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Toyota Highlander Hybrid Driving Tips & Tricks
Have a technique you're using to maximize the mileage performance of your Toyota Highlander Hybrid? This is the place to share and discuss your hypermiling tips.
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Many others here have good experience to share, I can only share what my family does locally with our HH. It may or may not work for your car, location, weather, etc ,etc
Q1. 5-10 mph.
If traffic allows, we accelerate to over 10-mph (13? 15?) and then let it coast back down to 10-mph, then either gently maintain speed or accelerate up over 10 and let it coast again.
If traffic does not allow, we just maintain at safe traffic speed and ignore the gas mileage. No point sweating it at such a low speed.
Q2.
The short trip I wrote refers to actually parking, turning off the engine and get out to run errand and then get in, start up and drive to the next parking. We did this 6 times in a 10-mile loop and it slaughtered our mileage.
"City driving" means driving on city streets dealing with stop-and-go, traffic lights and stop signs but the engine is ON so the car has a chance to switch between ICE and electric or both. Hybrid is supposed to be good for this.
Q3.
When our local temp drop to below 40-F, our gas-engine then tends to run more and more often. It does cut into electric-mode on very forgiving flat terrain but must less often. NOTE: this is not always bad, see footnote below.
Under some circumstances the AC might put drag on the motor-I think.toyotaken can probably correct me if I'm wrong.If you cruising along the interstate(no braking in last hr -battery low)have the AC on full blast,and you floor it,both-or all 3 on 4wd) "car" motors will come on-full blast,and the electric motor that drives the AC compressor will be on.I wonder if under these circumstances the car motor will be running an alternator-or generator to produce energy to keep the electric motors running(it will probably pass it thru the battery ist)??More likely,I think,is the electric motor will be cut back,and you will accelerate more slowly-depending on state of battery.
Bottom line-the AC cost gasoline-but it beats sweating.I think the electric power steering,and electric AC compressor are to keep the gasoline motor off-they aren't necessarily much more efficient than the gasoline belt driven counterparts,but that great big 230 hp motor is pretty inefficient if all you need it for is to provide 5 hp for your AC and 3 hp for your power steering,and 1/4 hp for you AC fan,and power windows,radio etc.Keep the gasoline motor off-that is the advantage Toyota has over Honda-they shut it off and hope you brake a lot-(you do)Charlie
Hope this helps.
For someone familiar with the 2WD, is the recommendation for premium gas only? I think I saw note on this board to that effect.
Does anyone know what Manual means by better performance? Would I expect to get higher mpg avg? Just less build up of stuff in engine (which perhaps getting engine flushed everyone now and again and staying with regular unleaded would be best? Nor suprisingly, much prefer saving 20 cents/gallon (in DC area) with purchase of regular unleaded but unclear what, if any, "cost" is associated with my savings at the pump?
Steve
I read that Toyota does their HP ratings tests using Premium gas. The electronic fuel injection is sophisticated enough to compensate for most grades of gas that you will encounter. You may lose a few HP by running regular unleaded. I doubt it will decrease your mileage. You can always run a test for yourself. There are those that claim higher mileage with premium. It may just be a waste of money.
"manual recommends regular unleaded but advises that premium unleaded produces better performance"
I watched the power guage and there does not seem to be much effect, even on steep San Francisco hills. The only time the power guage dips deeply into the blue range is on braking with the brake pedal. Hardly any indication during deceleration unless the foot brake is engaged.
Is this the way it should be?
Also, I wondered if the power guage is indicating the maximum regeneration when the needle reaches the bottom of the blue range.
Marvin
The trip was to a campground where parents have spent summer weekends for 30+ years, we pulled in, shifted to B and drove effortlessly on the battery at the 5 mph speed limit - driving the only air conditioned electric cart in the place. It used to require some effort whenever driving through just to keep the speed slow enough. No problem here. Only noise was the quiet whir of the fans and the motor, and the crunching noise of the stone path under the tires.
The first situation was real world but the second sure impressed the heck out of my dad, whose first car was a Model A.....
