Does Hypermiling Damge Your Vehicle???

[Jagdeep26]

Hello All,

First, I was hypermiling for a brief period, and saw great results in terms of my gas mileage. However, I was told by friends that by shifting from Drive to Neutral, coasting down hill, and then putting the car back in Drive, that I was likely causing damage to either the transmission or the engine. Hence I stopped. Those of you that have been doing it for a while, please tell me if I was doing it wrong, or if hypermiling actually does not damage your vehicle.

Second, I have heard that to hypermile properly, you have to inflate your tires to the max of what it says on the tire and not on what the car maker suggests (for example, the car maker suggests 29 psi, and the tire says 40 psi), that a hypermiler will inflate the tire to 40 psi. Some have said this is dangerous. Why would people say this? Please address both of these issues for me, because I don't want to do something that is dangerous or that could damage my vehicle.

Thanks,

Jagdeep

[abcdpeterson]

Welcome! Jagdeep26, Hope you keep hanging out here.
Lots of info to pick through and find what you want to use.

My opinions often get quested. But in friendly ways, that is what I like about things here.
So with that... here is my opinions on your questions.

Originally Posted by Jagdeep26

Hello All,

First, I was hypermiling for a brief period, and saw great results in terms of my gas mileage. However, I was told by friends that by shifting from Drive to Neutral, coasting down hill, and then putting the car back in Drive, that I was likely causing damage to either the transmission or the engine. Hence I stopped. Those of you that have been doing it for a while, please tell me if I was doing it wrong, or if hypermiling actually does not damage your vehicle.

Shifting from drive to neutral and back should not be a problem IF you don’t do something dumb.

Don’t put the car into reverse while moving.
Don’t put the car into park while moving.
Don’t floor the engine, redlining, then drop it into gear.
Don’t put the car into too low of a gear for a given speed.
Don’t try this at high speed 70-90mph?
Don’t try if your engine may stall.
Don’t do if you could have trouble getting back in gear.

-Some people will “rev match”, bringing the engine speed up so it the same speed as it would be if it was in gear.

-I have been driving for many years. At one time or another put every can I had into neutral while driving. I have never damaged a transmission.
-With a Manual transmission your going through neutral with every shift, with no damage. If you don’t do some rev matching in manual transmission your not going to get a smooth ride.
-Automatics I have never worried about it. The torque converter is a fluid coupling, IMO that fluid coupling will buffer out “most” everything.

-You “could” argue that cars with a lock up torque converter could have an issue, but then you would need to look at the conditions a lock up torque converter locks up in a given car. I have a lock up torque converter in my Mazda, I am comfortable putting that car in and out of neutral, and have.

-You could also argue your car needs to be flat tow able. I feel you would need a LONG cost in neutral before it would be an issue. Arguement agenst is stronger for this one if your turning your engine off while in neutral.

Originally Posted by Jagdeep26

Second, I have heard that to hypermile properly, you have to inflate your tires to the max of what it says on the tire and not on what the car maker suggests (for example, the car maker suggests 29 psi, and the tire says 40 psi), that a hypermiler will inflate the tire to 40 psi. Some have said this is dangerous. Why would people say this? Please address both of these issues for me, because I don't want to do something that is dangerous or that could damage my vehicle.

Thanks,

Jagdeep

IMO, there is nothing you NEED to do to “Hypermiling properly”. There is only Hypermiling - trying to get better MPG then EPA rating, or not hypermiling.
You should ONLY do things YOU want to do. NEVER drive in a way you would consider dangerous. NEVER drive how someone tells you to unless your or comfortable it is safe.

I firmly believe manufactures have listed a lower PSI to give satisfactory performance with smoothest ride possible.

“I” am TOTALLY comfortable max PSI listed on the tire, as the manufacture was also comfortable posting it there.

IMO here is my +’s and -‘s on PSI
+ It HAS increased my MPG notably.
- I am NOT getting as smooth of a ride.
+ My corning is better.
- Car responds quicker when I turn the wheel.
(I actually I feel it’s a plus, listing as "-" because some people like softer steering)
+ Traction if better
-/+ don’t know yet how snow traction is going to be.

Have Fun.

[Chuck]

Welcome to CleanMPG - Jagdeep!

Most of the "conventional wisdom" you have been hearing from your friends is misplaced. Check out Beating the EPA - The Why’s and How to Hypermile

Far more cars are underinflated than overinflated. Did you know bursting pressure is around 200psi? Blowouts are more likely to result from letting the pressure go too low. A number of members go as high as 60psi and don't experience bald middles.

