability of the previous generation top dog 6T80 (369 lb-ft) transmissions used in the 410 hp / 368 lb-ft 3.6L Twin-Turbo (LF3) powered Cadillac XTS. The lack of torque capability is also in part why Ford abandoned the use of the GM-Ford 9TXX transmissions, choosing instead to develop an 8-speed evolution of the decade old 6T80 for use in their high torque applications like the Ford Edge ST (2.7L Ecoboost V6 with 335 hp / 380 lb-ft). Ford also asserts that the new 9-speed autos did not yield any fuel economy improvement when tested with their engines and the refinement improvements alone did not justify the costs and weight increases.

View full article

Edited March 22, 2019 by dwightlooi

[G. David Felt]

THANK YOU Dwight!!!

This is very interesting information, so Ford then choose to write off the investment and go another route versus GM wanting to get money out of their investment and offer a rather pathetic power train.

These are the type of decisions that GM will end up hurting by. Yes it would be great if every dollar invested in R&D returned a profit, but sometimes, the best intentions means you throw it into the garbage bin and start over.

Very sad for sure, Hopefully GM will realize they need to offer something better. 

Put this in the Chevrolet's and bring in a proper Torque heavy Tranny! 

[dwightlooi]

13 minutes ago, dfelt said:

This is very interesting information, so Ford then choose to write off the investment and go another route versus GM wanting to get money out of their investment and offer a rather pathetic power train.

These are the type of decisions that GM will end up hurting by. Yes it would be great if every dollar invested in R&D returned a profit, but sometimes, the best intentions means you throw it into the garbage bin and start over.

The term for this type of behavior is the Sunk Cost Fallacy; go Google it.

But, I am not sure this is exactly true of GM's decision in this case. The 9-speeds do offer a few things -- better shift quality from one way clutches from gears 2-9 and smaller ratio steppings. The 6TXX trannies were very average boxes in this department. The new 9-speeds also have a pressure accumulator to prime the trannies for engine restarts with Start-Stop systems -- instead of having to spin the converter from stand still and pressurize the transmission fluid so the hydraulics will start working. The Accumulator stores pressurized fluids while the transmission is running and re-injects them during a restart. The only bad thing about the new 9As is that they are stuck at 280 lb-ft. which is OK for the LSY 2.0T and LGX 3.6 V6es. For high performance stuff, I guess GM is deferring to Longitudinal cars with the GM-Ford 10L80 and 10L90 transmissions good for 590 lb-ft and 650 lb-ft respectively.

[G. David Felt]

1 minute ago, dwightlooi said:

The term for this type of behavior is the Sunk Cost Fallacy; go Google it.

But, I am not sure this is exactly true of GM's decision in this case. The 9-speeds do offer a few things -- better shift quality from one way clutches from gears 2-9 and smaller ratio steppings. The 6TXX trannies were very average boxes in this department. The new 9-speeds also have a pressure accumulator to prime the trannies for engine restarts with Start-Stop systems -- instead of having to spin the converter from stand still and pressurize the transmission fluid so the hydraulics will start working. The Accumulator stores pressurized fluids while the transmission is running and re-injects them during a restart. The only bad thing about the new 9As is that they are stuck at 280 lb-ft. which is OK for the LSY 2.0T and LGX 3.6 V6es. For high performance stuff, I guess GM is deferring to Longitudinal cars with the GM-Ford 10L80 and 10L90 transmissions good for 590 lb-ft and 650 lb-ft respectively.

That is great info to know and I wonder if that is what they are doing with this years XT5 that I had as a service loaner for a few days. The start / stop was barely noticable compared to earlier year versions.

Thank you Dwight, I love this type of learning. You made my day as I am still working so a break like this is very welcomed by me.

You Rock!

[oldshurst442]

Interesting.

But I just wanna put out another point of view. A hypothetical if you will. 

This engine is a successor to the one that is in the ATS, right?

I know for a fact that one (of many) issue many journalists had with the ATS, and undoubtedly folks coming from Audi or BMW was that the 2.0T in the ATS was not as refined as the one offered in a Bimmer or Audi. Wasnt smooth. (A common complaint for GM 4 cylinders since, like...forever.)  

Well, this transmissions, as per the OP, and Ford apparently, is that it makes the LSY a refined powerplant.

Ford may not have had use for it because the refinement improvements alone did not justify the costs and weight increases for their Ford branded vehicles, but seeing GM kept it for their Cadillac small CUV, maybe GM and Cadillac engineers decided that refinement was an upmost  priority and since an XT4 doesnt really need tire melting torque to convince people to buy it, but silky smooth driving dynamics to lure folk from the German brands, then perhaps it was a wise decision?

Because that is how I choose to view this decision.  Because quite honestly, 237 horsepower and 258 ft.lbs of torque for a cute ute CUV in a segment that really doesnt care for power, nor would they understand it or feel or even want it, is good enough.

