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I just purchased my first manual transmission Volvo, a 1986 240DL. It's the 4-speed with pushbutton overdrive, and I'm still getting used to driving it. The shift points are different than the modern manuals I've driven, and the user's guide doesn't specify the best shift points. I have the DL, so no tachometer to help me.
Others with similar cars-- where (approximately) do you shift, in MPH? I've been doing approximately:
1st-2nd: 11 mph
2nd-3rd: 25
3rd-4th: 35
4th-overdrive: 51
I'd love to get a little better MPG, so any suggestions would be great.
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Nobody has mentioned the fuel economy gauge or manifold pressure gauge.
I installed one in my 91 245 M47. I ignore it when trying to make time but it is useful when driving conservatively... It is especially useful for finding an efficient rpm speed range on the highway going up long hills.
But the stock Volvo gauge is not a cheap or easy part to find. I'd think finding a VDO manifold pressure gauge wouldn't be that hard tho.
Bert
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I have an '84, also with the M46 4 speed + overdrive transmission. I usually shift:
1-2: 15 mph (3,000 rpm)
2-3: 30 mph (3,000 rpm)
3-4: 45 mph (3,000 rpm)
4-OD: 55 mph (2,700 rpm)
I get the same mileage as you, and I find that the car accelerates better with the shift points above than it does if I shift sooner - or later. Makes sense when you consider than peak torque is made at 2,750 rpm.
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I'd say that it does not make much difference when you shift as long as you are below the torque peak.
In my mind the two big factors in mileage are acceleration and speed. Force = mass X acceleration, the mass is constant, so the power required is related to the rate of acceleration. And the power needed to push the air out of the way goes up as the square of the speed. It takes 4 times as much power to go 60 than it does to go 30. The rate of fuel consuption is directly related to power produced.
Greg
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OK - I checked my shift speeds on my commute today (1990 240 w/ M47) I get a consistent 30 mpg.
1-2 12 mph
2-3 20-22 mph
3-5 38-42 mpg
I hit 4th (only) when slowing down
I drive the '98 V70 the same way, since new, and get upper 20s for mileage; have 354k on it with no engine or transmission trouble to date.
The car rarely sees over 3000 rpm. When I was teaching the kids to drive I suggested shifting so that they hit 1500 to 1800 rpm after the shift, which seemed to work.
I would suggest a tach -- should be available on ebay. You will have a white/red wire with connector behind the instrument cluster that plugs into it.
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I appreciate you checking your shift points, although I'm not sure they're relevant to me-- doesn't seem like I could skip 4th gear, as I need to be in 4th to engage the push-button OD.
Certainly getting the feeling that a tach is the answer, though I assume it would replace the clock, and I'll be sad to see that go.
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Swap in a big tach and small clock. Or put in a small tach (more rare).
They show up on TurboBricks a lot.
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For what it's worth, back when I had my '82 I always clutched when engaging and disengaging the electric overdrive...just seemed smoother on the old girl....never focused on actual mpg as I was just happy being in a Volvo.
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Hey Salt,
Uncertain about the other gears but I go into OD at 40
MPH. On the freeway in OD at 60 MPH (I'm usually in no hurry) I get 31 - 32 MPG. I've read to always clutch going into and out of OD. I always have and I've got the original transmission AND clutch with 247K miles and no problems with either.
Dukester '85 244 M46
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Difficult to answer you without a tach, but years ago I read that for the best shift points for economy you should shift well below the torque peak (around 2,700 rpm).
If you've got an M47-II transmission, this rpm equates to:
1st gear (4.03:1), below 15 mph
2nd gear (2.16:1), below 27 mph
3rd gear (1.37:1), below 43 mph
4th gear (1.00:1), below 59 mph
5th gear (0.80:1) -------
From a 240 owners manual, it also says, "Studies have shown that the best fuel economy is obtained by shifting gears at low engine rpm and high relative engine load." Of course, we used to call this (low rpm and high load) "lugging" the engine, so take this with a grain of salt.
If you're going to be close to lugging often, I'd suggest using higher octane gasoline to avoid ping and engine damage (despite the knock sensor), which of course cuts into your gas bill :-(.
Sorry I can't be more specific, but keep in mind that the load will vary with the slope of the road -- i.e., on the level or downhill, shift at lower speed, and when going uphill, shift at a higher speed.
The 240s used to have a "SIL" (Shift Indicator Light) on the dash, but not yours.
Good luck.
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The 240s used to have a "SIL" (Shift Indicator Light) on the dash, but not yours
'86 models for the U.S. market should have the shift indicator.
--
'80 DL 2 door, '89 DL Wagon
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I think it supposedly has a SIL but it doesn't work. From what I've read online, it's not worth the trouble to try to fix it.
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Might be just a burned out bulb.
Beyond that I wouldn't know what to advise.
--
'80 DL 2 door, '89 DL Wagon
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Ken C wrote --
"From a 240 owners manual, it also says, "Studies have shown that the best fuel economy is obtained by shifting gears at low engine rpm and high relative engine load." Of course, we used to call this (low rpm and high load) "lugging" the engine, so take this with a grain of salt."
I think Ken has misinterpreted the meaning of the owners manual statement. I believe the suggestion isn't to "lug" the motor (that is-try to accelerate at slower than minimum rpm) but to go through the gears with as open a throttle as possible/reasonable and to shift to the next gear at a relatively low RPM. That's what the BMW "e" models were all about a few years ago---low rpm torque peak.
I do have a tach in my M46 equipped 1980 245 B21F and find it accelerates most smoothly (high rpm in that motor just results in a lot of racket--and not much action) by shifting at around 3500 with the rpm falling to 2500 at the next gear. Works for me with 20-25mpg around Long Island and 27-29 on long trips. -- Dave
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Thanks guys. The engine on the 1986 supposedly has the M46 transmission and I'm getting around 24 mpg around town (mixed freeway and city streets with lots of traffic thrown in) so maybe that's the best I can hope for. Certainly being in a Volvo is satisfying enough.
As for the OD, when I shift into it (always with the clutch) while accelerating on the highway it sometimes feels like it takes a second to catch, so I'd been assuming I was shifting too soon (happens most around 49/50 if I try to jump the gun). I'll try waiting it out a little longer, and see if I can get into it while cruising at 40.
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A tach is a relatively inexpensive upgrade and an easy install.
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It could be other things if the OD is taking time to engage. Changing the fluid is preventive maintenance for the OD units.
I got around 20-22 mpg mixed driving, 25ish highway on my 84 240DL with a broken overdrive. The one time I got the overdrive to work for about 5 miles, I saw a massive jump in mileage. I drove like a jerk sometimes and other times like a grandma and never saw much change in mileage to be honest. If you have the B23 in that, it has a lot of torque and can take being shifted at as low a speed as the car will still accelerate from without lagging. No need to worry about a specific rpm, the factors determining fuel consumption are more complex than just the engine speed, unfortunately.
I'd look at things like spark plug gap (you can re-gap them, or replace them for <$2 each) and the air filter, and of course any missing vacuum lines or intake leaks. If the car's out of tune, it's going to be less efficient.
Also, my 84 240dl had a tach.
Cheers
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Regardless of the car I've always shifted by feel and sound. I try not to stress the car. You can also tell when there's nothing to be gained by any additional revving. I recently installed a factory tach in my 242 and found that what felt right before the tach turned out to be 3-3500 RPMs. For the best economy you could argue (and so would I) that you should shift earlier but it all depends on traffic conditions. No matter what you do you're not going to "hyper-mile" a 240.
I'll engage the OD any time it doesn't induce "lugging".
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