"#29 of 31 Possible cause of performance problems by rx400_owner Aug 08, 2005 (10:34 am)
Bookmark | Reply | E-mail Msg
Those of you experiencing poor performance might ask your dealers to try the ISC Learning proceedure which reinitializes the the idle speed control. It is in TSIB EG010-05. This is something that can be necessary if the 12 V battery dies (and possibly that happens during shipment or prep of some of the cars).
Some of the things this can cause are poor fuel economy, engine running too often and excess noise at idle.
The info came from a post on another board. It didn't say that it could cause the lurch some here have complained about, but it seems possible that engine idle being messed up might lead to that behavior as well.
This or something like it would explain why our experiences with this car vary so widely. "
I have already placed a call to my dealer....
1. Does the "B" engine braking position on the shifter truly regenerate electricity and charge the battery? I've read contradictory statements that it does and does not. Also, when on level ground, the car will move and accelerate slowly on its own when in the "B" position, as if it was no different than the "D" drive position. This seems sort of strange.
2. Is the fuel tank size really 17 or 19 gallons? I've read both numbers, and am inclined to believe the 17 gallons based on my experience.
3. Why are there several ticks in the region around zero kW on the kW meter? Why not just one tick for the zero mark?
4. Why does the kW meter indicate a positive (+) number when only the ICE is powering the wheels? Obviously, this meter is indicating more than just electrical power transfer. Perhaps a conversion factor from horsepower to kilowatts is applied here?
5. Sometimes the kW meter reads zero (right in the middle of the many tick marks), yet the power direction indicates "charging" the battery when drifting down the highway at high speed, or even down a gentle hill. Shouldn't the meter read negative (into the blue zone)?
6. For charging the battery, is it more effective to brake gradually or drift down (kW meter basically reading zero), or to apply the brakes firmly and force the kW meter deep into the blue zone?
7. Has anyone figured out how and where to tap into the computer system, specifically to get at the data that is used to calculate MPG? I have the basic HH (couldn't afford all the luxury features that came with the Limited), but I really would like to calculate total MPG for short trips, whether it's a 5 mile trip or a 50 mile trip, without having to refill the tank. I know the information is somewhere in my HH's little brain, since it will display a 6-second instantaneous MPG rate. For you computer nerds out there, I bet you could make some money if you came up with an interface and a program to download all this hidden data into a PDA or laptop. I would gladly spend $25-$100 for such a gadget.
8. Pulse and Glide method: Is the "glide" portion of this technique the same as being in "N" neutral? Please explain the technical differences if they are not the same. Does pulse and glide cause more wear and tear on any mechanical components or electrical relays?
9. What is the algorithm or equation that determines when the ICE switches on/off? What might some of the not-too-obvious inputs be? Is car attitude (levelness) one of them? Perhaps someone could do a whole lot of experimenting and figure it out.
10. Non-hybrid specific: why can't auto manufacturers make a linearly-accurate fuel gage? This just blows my mind, especially with today's technology! There are zillions of accurate tank level measuring systems out there in industry, just not in the auto industry!
geez - I guess I could have started a new discussion board here!
However, try this link to get you going for your question 7."
:-)
Here are my guesses . . . please correct.
“1. Does the "B" engine braking position on the shifter truly regenerate electricity and charge the battery?”
Truly doubt it. I often hear the engine revving when I’m in this gear and can see it on the screen. I believe it’s braking WITH the engine. Also, it’s different from drive in that when you release the accelerator it won’t glide.
“2. Is the fuel tank size really 17 or 19 gallons?”
At cut off, it’s around 17 in your tank (or even less) but you can get more than 19 in there if you go beyond this. By the way, some nozzles have a vapor vaccum. If your nozzle is in the gasoline, you’re putting in and sucking out gas at the same time. Make sure your nozzle is out of the liquid.
“3. Why are there several ticks in the region around zero kW on the kW meter? Why not just one tick for the zero mark?”
Please refer to the previous answer about how many angels can dance on the head of a pin . . . who cares on this one? Never even thought of it.
