Riddle Me This - Honda CRZ Forum: Honda CR-Z Hybrid Car Forums

HughJorgan · 12-12-2011, 07:00 PM

Doing a semi-scientific test on the mileage on my Z.

Last night, I drove a certain stretch of I-90. When I got up to speed and went under a certain overpass, I zeroed my Multi Display thingie. Set the cruise to 70 and hit Economy mode. Just before I got to my exit, I checked my mileage: 40.3

Tonight, I drove the same stretch of road and did the same thing, except was in Normal mode. Mileage 42.3.

No wind that I am aware of, in either case.

WTH????

Scotty001 · 12-12-2011, 08:04 PM

Moved to the MPG Forum..

wicked1 · 12-12-2011, 08:42 PM

Try sport next.. might get even higher.. it's common.

But otoh 2mpg isn't much.. a LOT affects it.. temp, air pressure, humidity, etc...

atteSmythe · 12-12-2011, 08:55 PM

Temperature? Water on the road? Passing semis and their wake?

...extra sammich at lunch?

TCroly · 12-12-2011, 08:57 PM

When you say that there was no wind that you were aware of, that really isn't very scientific. Even 5 mph headwind, would influence your fuel economy by as much as a couple mpg at 70 mph. You would have to make dozens of trips under the same conditions to even out the constantly changing variables of wind, temperature humidity, and some variation in driving style or traffic variations. For example drafting a truck for a while even 100 feet behind will result in better milage, and having to slow down and speed up for traffic could affect your results

Jayemtee · 12-12-2011, 09:57 PM

Have fun with it. How many miles was this alleged stretch of freeway?

Try it on a section of level road, then on a section of slight incline, then on a section of slight decline. Several times each should give you an idea of where you stand.

HughJorgan · 12-13-2011, 07:35 AM

Quote:

Originally Posted by TCroly

When you say that there was no wind that you were aware of, that really isn't very scientific.

I DID say "semi-scientific"....

It's just that, after keeping as many variables as I had under my control the same, and seeing the OPPOSITE results of what I expected, I thought "well was it windy yesterday?" I'll have to check the weather info. (I DO know the temps were the same, though).

I drive this stretch a LOT, so now I'm going to have to play with this a bit more.

I am somewhat troubled at how atteSmythe knows about that second sammich, though...

dntower85 · 12-14-2011, 10:57 AM

I sometimes get strange results also.

2 weeks ago I drove 200+ miles at 65 to 70 mph with a 15+ mph tail wind. The road was not flat but it only had minor hills and I started at an elevation of 1143 feet and dropped to 625 feet according to google earth. Temp was in the 40s to 50's with high humidity. I could barley manage 40 mpg. Even at 60 mph I could not get the instant reading to go above 50mpg even going down hill with the battery at 7 bars.
Checked Tire pressures when I got home and it was still 41PSI front and 39PSI Rear, did not add any air.
Ended the Tank with an average of 41.6 mpg

Filled up yesterday and drove the commute home, 49MPGs!!!! then Back to work this morning 47MPGs, Still humid and in the 50's, Although the average speed is down I'm still running between 60 and 65 mph.

The only thing I can think of is the previous tank of gas had a high % of ethanol.

gordonfc · 12-14-2011, 11:29 AM

In Ontario Canada.
The 'regular' 87 octane fuel has 10% Ethanol
The 89 octane, mid grade, has 5% Ethanol.
Premium has NO Ethanol.

Gas mileage WILL drop as the temperatures drop.
Also check tire pressures. Pressure WILL drop 1psi for every 5 deg. C. drop.

12-12-2011, 07:00 PM	#1 (permalink)
HughJorgan Member Join Date: Jun 2011 Posts: 36	Riddle Me This Doing a semi-scientific test on the mileage on my Z. Last night, I drove a certain stretch of I-90. When I got up to speed and went under a certain overpass, I zeroed my Multi Display thingie. Set the cruise to 70 and hit Economy mode. Just before I got to my exit, I checked my mileage: 40.3 Tonight, I drove the same stretch of road and did the same thing, except was in Normal mode. Mileage 42.3. No wind that I am aware of, in either case. WTH????

12-14-2011, 10:57 AM	#8 (permalink)
dntower85 Member Join Date: Oct 2010 Location: Texas Posts: 101	I sometimes get strange results also. 2 weeks ago I drove 200+ miles at 65 to 70 mph with a 15+ mph tail wind. The road was not flat but it only had minor hills and I started at an elevation of 1143 feet and dropped to 625 feet according to google earth. Temp was in the 40s to 50's with high humidity. I could barley manage 40 mpg. Even at 60 mph I could not get the instant reading to go above 50mpg even going down hill with the battery at 7 bars. Checked Tire pressures when I got home and it was still 41PSI front and 39PSI Rear, did not add any air. Ended the Tank with an average of 41.6 mpg Filled up yesterday and drove the commute home, 49MPGs!!!! then Back to work this morning 47MPGs, Still humid and in the 50's, Although the average speed is down I'm still running between 60 and 65 mph. The only thing I can think of is the previous tank of gas had a high % of ethanol. __________________ 2011 North Shore Blue CR-Z CVT 2001 Honda S2000 2000 Honda 125cc Shifter Kart

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12-12-2011, 08:42 PM	#3 (permalink)
wicked1 Elite Member Join Date: Sep 2010 Location: Midwest US Posts: 877	Try sport next.. might get even higher.. it's common. But otoh 2mpg isn't much.. a LOT affects it.. temp, air pressure, humidity, etc...

12-12-2011, 09:57 PM	#6 (permalink)
Jayemtee Senior Member Join Date: May 2011 Posts: 375	Have fun with it. How many miles was this alleged stretch of freeway? Try it on a section of level road, then on a section of slight incline, then on a section of slight decline. Several times each should give you an idea of where you stand.