And here I was, trying to find out what the XT4's competition is with a Car and Driver article that tested it that usually also mentions the competition, and the first thing in the title is:  The 2019 Cadillac XT4 Is More Smooth Than Sporty

They follow that up with: 

Cadillac continues to bifurcate its lineup into sporty sedans and milquetoast crossovers.

https://www.caranddriver.com/reviews/a23143999/2019-cadillac-xt4-crossover-drive/

 

But...crossovers, especially little shytbox crossovers like these, ARE NOT ABOUT SPORTY...despite what some of us want to believe...

And after looking at the competition's numbers, Porsche, Volvo, Alfa Romeo...all 3 have more HP and torque...but... like I said...crossovers, especially little shytbox crossovers like these, ARE NOT ABOUT SPORTY...despite what some of us want to believe...

This is what Car and Driver said:

 

Quote

 

Sure, it's too bad that the honey of an engine, which revs so smoothly you'd swear its cylinder liners were spun silk, must work through a transmission that positively neuters its output with lackadaisical responses. But the competent yet uncommunicative suspension and steering? That's par for this class. The rest of the baby Caddy's package has plenty of good stuff to look forward to.

Fresh Powertrain

The XT4's new engine, for starters, makes a good first impression. Producing 237 horsepower at 5000 rpm and 258 lb-ft of torque from 1500 to 4000 rpm, this turbocharged 2.0-liter inline-four is so smooth and quiet we found ourselves regularly checking the tachometer to see if it was running. And even at full throttle, it is almost disconcertingly quiet and vibration free. Cadillac's estimates of a 7.0-second zero-to-60-mph time with front-wheel drive (and 7.2 for AWD models) are only midpack for this segment, but turbo lag is virtually unnoticeable. The engine—code-named LSY—weighs 15 pounds less than the 2.0-liter four used elsewhere in Cadillac's lineup, 

 

 

 

 

 

Steering and suspension response is uncommunicative...par for the class. Porsche and M-B and BMW and Alfa Romeo is well represented...

Midpack for performance times vis-a-vis the competition, in a segment that doesnt give a phoque about performance...despite Porsche and Alfa Romeo and BMW...in this segment...and  an anemic XT4 is STILL midpack in performance times...BUT...ITS SMOOTH AND QUIET!!!

Something that 4 cylinder GM cars NEVER were...and THIS is a Cadillac, where smoothness and quietness IS A MUST!!!  For the FIRST time in like...forever!

Edited March 22, 2019 by oldshurst442

[dwightlooi]

1 hour ago, oldshurst442 said:

 The 2019 Cadillac XT4 Is More Smooth Than Sporty

The LSY (2.0T) and L3B (2.7T) are from the same (new) family of GM Tri-Power Inline-4 engines. They are a clean sheet designs which boasts a 3-stage cam switching valve train with dual continuous cam phasing. The cam switching system works by having 3 cam lobes for each intake valve on a sliding sleeve. There are four -- one for each cylinder -- on the intake cam. A pair of solenoid actuated pins acting on grooves in the sleeve commands the sleeve to slide back and forth on the camshaft. The switching can only occur when the valves' roller followers are on the base circle (zero lift). On the current implementation the three profiles are -- zero lift (cylinder deactivated), low lift and high lift. On the exhaust cam there are only two sleeves; for the two cylinders that can be deactivated. There are only two positions on the exhaust cam sleeves -- zero lift (deactivated) and regular lift. In addition to switch between cam profiles, the engine also has variable cam phasing (valve timing) which can advance and retard both the intake and exhaust camshafts. There are a total of 6 cam lobe switcher solenoid assemblies atop the valve covers. Unlike previous VVT phasers, the new ones park in the middle rather than one end of the variation range. The engine blocks are webbed for higher rigidity and feature a water cooled integral exhaust collector which terminate in a single divided outlet designed exclusively to support the use of a twin scroll turbo bolted directly to the cylinder heads. There is no exhaust headers. The engines are balanced by two counter rotating Lancester balance shafts in the oil sump. The aluminum block is of the deep skirt design with an integral girdle structure rather than a bolt on main bearing reinforcement. The engines only support direct injection and feature a revised oil separator and collector under the valve cover for the PCV system to minimize intake port fouling. If you know what a PCV oil catch can looks like, look for it on the top of the engine in the 2nd video @ ~ 6:52 on the top right of the frame. The engine also features advanced coolant and oil thermal management for fast warm up and the water pump is electric which decouples water pump speed from engine speed and allows continued full coolant movement even when the engine is shut down protecting the turbo and the engine from oil coking.

 

Edited March 22, 2019 by dwightlooi

[G. David Felt]

AWESOME, Thank you again @dwightlooi, This has been a great evening of working my job and learning some new stuff on new auto's. 

Very cool informative videos!

Question for you, with the complexity of these engines and the various cam phases, what do you think the engine life will be if the basic maintenance is done?

