Optimal speed for best MPG??
09-18-2004, 11:23 PM
#41
Moderator Alumnus
Originally Posted by fuque
That's nothing - I've gotten MPG so high it's off the scale (the MID just says "> 50"). One time I took a snap of the MID with my shitty camera phone. It's hard to read, but the MPG is 48 at an average speed of 72 MPH.
Hey, anyone could simply get ">50" on the downhills highway... don't put your foot over the pedal... LOL
(The car is moving without any fuel, this MID definitely will show ">50" after you reset it to re-calculate) 
09-18-2004, 11:43 PM
#42
Moderator Alumnus
Originally Posted by Road Rage
I have seen as high as 35 in the 50 mph zone or slightly below, as I predicted, but like you, I cannot stand it too long. I crusie in the 68 mph range and get about 31-32 with the 5AT - it is amazing. I wonder if the system is accurate?
Well, I have 17k mileage on my car now, and have record all my mileage/gallons info into my database since Day 1. In general, if your MID reads and displays MPG < 25, it's quite accurate.
But, I recently found out some of high MPG reading (>25) was not quite accurate after I calcuated my own mileage/gallons info. (I used my own standard method to fill up the tank since 1990 and have begun to record all my fuel usage/data into computers since that time)
Ok, I'll have a few trips soon and will tell you more after that.
09-19-2004, 04:06 PM
#43
Not a Blowhole
Rets, that is what I was thinking as well. I think a good GPS would help, but the "fillup" technique is not very precise, as those pumps can vary.
Others: Yes, one can get >50 mpg re-setting and then rolling downhill, but look at fuque's miles driven and time duration. Hmmmm??????
Others: Yes, one can get >50 mpg re-setting and then rolling downhill, but look at fuque's miles driven and time duration. Hmmmm??????
02-29-2008, 04:44 PM
#44
Cruisin'
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Originally Posted by Slava
I have about 6,000 miles on my exactly 2 months old automatic TL and just saw something weird for the first time today.
Normally I drive without too much traffic and get about 26-27-28 MPG if my speed is about 75 to 80 MPH. I thought that was pretty good considering 28 MPG is max as stated on the sticker
Well, today after the fillup at the gas station that was right next to the freeway I reset the trip computer right as I got on the freeway. There was some traffic there so I was going about 55-60MPH. When I checked my Trip Computer after about 15 miles of such driving it said 33 MPG
As traffic eased up and I went to my normal 80MPH the MPG slowly but surely went down all the way to 28
On the one hand it's great that my car is capable of such mileage, but on the other hand NO WAY will I be driving this slow to attain it.
So I was wondering what is the highest mileage anyone ever gotten and at what speed? Of course I am talking about highest gear so 5th for Auto and 6th for Manual.
Normally I drive without too much traffic and get about 26-27-28 MPG if my speed is about 75 to 80 MPH. I thought that was pretty good considering 28 MPG is max as stated on the sticker
Well, today after the fillup at the gas station that was right next to the freeway I reset the trip computer right as I got on the freeway. There was some traffic there so I was going about 55-60MPH. When I checked my Trip Computer after about 15 miles of such driving it said 33 MPG
As traffic eased up and I went to my normal 80MPH the MPG slowly but surely went down all the way to 28
On the one hand it's great that my car is capable of such mileage, but on the other hand NO WAY will I be driving this slow to attain it.
So I was wondering what is the highest mileage anyone ever gotten and at what speed? Of course I am talking about highest gear so 5th for Auto and 6th for Manual.
03-02-2008, 05:34 AM
#45
Morbid
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Keep the RPMS under 2000 on the highway, keep them at or around 1500 FTW!
I saw a post about national speed limits, as a side note my second car, a 1994 Chevy Caprice 9C1 (retired po-lice car), came with a sticker that said 'NOTICE close windows above 140MPH'
I saw a post about national speed limits, as a side note my second car, a 1994 Chevy Caprice 9C1 (retired po-lice car), came with a sticker that said 'NOTICE close windows above 140MPH'
04-03-2009, 12:29 PM
#49
Instructor
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If you coast in gear the engine is connected to the tires and the tires is what's keeping the engine rpm up, not fuel. Therefore, when coasting in gear in a MT car you're not using any gas at all as the tire spin is what's driving the engine.
