Motortrend MKS Review

[Xenon]

Originally Posted by syr74

Attempts at clever comments work better when you aren't wrong. There is going to be nothing at all uncommon about GTDi engines knocking down superior fuel economy compared to their n/a cousins under the right conditions. Example?

The Pontiac Solstice gets 19/24 city/hwy with the naturally aspirated four under the hood but manages to knock down 19/26 city/hwy with the turbocharged version under the hood. A miracle you say? Nope, just superior efficiency.

The same 2.4 also gets 32 mpg in the Cobalt...and displacement in the turbocharged version is also knocked down by almost half a liter. That's where the fuel efficiency is coming from, and for every example that you can come up with, I can easily come up with several that shows decreases in fuel economy.
Cobalt 2.4: 22/32
Cobalt SS(Turbo): 22/30
HHR(2.2L):21/30
HHR SS (Turbo): 21/29
Subaru Impreza: 20/27
Subaru WRX (Turbo): 20/25
VW Rabbit: 21/29
VW GTI (Turbo): 21/29

One thing to note however is that the GTI DID post increases in fuel economy vs the Rabbit before the new EPA fuel economy standards kicked in, but again you are also comparing a 4 cylinder to a 5 cylinder with half a liter higher displacement. So no, unless the engine is downsized significantly form the non turbocharged version, it WONT gain better fuel economy.

[syr74]

Originally Posted by Xenon

The same 2.4 also gets 32 mpg in the Cobalt...and displacement in the turbocharged version is also knocked down by almost half a liter. That's where the fuel efficiency is coming from, and for every example that you can come up with, I can easily come up with several that shows decreases in fuel economy.
Cobalt 2.4: 22/32
Cobalt SS(Turbo): 22/30
HHR(2.2L):21/30
HHR SS (Turbo): 21/29
Subaru Impreza: 20/27
Subaru WRX (Turbo): 20/25
VW Rabbit: 21/29
VW GTI (Turbo): 21/29

One thing to note however is that the GTI DID post increases in fuel economy vs the Rabbit before the new EPA fuel economy standards kicked in, but again you are also comparing a 4 cylinder to a 5 cylinder with half a liter higher displacement. So no, unless the engine is downsized significantly form the non turbocharged version, it WONT gain better fuel economy.

Your getting closer, but you are still missing more than a few of the finer points.

GTDi V6 MKS advantages over the naturally aspirated version include......

1: VVT (the 3.7L doesn't have VVT at all)

2: Direct Injection

3: .2 smaller displacement due to a smaller bore

4. Much flatter torque curve with a very low peak torque rating.

Where you are missing the point is that this isn't supposed to be like most other turbo engines, making virtually all of the turbo mills you reference above pointless. What we have in Ecoboost is a combination of light pressure turbocharging, VVT, direct injection, and revised engine management to bring light pressure turbo engines into their own offering great power and good fuel economy. At the moment the only other company that I am aware of with GTDi engine technology this advanced/refined is BMW.

To be fair these newest gen GTDi engines can often be expected to lose a little fuel efficiency compared to their naturally aspirated cousins all else being equal. BMW's 3 Series is the perfect example, the GTDi 335i knocks down 17/16 city/hwy compared to the 328i's 18/28 city/hwy from the naturally aspirated version of the same engine.

However, it's worth noting that the naturally aspirated version of the BMW I6 has Vanos and that it is also the same displacement as the GTDi version. As we saw above the MKS doesn't use VVT in the base n/a version and the GTDi V6 will be based upon the small bore block yielding .2L less displacement. Even more, the BMW isn't a particularly heavy car and isn't under-powered in base trim so the increase in low and mid range torque, while nice, doesn't garner the Bimmer much in fuel efficiency. Even so, we only see a loss in efficiency of 1mpg city and 2mpg highway. On the other hand, the MKS is a heavy car that is under-powered in base trim meaning the huge increase in low and mid range torque should lend themselves to an improvement in efficiency,particularly on the highway.

As I said earlier even these newest GTDi engines can often be expected to lose a bit of fuel efficiency compared to their n/a cousins all else being equal. The difference is that, in the case of the MKS, all else isn't equal...and the MKS wont be the last Ford product where you will see this kind of situation. In light of the above there is virtually no question the MKS with Ecoboost will at least equal the 3.7L n/a version and will more likely knock down superior fuel economy compared to that engine.

[Xenon]

1: VVT (the 3.7L doesn't have VVT at all)
2: Direct Injection
3: smaller displacement due to a smaller bore
4. Much flatter torque curve with a very low peak torque rating.

Notably, all of the turbocharged engines I listed up there have ALL of these traits, save for the Subaru. VW/Audi has been barking up this tree for a while with the 2.0T, and both versions of the ECOTEC sport VVT. But at this point I think its best to wait until the FE numbers come out , and let that speak for itself.

[Johnny P]

Originally Posted by syr74

1: VVT (the 3.7L doesn't have VVT at all)

According to MT it does:

Performance & Efficiency: 3,726 cc 3.7 liters V 6 front engine with 95.5 mm bore, 86.7 mm stroke, 10.3 compression ratio, double overhead cam, variable valve timing/camshaft and four valves per cylinder 99R. Premium unleaded fuel 91.

