Does the CVT always try to run at the most efficient RPM? And what's the best RPM to stay in? I feel that accelerating verrry slowly from a stop (like depressing the pedal just an inch all the way) isnt much better if at all than just boosting to cruising speed and coasting more. Then again, I'm sure gunning it at over 3.5k should use more gas?

 

It depends. With ECO on, my (semi-educated) guess is that the computer will try to keep the engine RPM in the peak torque range / best fuel economy range, which usually means lower RPM. ECO off will probably aim for peak HP / better acceleration, which is usually a bit higher RPM.

Here's the HP/torque curve for the 1.5L engine used in the 2014 Fit sold in Japan:



Note that torque peaks around 4500 RPM, HP near the redline of 6500 RPM.

Either way, if you floor it, it's going to rev up (that's where the HP are kept), and you'll burn more gasoline, because you're asking the engine to do more work in a given period of time.

My first tankful was run with ECO on and a light throttle. The on-board computer indicated a shade over 40 MPG for that tank. I'm halfway through my second tank and running with ECO off and more aggressive throttle (not redlining, but some 2/3 throttle runs up to the posted speed limit to help seat the rings). MPG doesn't seem to be suffering all that much.

I work for an earthmoving equipment manufacturer, and some of our machines use CVTs – they can realize a 10-15% reduction in fuel usage simply because the CVT keeps the engine in the power band sweet spot.

EDIT - to answer your original question on what the best RPM is, it's basically whatever your goal is for the car. Want higher MPG? Keep a light foot on the throttle. Like to hoon and don't care about economy? Put it in Sport Mode and rev it up, baby! You'll still easily get 30+.

Hope that helps,

es

 

My mother has a CRZ and she claims her best gasmileage is sport mode to get up to speed, then eco mode to maintain. But she has a traditional manual, not a CVT

very slow acceleration massively hurts mpg's

keep up with traffic getting to speed, then just drop back a lil bit and save your gas money proper!

 

Thanks, Stem. I tried looking for a power curve without luck. So looks like I'll keep accelerating at 3-3.5k rpm when diminishing returns creeps in :P

I tried ECO mode and found it didn't really help all that much. I would accelerate slowlyin the city, but will take many more seconds staying at under 30mpg according to the live gauge which isn't much better than turning ECO off, when I could already be coasting. Going up steep hills also shows little difference between D and S gear.

 

Please note that the posted power curve is not an actual dyno power curve or Honda official data but an estimation done by automobile-catalog using a proprietary software called ProfessCars (you can see this stated on top of the graph)


Estimation of the engine power/torque curve – the formula based on the maximum power and maximum torque points, the relationship between the power and the torque for an internal combustion engine and the typical shape of the curve for engines of different constructions.

ProfessCars simulation software