MPG while cruising without hurry

[foama]

In the light of covid19 confinement and curfew, I went for a cruise with my wife in our 1.0l car. This is the same car an idiot mechanic worked on when it was so full of gum the valves wouldn't close and it failed to start any more. The Mitsubishi mechanic removed the head and "fixed" it under warranty, but compression afterwards has remained only between 150psi and about 160 on all three cylinders but thankfully it doesn't burn oil. No idea what that nitwit did.

We drove along the Rhine valley region which is a flat area and there was no wind and not much other traffic on the country roads.
Here is a picture of the tach after about half an hour's drive. The MPG display was the same when we got home about one and a half hours later.
3.5l/100km works out to be 67 MPG/US. Not bad for a car with only 150psi compression.

How do I drive? I avoid high speeds, take my foot off the gas approaching a red light or traffic jam, and otherwise drive as if I were barefoot and there being thumbtacks on the brake pedal. The car has 165/65r14 Continental EcoContact5 LRR tyres at maximum allowable pressure being 3.0 bar or roughly 45psi.

There are plenty of good driving hints on Metro's pages, and on Ecomodder, see:
https://www.metrompg.com/posts/hyper...as-mileage.htm
https://www.ecomodder.com/

[MetroMPG]

Nice going, foama.

[MetroMPG]

That's a screaming good deal for Enasaves!

[javensbukan]

In the light of covid19 confinement and curfew, I went for a cruise with my wife in our 1.0l car. This is the same car an idiot mechanic worked on when it was so full of gum the valves wouldn't close and it failed to start any more. The Mitsubishi mechanic removed the head and "fixed" it under warranty, but compression afterwards has remained only between 150psi and about 160 on all three cylinders but thankfully it doesn't burn oil. No idea what that nitwit did.

We drove along the Rhine valley region which is a flat area and there was no wind and not much other traffic on the country roads.
Here is a picture of the tach after about half an hour's drive. The MPG display was the same when we got home about one and a half hours later.
3.5l/100km works out to be 67 MPG/US. Not bad for a car with only 150psi compression.

How do I drive? I avoid high speeds, take my foot off the gas approaching a red light or traffic jam, and otherwise drive as if I were barefoot and there being thumbtacks on the brake pedal. The car has 165/65r14 Continental EcoContact5 LRR tyres at maximum allowable pressure.

There are plenty of good driving hints on Metro's pages, and on Ecomodder, see:
https://www.metrompg.com/posts/hyper...as-mileage.htm
https://www.ecomodder.com/

Oh wow, that's really good! Also, I'm very jealous of your 'Eco meter'!...we don't get that here nor do we get the option for AS&G.

Best I've ever gotten is about 3.8-3.9 L/100km driving from Upper Tantallon back into Halifax along the old twisty highway that's relatively flat, about a 50 Km round trip, with speeds from 50-80 Km/h.

No modifications aside from suggested tire pressure and driving the car prudently at or slightly above the speed limit, it's a 2014 Mirage DE (1.2L) with the CVT and Kumho Solus HA31 tires.

These cars are crazy good on fuel if you don't drive like an idiot.

[foama]

These cars are crazy good on fuel if you don't drive like an idiot.

Aside from excellent EcoContact5 LRR tyres at max sidewall-stated pressure (3.0 bar / 45psi) and a well maintained car but unfortunately very bad, in fact really rotten compression (150psi) due to an idiot Mitsubishi mechanic, the car in the first post is completely normal.

Talking about not driving like an idiot:

It pays to fine adjust the nut behind the wheel!



@ Mark: The Nokian Nordman 7 are probably the best winter tyres available in Europe. In Norway they can be studded, in just about all other European States studs are prohibited.

[Mark]

@ Mark: The Nokian Nordman 7 are probably the best winter tyres available in Europe. In Norway they can be studded, in just about all other European States studs are prohibited.

The main two 165/65-14 size snow tires offered in the States are the Dunlop Winter Maxx (non-studded only) & the Nokian Nordman 7 (studded or non-studded). The non-studded Nordman 7 tires could still have studs added, because the hole for them are still there.

Ironically, studded tires are not allowed in Wisconsin or neighboring northern states. Winter/snow tires are not a requirement or law here either. I do wonder how some people get around with poor quality tires during the winter months?

I believe the Nordman 7 is Nokian's affordable snow tire that replaced their Nordman 5 tire. It's good to hear they are well received winter tires there. Nokian must have a tire plant in Russia, because mine were manufactured there.

[Loren]

Can you show us any data or research that proves over inflating tires beyond their maximum psi rating increases mpg?

It has been proven.

As I recall, it has to do with two things. 1. more pressure keeps the tire rounder, so that it's not constantly flexing the sidewalls and creating heat. (this is much of the principle of how LRR tires work) 2. you reach a point where you start crowning the tread and decreasing the contact patch.

It's not great for a lot of other things, but it absolutely increases MPG!

https://ecomodder.com/forum/showthre...ure-17151.html

[Mark]

It has been proven.