[Johnny P]

Originally Posted by syr74

4. Much flatter torque curve with a very low peak torque rating.

Does it make more torque at light throttle? Specifically any time out of boost? Because you can bet that any time air is being force into the intake the fuel economy will plummet.

[wescoent]

Originally Posted by Johnny P

According to MT it does:

Performance & Efficiency: 3,726 cc 3.7 liters V 6 front engine with 95.5 mm bore, 86.7 mm stroke, 10.3 compression ratio, double overhead cam, variable valve timing/camshaft and four valves per cylinder 99R. Premium unleaded fuel 91.

Motor Trend is incorrect. The 3.7L in current form has no VVT to speak of.

[Johnny P]

Originally Posted by wescoent

Motor Trend is incorrect. The 3.7L in current form has no VVT to speak of.

Thanks. I guess it's just another example of outstanding journalism.

[syr74]

Originally Posted by Xenon

1: VVT (the 3.7L doesn't have VVT at all)
2: Direct Injection
3: smaller displacement due to a smaller bore
4. Much flatter torque curve with a very low peak torque rating.

Notably, all of the turbocharged engines I listed up there have ALL of these traits, save for the Subaru. VW/Audi has been barking up this tree for a while with the 2.0T, and both versions of the ECOTEC sport VVT. But at this point I think its best to wait until the FE numbers come out , and let that speak for itself.

You're still making this more complicated than it really is. For example, I never said that the engines you referenced didn't have VVT or even DI and even implied that other companies have GTDi engines in this statement......

At the moment the only other company that I am aware of with GTDi engine technology this advanced/refined is BMW

.....my point being that, with the exception of BMW, nobody else is on the same level of refinement/advancement Ford is currently at. That said that the engines you reference aren't applicable because, to be blunt, even in the instances where they were trying to do what Ford and BMW are actually doing now they largely failed at it.

My whole point was and remains that Ford, and BMW, have figured out how to apply and refine existing tech to achieve superior power and fuel economy in a way other companies apparently haven't. (GM's 2.0L Ecotec arguably is on the right path but isn't even close to the power and economy were going to see from turbo fours from BMW and Ford in the next couple of years) Your argument implies that there is nothing new here since the fundamentals have all been employed before, but that does just doesn't hold water.

That argument is somewhat akin to arguing that since the old Windsor 5.0L employed EFI, pushrods, and 2-valves per cylinder it must be capable of the same kind of power and fuel economy that the LS1 is since all the basics are pretty much the same. Of course that isn't reality and the truth of the matter is that the fundamentals don't have to change much for the engine to behave in a completely different manner. GM simply built a better pushrod and they did it using tech and knowledge that was almost all a known quantity prior to the LS series of V8's.

Again, as for other companies trying to manage the same thing, we've known this for years. Audi has gone DI and turbo crazy and so has Ford's own Mazda. Volvo is another of the low pressure devotees but the reality is that most of these engines have been disappointments as an overall package to some degree failing either to deliver the power needed or the fuel economy desired. Ford even rejected the existing Mazda GTDi units, effectively snubbing their own engines, despite the fact that they perform admirably compared to other GTDi engines currently on the market. Why? Because they felt the engines underperformed overall and weren't focused on the same end Ford is trying to achieve. If that isn't enough to tell you that Ford's upcoming crop of GTDi engines isn't status quo stuff I don't know what would.

Although, I am curious to here what you're going to attribute the GTDi 3.5L's economy to when the official numbers do come in and fuel economy either stays the same or improves slightly.

Originally Posted by JohnnyP

Does it make more torque at light throttle? Specifically any time out of boost? Because you can bet that any time air is being force into the intake the fuel economy will plummet.

I just told Xenon that he is over-complicating the issue discussed above and now in a reversal I have to tell you that you are drastically oversimplifying this issue. I've heard this argument more than a fe times, but the problem is that there is a lot more to the equation than simply how much air is going into the engine. You have to address when that air is going into the engine, how that air is getting there, and what the engine can do with it when it does.

The real question you need to be asking is 'how efficient is each engine at making X hp' since that is what is really going to tell you how these engines will perform is comparable driving situations. And the reality is that the n/a 3.7L isn't even going to be close to the efficiency of the GTDi 3.5L.

[wescoent]

Did I mention the 325hp GDI 3.7L V6 in development?

[syr74]

Originally Posted by wescoent

Did I mention the 325hp GDI 3.7L V6 in development?

I'm familiar with it. Frankly I'm kinda surprised they are going ahead with it. A smaller displacement GTDi V6, say 3.0-3.2 liters, would deliver comparable hp and far superior torque while almost certainly turning in better gas mileage. One big difference between Ford and BMW's GTDi plan seems to be that Ford is playing both sides of the fence planning for GTDi and n/a versions of DI engines while BMW appears likely not to even have a n/a engine in their lineup within the next decade.

[ChevroletRevived]

Originally Posted by Bravada

www.hertz.com

Sorry, couldn't help

Oh yeah, I know Hertz is in the business of preordering now; and decked out top of the line models too.

[ausrutherford]

Originally Posted by ChevroletRevived

Oh yeah, I know Hertz is in the business of preordering now; and decked out top of the line models too.

I dont know about that.All I know is that Avis has been advertising them having CTSs..hmmm. lol. Sorry GM fans.