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Rav4WD said:
RAV4Don said:
Rav4WD said:
The torque converter is more efficient at the higher RPM's. If you ram it and drive at 3-4000rpm, there's less power loss thru the torque converter than if you were to baby it at 1-2000rpm.
Well, maybe. It all depends on when the TQ converter "locks-up". This maybe in (V6) fifth gear at 2k rpms.
IIRC.. the torque converters in most of the automatic gear boxes don't lock up until they've reached top gear (4th gear in the Rav4 4cyl and 5th gear in the V6).

I wouldn't baby the car until the torque converter has locked up and that would be cruising speed on the highway.
Well, Rav4WD, you are correct about TQ converters not locking up until the final gear...and at a certain RPM. I say certain RPM because this varies by engine, tranny and final drive (diff) gearing. I can tell you that once the converter locks at say 2k rpms in 5th gear on the V6 tranny, there is no added efficiency of increasing the rpms to the 3-4k as you mention.
 

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RAV4Don said:
Rav4WD said:
RAV4Don said:
Rav4WD said:
The torque converter is more efficient at the higher RPM's. If you ram it and drive at 3-4000rpm, there's less power loss thru the torque converter than if you were to baby it at 1-2000rpm.
Well, maybe. It all depends on when the TQ converter "locks-up". This maybe in (V6) fifth gear at 2k rpms.
IIRC.. the torque converters in most of the automatic gear boxes don't lock up until they've reached top gear (4th gear in the Rav4 4cyl and 5th gear in the V6).

I wouldn't baby the car until the torque converter has locked up and that would be cruising speed on the highway.
Well, Rav4WD, you are correct about TQ converters not locking up until the final gear...and at a certain RPM. I say certain RPM because this varies by engine, tranny and final drive (diff) gearing. I can tell you that once the converter locks at say 2k rpms in 5th gear on the V6 tranny, there is no added efficiency of increasing the rpms to the 3-4k as you mention.
The 3-4k rpms i mentioned was referring to the higher working efficiency of the torque converter than the 1-2k rpms before the torque converter locked up.

Obviously once the torque converter has locked up, there would be direct coupling and no slippage thru the torque converter, so the efficiency thru at the torque converter would be the same for 3-4k rpms or 1-2k rpms.

What I meant to say is during acceleration, the torque converter is more efficient at 3-4k rpms. Once the torque converter has locked up at cruising speed in top gear (it sounds like "5th gear engaging" in the 4cyl/4sp Rav4 and "6th gear engaging" in the V6/5sp Rav4), it's good to baby the car then.
 

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Just returned from a 1000 mi round trip.

1st fill up = 22 mpg (in town before trip)
2nd fill up = 24 mpg (100% highway, very windy)
3rd fill up = 26 mpg (90% highway, 10% city)
4th fill up = 29 mpg (100% highway)

Refilled the tank at the 1/2 mark most times. Highway speeds ~73 mph. The Rav had ~500 mi when I started, so this was part of the initail break in period.
 

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iowa

iowa530 said:
Just returned from a 1000 mi round trip.

1st fill up = 22 mpg (in town before trip)
2nd fill up = 24 mpg (100% highway, very windy)
3rd fill up = 26 mpg (90% highway, 10% city)
4th fill up = 29 mpg (100% highway)

Refilled the tank at the 1/2 mark most times. Highway speeds ~73 mph. The Rav had ~

500 mi when I started, so this was part of the initail break in period.


After 43,000 miles,i am getting a steady 28 to 30 MPG all round driving and my best highway was 33.4 MPG comeing home from Florida last spring,doin 60 to 65 MPH.
 

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Re: iowa

Jimbow said:
After 43,000 miles,i am getting a steady 28 to 30 MPG all round driving and my best highway was 33.4 MPG comeing home from Florida last spring,doin 60 to 65 MPH.
A little more info would be nice... what engine/drive train/model/year RAV4 do you have?
 