Coasting in neutral with the engine off (also known as FAS ) : First of all, the engine will not be harmed. The worst that could happen is the 12v battery and alternator could need replacement earlier - maybe.

We need to know more about your vehicle. If you have a standard transmission, you have nothing to fear regarding transmission damage. An automatic transmission is a brand-by-brand case. With an automatic, the bottom line is whether or not your car is towable....the owner's manual will have the answer. If the manual say your car is not towable, then you can't.

[Damionk]

Originally Posted by Delta Flyer

An automatic transmission is a brand-by-brand case. With an automatic, the bottom line is whether or not your car is towable....the owner's manual will have the answer. If the manual say your car is not towable, then you can't.

I think you mean flat-towable, Delta. I have talked to my brother, who has been working at a tire shop for years about increased pressure. Not once did he say anything about the tires failing due to increased pressure. I rev-match in my car, granted I have not had the car long, but the car is 12 years old. To know if you need to rev-match get to about 20-30 MPH and go into N then let the RPMs drop. When you go back into D make note if there is a jerk when you do so. If there is then you need to rev-match. If not try at a little higher speed. With my car I need to rev-match above 30 MPH.

[phoebeisis]

Jagdeep26,
I didn't notice if your car is a MT or a AT. We, folks here, use some of the techniques, most of them , or all of them; we pick and choose depending on just how adept we are , or how much brain power we want to devote to hypermiling, or even on how much we 'think" we might be risking a car part( the starter for example- use it more, it wears our faster- but really not fast, even heavy full hypermilers get 80,000 miles out of a starter.

My point, some AT vehicles -my 1998 Suburban for example-don't display-on the ScanGauge- better mpg when gliding in N than they do by just lifting off the gas and leaving it in D. Odd, I agree, but somehow the AT just freewheels with no engine braking despite the low RPMs and highish(35-40 mph is the speed I pulse to in the city).

Charlie

[PaleMelanesian]

I've seen similar in a Buick - GM did the right thing with those auto transmissions.

[phoebeisis]

PaleMelanesian,

Yes,GM did something right in those ATs- no engine braking at all..

I drove out to UNO today (32 miles roundtrip to University of New Orleans) and got 16.9 mpg roundtrip- a new record!. Terrible mpg for anything but a 1998 Suburban with 207,500 miles. It it mainly pure city/city expressway- probably at least 30 full stops/starts. The Prius get 56mpg with no effort , but my son gets the "good" car,I get the heap(you'll find out about that soon enough when you blink and your baby is 22 yo).

Charlie

PS To original poster maybe you can glide in gear if you have a no engine braking AT like mine? No worry about damaging the vehicle , less wear in fact , so longer parts life.

[The Fridge]

My car is a manual transmission.
As I learn the specifics of hypermiling this car, I sometimes end up lugging the engine or running on the verge of lugging.

I have read that lugging is worse for your engine when you have the throttle wide open and are trying to accelerate hard in a gear that's clearly too high.
I only lug during very light acceleration, but I'm curious, how much is too much?

Also, a friend of mine told me the reason he had to replace the transmission in his (manual) nissan pickup was because he lugged it at higher speeds in 5th gear (eg going up hills.)
Can anybody speak to the effect of lugging on the drivetrain?

Thanks!

[Jagdeep26]

Hi All,

Thank you for your replies to my post. I drive a 2002 Camry Automatic Transmission, with about 90,000 miles on it. If this helps in the replies, please let me know. Is there anything else I should take notice of or change in terms of my driving that will help me increase fuel economy?

Thanks,
Jagdeep

[phoebeisis]

The Fridge,
I'm pretty sure there isn't any safe lugging.
Yes, full throttle lugging at low RPMs is the worst because the forces of the piston/connectingrod/to crank bearings will be highest, and at low RPMs the forces pushing the connecting rod bearing face into the oil film it is floating on will "be around" longer.High force because of the full throttle allows the cylinder to get a full load of mixture, and long periods of time because of the low RPMS- bad bad.On the other hand High forces for a short time-OK. Long time with low forces(tiny throttle low rpms) ok- .

I read that lugging damages the engine by forcing the between the connecting road and the crank to squeeze the thin oil layer it is floating on out. So, the lubrication layer fails more or less because of the high forces over long periods of time.

I think the sensation of lugging is the driver actually detecting the crank slowing down between firing pulses. High load at low rpms is supposed to be the worst situation.

I could be wrong about the lugging-this is just "stuff" I read that seemed plausible.
Charlie