“4. Why does the kW meter indicate a positive (+) number when only the ICE is powering the wheels? Obviously, this meter is indicating more than just electrical power transfer. Perhaps a conversion factor from horsepower to kilowatts is applied here?”
Yes, you got it at the end.
“5. Sometimes the kW meter reads zero (right in the middle of the many tick marks), yet the power direction indicates "charging" the battery when drifting down the highway at high speed, or even down a gentle hill. Shouldn't the meter read negative (into the blue zone)?”
It could, I guess. But it seems to only work in the +. It would be better to see how much energy it’s getting back.
“6. For charging the battery, is it more effective to brake gradually or drift down (kW meter basically reading zero), or to apply the brakes firmly and force the kW meter deep into the blue zone?”
Slow. A firm press actually uses the conventional brakes and you get no regeneration. There’s also the power assist, where the car thinks it’s an emergency and clamps down the calipers for you and then you get zero regeneration.
”7. Has anyone figured out how and where to tap into the computer system, specifically to get at the data that is used to calculate MPG? I have the basic HH (couldn't afford all the luxury features that came with the Limited), but I really would like to calculate total MPG for short trips, whether it's a 5 mile trip or a 50 mile trip, without having to refill the tank. I know the information is somewhere in my HH's little brain, since it will display a 6-second instantaneous MPG rate. For you computer nerds out there, I bet you could make some money if you came up with an interface and a program to download all this hidden data into a PDA or laptop. I would gladly spend $25-$100 for such a gadget.”
You can bet it’s gonna cost you more than that and few are going to dabble there till their warranty’s up.
”8. Pulse and Glide method: Is the "glide" portion of this technique the same as being in "N" neutral? Please explain the technical differences if they are not the same. Does pulse and glide cause more wear and tear on any mechanical components or electrical relays?”
On a normal car, it would be like neutral with the engine ala Kerouac’s On the Road (which I did all the time). But in the HH neutral gives no regeneration and you inevitably slip from one arrow to the other. Definitely don’t do this in neutral in a HH.
“9. What is the algorithm or equation that determines when the ICE switches on/off?”
Of course, I don’t know but I wish T had made this so you could set it yourself. How nice it would be to say only electric, for instance? Or even to have the equivalent of cruise control but where the car would pulse and glide for you between a high and low you’d set. Because P&G’s damn dangerous now as you have to watch the instrument panel every second.
http://techinfo.toyota.com/
It is a Toyota site that has all technical documents and user manuals in PDF form. When you access each document, it pops up so you will need to enable "Pop-Up" for your browser.
There are wiring diagrams & Toyota Diagnostic Tester info for the HH. Whoever is handy with a diagnostic unit can easily use such info to tap into the on-board drive system and decipher the data being passed to the instrument panel display. This can be like the system an owner did for his Prius (another poster has link).
Whoever can do this and provide a read-out for us will likely charge beyond $25. It will involve wiring connection and installation of a device that provides such read out.
Can only answer #1. The info below is based on observing the arrows/flows on the Energy display on one of our trips.
"B" - Engine braking, enginge does not charge the batteries as shown on the energy display. No flow into or out of the engine but we can feel car slowing and engine is reving.
"N" - No charging at all. Display shows no energy flow anywhere.
"D" - When driving, engine sometimes charges the batteries via the front motor. This is normal, it charges whenever it needs to.
"Coasting in D or B" - foot off accelerator, car is coasting in D or B, charging occurs automatically from all 4 wheels. Have not seen engine charging the batteries when coasting in these modes.
"Gentle Braking in D or B" - Tricky. Often, when we coast to a stop, regeneration is happening before we apply the brakes. Soon after we apply our brakes, regeneration stops and energy display shows no flows anywhere. While we believe we were gentle on the brakes, the car thinks otherwise and actuates the real brakes sooner than we think. This cuts off regeneration sooner than we think.
"Hard braking" - No charging. Energy flow display shows no flows at all anywhere.
"Pulse and Glide" Excessive Wear question - I do not believe so. It is all just normal driving, no hard acceleration, no hard braking so only "normal" wear and tear occurs.