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MPG

Just got 26.6 on a long trip. 75 mph for most of it. Can't bring myself to slow down, but if I did, i'd bet the MPG would be better.
 

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TaxiGuy said:
At 14K, I'm getting 25-26mpg at fillup in mixed driving.
Nice MPGs guys. I usually get like 20-22 mpg in all city driving, and have never broken the 27 mpg barrier. But I drive mostly very short distances in the city (3-4 miles), and rarely ever on the highway. But I am hoping it will get better when the car gets a bit older, I have 5,000 miles on the clock thus far.
 
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I have measured evey tank since I got the car new 5 months ago. I am averaging 22.1 mpg. Most of my driving would be considered suburban (stop and go, up to 80 kph), on the highway it is pushing 24 mpg. With the trailer, about 16. Driving style doens't seem to mater much, how much weight I am carrying, and the air temp seem more important factors. I have the V6 4WD.
 

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A mix of city/hwy driving commuting to work. For a 4WD V6, I can't complain.



The RAV4 is pretty high geared in 5th I noticed. At 70 MPH, I am only turning 2000 RPM.
 

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Coasting hills in neutral has negative impact on the fuel consumption. At least V6 has a very aggressive (in my opinion) fuel management and as a result at even the slightest downhill it cuts the injectors and the threshold for reconnect is very low (below 1000rpm). Going downhill in neutral prevents cutting the injectors and as a result instead of 0 gallons / hour it will use idle consumption which for the V6 is around 0.3 gal/hour. I would expect that I4 has a similar fuel management.
My consumption (V6) is ~19 mpg in the city and 27-30 on the highway depending on the terrain/number of persons in the car.
I'd heard that modern automatic transmissions cut fuel when the throttle is lifted. But I coasted down a pretty steep mountain road - about 3 miles in neutral, very careful not to apply any throttle. The gas needle looked like a minute hand on a sweep hand clock. You couldn't see it actually move, but look at it every 30 seconds and the movement was easily detectable.

What I've noticed is that when I coast in gear, the engine drage, then there's a boost as the vehicle hits a certain speed and that boost (fuel delivery) stays on until stopping.

I've also noticed the fuel cutoff in my 1996 VW golf manual. I'll start decelerating in gear and about 3/4 second after lifting off the throtle, I'll feel the engine dragging. So this isn't just an automatic transmission thing.
 

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The rav4 does not have a coast gear like the gm sedans. It stays locked in 4th even going downhill.
I have tried all ways of driving and it seems to get the best mileage in very hilly terrain with the speed below 50 mph, even better at 30-40 mph.

The problem with engine braking down hill is the car slows down if the hill is not steep. Not good. You then have to burn fuel to hold your speed or speed back up at the bottom.

If the hill is steep enough for you to maintain speed while in gear and no fuel, your mileage is infinite.

If the hill is not steep enough to hold speed while engine braking, you either give it some fuel or go to N and burn fuel at idle rate. If you can maintain enough speed in N to where you are burning less fuel at idle than you would be by driving then your mileage will be proportionately higher than your average.

Not having a coast gear drives me nuts when I have always had one and seemed to get good mileage with one.

Turning the engine off while rolling down the road can have certain problems depending on the situation. It seems toyota has found a somewhat sweet spot for the rav4 with gearing and not coasting. 4th gear is direct drive, and when above the minimum shift speed it remains locked. This means that the engine is either cutting fuel completely while going down hill or at least using less by using gravity to reduce the required power. If the hill is not steep enough to cut fuel, the engine could use less than idle if the engine load is reduced enough. Where that load point is, I don't know.

The big question is whether or not the fuel used while going downhill is more or less than at idle. If it's less than idle, we have an improvement by staying in gear. If it's more than idle, then we could benefit by having a coast gear.

i think the biggest factor would be how fast you are going down the hill because that will determine engine rpm, which determines fuel demand to some degree. If we had several grades of slope and a scanguage, I think we could make a quick determination of how this all relates. Tire pressure is a big deal and would need to be at a set point, or multiple points for better data collection.

maybe toyota has already done this and planned for "most common conditions"? I would hope so, but that's all I can do right now.

