Itravelalot

From the very few numbers I have seen, the power difference is minimal at best. As for fuel economy, there are a lot of very thirsty 4 cylinder turbo cars. A 4 cylinder turbo is not always more efficient than 6 or even some 8 cylinder engines. Reliability and cost of repair in turbocharged engines just cannot beat N/A. Ford showed numerous videos of the very extensive testing they used to overcome many of the drawbacks that come with turbos, and even then I am not sure it will hold up as well long term. Without any very specific info that shows that their turbo system will really hold up to as much abuse as a N/A V6 can take, I just will not trust a car with a turbo as a daily driver.

There are some very good reasons why turbos are not all that popular in the states. It puts the burden of proof on Chevy to show that theirs is the exception.

cdynaco

I've never driven or owned one, but isn't the only issue with a turbo the heat on the turbo bearings? And haven't they improved bearings and cooling to counter that?
Other than that, it's still a 4. And there are plenty of 4 bangers with great longevity.
Chrysler got a lot of miles & years out of their turbo 2.4L in the Neon & Cruisers.

bob

Heat coking the oil in the bearings was an issue for the most part but with water-cooled housings and better oil, the situation has improved greatly and as a factory setup, GM might even have had the foresight to let the engine idle for a bit after the key is turned to the off position allowing the oil to circulate and preventing it from sitting in a hot turbo.

Itravelalot

I have owned one, and will not do so again anytime soon. If a company wants to claim theirs will be as reliable, then they had better do a lot to prove it.

bob

Alot of what makes a super-charged or turbocharged engine thirsty was a requirement for the fuel to act as a coolant. Historically forced induction engines have had to run fat A/F ratios to prevent detonation and the problems associated with it, however the 2.0T engine GM seems to be using which IIRC is called the LF is the same engine used in the Cobalt SS and its equipped with DI and piston squirters both allowing a higher compression and leaner A/F ratios and in combination with VVT will produce fuel economy numbers (hell this engine at atmospheric pressure probably makes more power an torque than its turbocharged predecessors did on boost). I dont know what strategy GM will use but the only drawback to using a turbocharged engine is the pumping losses associated with turning the compressor.

Off-topic, but I wonder how hard it would be to design an internal bypass in the turbo? Just imagine bypassing the turbo at cruise and using the VVT to minimize pumping losses just like current engines like the coyote and 4.6 3v do? Maybe Ford already does this with it current FI engines?????

Most NA engines are fairly low stress compared to super or turbo-charged engines but forced induction engines still have to meet the same durability requirements that NA engines when it comes to emissions (100k+).

Won't argue there, only time will tell