We do pulse and glide a lot on local roads and it helps with our MPG. We are now up to 26.5-27 MPG mixed at 2300+ miles. We also stay in the right lane more and coast to a stop as much as possible before applying brake pressure.
Using analogy from flying, streets are like taxi ways, freeway on-ramps are like take-off's while freeways or high speed expressway are like crusing at altitude.
The owner's manual clearly says 17.2.
3. Why are there several ticks in the region around zero kW on the kW meter? Why not just one tick for the zero mark?
No kidding. I don't get this, either.
4. Why does the kW meter indicate a positive (+) number when only the ICE is powering the wheels? Obviously, this meter is indicating more than just electrical power transfer. Perhaps a conversion factor from horsepower to kilowatts is applied here?
Conversion from HP is my assumption. If you hit car pages from other nations (you know, that whole rest of the world which is on ISO units) they report power in kW, not HP.
5. Sometimes the kW meter reads zero (right in the middle of the many tick marks), yet the power direction indicates "charging" the battery when drifting down the highway at high speed, or even down a gentle hill. Shouldn't the meter read negative (into the blue zone)?
I'm glad I'm not the only person to wonder this. Makes no sense to me, either.
10. Non-hybrid specific: why can't auto manufacturers make a linearly-accurate fuel gage? This just blows my mind, especially with today's technology! There are zillions of accurate tank level measuring systems out there in industry, just not in the auto industry!
No kidding. This drives me bananas in all cars...
I can have a full battery but when I start (after a few seconds of READY), even when parked or rolling slow, the engine will start and won't stop no matter if completely still or moving.
The only explanation I can think of is that the engine always starts to warm up the catalytic converter (there MUST be a more energy efficient way to heat up that tiny little thing!). That’s doesn’t bother you if you’re straight onto a road beginning with I- and you’ll be cruising at 70mph but to roll through a neighborhood it’s pointless.
I take my wife on a 2.5 mile commute. I get 15 MPG there and 30 MPG back (and it’s level).
In my old 4Runner I would switch off the engine and roll in neutral, which you can do in the HH but you can’t start back up until you’re stopped and put it back in Park. The Runnner could statt in N or P. So, you could start on a roll.
If there was away around this early engine running, you could save significantly on short cold runs and at least 2mpg on total use. By only using the engine when you needed it and not to warm up a catalytic converter, which isn’t only wasteful but you must emit more pollution this way (why not just let normal use of the engine warm it up? Using the battering for the first 3 minutes doesn’t pollute).
Can anyone think of a way to prevent this early engine start-up or starting the car while in N?
We observed a slightly different behavior:
1. Approx. 10 seconds after READY, ICE comes on. Display shows it charges the battery even when battery already has 6 bars.
2. Charging continues for approximately 20 seconds then display shows charging ends, no energy flows anywhere. ICE remains on. Battery remains at 6 bars.
3. ICE continues to run for about 10 more seconds and then shuts off.
Total time from start-ready to ICE shut off is about 40 seconds and ICE stays on for about 30 seconds. This all happens consistently in ambient temperature range of 60-78 degrees.
Will it charge longer if battery is less than 6 bars? or will it stay on longer to heat the converter as you surmised if ambient temperature is colder? We are not sure.
We paid attention to this after reports of HH not starting overnight and HH ICE runs too long (NYT article). So far, we have noticed no such behavior.
Ambient air will never be warm enough to heat the CC but I assume it'll take longer in winter.
Look, I've got neighbors . . .
Anyone who doesn't care about looking foolish or lives on a farm or has a garage, would you be willing (and foolish enough) to stick a heater under the CC and give it 10 minutes then see if the engine comes on still?
:-)
Anyway, I thought the reason the ICE came on was to heat the oil, not the CC. IIRC, the HH doesn't have the "thermos" system to keep the oil warm that the Prius has, so it runs a bit to warm up the oil. Anyone know for sure?
We camped at Los Padres national forest for a night 2 weeks ago with day time temperature at 112-deg as reported by the car. The ICE came on anyway and stayed on for about half a minute before turning off.
