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First, my '94 850 is getting about 24 MPG overall, about 30 on the road. No complaints with that.
As always, I'm keeping up with all maintenance, inlcuding filters, state of tune, tire pressures, blah blah blah, and driving with a fairly light foot. So all the easy thing for mileage improvements have been done. I still need to check my O2 sensor function though.
With gas prices what they are, what else can be done? Can ECMs be tweaked for improved mileage? What about different cams? (Yeah I know, that probably wouldn't ever pay for itself), anything else?
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Hi Champ,
It might sound extreme but if you do a lot of driving at highway speeds, consider some aerodynamic changes.
Tape up your fog lights or grilles and the seams around the center grille / headlights. Keep your incoming vents closed. Make the air go around your car instead of through it. It helps a little but maybe not worth the weird looks or potentially the discomfort of not getting fresh air.
If you've got 'big hole' wheels, go to something smoother. Reducing wheel weight will help, too, but maybe not worth the expense. If you can drop from a 17lb wheel to a 13lb wheel, I've read that it's like removing 100 lbs from the car. Never really tried it myself.
I've gotten a 2mpg increase from oil additives and a K&N filter in the past but that was on an older / less efficient car.
I hope you can break 25mpg! I'm trying to get my V70AWD up into the 23mpg range now (currently around 19 or 20.)
Mike K
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Oh, I get 30 MPG on occasion on the road, more like 28 regularly, and overall average with in-town driving is 24. I don't want to go extreme inthe sealing of gaps and all, and I have the wire wheel look rims ( forgot what they are called).
I just think it'd be great if I could make my existing car do even better!
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posted by
someone claiming to be BG
on
Wed Mar 26 15:27 CST 2008 [ RELATED]
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Smooth wheels will help, especially if the rest of the car is reasonably streamlined. The contemporary trend to equip cars with 19-inch or larger wheels with all sorts of spokes and protruding allen bolts is very poor for fuel economy, along with many other reasons that make such wheels an outstandingly stupid choice for a normal road car.
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Are you using synthetic engine oil? If it is an automatic, have you put synthetic ATF in it? Have you used a good gas additive, such as AMSOIL PI or BG-44K?
If you put AMSOIL synthetic engine oil and ATF in it, and use a good fuel additive, I would think you could pick up 3-5% fuel savings. It has worked for me for over 30 years. Actually, fuel savings are a bonus to the other benefits.
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After the invention of clearcoat paint for the masses, a lot of people forget to wax their cars with paste wax. Removing the friction usually helps when doing highway driving.
Using 195 tires will not make your car unsafe. Unless you like cornering under full throttle, the added roll resistance will only hurt mileage. Besides, they make all kinds of compounds for tires at 195 as in the 205 width.
Klaus
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The 164 has a new home, all I am left with are a 95 854T and a 98 V70R :)
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posted by
someone claiming to be BG
on
Thu Mar 13 16:22 CST 2008 [ RELATED]
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Waxing is a great idea, but is highly unlikely to help with friction on an automobile. There is too much turbulent flow over the surfaces. With an airplane, that is another matter. The experiment to perform would be to mount some sort of smoke device at the front bumper of your Volvo. Then, as you drive down a road, have a friend hold a video camera out the rear window and photograph the flow patterns across the roof. The "right" way to do it is to rent time in a wind tunnel....
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I have waxed the leading edge of the wing on a small plane. It went 5 knots faster (air speed) at the same rpm.
And it certainly feels better driving a freshly waxed car :)
Klaus
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The 164 has a new home, all I am left with are a 95 854T and a 98 V70R :)
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this may or may not apply to Volvo 850's but...
I owned a car from another manufacturer and when it was time to replace the factory tires the shop was out of the "ideal" size 13" 205/65 and sold me the thinner tire 13" 195/65. the 195's seemed fine for everything, i didn't notice any difference in MPG but i DID notice the difference in turning the wheel in parking lots. it was more difficult to turn in parking lots with the thin tires. id love to get even slightly better MPG and am wondering about this tire question/puzzle.
so i wonder...
does less tire contact (narrow tire) surface = less rolling friction but more turning friction???
and does more tire contact (wider tire) surface = more rolling resistance and easier turns???
my unscientific observation showed results that puzzled me and didn't seem to correspond to my freshman physics classes. please share your insight...
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-woodsytf '95 850 wagon 157k
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Factory tires tend to have a harder compound than what tire stores try to sell. Seems that you got a set of "stickys" with more aggressive tread.
Normally, your gas mileage will decrease by 2-3mpg with brand new tires of the same size until some of the tread wears down.
13" wheels????
Klaus
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The 164 has a new home, all I am left with are a 95 854T and a 98 V70R :)
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the 13"s were on (shh, i'll whisper) a h-o-n-d-a.
but the difference in the effort required to turn my steering wheel was dramatic. i drove the car long enough to wear the skinny tires out and then go back to the wider tire... wider was better for that car.
i will likely need tires for my 850 non-turbo wagon next year so i am curious to see what pops up on this thread.
cheers!
