Saw this first drive review of the Verano. Sounds like they did a great job, be interesting to see how it sells.

http://www.autoblog.com/2011/10/25/2...-drive-review/

The summary paragraph:

 

Looks like a pretty solid value, but I'm REALLY scratching my head over the 21/31 rating. This Verano is smaller and lighter than my Aura, right? It has the same 6-speed auto as my Aura, right? It has the same 2.4 liter 4-cyl, except it has the added benefit of direct injection (which supposedly on average increases fuel economy by ~7-8%), and it's a newer design... and yet it's rated 21/31 and my Aura is rated 22/33?

 

Good questions. Quick google search shows that the Verano should be ~400 lbs lighter than the Aura. You'd think the drivetrain friction would be similar if they have the same transmission, and drivetrain layout. Perhaps aerodynamic drag could be different. I wonder if the verano has softer, more 'comfy' tires that hurt rolling resistance in comparison with the Aura. Perhaps it comes down to engine calibration difference (though, like you said, you'd think with direct injection they'd be able to get better results, not worse).

 

Looks sharp for sure. However, how much smaller is it than the Regal? I don't know if Buick should have such a low entry point. It may cheapen the brand. I hope sales are good though.

 

Was your Aura rated before that SAE ratings change thing a few years back?

Perhaps that accounts for some or all of it?

Also, perhaps the Verano is more aggressively geared?

I dunno... just thinking out loud.

 

The difference between the Aura and Verano will boil down to gearing.

 

Couple of things; I don't believe the mileage ratings are yet final (these are GM estimates; Edmunds lists 22/31 rating), and the weight difference is negligible (3,300 Verano vs 3,436 Aura). I would guess that mileage (as compared to Aura) is compromised a bit by larger wheels and wider tires, and by more aggressive gearing that gives the Verano slightly better straight-line performance.

 

Assuming the issue is gearing, does anybody else think it's a mistake for GM to reduce this car's fuel economy in the name of a few tenths better time to 60?

I don't know what my 0-60 in my Aura is but I know it's under 9 seconds, and that's despite the weight disadvantage and power disadvantage (since I don't have direct injection).

So this car runs to 60 in 8.6 seconds, which is at best 3 tenths of a second better. I don't think it's worth it for the typical Verano consumer. Greater fuel economy would sell more of these than a few tenths in acceleration.

 

The transmissions are not the same. The Aura had the 6T70 whereas the Verano has the 6T45. The 6T70 series was the joint venture between GM and Ford. The 6T40's are described as a smaller unit based on the 6T70's. The 6T45 is the higher torque rated version of the series. The 40's have clutch to clutch shifting, I don't think the 70's had that.

Ratios

6T70
4.484 - 2.872 - 1.842 - 1.414 - 1.00 - 0.742 - R 2.88 - Final 2.77, 3.16, 3.39 (depends on application, options)

6T45
4.584 - 2.964 - 1.912 - 1.446 - 1.00 - 0.746 - R 2.94 - Final 2.89

The 6T40 was first used in the '08 Malibu apparently.

As far as the fuel economy goes, it hasn't been officially tested.

 

My 2009 Aura 4-cyl has the 6T40, as do all 4-cylinder 6-speed automatic Auras, which I believe started production for MY 2008 but it could be 2009.

 

This

 

Yeah you are right. What I was looking at had the Aura listed as only using the 6T70 for both. The non-hybrid I4's did get the 6T40.

I guess the final could have changed. Otherwise the ratios should be the same between 6T40 and 45.

So supposedly the Verano gets 225/50R17 (standard) or 235/45R18 (optional) tires. The Aura was standard with 215/55R17. Not really any big difference in overall height there. The extra width reduces rolling resistance, although it increases aerodynamic drag, if it is at the same pressure as the narrower tire.

Guess we will see when the EPA numbers come out.

 

I think the newer, more 'harsh' fuel economy numbers started for 2008 model year vehicles.

And, just to split hairs, it's not SAE that rates fuel economy, it's the EPA.

 

Mileage ratings were also adjusted for older vehicles so all published figures should be up to date with today's standards.