18-20mpg, 80% of driving is highway at 58-65mph. These cars not a pirus

 

i had 5w-30 in my car and was getting around 23 mix city hwy...now the dealer put in 5w-20 and i can barely get 20mpg

 

Strange. Thinner oil usually increases fuel mileage. Nearly every new car over the last few years has been designed for 5w-20 for that reason.

 

it could also be that they switched over to the winter grade gas cause i also filled up after the oil change

 

24 is the best that I could hope for. In town, I am usually about at 17-18. Stop and go traffic murders my fuel economy.

 

On the highway, I get about 28-29 mpg. In the city, I get around 20-21 mpg.

 

I think they've switched over to the crappy oxygenated and ethanol laden winter gas, because on the long trip to see my family for Thanksgiving, the best I could average was 25.5 mpg. During the summer I made the same trip and averaged 28 mpg!! The only other thing I can think of that might account for the change is that I got a brand new pair of All-Season front tires for the car since then, so maybe they have a greater rolling resistance or something.....

 

The colder it is out, the less MPG you get. Reason being is that you have more denser air coming in, and the computer compensates for it by adding more fuel ( i think anyways...someone confirm this?)

I know up in Canada winter fuel does affect fuel economy... not enough to care but up here everything is more expensive anyways so i don't think about it. Does the USA change the fuel for winter as well? Cause if so, there would be another reason.

Also, it takes longer for the car to warm up and will burn more fuel to get to the optimal operating temperature which is one of the bigger reasons why fuel economy is affected.

Bearings are colder and tighter thus more resistence... tires are harder.. denser air means more aerodynamic drag... etc... all that stuff adds in there too!

 

I'm completely stock and my best was 25 mpg today all highway cruising between 70-80 mph

 

i was cruising at 80-90 on the turnpike yestarday and after going 1hr of no braking i only got 23mpg. i guess thats not that bad for the speed.

 

My best was 33mpg on my stock turbo that was with gst custom tune. Igot a pic but I'm at work right now

 

And with the EVOX the numbers are

 

Now my best is 25mpg with evo turbo but I average 18 because I moved and do more city driving

 

best ever was 31 mpg on stock tune @70 - 75mph. Flashed to GST + Boost Pill flash, and so far my best MPG hasn't gone past 25MPG. Then again, the change over wasn't very long ago, and i've been driving a bit faster 75-80mph. Still having too much fun with the added power to be settled down enough to go for a true MPG run.

I thought I would do good on a road trip I took over Thanksgiving, but several high speed bursts to get around people driving under the speed limit in clear conditions killed the MPG average.

To get good MPGs, I have to go slower than i'm willing to for the time being.

 

Not cool! RA's and Evo's take 5W-30. It's not a big difference but I hope this doesn't damage/take life away from your car.