• 250,000 miles
• 350,000 miles
• ??????

Appreciate your take on the engine life of these new designs.

[Drew Dowdell]

The new 2.0T in the XT4 is disappointing when the dealership across the street selling Denali Terrains has a much more powerful and faster 2.0T.

[dwightlooi]

11 hours ago, dfelt said:

AWESOME, Thank you again @dwightlooi, This has been a great evening of working my job and learning some new stuff on new auto's. 

Very cool informative videos!

Question for you, with the complexity of these engines and the various cam phases, what do you think the engine life will be if the basic maintenance is done?

• 250,000 miles
• 350,000 miles
• ??????

Appreciate your take on the engine life of these new designs.

I have no idea. Ask me in 15 years... LOL!

But, certain design decisions potentially increases the failure probabilities. For example, a electric water pump may fail to operate because its motor failed independently of the engine, whereas a traditional water pump will turn if the engine is still turning. Sure, the impeller can break and the engine itself can fail, but that applies to both electric and crank driven pumps. Motor failure is a new failure mode exclusive to an electric water pump. The cam switching system is also NOT a safe-in-fail. If the pin solenoids fail it is possible for the switcher to be stuck between lobes which will be a damaging event. Again, engines have adopted design decisions that are not safe-on-fail before... the most common being interference valve actuation. Should the timing belt of chain break, the piston will smash into the valves and grenade the engine. But that is almost universal today and I haven't heard of chains breaking. Active oil and coolant flow management also presents the possibility of solenoid failure cutting off the engine from the coolant and oil radiators which will be leave you on the side of the road, whereas traditional thermostat failure will simply be a emissions event from the engine not ever reaching the optimum operating temperatures.

[dwightlooi]

42 minutes ago, Drew Dowdell said:

The new 2.0T in the XT4 is disappointing when the dealership across the street selling Denali Terrains has a much more powerful and faster 2.0T.

Not for long... the LTG is not long for this world. BTW, the LTG in the Terrain was also detuned to 252 hp (from 275 hp) and 260 lb-ft (from 295 lb-ft). Again, because the 2018+ Terrain picked up the 9T50 9-speed Automatic.

Edited March 22, 2019 by dwightlooi

[dwightlooi]

Anyway... I suspect that GM will have a high output Tripower Four at some point, just not for the Transverse FWD  cars.

I'll like to see a 2.7T High Output 4-cylinder probably around 450 bhp @ 5,700 rpm, 420 lb-ft @ 2,600~5,600 rpm, rev limited to 6,200 rpm. This will pair quite well with the 10L80 10-speed automatic transmission and it will be a true V8 replacement 4-potter. It'll be more than good enough for a CT4-V. Maybe even an XT4-V if GM will buy Ford's 8-speed Auto.

Edited March 22, 2019 by dwightlooi

[Drew Dowdell]

28 minutes ago, dwightlooi said:

Anyway... I suspect that GM will have a high output Tripower Four at some point, just not for the Transverse FWD  cars.

I'll like to see a 2.7T High Output 4-cylinder probably around 450 bhp @ 5,700 rpm, 420 lb-ft @ 2,600~5,600 rpm, rev limited to 6,200 rpm. This will pair quite well with the 10L80 10-speed automatic transmission and it will be a true V8 replacement 4-potter. It'll be more than good enough for a CT4-V. Maybe even an XT4-V if GM will buy Ford's 8-speed Auto.

Yeah. They haven't released the specs for the CT5 yet.  That is coming with the 10-speed RWD paired with the 2.0T, so hopefully it will be a much higher output version of the same engine. 

[riviera74]

So the really smooth 9AT coupled with a smooth and quiet 2.0T engine in a FWD luxury crossover lacks the performance punch a lot of people here expected.  Good to know.  When my '08 Lucerne was being serviced, I asked a salesman about the new Terrain.  We looked at a loaded SLT and he mentioned how quiet the engine was and the lack of turbo lag and the smooth ride.  What the salesman told me corroborates with what dwightlooi mentioned here.  For the FWD crossovers, the demand is for smooth-running quiet fuel-efficient four-cylinder engines.  This setup matches what is required. This is what most people want in their powertrain.

Now as for the CT5 and any RWD sedans that get the 2.0T or the 2.7T, I do not see the current 9AT installed in such a performance car since there would be too little torque available for those engines.

[Guest]

However the Buick envision now had 295lb torque from the 2.0 and its 9 speed.  So which 9 speed is it using or is it not a GM transmission. 

• 9T50   -- 258 lb-ft
• 9T65   -- 280 lb-ft

By the way I have a Terrain Denali and the 2.0 is plenty of powerful for it.  Everyone that has drove it thinks it has a v6.  These don't need super powerful engines

[dwightlooi]

47 minutes ago, Guest said:

However the Buick envision now had 295lb torque from the 2.0 and its 9 speed.  So which 9 speed is it using or is it not a GM transmission. 

