Is this poster insane

[bankrobber]

The disk brakes on your wheels also use no fuel whatsoever when you apply them. Yet, one of the effective ways to increase your gas mileage is to drive to use your brakes as little as possible.
If the people at Consumer's Report ever mangage to make a stock 5speed Yaris get 45+ mpg, I'll gladly listen to what they say, until then, I'll take the advice of the group of people who actually do get that kind of gas mileage.

However, if the situation is such that you have to use your brakes anyway, you should leave it in gear and cut off the fuel.
You can actually feel when the fuel comes back on as you coast down, there is a sudden decrease in engine braking when that happens. On my Yaris, this happens at about 17 mph in fifth gear, 24 mph if the AC is on. I bump it into neutral as soon as I feel the DFCO (deceleration fuel cut off) end

Holy crap, 17 MPH in 5th gear. Wont that lug the engine even if not on the gas? That cant be good for it. Does anybody on here do that when slowing down?

[dean_park]

I'm not as extreme as that, but I also do the same. Unfortunately, since I don't have a tach yet, I really don't know when I'm about to approach DFCO off point, so I usually go more cautious. 17mph in 5th sounds low, but that's probably about right for 1100rpm.

I do avoid the brakes more and do more coasting toward a stop as well as brake with my foot off the clutch until I really think my RPMs are going to drop. I only started doing this in the winter, so with winter gas, I can't say how much of an improvment I've made, but I was getting 37-38, dropped to 33-35 ish and I'm back up in the 37 range. My calculation methods are not ideal tho since I do travel, so I don't always use the same pump/brand gas.

[127.0.0.1]

The disk brakes on your wheels also use no fuel whatsoever when you apply them. Yet, one of the effective ways to increase your gas mileage is to drive to use your brakes as little as possible.
If the people at Consumer's Report ever mangage to make a stock 5speed Yaris get 45+ mpg, I'll gladly listen to what they say, until then, I'll take the advice of the group of people who actually do get that kind of gas mileage.

However, if the situation is such that you have to use your brakes anyway, you should leave it in gear and cut off the fuel.
You can actually feel when the fuel comes back on as you coast down, there is a sudden decrease in engine braking when that happens. On my Yaris, this happens at about 17 mph in fifth gear, 24 mph if the AC is on. I bump it into neutral as soon as I feel the DFCO (deceleration fuel cut off) end

Holy crap, 17 MPH in 5th gear. Wont that lug the engine even if not on the gas? That cant be good for it. Does anybody on here do that when slowing down?


the engine can be in 5th at 17mph decelerating. you aren't going to lug unless you step on the gas. never step on the gas though, if you are that much over-geared, and it is fine (but rather useless)

[Loren]

I have a tach and use it. If I'm doing an extended coast (not coming to a stop right away, but trying to coast as far as possible in DFCO), I'll leave the car in the highest gear possible for less engine braking for as long as possible. For me, that's about 1200-1500 rpm. I have no idea what speed that is in 5th gear, but it doesn't lug until below 800 rpm. (remember, this car idles at about 650) Now, you can't ACCELERATE meaningfully from that kind of RPM in a high gear. But, if you're babying the throttle, you can (very, very) gentlly accelerate from 30-35 mpg in 5th gear.

If you don't want to invest in a tach and/or a ScanGauge, just listen to what the car is telling you. As stated, you can feel when the car comes out of DFCO... it does it at about 1200 rpm. At that point, there is no benefit in coasting down any slower in that gear. Grab 3rd to continue your DFCO coast a little further. Then you can grab 2nd if you still have room to coast after that. It's generally not worth trying to downshift to 1st, as it's difficult to do without blipping the throttle to rev-match... and blipping the throttle defeats the purpose!

[bankrobber]

I didn't know I could leave in such a high gear at slow speeds. I will try that tomorrow. I go to work very early so no traffic. I averaged 38 MPG till I switched to a synthetic blend transmission fluid and that got me to 40 MPG. 70% of my driving is rural roads 60 MPH

[Loren]

If you travel rural roads with little traffic to fuss with, keep the speed below 60 and practice a little gentle "pulse and glide" and you should be able to hit 45-48 without too much trouble. Just have to learn the tricks and apply them consistently.

[Falconia]

What is the good speed for using 5th gear? And how about 4th gear?

