The projected EPA highway rating for the SS 6 speed manual is 23 mpg.

From personal experience with my 99, and reports from others, the 4th gen LS1 6 speed easily exceeded its EPA highway number when cruising in 6th.

Now, the 2010 SS 6 speed manual uses similar gear ratios to what my 99 LS1 6 speed has. And 6.2 isn't enormously larger than 5.7. Then consider that since the 4th gen ceased prodution, the EPA has revised the way the mpg numbers are figured to show lower numbers - meaning that if you could exceed the old highway numbers, you can certainly exceed the revised highway numbers by an even greater amount.

The only question mark is how much frontal area and drag the 2010 has v. the 98-02 4th gen.

Until the cars are on the ground this is speculation on my part, but I think cruising at 80mph in 6th on a road trip a 2010 SS manual is going to be able to knock down 27 mpg, despite the 23 EPA highway rating.

 

Well, considering a LT1 6-speed car is now rated at 15/24, I think it will be easy to exceed that number. The only time I ever got below 24mpg was when I had my 4.10 gears, and was doing 80mph. I got ~23mpg. 3.42s would get ~28, doing around 70. But the 6th gear ratio is not as tall as it was in the 4th gens (.57 vs .50 in 4th gens). And the rear axle ratio is shorter (3.45 vs 3.42). While that doesn't make a huge difference, it will probably cost about 1-2 mpg (final drive 1.97 in the '10, and 1.71 in the 4th gens). I think the car will get between 26-27 hwy, if you keep it below 75mph. This analysis is only for the manual transmission car.

 

according to this article:
http://www.edmunds.com/insideline/do...ticleId=129586
a bit higher than the 4th gen which was 0.33-0.34

some sources i found say the 2005+ Mustang has a Cd of 0.38.

 

I think the EPA estimates will be exceeded. Those LT1 numbers cant be for real unless you're ragging on the car from light to light. I was seeing ~18 city and up to damn near 30mpg highway when my car was stock(ish). That was getting on it a few times too but driving rather conservatively.

For comparison though to a more relevent rating, my Malibu is basically right at its 22/32 rating and maybe just a bit higher as its just been broken in. Can the new SS do better? I think so but maybe not by much. We'll see once they're on the roads and broken in.

 

No, b/c why would GM under estimate MPG at this time? They would be foolish to publish a false MPG with the way gas prices are at and the numerious hybrid cars. (Every New and Old person looking at the Camaro will tend to look at MPG now then they did 6-8 years ago. Do I think GM will do everything in its power to raise the MPG by 1-2 MPG by the time the car is in dealerships? YES!!

Put a gas sipping 4 cyclinder in the Camaro, this way you have the game covered. 4,6,8. 225 hp would be great in a 4.

 

It will be exceeded. The EPA gives GM the mpg rating. GM can't say a car gets better mpg's than what the EPA will rate. That will be the numbers you see on the build sheets. The 4th gens surpassed EPA mileage and that was with the old measure. Here are some reasons why the new SS should get 28 mpg on the highway. New standards for measure are lower for example my 08 escape is rated at 27 highway and I have seen 28 with mixed driving. Secondly the LS3 is a more efficient engine than the LS1 which will level playing field of the weight issue. Expecct to see the same mileage you would get from an LS1 six speed in both the M6 and A6 fifth gen SS.

 

Too lazy to grab the links now, but Scott said we can expect better than the LS1 4th gen in the new SS. I get 30 MPG in my 98 Z. Has to do with the way EPA calculates it now or something he said.

 

It better. My "ragged-out" old cam/heads LT1 gets 28-29 mpg on the highway with 3.73 gearing.

 

My old LT1 got 30+ MPG on the freeway at 80 MPH. Those 3.42s and M6 helped, but I don't think the '10 will be very far behind. I could see it's aerodynamics hendering it a little, but I'm sure that LS3 is more efficient, and could likely make up most of the aero' difference.

 

Same here. IIRC, the best I was able to get was 33 mpg.

Seeing as it's 15 years newer than my jalopy, it shouldn't be behind at all.

 

Well, there is a difference between what GM got for the motor, and what the EPA got.
But the EPA figures are on the sticker. So keep that in mind. We're seeing what one independant group got, we have nothing to compare their test results on.

 

I have exceeded rated highway MPG on most cars I have owned. My wife beat EPA by 5 mpg in here 05 AWD V6 Saturn Vue. With the a/c on no less.

 

I wouldnt be surprised to see GM improve on those numbers a tiny bit when EPA certification happens. I fully expect to be able to exceed the HWY mileage, whatever it ends up EPA wise.

 

My Vette get's 27mpg even with a cam and bolt-ons on the hwy. Thats at 75-80 in 6th gear.

 

The only car I've had that doesn't beat the numbers is my current Impala SS. That thing gets hideous mileage. Avg on the highway is about 23.5-24. It always has. It was rated at 28 when we got it, but is re-rated to 26 now. It's nowhere close. City we get about 13-14.

On the flip side, the vette gets 19 city, and about 31 highway