• 9T50   -- 258 lb-ft
• 9T65   -- 280 lb-ft

By the way I have a Terrain Denali and the 2.0 is plenty of powerful for it.  Everyone that has drove it thinks it has a v6.  These don't need super powerful engines

If it's the 9A it's probably the 9T65. It can work if they limit boost in 1st gear to moderate the input torque when the greatest amplification happens. 280 is not that far from 295. The Focus ST did that in 1st (back then) too. You can't responsibly drop in the 348 lb-ft 2.7T or th 368 lb-ft 3.6TT engines on the 9T65 like you could the 6T80 though.

57 minutes ago, riviera74 said:

So the really smooth 9AT coupled with a smooth and quiet 2.0T engine in a FWD luxury crossover lacks the performance punch a lot of people here expected.  Good to know.  When my '08 Lucerne was being serviced, I asked a salesman about the new Terrain.  We looked at a loaded SLT and he mentioned how quiet the engine was and the lack of turbo lag and the smooth ride.  What the salesman told me corroborates with what dwightlooi mentioned here.  For the FWD crossovers, the demand is for smooth-running quiet fuel-efficient four-cylinder engines.  This setup matches what is required. This is what most people want in their powertrain.

Now as for the CT5 and any RWD sedans that get the 2.0T or the 2.7T, I do not see the current 9AT installed in such a performance car since there would be too little torque available for those engines.

GM doesn't have a longitudinal 9A. They have the 8L45, 8L90, 10L80 and 10L90 with 8 or 10 speeds.

[smk4565]

Great info and research on that.  The science explains their thinking.

[smk4565]

10 hours ago, Drew Dowdell said:

The new 2.0T in the XT4 is disappointing when the dealership across the street selling Denali Terrains has a much more powerful and faster 2.0T.

Seems like a typical GM move, and why Cadillac is where they are. 

I don't see why they don't make a better FWD transmission that can handle over 300 lb/ft with 8-9 gears or whatever they deem they need.

[oldshurst442]

31 minutes ago, smk4565 said:

Seems like a typical GM move, and why Cadillac is where they are. 

I don't see why they don't make a better FWD transmission that can handle over 300 lb/ft with 8-9 gears or whatever they deem they need.

No need for speed in this segment.  Its just a cute ute CUV. 

Define better transmission?

Because as I understand it, this 9 speed is smooth and makes this 4 cylinder rev even smoother. 

I know Drew mentioned that the Denali Terrain has got more power, but as much clout as a Denali has got,  its still not a Cadillac. And Im willing to bet that the Denali aint as smooth as the XT4 is said to be...

If you are gonna blast Cadillac for something, blast Cadillac for even being in this segment to begin with...

While I did say a couple of weeks ago if they are to do a vehicle this small, then they should go all in, but I also said that I wouldnt want any Cadillac to be in a 40 000 dollar price range. I would want Cadillac to START in the 55 000 dollar range. And therefore a XT4 better be a V trimmed CUV...

But as is...we all could moan about the XT4 not being a tire melting Hellcat beating motor vehicle, to my understanding, the XT4 is one smooth and quiet ride. And THAT would and should  be the main focus here. And I think it was wise for Cadillac to choose smooth and quiet over unnecessary torque figures and risking having a ride that some Euro loving badge snob complain about how harsh the engine or ride is! 

Its a Cadillac after all. No...not a V Series Cadillac. Just a luxury ride Caddy! 

Edited March 23, 2019 by oldshurst442

[smk4565]

Cadillac issues aside, GM probably doesn’t have any transverse mounted engine with over 300lb-ft other than the soon to be dead XTS V-sport.  So if they made one 9-speed transverse mount transmission it could be used in everything from a Sonic to a Traverse .  Better economies of scale that way.

Then in rear drive maybe you have a couple torque ratings for a regular duty and the high torque outputs.

[regfootball]

The older GM 2.0 is a good motor, and so is the new one.  But the new one is new, which means unproven, and it is slower.

It's fast enough in the XT4 for volume models.  They will want to look at getting a higher tune of that motor as an option.  It is smooth once up to speed, and sporty but it is not blazing quick.  It's like a 7-7.5 second to 60 car.  I am certain it will cruise well on the highway.

The CT6 base 2.0 through 2018 had the old 2.0.  When they swapped in the new one for 2019, it lost a second of 0-60 time...i.e. slower.

I thought the CT5 just announced was getting the older 2.0?  I don't think the new one is slated for the CT5, yet.

The 2020 Acadia gets the new 2.0 as an option.

I really am jazzing on a Regal, and probably a TourX.  The AWD tourX is slower by a bit with the 8 speed instead of the FWD 9 speed sportbacks but maybe that's a good thing.  Sounds like the 8 speed tranny might handle power and torque better.  Having the older proven 2.0 may be a good thing.

