Quote:
Originally Posted by DSX_Camaro
Don't get me wrong, I understand what you're saying, it's just that yes, there are a couple assumptions in there that change the figures a lot. The CTS VSport has 25.7" tires which drop the OD by 3" compared to the Camaro, or just over 10%. Stick those on the Camaro and it'd be like having a ~3.60 rear end ratio. CTS VSport 24mpg, Camaro LFX 27mpg, CTS LFX 29mpg. The CTS also has a much better coefficient of drag plus the 8 speed which logically helps the mileage, like with the LFX numbers. (Point being: at 2000rpm it's still running the same speed as an LFX equipped car, instead of turning lower rpm. It should get at least similar gas mileage, not this much worse. Such as how the new Mercedes TTV6 E400 gets identical gas mileage to the E350, 30mpg.)
On the other hand, the C7 is better than the C6 and the LT1 is better than the LS3. I think that is an objective statement - essentially identical, but the LT1 has DI, VVT, DoD and an extra gear(s depending). Denying the LT1's efficiency would be ridiculous, also. I simply have a hard time believing the LF3 is any manner of optimized since #1 it doesn't exactly fill any gaps and #2 probably won't be around much longer (like the good ole' LS6)... and #3 GM engineers can't seem to gear anything short of the Corvette for crap.
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No one should be comparing FE of a C7 and pretty much anything else. The mass and CD of the Corvette are so far better than anything you are comparing to.
To determine the FE benefit of the 3.6 TT, better off comparing to a car with the LS3 that is about the same weight, that would be the SS Sedan.
The 8 speed in the CTS V-sport would be about 1 mpg improvement and if memory serves, the SS is 21 mpg highway and the CTS V-sport is 23. So put the 8 speed in my SS (which turns about 2,000 rpm at 70 mph) and I would expect to get the 1 mpg improvement or at best match the CTS V-sport.
Technically, the TT should do better than that as when not under boost it is basically a much smaller displacement engine.
LT1 with cylinder deactivation should help, but basically it will likely only offset the HP increase.
But we are discussing unicorns as our car has not been revealed or with what powertrain.