2010 Prius III fuel efficiency hypermiling results

I didn't say it had no effect, I said it doesn't have much affect. How much more flex do you think 35 psi provides? What exactly do you think causes 35 psi to provide more traction? If you don't answer you will have shown that you don't know what you are talking about.

Tire footprint and optimization with suspension dynamics.

Footprint is correct. The rest is grasping at straws. Now how much do you think the footprint changes when going from 35 to 45 psi? I think we can agree that you would be hard pressed to tell the difference by just looking at it. When you see a tire and think "soft tire" it is usually in the low 20s if not lower.

Now let me ask you, do you run the latest sticky sport compound tires on your car? No?! Why not? Could it be because they are expensive and wear out quickly? IOW you are passing up the option of having higher cornering limits and shorter braking distances to save a few bucks. To quote you, "Make sure you note it in your next accident report, and pay up on contributory negligence."

Many people run all season tires year round rather than switch back and forth between summers and snows. They don't provide the traction of snows, but they are willing to accept that compromise based on the mix of driving conditions they expect to encounter. Inflating your tires to the high side of the stock specs is no different. It is a trade off we are allowed to make. And again, the effects are minimal. I drove home on snow covered roads again today with no problems.

Good luck. Suit yourself. The contact patch changes dramatically with inflation pressure as well as suspension loading, camber, roll steer. I would expect this to be particularly so for low rolling resistance tires.

Perhaps you should ask someone at Toyota what they think of your street driving experimentation. Better yet, ask a product liability attorney.

Yes, I do run soft compounds on the sports car, and I have dialed in the proper pressures for a variety of road surfaces and events. None of them on the street.

Yes, I do use separate sets of high performance and winter snows for each street vehicle. Properly inflated.

Better dial up that attorney.

LOL, Sure you do, In your dreams. Ha Ha

I'm not talking about preferences, I'm talking about things like drivetrain longevity. You don't know what factors affect that, and why the engineers made the "compromises" they did.

It's not all about "what people prefer".

For example:

bzzzzzt, thanks for playing. It most certainly does hurt the car to "converve heat" by not using the heater. The engineers designed the traction battery to operate best within the same temperature range as what makes the human driver comfortable. Ever notice that it's vented to the cabin? That's to take advantage of cabin climate control. And by the way, that's why the Prius *has* automatic climate control--not because Toyota wanted to give a premium feature like that to someone buying a $20K car, but to give the battery the best chance to be in its optimimum temperature operating zone. Give the driver the ability to set it and forget it, and let the body computer make all the decisions on how to get the cabin--and the traction battery--to where it needs to be.

So now you come in and play your rolling video game, but you ignore the big picture that you clearly don't know anything about. When you choose not to heat the cabin, out of ignorance, you're screwing with the highly engineered system that lots of highly paid professionals designed and created. You're actually hurting the traction battery.

nope. The engineers made many decisions, and of course cost came into play, but it's nowhere near as simple as what you think. The engineers need cabin heat in the winter--they need the human to be comfortable--in order for the entire system to work as designed. Your claims of "well, they just did it for cost saving" are nothing more than self-serving excuses for you to play your rolling video game and hyperfocus on one thing: that dashboard number.

You're sacrificing the traction battery long-term just for your short-term goal of making numbers appear on your rolling video game. Is that a PREFERENCE of yours? Add up your total per-mile cost--not your miles per gallon, but your total per-mile cost--over the life of the car, and do so by adding in an early traction battery replacement that you wouldn't have otherwise needed if you weren't playing your rolling video game.

That's just one example of what happens when amateurs convince themselves that they know more than the guy who engineered something as complicated as the hybrid synergy drive.

hardly. I'm a knowledgeable man explaining the world to an ignorant, selfish youngster.

Laugh it up. Remember to drive it all the way through the crash.

bzzzzzt, back at you. Heat would hurt the battery but being cold just reduces its capacity while it is cold. Start working it and it will warm up the battery restoring its capacity. Also it seems you don't know that much about hypermiling. The pulse and glide technique avoids discharging and charging the traction battery, so it reduces the work load on it and should extend its life.