 

 

Edited March 23, 2019 by regfootball

[dwightlooi]

6 hours ago, smk4565 said:

Cadillac issues aside, GM probably doesn’t have any transverse mounted engine with over 300lb-ft other than the soon to be dead XTS V-sport.  So if they made one 9-speed transverse mount transmission it could be used in everything from a Sonic to a Traverse .  Better economies of scale that way.

Then in rear drive maybe you have a couple torque ratings for a regular duty and the high torque outputs.

Not exactly... Unlike the difference between transverse and longitudinal transmissions -- which are totally different animals -- there is no substantial difference between a lengthwise or sideways engine installation. We are talking about a different exhaust pipe, new air box and new dress cover. The last being largely cosmetic (so the lettering don't don't face the wrong way). 99% of the engine is identical. The differences are minute enough that GM doesn't even have separate RPO codes for transverse and longitudinal versions of the same engine. The FWD and RWD 3.6TT are both the LF3. The FWD and RWD 3.6 NA are both the LGX or LFX. The FWD and RWD "old" 2.0Ts are both LTG.

[loki]

I always liked your analysis of things changing and technical options @dwightlooi.

[KevinW]

16 hours ago, regfootball said:

The CT6 base 2.0 through 2018 had the old 2.0.  When they swapped in the new one for 2019, it lost a second of 0-60 time...i.e. slower.

The EPA ratings went from 22/25/30 to 24/28/34 MPG (US) with the new 2.0 and 10-speed automatic, which is more useful in the real world (along with improved NVH characteristics) than ~6 vs ~7 seconds 0-60 MPH.
 

[regfootball]

The mpg improvements particularly for a big car are impressive however losing that much acceleration for a luxury brand is concerning.  

 

[Drew Dowdell]

2 minutes ago, regfootball said:

The mpg improvements particularly for a big car are impressive however losing that much acceleration for a luxury brand is concerning.  

 

Not when there are 4 additional engine choices above that. 3.6, 3.0TT, 4.2TT, 4.2TT-V

7 seconds to 60 is fine for most people anyway. Someone buying a base base base CT6 isn't going to be concerned with 0-60, they're going to be concerned with heated seats. 

[regfootball]

https://www.motortrend.com/cars/cadillac/ct6/2019/2019-cadillac-ct6-20-first-test-review/

 

“At the track, the 2019 CT6 sprinted to 60 mph in 7.5 seconds and finished the quarter mile in 15.7 seconds at 89.2 mph. That's 1.1 seconds slower than a 2017 model we tested to 60 mph and a second slower in the quarter mile. The culprit is GM's new 2.0-liter turbo I-4, which is down 28 hp and 37 lb-ft of torque versus the outgoing unit. Power delivery is smooth, and turbo lag is minimal; however, the new engine is barely adequate for a 3,930-pound car like the CT6. The 10-speed automatic is also poorly calibrated; in typical GM fashion, it shifts quickly but immediately goes to the highest gear, preventing you from taking advantage of the engine's midrange torque. Road test editor Chris Walton noted that the engine likes to short shift well below the engine's 7,000-rpm redline and sounds labored when pushed hard. There is a fuel economy payoff, though; our friends at EQUA Real MPG achieved 23.5/38.5 mpg city/highway during their tests. That's a smidge lower in the city but significantly higher on the highway versus the EPA's official 24/34 mpg rating.”

 

translation: this is not an improvement for anything besides fuel economy reasons. 

Since the 10 speed is used here then they should retune the engine for lots more power. The premise of this thread was the tranny was limiting the output of the new motor. But that is not the case here. 

The 2.7 would be a good candidate for the CT6 actually. 

Edited March 23, 2019 by regfootball

[smk4565]

Detuning the 4 cylinder for fuel economy, in a luxury car that is $60k doesn't make any sense.  Maybe it would make sense if there was some great NVH improvement, but 7.5 seconds is slow.  Granted the old folks in Florida taking it to Cracker Barrel won't care, and there is a more powerful engine for people that do care.  It just seems like more bizarre GM decision making, that isn't based on customer demand, but rather supplier issues, manufacturing costs, parts bin inventory, bean counters, etc.

Edited March 23, 2019 by smk4565

[regfootball]

10 minutes ago, smk4565 said:

Detuning the 4 cylinder for fuel economy, in a luxury car that is $60k doesn't make any sense.  Maybe it would make sense if there was some great NVH improvement, but 7.5 seconds is slow.  Granted the old folks in Florida taking it to Cracker Barrel won't care, and there is a more powerful engine for people that do care.  It just seems like more bizarre GM decision making, that isn't based on customer demand, but rather supplier issues, manufacturing costs, parts bin inventory, bean counters, etc.

They probably wanted to globalize moving to one four pop engine choice for the ct6. Particularly if they end up importing the car from China. If caddy killed the ct6 they’d want to sell the ct6 in China with the new motor  

Side benefit to the new motor. No recommendation to use premium fuel.  Should run fine on typical garbage gas available anywhere in the USA. 

