[Bubbles]

A buddy and I performed an informal experiment to test gas mileage. His car was due for a progman update so we picked a 43-mile stretch of flat highway with no traffic to compare Progman 30.0.2 mpg and Pre-29.2 mpg performance. For each test, we filled the tank with Sunoco 93 at a gas station located near the beginning of the 43-mile stretch. So in each case the car had a full tank of gas from the same gas station. We allowed 2 days of 300+ miles for his car to adapt between the tests. The results were a bit surprising. My car was the informal "control" car.

Car: E92 June '07 Build
Trans: 6mt
Mileage: ~18k
Mods: None
Cruise speed: 80 mph
Same driver, no passengers.
No A/C, just windows cracked.

Test #1: Progman pre-29.2
Time: 9:18am
Temp: 84 F
Humidity: 71%
Headwind: 6 mph
MPG: 29.7 mpg

Test #2: Progman 30.0.2
Time: 8:55am
Temp: 79 F
Humidity: 70%
Headwind: 4 mph
MPG: 26.1 mpg

So we estimate a ~3.5 mpg drop after the 30.0.2 update. I ran my Dinan stage II E92 as well and averaged nearly identical mpg for each day, 28.1 mpg and 28.8 mpg, respectively. FYI, I ran my A/C for both days.

Of course this is unscientific way to kill some time, but interesting nonetheless.

[techforge]

Also perhaps worth noting is how the 335i was rated 20-29 for 2007 and for 2008 dropped to something like 17-25. At least that's what the window stickers show for the two I looked at. Maybe that was a government thing though?

[hotrod182]

Originally Posted by techforge

Also perhaps worth noting is how the 335i was rated 20-29 for 2007 and for 2008 dropped to something like 17-25. At least that's what the window stickers show for the two I looked at. Maybe that was a government thing though?

That was just a change in ratings that even affected identical cars.
You would think that newer programs that hold the wastegates open more, would get better gas mileage.

[Bubbles]

Originally Posted by hotrod182

That was just a change in ratings that even affected identical cars.
You would think that newer programs that hold the wastegates open more, would get better gas mileage.

+1

My buddy and I did not notice much of a lag increase after the update, which supports the notion that this lag issue is less likely to affect 6MTs.

[getInline]

Interesting. I just run some quick calculations and over 50,000 miles this would consume an extra 230 gallons of fuel. Assuming $4/gallon, that would be an extra $920 and 4462lbs of CO2 emmissions, all because of a crappy wastegate arm.

Maybe we should protest them on environmental grounds!! It's the only way to get things done these days.


CO2 source: http://epa.gov/otaq/climate/420f05001.htm

[Nick@aep]

Interesting results. Even more of a reason to avoid 29.2+. '29.2- killer of gas mileage AND fun'

[mistermojorizin]

Originally Posted by Bubbles

+1

My buddy and I did not notice much of a lag increase after the update, which supports the notion that this lag issue is less likely to affect 6MTs.

its random. some people get the lag after update, some don't. some with 6mt get it, some with 6mt don't. some with auto get it and some don't. we haven't determined what the 3rd variable is. i have 6mt and i have the lag, and so do a lot of other people with 6mt. but everyone with 6mt that doesn't get the lag jumps to the conclusion that its because of the 6mt, without any evidence.

[Bubbles]

Originally Posted by mistermojorizin

its random. some people get the lag after update, some don't. some with 6mt get it, some with 6mt don't. some with auto get it and some don't. we haven't determined what the 3rd variable is. i have 6mt and i have the lag, and so do a lot of other people with 6mt. but everyone with 6mt that doesn't get the lag jumps to the conclusion that its because of the 6mt, without any evidence.

The lag may be pronounced in 6mts with failing wastegates/turbos.