Preliminary 2010 mph vs MPG

I picked up our 2010 Prius from the dealer and here is my initial data:

	speed	MPG
1	50	65.3
2	60	61.2
3	65	54.8
4	70	52.5
5	75	49.4

Due to traffic, these were fairly short runs, 5.2-14.3 miles, 82-86 F, wind from West-North-West, ~15 mph, steady, Shell 89 octane E10. As I get time to refine and repeat my runs, I'll expand the speed range and accuracy. Raw data:

	direction	MPG	speed	distance
1	E	65.3	50	5.2
2	N	58.3	60	8.1
3	S	64.1	60	8.2
4	N	55.3	65	7.9
5	S	54.2	65	8.2
6	E	57.1	70	14.3
7	W	47.9	70	13.2
8	E	51.6	75	10.5
9	W	47.1	75	14.3

To put things in perspective, I get 39 MPG with my NHW11, 2003, at 75 mph. The high speed performance is significantly improved. The lower speed is OK but not as good as expected. After I get a chance to audit the tire pressure, check alignment, and oil level, I'll repeat the tests. Note the higher temperature means these are somewhat 'optimistic' values.

Vehicle observations:

• steering felt like there was a little mechanical friction, not so 'figity neutral'
• road tire noise a little louder than expected
• seats are OK but a little padding would help
• accelerator uses the plastic beam, is different from NHW20
• No evidence of Eco mode having a cruise control effect
• Speed indicates about +1 mph compared to GPS and tripmeter
• Belkin FM modulator for iTouch worked but a lot of volume required

Bob Wilson

 

Later, my wife sent me out on another errand so I also ran up Brindley Mountain four times:

	mph	MPG	gal
1	55	19.1	0.0681
2	65	18.1	0.0718
3	77	16.6	0.0783
4	84	15.4	0.0844

At 84 mph, the engine ran pretty much at max rpm, 5200. But it was too dark and I was too tired to make another high speed climb. Maybe Sunday morning I can try a run at 90 mph.

Bob Wilson

 

Well I had the adapter but I didn't have the cable needed for the AUX port. <grins>

Honestly, I was more interested in getting the mileage runs. Audio comes later ... after I get my instrumentation in ...

Bob Wilson

 

Not yet. Heck, I did the high speed runs on the way home from the dealer. The hill climb was done between 10:00-11:00 PM. But I did survey the engine compartment and took photos that I'll post later. One impression, there sure is a lot of space between the engine and firewall. Those installing block heaters will probably find this a joy.

Bob Wilson

 

The dealer bought and filled the tank. But since everything is now E10, I have to go back and re-run my previous gas studies.

Bob Wilson

 

All test runs are cruise control speed regulated and I use my Garmin nuvi to calibrate the the speedometer and trip record average speed. My findings are speedometer indicates +1 mph but the trip meter average speed is right on.

I don't want to project any performance until I get a chance to check the 'usual suspects.' I'm pretty sure the tires are "dealer standard" and I also want to check the alignment. I haven't really checked the oil level but the new engine has some pretty sophisticated oil management systems.

Understand that my tests do everything possible to be reproducible and eliminate any human elements. I am testing the vehicle, not the driver. If my testing is accurate, anyone should be able, within the limits of local conditions, replicate the results. I need reproducible results so I can use these graphs year round to predict everything from trip costs to current vehicle health.

Bob Wilson