Tested: speed vs MPG - 2006 Toyota Corolla automatic - Page 2 - Fuel Economy, Hypermiling, EcoModding News and Forum

JohnnyGrey · 01-12-2009, 08:16 PM

I would bet fuel economy is better at higher elevations. You get to open the throttle wider and the air hitting your frontal area is thinner.

roflwaffle · 01-13-2009, 06:34 AM

Quote:

Originally Posted by MetroMPG

roflwaffle: I didn't really do a lot of driving in the car. I did a couple of mostly rural trips in cold weather (-5 to -10C) that netted mid 40's MPG (US). Left to his own devices, my dad's mileage was 22.4 mpg in wintertime 100% sub/urban driving (from: Win an EM Sticker: guess Dad's mileage (Toyota Corolla automatic). Ends Jan 13. ). Not sure what he's getting on the open road.

Sounds like my grandpa. He has a 2002 and pulls ~25-30+mpg (~40/60 city/highway?) driving like everyone else in pretty nice weather.

MetroMPG · 01-13-2009, 08:50 AM

Revised graph!

Added the car's official highway fuel consumption ratings that also shows the constant speeds at which those figures were attained in these conditions.

Shows EPA "new", EPA "old" and NRCAN. I was surprised to see the Canadian rating so much higher - I was under the mistaken impression that they were nearly the same as the "old" EPA figures.

MetroMPG · 01-13-2009, 08:58 AM

One of the things that surprised me about the car/graph was the point of best fuel economy at 40 km/h.

That speed happens to be pretty shortly after the transmission shifts into 3rd gear (of 4), so the engine is turning fairly slowly. It surprised me because it's the first speed vs. fuel consumption graph I've ever seen where the best performance isn't in top gear.

You can tell from the graph that the shift from 3rd to 4th (with torque converter lockup) happens between 60-70 km/h (shifts right in the middle at 65 km/h or 40 mph, actually).

It's possible to bleed speed down to 60 km/h and then hold 4th gear there, which would have raised that MPG point on the graph quite a bit, but I didn't. The transmission will downshift at the slightest prod under those conditions.

Formula413 · 01-13-2009, 07:17 PM

Thanks for collecting and posting this data. This is motivating me to do a similar test for my car.

Quote:

Originally Posted by MetroMPG

You can tell from the graph that the shift from 3rd to 4th (with torque converter lockup) happens between 60-70 km/h (shifts right in the middle at 65 km/h or 40 mph, actually).

It's possible to bleed speed down to 60 km/h and then hold 4th gear there, which would have raised that MPG point on the graph quite a bit, but I didn't. The transmission will downshift at the slightest prod under those conditions.

This sounds just like my car. There is a straight and relatively flat stretch of road about 1 mile long in my daily commute. The speed limit is 35 mph, I try to go just fast enough to get the TC locked and keep it there, which is about 37-38 mph (~60 kph) at just a shade under 1500 rpm. This requires a very delicate touch with the throttle, and careful monitoring of the TPS. On my way to work the car is not fully warmed up yet, usually just hitting the 150*F coolant temp required for lockup, and the road is very slightly uphill in this direction, and I see mpgs in the low 30s. On my way home the car is fully warmed up and has the slight grade working in it's favor, and I see low-mid 40s, as high as 50 mpg in warm weather with summer fuel.

metroschultz · 01-14-2009, 10:05 AM

I was wondering if you would mention the TC Lockup between 60kph & 70kph.
I can force the TC to lock up in my wife's car at 55kph, by turning off OD then when I hit 55kph turn OD on. The trans will go straight to lockup, but as you said any extra load at this point drops it immediately out.
Nice work, Thanx,
S.

i_am_socket · 01-14-2009, 02:49 PM

Graph looks about right. Too bad I can't get the "no traffic" conditions.
Good baseline info right there

I've noticed the best straight/level/low traffic MPG I can get is at about 33/34 MPH on one stretch of road near my house. Once in third gear it gets pretty high (needs-more-calibration 'Guino reads between 60's and 70's).

MetroMPG · 01-14-2009, 06:41 PM

Quote:

Originally Posted by Formula413

Thanks for collecting and posting this data. This is motivating me to do a similar test for my car.

Don't let me stop you.

That would be interesting to see.

Quote:

Originally Posted by metroschultz

I can force the TC to lock up in my wife's car at 55kph, by turning off OD then when I hit 55kph turn OD on. The trans will go straight to lockup

Oh - that's a neat trick! I didn't try that. It would sure save the extra energy spent getting to 65 kph just to get it to lock and bleed back down to a slower cruising speed.

roflwaffle · 01-14-2009, 07:47 PM

IME it's also more likely to lock-up at lower speeds if you give it a bit of gas, say going ~5mph above the lock-up speed, and then setting the cruise control as you let off the gas.

RobertSmalls · 01-17-2009, 11:50 AM

Quote:

Originally Posted by MetroMPG

Phil: I wonder if we're seeing the slope of the Corolla graph getting less steep as speed increases to 120. That would be consistent with other graphs I've seen, eg:

( source: Speed kills: testing MPH vs. MPG in top gear - MetroMPG.com )

Where can I get raw data for one of these cars in the high-speed runs? I'd like to plot fuel consumption (gal/mi) versus speed and versus speed squared in the 50-85mph range, among other things.