As I recall, it has to do with two things. 1. more pressure keeps the tire rounder, so that it's not constantly flexing the sidewalls and creating heat. (this is much of the principle of how LRR tires work) 2. you reach a point where you start crowning the tread and decreasing the contact patch.

It's not great for a lot of other things, but it absolutely increases MPG!

https://ecomodder.com/forum/showthre...ure-17151.html

Control, 35psi (manufacturer recomendation)
tyres at 10psi = 3.7% increase in consumption
tyres at 30psi = 1.2% increase in consumption
tyres at 40psi = 6.2% decrease in consumption
tyres at 60psi = 7.6% decrease in consumption

Those numbers don't prove much of a gain. A tire at 40 psi is probably not at the maximum psi rating of the tire. What is gained if the tire is inflated to the maximum rating of 44 psi verses an over inflated tire?

If we are talking about a tire rated @ 44 maximum psi tire inflated to 44 psi (not over inflated), the gain of going above that would be what? Maybe 1%. From the data share above I wouldn't estimate any more than that.

Looking at Metro's data below - a 50 psi tire did better than the 55 psi tire. How does that happen?

I never run my tires @ manufacturer recommended psi, but I do stay below the maximum psi rating of the tire.

When it's 90F plus in the summer & Eggman has just traveled a good distance in his Mirage, I would like him to pull out a tire gauge & share the psi of his tires at that moment. I sincerely hope he does that for us some day this summer.

A somewhat lame study I have read on this was done by Popular Mechanics. They drove a Honda Fit with recommended 32 psi tires and 45 psi tires & found very little difference in mpg. I wouldn't tout that as super accurate, because I have problems with how this study was done myself. Wind speed & direction in particular have a huge impact. They didn't keep all the variables consistent enough for me. Even getting a tank of gas somewhere else changes things. As a science teacher, I think Popular Mechanics was lazy in their testing of this. So don't bash me for sharing it. I've already done that!

https://www.popularmechanics.com/cars/a940/4199963/

I am finding very little data that shows over inflating tires enhances fuel economy. I am not talking about comparing an under inflated tire verses a fully inflated one here. I am talking about going above the maximum psi rating on the sidewall of the tire. Maybe there's a good reason for that? Who wants to be sued for something that shouldn't be recommended in the first place?

No one denies under inflated tires reduces fuel economy. I am just being the devil's advocate here. When I research this topic I find - over inflating tires to increase fuel economy is a myth.

Metro's shared data -

Raw results for PSI/feet travelled

20 / 479.3
25 / 524.8
30 / 621.0
35 / 621.0
40 / 639.6
45 / 687.5
50 / 702.0
55 / 699.3
60 / 702.0

[Eggman]

Can you show us any data or research that proves over inflating tires beyond their maximum psi rating increases mpg?

Some people way smarter than me beat me to it. I would have only bumbled the explanation and gotten lost looking or a Wikipedia article as a reference.

Those numbers don't prove much of a gain. A tire at 40 psi is probably not at the maximum psi rating of the tire. What is gained if the tire is inflated to the maximum rating of 44 psi verses an over inflated tire?

If we are talking about a tire rated @ 44 maximum psi tire inflated to 44 psi (not over inflated), the gain of going above that would be what? Maybe 1%. From the data share above I wouldn't estimate any more than that.

Not much. But that Vredestein number that goes to 51 looks pretty sweet, don't you think? Yet another Spinal Tap reference (Whew - got in my requisite Wikipedia link.)

When it's 90F plus in the summer & Eggman has just traveled a good distance in his Mirage, I would like him to pull out a tire gauge & share the psi of his tires at that moment. I sincerely hope he does that for us some day this summer.

I doubt I'll get to this. I don't put a lot of miles on Speck, and if last summer is any indication, it will sit in the driveway a lot.

However (and this is debatable) it is my understanding that an overinflated tire will develop less heat through internal friction than a normally inflated tire. Discuss.

I am finding very little data that shows over inflating tires enhances fuel economy. I am not talking about comparing an under inflated tire verses a fully inflated one here. I am talking about going above the maximum psi rating on the sidewall of the tire. Maybe there's a good reason for that? Who wants to be sued for something that shouldn't be recommended in the first place?

No one denies under inflated tires reduces fuel economy. I am just being the devil's advocate here. When I research this topic I find - over inflating tires to increase fuel economy is a myth.

A-ha! Here we have something nit-pickable. If you mean inflating more then the vehicle manufacturer's recommendation as found on the door jamb placard, then there are fuel economy gains to be had. If you mean inflating more than the tire manufacturer's criteria as found on the tire sidewall, you are spot-on correct - little is to be gained. But of course, all along you focus on the tire manufacturer criteria and not the vehicle manufacturer, so really there's nothing to see here.


Mark, I hear what you're saying and you make a lot of good points. If you think overinflating tires is not for you, I think that's great.

[MetroMPG]

Here's some more - I've done a couple of tests comparing coastdown distances at various tire pressures, including with RE92's - same size & LRR like the Enasaves:


from: https://ecomodder.com/forum/showthre...tire-2721.html


from: https://ecomodder.com/forum/showthre...tire-2721.html