Goal is to reach best fuel efficiency without breaking down car

[Yaris Hilton]

It's pretty hard to hurt an engine by "lugging" when it has a computer controlling the ignition timing and a knock sensor giving feedback on it. Detonation is the real bugaboo of lugging.

[bankrobber]

If you travel rural roads with little traffic to fuss with, keep the speed below 60 and practice a little gentle "pulse and glide" and you should be able to hit 45-48 without too much trouble. Just have to learn the tricks and apply them consistently.

What is "pulse and glide"?

[1stToyota]

What is "pulse and glide"?

I believe it's the newest "device" that Penthouse Pet Shay Laren is endorsing now. :wink:

[fmicle]

What is "pulse and glide"?

Instead of keeping the car at a constant speed, you gently accelerate and let it coast or glide, say you accelerate to 65 then let it coast to 50 or 55, then accelerate back to 65 then let it coast; and you do this over and over again :)

[bankrobber]

Hmm, I always thought a constant speed was good. I think that would drive me crazy!!!
I will try it and see though

[fmicle]

Hmm, I always thought a constant speed was good. I think that would drive me crazy!!!
I will try it and see though

Don't forget, the emphasis is on *gently* :smile:

[Loren]

Very, very gently. And try to top out at 60 if you can. Economy nose-dives above 60.

Literally take at least 2 minutes to accelerate from 50-60, you're just barely toeing the throttle. Then lift all the way off the throttle and DFCO coast back down to 50, and repeat.

For a typical 20-30 minute trip, I gain at least .1 mpg for every 3-5 second coast. The trick is to hang onto what you've gained and not lose it to acceleration.

There are other ways to do P&G. I think IF you have the patience and a proper road to do it on (NOBODY around but you, and an appropriate speed limit), you can actually pulse more aggressively (just don't go full-throttle, if you go full-throttle, the ECU goes open-loop and runs rich due to no O2 sensor feedback), but you have to coast A LOT more to balance it out. Maybe accel up to 60-65 and coast all the way down to 40.

Footnote: I did an "economy run" with a friend once, and he was P&G from 70 to 30, but not in a Yaris. He had a Sentra SE-R w/ a 6-speed and a 2.5 with buckets of torque, and that method worked for him. Of course, he's from NJ and didn't care that he was pissing off the traffic behind him! He pulled something like 45 mpg out of that run, which was impressive for that car.

[RedRide]

It's pretty hard to hurt an engine by "lugging" when it has a computer controlling the ignition timing and a knock sensor giving feedback on it. Detonation is the real bugaboo of lugging.

Granted, pre ignition/knock is not really a problem anymore.
However, what about increased load on con rod bearings when "lugging' an engine? :smile:

[Yaris Hilton]

There is no increased load on connecting rods or bearings when "lugging" an engine. (Unless you make the engine start knocking.) Those forces are the same at a given percent of engine load, regardless of the RPM. "Lugging" is mostly imaginary. Usually people think they're "lugging" an engine when they fall off the torque curve on the low end.

[127.0.0.1]

There is no increased load on connecting rods or bearings when "lugging" an engine.


incorrect.


lugging = bad

low rpm growl = no issue

[Yaris Hilton]

incorrect.


lugging = bad



Incorrect on those counts.

[BuildCode]

I'm curious about lugging subtopic :) I always thought lugging was bad no matter what, but what Yaris Hilton says makes sense. Either way, I still won't go below a low RPM growl because it just feels wrong!

[advocate]

If you shift fast enough you can stay in DFCO and drop the car down in gears.

[Loren]

I'm curious about lugging subtopic :) I always thought lugging was bad no matter what, but what Yaris Hilton says makes sense. Either way, I still won't go below a low RPM growl because it just feels wrong!
For best MPG, it makes no sense to let the revs dip below 1200 rpm on a DFCO coast. (the ECU goes out of DFCO and into idle at about 1200) The engine won't lug at 1200 rpm unless you're trying to accelerate up a hill. On flat ground, it won't accelerate QUICKLY from 1200 in 4th or 5th gear, but it WILL do so without lugging. I do it all the time. Smooth, no lugging.

Listen to what the car is telling you. If it's not complaining, it's happy. If it starts bucking, or doesn't have enough grunt to climb the grade you're on... downshift!