Does the LS3 deactivate cylinders to get such good fuel economy?

If not what is the magic?

 

No, it runs on all 8 unless you break something.

 

No deactivation.. Just lots off low end usable torque.. so you can keep the rpms low. Great ECM programming that keeps everything running efficiently.. low drag CD. all add up

 

-- -- + O.D. gearing.

 

3200lb car 430Hp low drag you do the math. That said put your foot to it all the time around town and see how low the numbers go.

Won't trade it for the world

 

 

My 2007 c 6 with 2.56 rear axle has a 1.715 final drive ratio in 6th gear. It typically gets 30 plus average mpg on highway trips at 70 mph. This is as high a ratio as I have seen in a street vehicle.

Same LS Corvette engine in my 07 Trailblazer SS rated at 395 hp, is geared with a 4 speed automatic and 4.10 rear axle.

With correction for 20 inch tires on the SS the final drive ratio is 3.10. This is very close to the 2.944 in 4th gear in the Vette, and there are 2 more higher gears to go in the Vette.

The SS is 1250 pounds heavier and obviously has a higher cd. This reduces the average highway milage to around 19.

So the combination of higher gearing, less weight, and lower drag coefficient produces the Vette's high gas milage.

The 6 speed makes this possible. Without the 6 speed it would not be practical to have the really high ratios (low numbers) and low speed performance as well. If you have ever noticed a salt flats car leave the line they sometimes have to be pushed to get started with high speed gearing. Your Corvette will run 180 mph plus and still has great off the line acceleration thanks to the 6 speed transmission.

I thought the 2.56 ratio was way too high until I drove mine. I was very surprised at the acceleration. However this was my first 6 speed anything. That is what started my gear quest comparing the SS to the Vette.

LJ

 

Cylinder deactivation isn't all it is meant to be anyway unless you drive long trips on extremely flat highways. I know a few people that deactivated their DOD on the 5.3 and their gas mileage didn't drop at all but it felt smoother. Vette already spins at around 1500-1600rpm at 60mph. You can't beat that for efficiency.

 

Given the new CAFE requirements, this copuld be in the future for Corvette and other GM V8s. They are working on it now.

 

That cylinder deactivation is a joke. I bought an 07 Chevy 1500 crew cab and in 7500 miles only averaged 14.8 miles per gallon w/ 75 percent highway miles. I don't drive my trucks that hard either. I ended up trading that in for an 07 Chevy 2500 Duramax and am getting 19.4 miles per gallon and it has 10500 miles on it with same driving habits and even with some towing in there. It is very hard to get the cylinder deactivation to kick in inless you are feathering that gas pedal just right on totally flat highway.