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-woodsytf '95 850 wagon 157k
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Nothing wrong with that, lots of us have/had Japanese cars. Really nice, too, but no personality. And a tight squeeze for the rear passengers.
Klaus
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The 164 has a new home, all I am left with are a 95 854T and a 98 V70R :)
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Yeah, "Honda" does not answer my question. I'm keeping the 850. I'm just curious about more radical mods, such as cams, cam timing, ECU programming, thta kind of stuff. I dunno, Maybe Volvo's already done all of that for me.
Like I said, I'm happy with my mileage, just curious waht else could be done, and what kinds of gains could be made.
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posted by
someone claiming to be fixit2003
on
Wed Mar 12 05:43 CST 2008 [ RELATED]
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I think you're doing pretty darn good allready! You can always reduce your weight by only half filling the tank and taking any unneccessary stuff out of the trunk.
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Ain't no junk in my trunk!
Dropped about 35 lbs myself too!
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Try going high on your tire pressure. My S60 owners manual prescribes the usual 32/30 for comfort, but recommends 38psi on all 4 wheels for optimum fuel economy. I run about 36psi and get 27/33 in city/highway real world mpg. That beats the EPA's estimate by about 10%. Handling and braking are still fine at 36 or even 38psi, but the ride is a bit more jittery. I've gotten used to it.
Low rolling resistance tires like my OEM Michelin Energy are purported to get better fuel economy. There's a website with a somewhat dated list of "green" tires and a discussion of the effects of rolling resistance. Nokian has a green tire that I may try next. http://greenseal.org/resources/reports/CGR_tire_rollingresistance.pdf
My own personal experience is that the so-called "performance" tires that the sales people at places like Tirerack push off on people really do get poorer fuel economy than OEM tires. That makes them VERY expensive over the lifetime of the tire.
The "light foot" you mention is the other big thing. A light foot also makes tires and other components last longer. So you save a lot of ways.
I haven't heard from a disinterested or convincing source of any mechanical, filter, or lubricant gimmicks out there that are worth the expense or trouble. Most of what you hear or read is just advertising copy. Tire pressure and driving habits are 99% of the battle.
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do you find the high pressure wearing your tires differently?
i would think that 38psi might wear the center of the tread out a pinch sooner.
i usually put 2~3 psi more in the tire than the car maker recommends... this way with the normal reduction i find in tire air over a few weeks time, i have spent most of that time at or slightly above the recommended pressure and dont wear my tire edges out or feel the slop when i make a turn.
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-woodsytf '95 850 wagon 157k
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I'm running 38 PSI too, makes it ride like a dump truck, but on all but the worst roads, it's worth it.
Oh yeah, I'm running 5W-30 in the winter, 10W-40 summer, Red Line gear lube and wheel bearing grease. Brakes don't drag, and the parking brake cables don't stick. So, I think I have the easy stuff convered, and am wondering what else might work so I can decide if the payoff is worth the expense of more intensive modifications..
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Although these are not choices that I would do myself, anyone desperate for more mpg's could reconsider the tires that one buys the next time. Select:
1) narrow, high-profile or aspect ratio, e.g., 70 or 75 or higher.
2) high-mileage, and/or rated traction=C, model tire -- this ensures a harder rubber compound.
These will reduce "rolling resistance", and thus increase your mpg.
Not that I would do it, though -- I like maximizing my traction, instead.
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I like traction too. I've found it usefull in cornering, starting, stopping, and everything except anti-gravity flight .
Seriously, I'll keep stock tire sizes, but I did find a decent balance between traction and so-called low rolling resistance tires in a Khumo.
Thanks!
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Tyre pressures are crucial for good fuel economy. The engine runs less efficient when it is cold and you can even smell the petrol out of the exhaust when it is started. Until the engine reaches normal operating temperature, the O2 sensor is doing nothing. In fact the 02 sensor only works when you are cruising and idling. Otherwise it is just stuffing petrol straight into your engine like a big pair of dirty twin choke webbers of olde. The quicker the engine warms up, the more economic it will be in that period. Something I have always wanted to try but never got around to it, was to have a heat source, say a lamp, under the sump, to warm the oil beofre starting out in the morning to see if this will speed the warm up process or just confuse the ECU. I don't know. Another idea to aid warm up would be to equalise the pressure at the radiator by spinning the electric radiator fan in reverse so it is blowing out the way and reducing/stopping airflow into the engine. This wouldn't work if you had air-con on of course. The fan would have to vary its speed releative to road speed too.
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Tek
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How about adding a curtain in front of the radiator like the PV had? My '60 SAAB had one and really needed it on cold days.
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'96 855R,'64 PV544 driver, '67 P1800 basket case, '95 855, '95 854, the first three are mine, heh, heh, 435,000 miles put on 9 bricks
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