 

Another point. It’s not just the 0-60 that suffered.  The quarter mile time is off by a second also. That doesn’t suggest the car is improved in highway cruising either compared to the older power train.  I would like to see the roll on acceleration number comparison but it bet those suffer as well. Again a backwards decision in a luxury car brand regardless of model or trim positioning. 

And at the end of the day any car like the CT6 if they want it to be a viable seller in all 50 states the car should have AWD available 

Edited March 23, 2019 by regfootball

[oldshurst442]

19 minutes ago, smk4565 said:

Detuning the 4 cylinder for fuel economy, in a luxury car that is $60k doesn't make any sense.  Maybe it would make sense if there was some great NVH improvement, but 7.5 seconds is slow.  Granted the old folks in Florida taking it to Cracker Barrel won't care, and there is a more powerful engine for people that do care.  It just seems like more bizarre GM decision making, that isn't based on customer demand, but rather supplier issues, manufacturing costs, parts bin inventory, bean counters, etc.

This one...Ill agree to.

 

[Drew Dowdell]

Guys, the 2.0t hardly sold here anyway. The base engine is effectively the 3.6.  This is a Chinese market move for a chauffeur driven car.

[smk4565]

1 hour ago, Drew Dowdell said:

Guys, the 2.0t hardly sold here anyway. The base engine is effectively the 3.6.  This is a Chinese market move for a chauffeur driven car.

They should drop the 3.6 also.

I imagine this 237 hp unit will be the volume engine of the CT5.

[dwightlooi]

6 hours ago, regfootball said:

“At the track, the 2019 CT6 sprinted to 60 mph in 7.5 seconds and finished the quarter mile in 15.7 seconds at 89.2 mph. That's 1.1 seconds slower than a 2017 model we tested to 60 mph and a second slower in the quarter mile. The culprit is GM's new 2.0-liter turbo I-4, which is down 28 hp and 37 lb-ft of torque versus the outgoing unit. Power delivery is smooth, and turbo lag is minimal; however, the new engine is barely adequate for a 3,930-pound car like the CT6. The 10-speed automatic is also poorly calibrated; in typical GM fashion, it shifts quickly but immediately goes to the highest gear, preventing you from taking advantage of the engine's midrange torque. Road test editor Chris Walton noted that the engine likes to short shift well below the engine's 7,000-rpm redline and sounds labored when pushed hard. There is a fuel economy payoff, though; our friends at EQUA Real MPG achieved 23.5/38.5 mpg city/highway during their tests. That's a smidge lower in the city but significantly higher on the highway versus the EPA's official 24/34 mpg rating."

It sounds labored because it is 237 bhp trying to lug 4,000 lbs around.

It short shifts because it is smart! The new 2.0T (LSY) engine hits its torque peak of 258 lb-ft at 1,500 rpm. It hits its 237 hp power peak at 5,000 rpm and spend every bit of the last 2000 rpm running out of breathe.  By 6000 rpm it is making less than 200 lb-ft. By 7000 rpm it is making closer to 150 lb-ft. You really don't want to rev that thing.

The LSY is very quiet, refined and responsive from 1000 rpm through about 5000 rpm where it does its best work. In many ways it feels like the old Supercharged 3800 which -- despite popular slander -- is actually a very refined engine when not hustled. Most of the fuel economy gains come from shutting off the two middle cylinders in cruise and from the low lift economy cams also having a long intake duration which can then be phased to eat into the compression stroke and reduce the effective displacement as well has create an asymmetrically long power stroke. It's a part time "mild Atkinson" cam if you will.

Edited March 24, 2019 by dwightlooi

[riviera74]

10 hours ago, smk4565 said:

They should drop the 3.6 also.

I imagine this 237 hp unit will be the volume engine of the CT5.

No. They should replace the 3.6 with the TT3.0 V6.  The 2.0T will probably be the base engine.

[loki]

13 hours ago, dwightlooi said:

It sounds labored because it is 237 bhp trying to lug 4,000 lbs around.

It short shifts because it is smart! The new 2.0T (LSY) engine hits its torque peak of 258 lb-ft at 1,500 rpm. It hits its 237 hp power peak at 5,000 rpm and spend every bit of the last 2000 rpm running out of breathe.  By 6000 rpm it is making less than 200 lb-ft. By 7000 rpm it is making closer to 150 lb-ft. You really don't want to rev that thing.

