I am almost ALL highway.
Most of the guys I know are getting 20 on the highway. Of course, I am sure it's because they can't keep their foot out of it. After filling up and resetting, I usually get 28 from the gas station to my office. But, by the time I complete my round trip it's usually down to 24. Been more like the 22-23 lately with extreme cold.
Drove my wife's '12 SRX (3.6L 6AT) to Sandusky, OH and back this past week. This was my first opportunity to see what it could get. Got 24.2 MPG at a steady 68 MPH over about 200 miles. Though we consisted of two adults and two kids plus all the luggage that would fit, I realize weight is not a big factor at constant speeds, but I had hoped for it to do better. Not sure what the Cd is on it, but it's gotta be > 0.30.
So, now that I think about it, maybe 30 MPG in a TT3.6 ATS-V is a bit optimistic afterall.
Here's a thread in gminsidenews about the TT3.6 plausibly putting out "in excess of 400" hp and is the probable engine for the ATS-V:
One poster predicted a TT3.6 making 425-480 hp. Works for me.
Well, with 3400-3500lbs, a more aerodynamic body and more advanced technology, I would think 30mpg would be doable.Quote:
Originally Posted by M5eater
My V1 with 3850lbs, an unaerodynamic body and a V8 would get 26mpg all day long on the highway...
Tailoring the turbo to get the best compromise between lag and top-end performance is another, related aspect.
I still question the longevity of these highly boosted motors. Randy, aren't you worried what the maggie will do to your internals over the long run?
Your LS6's internals, I mean :D
There's no question that if average cylinder pressures run high due to high throttle openings and times of boost over the life of the motor, it would put increased stress on wrist pin bearings, on rod bearings, on piston skirts and rings, and probably on main bearings. In my case, I really don't spend a lot of time at boost conditions, so I don't really feel my motor is detrimentally affected especially with good oil pressure and fresh Mobil 1 in it all the time.
In another example, if you look at guys like ronr who has 70k maggied miles on his LS6 and drives more frequently while under boost conditions (i.e. "spirited") than I do, that might be something to look at. But, I'd bet his motor goes close to 200k miles before he needs a rebuild, but that's because it's a proven LS motor design. We're talking here about a 3.6L V6 that's almost exclusively found in passenger cars, and I'd be concerned that there is less known about this design under severe operating conditions than LS motors in general. I would hope that GM has flogged the piss out of this motor and has addressed any weak points in it before sending it out into the public with a couple of turbos slapped on it to be flogged by all of us.
Anybody follow common issues with the 3.6 motor? I have not myself, so I'm all ears.
Looking in the 2nd gen CTS forums, there are not many complaints about the engine, other than the premature timing chain wear problem.
Not to change the subject but speaking of the timing chain/belt (whatever is in there) situation. My brother in law has 10,000 miles on his 2008 or 2009 CTS sedan and at a recent service noticed that Cadillac adjusted something to do with, I believe timing, and mentioned something about the belt/chain on the invoice - and the car had been noticeably slower since. Has GM "fixed" this potential issue by making the car weaker? Is there already a discussion going on in reference to this?Quote:
Originally Posted by JimmyH