Economics of hypermiling vs. vehicle longevity

[elhigh]

Originally Posted by Frank Lee

1) Grille blocks, engine heating in the summer, engine insulation. He claims that higher temperatures for longer times is reducing the lifetime of the engine. He says that the higher temperatures actually change the molecular composition and weakens the metal."

Pshaw. The temps aren't that much higher. Insulation as it is on my stuff mainly serves to prolong cool-downs thus reduce cold starts while not increasing running temps- according to coolant gauge- all good stuff.

Pshaw indeed. I saw that and rolled my eyes. Yeah, hotter, maybe...and if the grille block is done wrongly the engine will overheat. But overheating an engine isn't the same as holding a blowtorch on a piece of metal until its crystalline structure starts to change.

[bestclimb]

To evaluate the economics lets start with what we can save then compare it to what it costs.

In 100,000 miles of driving and getting 30mpg you spend about $13,333 in fuel. (at an average of about $4 per gallon

If you hypermile and increase your mileage;
at 35 you spend $11428
at 40 you spend $10000

If you get 33% over EPA which pretty easy to do looking at some fuel logs and by personal experience, the maintenance costs would have to be $3,333 more.

With reduced wear on tires and brakes you would have so see a significant increase in wear for it to not be cost effective.

1) Higher temps does weaken metal but the effect is not significant till you getting into the 300-400 f levels when strength of aluminum really drops off dramatically. (this is one of the reasons piston aircraft CHT temp red lines are set where they are). A water cooled engine would boil over well before then. The only time I ever saw elevated temps was climbing on an unseasonably warm day with a full grill block, mea culpa, trimmed open my grill block and the problem was solved.

2)Thinner oils do not increase friction, they do decrease the oil film thickness which may allow particles suspended in the oil to cause wear (a bit of material contacting both surfaces at the same time). keep your oil clean and think long and hard if you are considering using thinner than recommended. Using a too thin oil can cause problems if the oil won't stay on bearings due to loose tolerances or low pressure, so don't use thin oil if it is a concern as it's benefit is small.

3) They say most wear happens at start up, which is true at cold starts, as oil pressure is not up and oil has dripped off parts, no oil film and loose tolerances due to cold parts causing wear (thinner oil can help if it will stay where needed by getting to parts quicker) A warm start does the same amount of wear as would have happened while idling for the same amount of time as the start (possibly a net of reduction of wear)

As to wear on the starter, meh, we would have to go through quite a few starters to cut into the fuel savings, in my experience it just ain't happening and I think a lot of other people have a similar experiences.

How would starting and stopping wear on a cooling system, that makes no sense to me.

Since I started hypermiling my batteries have lasted about as long, the cold and inactivity have been harder on them than an increased number of starts (which is minimal due to bump starts)

Clutch wear may be a concern but a bump start is easier on a clutch than a big down shift without rev matching and I see and hear people do that all the time. There are also examples of people hypermiling a couple hundred thousand miles on a clutch. If it were causing a problem we could be hearing about it.

[mcrews]

@BESTCLIMB
see what a holistic & comprehensive approach will do!!!!!!

ALL that worry about running a smelting plant under the hood.

What is missing from a VERY complete analysis is the subliminal, subtle improvements.
1. ecomodders/hype milers tend to be more aware of the details of their vehicle. so the catch things before they go bad.
2. most are running scangauge/mpggauge/etc and are constantly monitoring.
3. almost all 'drive easier' creating LESS wear over time
4. most are inherently cheap...we want parts and tires etc to last a long time

[Fat Charlie]

Originally Posted by bestclimb

Clutch wear may be a concern but a bump start is easier on a clutch than a big down shift without rev matching and I see and hear people do that all the time. There are also examples of people hypermiling a couple hundred thousand miles on a clutch. If it were causing a problem we could be hearing about it.

My Subaru's clutch died after 41,000 miles of hypermiling. Okay, the clutch had 166,000 miles on it when I started hypermiling...

[Xist]

Originally Posted by Fat Charlie

My Subaru's clutch died after 41,000 miles of hypermiling. Okay, the clutch had 166,000 miles on it when I started hypermiling...

Heh.

I wish that my Subaru had a clutch. Why do people purchase automatics?

Well, considering how people drive, they would probably wear out clutches quickly...

[RiderofBikes]

...THIS

Originally Posted by mcrews

4. most are inherently cheap...we want parts and tires etc to last a long time

62,252mi on OEM Kumho Solus KH21 185/60/15 tires
Rotated 1 time only still have 9k mi to go before replacing...
Still don't feel a need to Balance nor Alignment until new tires put on also moving up to better 185/65/15 for $30 less for a full set compared to OEM brand

Only 5 oil + filter changes (could probably had got away with only 4)
OEM Front brake pads replaced @ 25k mi(they were junk)
w/ $60 Ceramics w/lifetime warantee(basically when these go bad, i get new pads for free )

Considering my fuel log status, What ive been able to save, has already paid for the maintenance performed + the tires i still need to get... Breaking even, then next year i'll actually be saving, and applying towards insurance haha...

[NeilBlanchard]

I have a grill block that covers at least 3/4 of the openings, and my engine temperatures are totally normal. The electric fan kicks on maybe a couple of times a year more than it might otherwise, and various bits like exhaust headers *might* be hotter, but the engine has never overheated.

Modern engines use thinner oil like 0-20W or 5-20W, and I very much doubt that using thinner oil makes any difference to the FE.

And almost all the time that I EOC - I bump start, so only when I shut off the engine at a stoplight do I use the starter. I've got over 150,000 miles on my xA and still on the original clutch and starter.

I've saved probably 1,500 gallons of gas, so even with buying two sets of video cameras and monitors, I've come out way ahead by ecomodding and ecodriving.

[redpoint5]

Originally Posted by SentraSE-R

My engine ran cooler with engine on P&G than it did cruising at roughly the same steady speed.

It follows that an engine would run cooler overall if it is operated more efficiently. The more fuel burned, the hotter things get.

Originally Posted by Occasionally6

Something else: The premise behind pulse and glide is to operate the engine at high load. I expect that is also going to wear out the engine faster than operating at 'normal' loads. Against that the duty cycle is lower.

I tend to think the engine would wear faster running it at higher loads than normal. But then again, running higher loads and lower RPM would have the pistons travel less distance overall, so perhaps wear is approximately equal between the 2 styles of driving?

[elhigh]

I've been hypermiling my truck almost since Day One. It needs a new clutch. It needs its first new clutch. I think teaching my boys how to drive stick is what killed it.

It's on its third starter. The first one died around 2004, the second one, a no-name reman, died early this year. The new one is factory OEM, so I have better hopes for it.

I replace front brake pads about every five years. Maybe. I coast a lot.

I replaced the rear brake shoes for the first time three years ago.

I don't think my vehicle is suffering much for the sake of my wallet. Rather, I think it's being coddled, very gently coddled, and the result is an awful lot of avoided cost.

[songman]

Originally Posted by euromodder

Which may not go down well with the catalyst ...

I believe this theory has been comprehensively disproven.