You already used your cabin heat excuse, and it doesn't apply here anyway. The car loses heat from the engine compartment directly to the outside whether you are using the heater or not. I quite often do use the heater because I like being comfortable and not looking through fogged up windows. I have taped the grill off to prevent the uncontrolled loss of heat that can be put to good use. With the grill taped off the engine gets up to normal operating temperature quicker, giving me heat for the interior and reducing engine wear. The thermostat still controls the engine's temperature when it is up to temp, and it is unlikely there will be any overheating with the cool ambient temps. The quicker warm up also gives it a better chance of boiling off condensation in the engine during my 11 mile commute to work in winter weather. It also helps me save gasoline. That's four reasons why taping off the grill is a good thing to do. Can you list even one reason not to? Like I said, the main reason for not doing more to control heat lost was probably cost.

I never said I know more than the engineers, but it seems I know more than you do. BTW, when using the pulse and glide technique the computer still has the final say on when the battery will be charged/ discharged or the engine shut down/started. I just control the gas pedal which is one of the inputs to the computer. I do not have an EV switch and I have not over ridden the computer's programing.

It's selfish of me to want to conserve fuel? Wow, do you have a warped way of looking at things. And speaking of ignorant, you don't even know how old I am.

Previously, I had read that setting the tire pressures to

If the Scangauge II coolant temperature (FWT) goes over 198 F (Thermostat at 80% open) the grill blocks will be removed - sofar my max coolant temperature has been 190F. The main reasons that I haven't been able to go over 190 F is that I haven't driven longer than 65 minutes and it takes about 50 minutes just for the coolant temperature to get up to 180 F when the outside temperature is from about 20 F to 34 F. In generation 2 the inverter air intakes are in the bottom grill. My generation 3 Prius has the inverter air intakes at the top grill. When the temperature climbs back up to 50 F the (top) grill blocking for the inverters comes off. When the temperature climbs back up to 60 F - I will removing the rest of grill blocking at the bottom. The inverter coolant is use to regulate the temperature of the motor/generators - it prevents the motor/generators from overheating. I had grill blocked incrementally - adding more blocking to see if I could reduce or eliminate the number of times the ICE had to turn on to warm up the catalytic converters.. Initially, I blocked 100% the bottom grillI, which reduced the frequency of the warm ups events during my commute of 60 minutes to two to three times . Blocking the top grill 50% reduce the frequency of the warms during a

My guess is that the thermostat (spring) behaves linearly with temperature but the loss of energy/temperature due to an extreme drop in temperature behaves in a non-linear fashion. Hence, the thermostat cannot easily compensate. Grill blocking is a very cheap solution ($3 of pipe insulation) too. I've seen school buses and diesel trucks do grill blocking in the past so it's not a new ideal.

The risk to grill blocking is that the ICE or the MG could overheat on a long drive. So the maximum internal temperatures need to be known and monitored. for the 3rd/2nd generation Prius the max coolant temperature is about 200 F - this is when the thermostat is opened 100% and coolant flow is operating a peak speed. When the maximum internal temperatures there is a risk that the coolant system will not be able to remove the heat from the ICE fast enough to prevent internal damage. So before that maximum temperature is reached the grill blocking needs to come off. While engineering wise grill blocking is not necessary to run the Prius - it is an inexpensive way to increase its fuel efficiency by about 10% in extreme cold. So while the outside temperature is hovering somewhere between 20 F and 32 F, the Prius is still averaging somewhere between 52 to 54 mpg in mainly urban driving.conditions for short distances. The advantages of grill blocking in cold weather is less clear for highway driving ( > 50 mph) for long distance ( two or more hours per driving session) because at high speeds and for long distances - the ICE is running more often and heat loss is less of a problem.