This is another reason why it's widely acknowledged that MT cars get better gas mileage than their AT equivalent.
So stop Neutral coasting it doesn't save gas; it's dangerous and illegal in many states.
11-21-2009, 10:08 AM
#50
4th Gear
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When the car is in gear there is drag present there for reducing efficiency
For a MT car shifting out of gear and Neutral Coasting will not net you better MPG. When neutral coasting the engine is disconnected from the tires and idles using a small amount of fuel.
If you coast in gear the engine is connected to the tires and the tires is what's keeping the engine rpm up, not fuel. Therefore, when coasting in gear in a MT car you're not using any gas at all as the tire spin is what's driving the engine.
This is another reason why it's widely acknowledged that MT cars get better gas mileage than their AT equivalent.
So stop Neutral coasting it doesn't save gas; it's dangerous and illegal in many states.
If you coast in gear the engine is connected to the tires and the tires is what's keeping the engine rpm up, not fuel. Therefore, when coasting in gear in a MT car you're not using any gas at all as the tire spin is what's driving the engine.
This is another reason why it's widely acknowledged that MT cars get better gas mileage than their AT equivalent.
So stop Neutral coasting it doesn't save gas; it's dangerous and illegal in many states.
10-20-2014, 10:58 PM
#52
Drifting
I bet if I could muster the courage to only go 55 mph, I would get 36+ MPG. With that said, I can easily get 30MPG going 68-72. For me that's the best speed when you have to get someplace and don't want to spend an extra hour when driving 400 miles.
The TL's gearing and aerodynamics are great so there doesn't seem to be a huge difference in steady speed highway cruzing when you compare it to the time saved. On my typical San Diego to Santa Cruz run, it would take 1.5 hours longer at 55mph and I would get pretty much run off the road in some places.
The TL's gearing and aerodynamics are great so there doesn't seem to be a huge difference in steady speed highway cruzing when you compare it to the time saved. On my typical San Diego to Santa Cruz run, it would take 1.5 hours longer at 55mph and I would get pretty much run off the road in some places.
10-21-2014, 12:26 AM
#53
Just to chime in on this thread,
Took my new 08 TL 5AT from home in Toronto to a friend's cottage on the shores of Lake Erie, a distance of about 305 km return (190 miles).
Reset the MID trip computer on departure. On the way out there I was showing 7 or 8 L/100km (33 MPG). On the way back, I held an almost unbelievable 6 L/100km (39 MPG) all the way into downtown Toronto.
Used Cruise Control as much as possible. No need for A/C. Avoided exceeding 4k revs except to pass quickly. I'd set a speed at or between 110-120 km/h (68-74 MPH), occasionally passing at 130-140 km/h (80-86).
Michelin Pilots, the original tires, in fact.
On my daily commute, a mix of city and highway, I'll usually get something between 8 and 9 L/100km (26-29 MPG).
Took my new 08 TL 5AT from home in Toronto to a friend's cottage on the shores of Lake Erie, a distance of about 305 km return (190 miles).
Reset the MID trip computer on departure. On the way out there I was showing 7 or 8 L/100km (33 MPG). On the way back, I held an almost unbelievable 6 L/100km (39 MPG) all the way into downtown Toronto.
Used Cruise Control as much as possible. No need for A/C. Avoided exceeding 4k revs except to pass quickly. I'd set a speed at or between 110-120 km/h (68-74 MPH), occasionally passing at 130-140 km/h (80-86).
Michelin Pilots, the original tires, in fact.
On my daily commute, a mix of city and highway, I'll usually get something between 8 and 9 L/100km (26-29 MPG).
10-21-2014, 12:42 PM
#54
Coasting in Neutral or Gear to Save Gas - Coasting and Fuel Economy - Popular Mechanics
10-23-2014, 01:44 AM
#55
Mr. Detail
Just drove out to Phoenix from Dallas this past weekend. Due to my son's transmission losing top gear about 200 miles outside of Dallas and him having to travel the next 800 miles at 4000-4200 rpm in 3rd gear (4 speed automatic which we had to have rebuilt when we got here), that kept our speed to around 60-65 mph.
