What RPM range do I accelerate and shift for best fuel economy?

[kafer65]

You have to guess at the load unless you have a device that can access your cars software through the OBD port. Also, throttles are not linear. You may be only breathing on the go pedal but the software may be programmed to give 50% instead. Chryslers I've driven lately want to get after it pretty hard even if your trying to be gentle on take off. With an automatic your going to have frictional loses from the torque converter. I've been told that there may be as much as 20% loss on my 87 Dodge pickup under heavy load. I have rigged an overdrive switch so I can get lockup very early to avoid a lot of that loss. It will only lock in 3rd gear so I have to deal with the losses until I get to that gear and then I may be lugging the engine too much to get the most mileage from it. I can only manage 13mpg in that vehicle. My wifes auto gets 31-35mpg and its a conventional three speed automatic that with lockup in between every gear to get six effective speeds. Thirty mpg is about what I've seen in Camry's like yours. I think if you have an automatic 4 cylinder its better to get briskly going at first and get to torque lockup maybe around 30mph? I seem to remember that 2200rpm being good point for 2 liter 4 cylinders in general.

[Daox]

From all the testing I've seen, acceleration technique really doesn't matter that much. Its much more important to avoid brake use, keep your speed down on the highway, etc.

I generally accelerate at a moderate rate. I try to load the engine to ~80%. RPM doesn't matter much unless you're redlining every shift. If you want to go accelerate a bit faster, go for it. Typically, I shift most cars around 2500.

[davelobi]

You should be able to achieve a fair bit better than 30 mpg in that Corolla.
Learn more about DFCO and when your car is in/out of dfco. You can run along the back roads slowly getting up to 55 mph and coasting (in gear) back down to 45 then repeat the cycle over and over. Watch your mpg jump.

I drive almost exclusively stick shift cars so my automatic transmission advice is more limited to the dfco testing I have done than when to upshift on acceleration. I do however believe that accelerating too slowly will reduce, not increase, your economy. Get up into the highest gear at a reasonable pace and then do your cruising as slow (traffic allowing) as you can in the tallest gear without lugging the engine. I'd guess a good engine rpm for that 1.8L would be 17-18 hundred rpm. Hopefully that will keep you in the 45-50 mph range. Back roads (as opposed to the expressway) are really your friend for economy.

Welcome to the nut house. Strength in numbers!

EDIT: oops, my bad. I thought I read Corolla. The Camry is a fair bit heavier and the 2.2 will be a tad thirstier than the corollas 1.8. 30mpg isn't too bad but with information and the formation of new habits you will see an increase. Good luck.

[roosterk0031]

Just easy into it smooth and keep pushing till target rpm but you don't need to floor it or it may go into fuel enrichment. I doubt you make it to half throttle. You want to get out of first quick, but not by leaving a trail of rubber.

Pick a new target rpm say 2500 so not that big of change. Try that for a tank, next tank try 3000. As SGII or other instrumentation helps a lot here as it doesn't take as long to get feed back.

You won't be able to use too much throttle after first gear because it will cause a downshift. Right up to that point is the right amount (IMO).

[SilverCrown9701]

Originally Posted by kafer65

Thirty mpg is about what I've seen in Camry's like yours. I think if you have an automatic 4 cylinder its better to get briskly going at first and get to torque lockup maybe around 30mph? I seem to remember that 2200rpm being good point for 2 liter 4 cylinders in general.

I'm not exactly sure when my car reaches torque lockup but I do know I reach 4th gear/OD around 47 MPH. I should probably use a stopwatch to record my acceleration rates and keep a record.

[SilverCrown9701]

Originally Posted by Daox

From all the testing I've seen, acceleration technique really doesn't matter that much. Its much more important to avoid brake use, keep your speed down on the highway, etc.

I generally accelerate at a moderate rate. I try to load the engine to ~80%. RPM doesn't matter much unless you're redlining every shift. If you want to go accelerate a bit faster, go for it. Typically, I shift most cars around 2500.

I completely agree! I'm no speed demon, I like to be safe as well as efficient, though I do wish trucks could get the same mileage as cars

[SilverCrown9701]

Originally Posted by davelobi

You should be able to achieve a fair bit better than 30 mpg in that Corolla.
Learn more about DFCO and when your car is in/out of dfco. You can run along the back roads slowly getting up to 55 mph and coasting (in gear) back down to 45 then repeat the cycle over and over. Watch your mpg jump.

I drive almost exclusively stick shift cars so my automatic transmission advice is more limited to the dfco testing I have done than when to upshift on acceleration. I do however believe that accelerating too slowly will reduce, not increase, your economy. Get up into the highest gear at a reasonable pace and then do your cruising as slow (traffic allowing) as you can in the tallest gear without lugging the engine. I'd guess a good engine rpm for that 1.8L would be 17-18 hundred rpm. Hopefully that will keep you in the 45-50 mph range. Back roads (as opposed to the expressway) are really your friend for economy.

Welcome to the nut house. Strength in numbers!

EDIT: oops, my bad. I thought I read Corolla. The Camry is a fair bit heavier and the 2.2 will be a tad thirstier than the corollas 1.8. 30mpg isn't too bad but with information and the formation of new habits you will see an increase. Good luck.

I think that's what my problem has been was taking my time getting up to speed, after reading many different sites suggesting that slower is better but I guess they failed to mention not in this case.


My car is at 1,800 RPM at 50 MPH, 2,000 RPM at 55 MPH, and so on...



Haha, it's perfectly alright! The Corolla is just a "mini" Camry, so don't feel bad!

[SilverCrown9701]

Originally Posted by roosterk0031

Just easy into it smooth and keep pushing till target rpm but you don't need to floor it or it may go into fuel enrichment. I doubt you make it to half throttle. You want to get out of first quick, but not by leaving a trail of rubber.

Pick a new target rpm say 2500 so not that big of change. Try that for a tank, next tank try 3000. As SGII or other instrumentation helps a lot here as it doesn't take as long to get feed back.

You won't be able to use too much throttle after first gear because it will cause a downshift. Right up to that point is the right amount (IMO).

That sounds like a good experiment to try.
I ordered an Ultragauge because it's priced lower than the ScanGauge II.


The only thing I'm not looking forward to is calibrating it, according to the manual, it looks like a pain!

[dirtydave]

You just need to get a scangauge or other obd2 software find a road from 0-55 like a left turn onto the highway. And test it. I have found in my KIA most efficient is holding the thottle to TPS 25 and that's about half throttle. Shifting from 1> 3> 5 slowly going.

In my girlfriends 6 speed auto 2.5 I-5 2009 jetta its best to push it 3/4 of the way in getting to speed quickly and into 6th as soon as possible.

I would think most if not all automatic transmission cars are better off going slowly from a dead stop until 5MPH and then using 3/4 throttle.

I also think the manual transmission can accelerate more efficient ly. The difference in my KIA accelerating slowly and smooth vs quick heavy throttle and shifting at 2k rpms is nothing I have seen a difference at 1-4 mpg and during accelerating. Now in the jetta it is a much larger 4-8 mpg from a dead stop to 55 or 65 mph

[user removed]

Basically without getting too technical, accelerate at the highest throttle opening possible without delaying your upshift points.

regards
Mech