The LSY is very quiet, refined and responsive from 1000 rpm through about 5000 rpm where it does its best work. In many ways it feels like the old Supercharged 3800 which -- despite popular slander -- is actually a very refined engine when not hustled. Most of the fuel economy gains come from shutting off the two middle cylinders in cruise and from the low lift economy cams also having a long intake duration which can then be phased to eat into the compression stroke and reduce the effective displacement as well has create an asymmetrically long power stroke. It's a part time "mild Atkinson" cam if you will.

sounds like a very similar setup to how mazda tuned the 2.5LT. Give it lots of grunt way down where most people drive anyway...even at the expense of high end(5K+) power

from https://www.caranddriver.com/reviews/a25693266/2019-mazda-cx-5-turbo-by-the-numbers/

" The turbocharged CX-5's appeal isn't really about scorching performance, although the 250-hp engine does send it to 60 mph in 6.2 seconds, nearly two seconds quicker than the base engine. But this engine is more effortless than exciting and is almost diesel-like in the way it doesn't like to rev. To maximize acceleration, the transmission upshifts at 5300 rpm—1000 revs short of redline—because the 2.5T's output tapers off so dramatically at high rpm. "

if you want ease of driving, tune the engine this way. if you want highend power, you want it tuned differently...adding noticable turbo lag when not driven hard... or it'll be NA or super-charged...which it seems supercharged engines are only for the larger v-8s now...

[smk4565]

7 hours ago, riviera74 said:

No. They should replace the 3.6 with the TT3.0 V6.  The 2.0T will probably be the base engine.

I was thinking 3 liter turbo as the base in CT6.  Turbo 4 base in CT5, and turbo 6 optional.  

[regfootball]

I thought the Mazda CX-9 turbo mill was a dud. Mazda always gets way too much praise for their average stuff. GM’s turbo fours are actually just fine and better in comparison. 

[Drew Dowdell]

On 3/24/2019 at 7:19 PM, regfootball said:

I thought the Mazda CX-9 turbo mill was a dud. Mazda always gets way too much praise for their average stuff. GM’s turbo fours are actually just fine and better in comparison. 

It's not a dud... it's just not enough engine for that vehicle.  Even when suckling on premium.

[regfootball]

Bad turbo lag when I drove it

[dwightlooi]

2 hours ago, regfootball said:

Bad turbo lag when I drove it

It's not bad really. Not stellar, but not bad. And, you don't have to put Premium Gas in it -- as long as you don't mind losing 23 hp (227 vs 250).

[G. David Felt]

9 hours ago, dwightlooi said:

It's not bad really. Not stellar, but not bad. And, you don't have to put Premium Gas in it -- as long as you don't mind losing 23 hp (227 vs 250).

Yea, I do not mind the loss in HP, but the Torque I thought was not that great.

[dwightlooi]

32 minutes ago, dfelt said:

Yea, I do not mind the loss in HP, but the Torque I thought was not that great.

The 2.5T makes 310 lb-ft @ 2,000 rpm. Not exactly GM's 348 lb-ft @ 1,500 rpm from the double volute L3B (2.7T) but not bad. Also, the fact is that a 2.5L mill making 100hp/L (or less with 87 Octane) and 124 lb-ft/L is not exactly highly stressed. And, I am surprised that anyone thinks the lag is excessive when it is one of the least laggy turbocharged engines in production.

The SkyActiv's 10.5:1 compression is about as high as you are going to get with a turbocharged engine. The turbo is technically very interesting although the results are somewhat inferior to GM's simper approach... Mazda has a flap in the manifold between the turbine and the exhaust ports. At below 1600 rpm, the flap close and forces the exhaust through a narrower passage. This increases exhaust velocity and helps spool the turbo quicker off idle. At higher engine speeds, the flap opens and allows the normal flow to the turbo. 310lb-ft @ 2,000 rpm, with possibly the best 800~1600 rpm spool characteristics, is more than you can expect from a 3.0~3.8L V6 and no slouch. High compression and excellent low speed spooling is great for cruise economy.

I think the problem comes down to simple physics. 227~250 hp is not much to move around 4,300 lbs of stuff. The not too quick Acura MDX for example is "only" lugging 4,050 lbs with a 290 hp V6 engine. In the end, horsepower matters. Horsepower allows you to gear the transmission to solve a lot of problems. I don't see the CX-9 has "laggy". It is not. It is simply underpowered. It's power to weight ratio is similar to that of a 2.5L 4-cylinder, NA, Camry. And, hence, it performs like one.

[dwightlooi]

Having said the above... the claim by the illustrator that this has a similar effect to a twin scroll turbo is RUBBISH.

A twin scroll turbo has nothing to do with accelerating exhaust flow or turbo spool up. It has everything to do with not contaminating the intake with exhaust back flow during the exhaust and intake valves' overlap period. At bottom dead center of the power stroke, the exhaust valves open sending high pressure exhaust pulse into the exhaust. At this same moment, the exhaust valves of the cylinder at top dead center of the exhaust stroke is still open while the intake valves are opening. This allows the exhaust gases to enter both the turbo and the cylinder at the beginning of the intake stroke. This is an INTAKE BREATHING problem.

By keeping the exhaust paths of cylinders 1-4 separate from that of 2-3 the exhaust pulses cannot contaminate and interfere with the intake aspiration. That's the purpose of a twin-scroll turbo. Having two scrolls in parallel actually reduces the turbo's flow capacity and increases wall drag. The GM Double Volute design solves that and allow for exhaust segregation without flow restriction. The reward is 348 lb-ft from 2.7L at 1,500 rpms.