Elmo's fears and assessments are incorrect in several ways. Hypermiling actually puts less wear and stress on the car because acceleration and braking are done more gently. For example, hypermilers often report extremely low brake system wear. Hypermiling is generally focused on speeds between 25 mph to 45 mph (with 55 mph being a niche interest) inwhich special driving techniques are use to optimizing one's driving for the current driving environment. Some organizations like AAA discourage hypermiling due to one hypermiling technique call drafting. However, I have not advocated drafting. Rather I am using other easier and safer hypermiling techniques, traffic light timing- DWB (driving without brakes), pulse and glide, SHM, etc. Increase fuel mileage also translates to lower fuel cost. My thread is not about bragging but about how to maximize fuel efficiency of a Prius and understand why it works and when it won't work. In a few years, there will be other cars whose fuel efficiency will overshadow the Prius. While the 2010 Prius can't best a 1999 Honda Insight in hypermiling - its easier to drive. My goal has been to see how close I could get to MPG levels reported by hypermiler Wayne Gerdes (98 mpg on a 2010 Prius) and to see what I could learn.

LOL. I look like a gearhead?

Engineers must design based on performance and cost compromises - Many major engineering compromises are not done by engineers but by the CEO and Marketing types. For example, those tail fins on cars in the 1950s were never and engineer decision. Having a solar panel on the 2010 Prius was more of a marketing than an engineering decision.

The life of the tire probably going to be a little over three years at best - I doubt my experiments will increase or decrease the life of the current tires. I've read and heard many allegations that this tire's manufacture products are of poor design and quality , e.g. claims of tire rot. Sofar I haven't notice anything unusally bad about these tires though. The grill blocking is a well know and safe technique; I am monitoring the coolant temperature and I know what temperature to look for too. . My hunch is that hypermiling will extend the life of the car. Reports by 1st Gen Prius owners seem to suggest that the Prius traction battery has a very low failure rate and that hypermiling will not prematurely wear it down.

In a way learning can be like a game -- so the analogy that what I am doing looks like a game has some truth to it.

The question is not whether one might be able to play this game, but whether one is any good at playing this game

but to be more direct and explicit...

I am incrementally testing and verifying what I've read about hypermiling and I am humbly passing on what I have found.

One truth, I would like to pass on is that one cannot learn hypermiling effectively by reading about it or watching a video. its more like a skill or a talent that one acquires over time through practice .

Meanwhile, you take the driving public hostage to your foolish experimentation. Your insurance carrier will no doubt appreciate this behavioral insight for rating purposes.

Meanwhile you amuse this group by posting with your head up your ass.

You have the recto-cranial insertion franchise all to yourself, skippy.

So tell us all about the Prius that you drive, and why you bought it.

quoted text -

Neither the 3G Prius nor other current hybrids meets my requirements.

I will look at the 2012 Prius v, when offered.

Meanwhile, keep telling us how you are a menace on the public roads.

So why do you come to this news group? Just like being a troll?

Usually, a post like yours is the result of someone shoving the truth up your ass until you realize it.

Not directed to me, but I'll take this one: when I got my 07, my choices were that, a Malibu, or continue to drive my own car and get reimbursed.

Yes, mine is a company car (and it's a nice bennie, saves me money). Sight unseen, without having so much as sat inside one, I chose the Prius. And for comfort and driveability, I know I made the right choice. It's amazing that you can acquire a Toyota sight unseen and know you won't regret it for ergonomic reasons.

Before getting it, I read up on it--extensively. I've forgotten more about it than most owners will ever know. (That's OK; it's documented somewhere.) I got it on a Wednesday; by 11am that Saturday it looked like this:

I didn't get one to play a rolling video game or to save the earth or anything like that. So, mine is JUST A CAR. As such, I give it no excuses--it must *be* a car. The climate control is on, making ME comfortable. I get tires that are appropriate for DRIVING, not for playing a rolling video game.

So play your rolling video game on your own time, on your own roads, and get the f*ck out of the way of the driving public.

Hide quoted text -

quoted text -

Me? Product-user research, primarily.

You, on the other hand, apparently to show off your ignorance.