just joined, looks like great forum. has any one had fuel econ issues with 05 mcs 6 spd we just cant get past 28

 

Is that hand calc'd or OBC. Last tank with mine was mostly highway and the OBC indicates 28 average. Hand calc = 31.5.

 

When i keep my foot out of the throttle i regulary get 30+ and when
i'm really not in a rush the best i've gotten is about 34mpg

 

hand calc, many times hwy spd 73 ,40000 miles on 05 mcs, maby not broke in, shell or exxon only

 

Is that all highway driving, or mixed? With mixed driving I've been averaging 25-28 mpg over the past six years (2004 MCS)

 

I never managed more than 26.4 (calced, the computer said 27.6), so you're doing fine.

 

I never trust a computer read on mileage, always amount of fuel used divided into miles driven. You "S" drivers are obviously paying a premium for the power you have. I just got thru runing 375 miles in a very agressive style with the tach at 3500 to 6200 nearly all the way and got 33.5 mpg. Do
n't think I would be happy with an "S".

 

I think that that there is a big dif. in MPG depending on what city you are in when you talk "city" MPG. For example, I live in NYC and I have to stop and go every 100 feet and frequently MUCH less and that's NOT in rush hour or a busy part of town. I rarely get to 5th or 6th gear in the city until I get on the highway and even that's not so fast here. SO, in NYC driving with your car I would think 28mpg would be OUTSTANDING imho and in MY situation.

I grew up in Fl in Clearwater and would frequently drive US 19 and not stop for over a mile. I would expect much better gas mileage there.
than here. Completely dif. city and still busier than some other cities say out west where people can drive 100 miles and never stop lol. I'm not sure if some cities would be considered "cities" for MPG purposes though, lol.

Add to what I am saying that some folks drive more aggressively. My wife for example hits 4 on he tach frequently when she shifts and I rarely do if ever. A whole tank of 4+ on the tach and you will notice a decent dif in MPG I would assume.

All that said, my justa clubbie is averaging 31.5 OBC MPG on it's first tank of driving here in NYC with some highway miles out of town as well. Not too bad but I as well expected a little better but maybe i wasn't being realistic.

 

That is about what an 05' is good for. Some folks have stated that they actually get better MPG in 5th gear on the highway than 6th...might depend on the speed that you drive...but during the winter, with the car running cooler, and now with 10% ethanol in fuel, it is pretty hard to do better. I used to do 30 pretty regularly on the highway...but since all gas is E-10 now, my MPG has dropped a bit. This is expected...as e-10 has fewer BTU per gallon of fuel.
A cold air intake, or performance exhaust can help MPG....but since most folks use the extra HP they get from these mods....actual observed MPG often drops.

 

Part of the difference is that the mileage being discussed here is for 1st Gen MCS's, as opposed to your 2nd Gen MC. There's still a "premium" to be paid between the R56 MCS and R56 MC, mileage-wise, but the gap is significantly bigger between the R56 MC and R53 MCS than it is between the R56 MC and R56 MCS.

In general, the 2nd Gen cars are significantly more efficient than the 1st gen cars.