My car was right around 1800-1900 rpm and gas mileage was pretty decent for a 3 liter V6
And what's funny is my son was still getting about 27-28 mpg in a 2000 Prelude that is EPA rated at around 26 mpg freeway-and he was in 3rd gear instead of 4th. Go figure.
My car was right around 1800-1900 rpm and gas mileage was pretty decent for a 3 liter V6
And what's funny is my son was still getting about 27-28 mpg in a 2000 Prelude that is EPA rated at around 26 mpg freeway-and he was in 3rd gear instead of 4th. Go figure.
10-23-2014, 01:13 PM
#58
Keep Right Except to Pass
Damn, there are some old threads being bumped lately.
In theory, the ideal speed for fuel economy is the one that allows you to cruise comfortably in your highest gear without lugging the engine or needing to downshift when you go up a hill or the like. The answer to the question about "the ideal speed" will therefore differ for automatic- and manual-shift TLs due to the different gearing.
Of course, in this thread the original poster referred to his TL having the automatic shift, and most automatic users seem neither to know nor care what gear they may be in at any particular time. I think this is one major reason why a lot of media reports blithely quote an "ideal speed" as though it applied to all cars, which of course is a load of nonsense. The average American driver is not sophisticated enough to understand the concept of which gear to use.
I've found over the past ten years that in my TL, which is a six-speed manual, the optimum speed for shifting into sixth gear is around 62 mph, roughly right on the 100 km/h mark on the speedometer. While I could shift up at a slower speed than that, I've found it doesn't do as well going up hills if I'm much below 62. Engine revs too low and I wind up downshifting.
But it also doesn't make all that much difference in fuel economy if I go a bit faster than that, either, because in all-highway driving I've averaged 30 or 31 mpg at average speeds of 70 or 71 mph. Could I maybe do a bit better at 62 mph? Perhaps, but (a) I'd be obstructing traffic on roads where the speed limit is 65 or 70 mph and (b) the difference wouldn't be significant enough (maybe 1 or 2 mpg) to make it worth the trouble.
In theory, the ideal speed for fuel economy is the one that allows you to cruise comfortably in your highest gear without lugging the engine or needing to downshift when you go up a hill or the like. The answer to the question about "the ideal speed" will therefore differ for automatic- and manual-shift TLs due to the different gearing.
Of course, in this thread the original poster referred to his TL having the automatic shift, and most automatic users seem neither to know nor care what gear they may be in at any particular time. I think this is one major reason why a lot of media reports blithely quote an "ideal speed" as though it applied to all cars, which of course is a load of nonsense. The average American driver is not sophisticated enough to understand the concept of which gear to use.
I've found over the past ten years that in my TL, which is a six-speed manual, the optimum speed for shifting into sixth gear is around 62 mph, roughly right on the 100 km/h mark on the speedometer. While I could shift up at a slower speed than that, I've found it doesn't do as well going up hills if I'm much below 62. Engine revs too low and I wind up downshifting.
But it also doesn't make all that much difference in fuel economy if I go a bit faster than that, either, because in all-highway driving I've averaged 30 or 31 mpg at average speeds of 70 or 71 mph. Could I maybe do a bit better at 62 mph? Perhaps, but (a) I'd be obstructing traffic on roads where the speed limit is 65 or 70 mph and (b) the difference wouldn't be significant enough (maybe 1 or 2 mpg) to make it worth the trouble.
10-23-2014, 07:52 PM
#59
Intermediate
I could be mistaken, but I have always thought that an engine is at its maximum efficiency, when it is operating at the highest point of its torque curve…
I understand that even if that is true…there are many other variables that come into play.
I understand that even if that is true…there are many other variables that come into play.
10-25-2014, 08:59 AM
#60
All said and done I'm a little old fashioned when it comes to this. I fill up the tank, take the trip and then do the following: refill the tank and divide miles driven by gallons used = mpg. I then take miles driven and divide by time to drive (less piss breaks) to get average speed. I recently got 31 mpg on 300 mile trip averaging 70 mph.
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