Edited March 26, 2019 by dwightlooi

[G. David Felt]

Interesting read on GM's 9 speed and the clicking sound they make.

https://gm-techlink.com/?p=11283

Weird, but I see no reason in this day and age for a transmission to make a clicking sound.

[Drew Dowdell]

1 hour ago, dfelt said:

Interesting read on GM's 9 speed and the clicking sound they make.

https://gm-techlink.com/?p=11283

Weird, but I see no reason in this day and age for a transmission to make a clicking sound.

It's normal operation and it is only for a few moments after the engine is shut off.  Nothing to see here. 

[Guest]

Yes I hear that noise in My 2019 Terrain. I first I was concerned but I figure it out what is was after a while.  You can only really hear it when the car is in a garage and there is no noise.  It last maybe 15-30 seconds.  If you in parking lot its very hard to even notice it.

[G. David Felt]

28 minutes ago, Drew Dowdell said:

It's normal operation and it is only for a few moments after the engine is shut off.  Nothing to see here. 

I understand the point you making, but the engineer in me says attention to detail that there should never have been a noise to begin with.

I understand there is no problem here other than a noise that will bother some, be ignored by many others.

[dwightlooi]

If you define "problem" as "indicative of mechanical failure or impending failure" it is not a problem.

If you define "problem" as "lack of refinement or not confidence inspiring" it is a huge problem that damages the value of your brand!

The LF3 (3.6TT) engine makes a rattling noise that sounds like a lose exhaust heat shield for about 5 secs when you start it. That's from the vacuum actuated turbo waste gates rattling before the engine build up enough vacuum to pull them open. The engine also makes a buzzing sound from the electric circulation pump after you shut it off for about 10 seconds. These are both normal and noted characteristics of the engine. But in a CTS VSport Premium that sells for $73K new, that is decidedly unrefined and I would have fired the engineer who allowed this kind of nonsense on the engine (were I in charge at the General).

Edited March 29, 2019 by dwightlooi

[G. David Felt]

4 hours ago, dwightlooi said:

If you define "problem" as "indicative of mechanical failure or impending failure" it is not a problem.

If you define "problem" as "lack of refinement or not confidence inspiring" it is a huge problem that damages the value of your brand!

The LF3 (3.6TT) engine makes a rattling noise that sounds like a lose exhaust heat shield for about 5 secs when you start it. That's from the vacuum actuated turbo waste gates rattling before the engine build up enough vacuum to pull them open. The engine also makes a buzzing sound from the electric circulation pump after you shut it off for about 10 seconds. These are both normal and noted characteristics of the engine. But in a CTS VSport Premium that sells for $73K new, that is decidedly unrefined and I would have fired the engineer who allowed this kind of nonsense on the engine (were I in charge at the General).

Thank you Dwight, Yes in this case lack of refinement or not confidence inspiring is what I think of here. To me, be it a 30K Chevy or 73K Cadillac, this is not inspiring when put up against the competition. This is incompetence of the engineer who allowed this and the bean counter who figured people could just live with it.

No need ever for these noises, especially on more expensive auto's. The noise one hears of the direct injectors is another of my pet peeves. This should not be on a luxury auto that is heard either inside or outside the auto.

[dwightlooi]

2 hours ago, dfelt said:

Thank you Dwight, Yes in this case lack of refinement or not confidence inspiring is what I think of here. To me, be it a 30K Chevy or 73K Cadillac, this is not inspiring when put up against the competition. This is incompetence of the engineer who allowed this and the bean counter who figured people could just live with it.

No need ever for these noises, especially on more expensive auto's. The noise one hears of the direct injectors is another of my pet peeves. This should not be on a luxury auto that is heard either inside or outside the auto.

Direct Injection resulted in the GREATEST LOSS OF ENGINE REFINEMENT in the last 50 years. A 1980s VW SOHC 8 valve engine is more refined at idle thann a direct injected BMW V12 of today. There is no getting around the fact that opening and shutting off a pintle with 1000+ psi of fluid pressure makes your engine clatter like a diesel. Manufacturers put acoustic insulation on their DI heads and use fuel rail accumulators to dampen the sound, but it'll never be quiet like port injectors working with tens of psi not thousands.

The ONLY SOLUTION is what Toyota does on the Lexus engines. Use port injection at idle and low engine speeds. Switch on the direct injectors at higher RPMs and throttle openings. This also has the side effect of having fuel spray on the intake valves and keeping them clean of carbon deposits from the valve overlap and the PCV system. Only Lexus spends the money on having two fuel systems and two injectors per cylinder. That is why they are the king of refinement.

Edited March 29, 2019 by dwightlooi

[Drew Dowdell]

@dwightlooi I think Ford is doing that too on at least one engine line.