If someone has a scanguage and wants to do these tests, that would be great. I would be plenty happy to do them since we have lots of different hills around here, but I don't have a scanguage. I am near Eau Claire, WI if anyone wants to get together and learn.
 

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When I coast, I do it in Neutral. That's my "coast gear".

The costing in gear comment I made was steep and continuously downhill. I did not need to apply throttle for about two or three miles. Sometimes I even had to shift down to 3rd or 2nd to keep from using brakes and not drive too fast for the curvy road.

My mileage during this test was far from "infinite". I was surprised to see my gas tank meter fall perceptibly.

I refrained from coasting in neutral for the length of this test period.

I may repeat this test with the trans in 4th instead of Drive (or lower gear to keep from going too fast).

I wrote this partly in response to some statements that there's no need to coast recent versions of this car in neutral to save gas and that, in fact, it gets better fuel if left in gear since the gas is automatically cut when the car is decelerating in gear. My observations are that, that is not the case.

I will continue to coast when it is safe. It saves wear on the transmission and probably yields better fuel mileage.

Thanks for the analysis.
 

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When I coast, I do it in Neutral. That's my "coast gear".

The costing in gear comment I made was steep and continuously downhill. I did not need to apply throttle for about two or three miles. Sometimes I even had to shift down to 3rd or 2nd to keep from using brakes and not drive too fast for the curvy road.

My mileage during this test was far from "infinite". I was surprised to see my gas tank meter fall perceptibly.

I refrained from coasting in neutral for the length of this test period.

I may repeat this test with the trans in 4th instead of Drive (or lower gear to keep from going too fast).

I wrote this partly in response to some statements that there's no need to coast recent versions of this car in neutral to save gas and that, in fact, it gets better fuel if left in gear since the gas is automatically cut when the car is decelerating in gear. My observations are that, that is not the case.

I will continue to coast when it is safe. It saves wear on the transmission and probably yields better fuel mileage.

Thanks for the analysis.
gas tanks usually have a baffled chamber for the fuel sensor and pump. Your needle dropping was likely the fuel shifting in the tank and the chamber slowly draining to match the fuel level in that part of the tank. I've seen it too.
 

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How on earth am I getting 17L/100km? Which is about 14Mpg. My 2011 Rav4 is a 4WD 4cyl with no trouble codes. I do mostly city driving with some very rough roads. I use the AC almost all the time because of high temperature. Vehicle has about 140k Miles on it.
 

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How on earth am I getting 17L/100km? Which is about 14Mpg. My 2011 Rav4 is a 4WD 4cyl with no trouble codes. I do mostly city driving with some very rough roads. I use the AC almost all the time because of high temperature. Vehicle has about 140k Miles on it.
City driving will yield the worst gas mileage and depends how much stop and go you do. I do 99% city stop and go most of the time and yes the gas mileage sucks so why bother looking at gas mileage. Fuel mileage is fantastic when doing all highway driving.
 

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I vaguely remember an episode of Canadian Show Driving Television; they took several vehicles of different sizes and tested fuel consumption over 2 equal periods of time and distance (no hybrids). One period they drove very conservatively, the next, aggressively, to see what the fuel consumption difference would be. The actual average difference was only about 6% over all the vehicles. I thought it would be much higher, in the 15-20% range, but I started driving in the 70s with big inefficient cars with carburetors.
 

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gas tanks usually have a baffled chamber for the fuel sensor and pump. Your needle dropping was likely the fuel shifting in the tank and the chamber slowly draining to match the fuel level in that part of the tank. I've seen it too.
But something had to cause the draining. And it must be associated with changing levels in the fuel tank - fuel consumption.
 
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