I do not think there is much we can do except to change Toyota's software. Does a 30-second burn at idle at start-up really impact the MPG that much? The ICE shuts off almost every time we stop at a traffic light, stop sign or turn, that should help with MPG.
I hope its SULEV rating applies even at ICE idle cycles.
It's a bit like digging a hole to put some dirt in.
http://hybridcars.about.com/od/ownership/a/pulseandglide.htm
I'm not sure that it's better or worse than going into N, but who wants to shift into N anyway?
I've been trying to push it along on electric and preventing the engine starting for as long as possible and then revving up and getting a cruising speed. Getting between recharge and elec only use is far too difficult for me.
But we should be able to tell what works best.
We have used pulse and glide for a while but with a different speed than that suggested on the Prius board. The roads and weight of the car may dictate what speed to use.
Our HH can easily maintain 30-35 MPH in electric mode for long distance on flat roads before the ICE has to come on to charge. The on-board computer gives an impressive 60-65 MPG reading at this speed.
We have been trying to run on electric at 40-45 MPH but it is so far very difficult. There is only 1 stretch of road where we can do this consistently. When it does work, we get a consistent 43-45 MPG reading off the on-board computer.
We still have a little over half a tank of gas so will see how it really comes out at the end of the tank. Right now, the consumption data shows 27.8 MPG for 201 miles driven.
oh, on the tax issue - husband got called out of town on an emergency so it may be a bit before he can get back to this Forum on the specifics of the tax breaks for 2006 with a hybrid. . .sorry for the delay.
mmreid
Ours is a Ltd 4WDi and we are *not* experts yet, only 1000+ miles now. When we can consistently get 29-30 MPG mixed with our driving techniques, then we may have more meaningful tricks to share.
We will love to hear from those who have succeeded in running in electric at 45 MPH. Anyone?
For now, we do a "modified" version of Pulse and Glide, not the same as described in the Prius forum.
On freeway, we keep to 65 MPH as much as possible. This seems to always return 30-35 MPG.
On city streets, we try to use electric to get moving from a stop whenever traffic condition allows. Electric can easily take us up to 20 MPH before ICE kicks in.
When ICE kicks in at 20 MPH, we continue to accelerate up to traffic speed and then a tad more. Then foot off accelerator (pulse?) for car to slow down to traffic speed or posted speed. ICE almost always cuts off at this point and we will gently press on the accelerator again so that only electric is used to maintain speed. Electric-only does not seem to work beyond 45 MPH.
When battery begins to run down on an electric run, and when traffic condition allows, we take foot off gas to let car glide and regenerate. From 45 MPH, we let it drop to about 30+ and then start another electric run by slowly increasing speed up to 45 MPH. If we were cruising at 35 MPH, we would just let it glide down to 30 MPH and then start the next electric run up to 35 MPH. We have had no luck to just drop from 45 MPH to 40 MPH because the ICE kicks in everytime we try to maintain speed using electric at 40 MPH.
Before the next stop, foot off accelerator and just glide. This car glides very well so we are learning to let it glide earlier to a stop when traffic condition allows. Gliding is also great for regeneration to prepare for the next stretch of electric-only run.
Often, glide timing fits traffic light pattern and we will get a green with speed (~10 MPH) and distance to spare. So we gently accelerate through the light using electric as much as possible.
So far, it seems the car can easily use electric mode to maintain 30-35 MPH for long distance until battery runs low. On very flat or slightly downhill road, it can also use electric to maintain 45 MPH.
In general, it is just a lot of careful acceleration, careful cruising at traffic or posted speed and lots of gliding to regenerate for the next electric only run.
We are still experimenting and enjoying each discovery, so you will likely have to find your own custom approach as well.
We will love to hear from those who have succeeded in running in electric at 45 MPH. Anyone?
We did that in the beginning and noticed there is no charging occurs when in N so the battery stays low. This will make continuous electric runs impossible.
We needed to stay in N even when gliding so battery is charged and ready for the next electric run.
I sometimes wish that I had the facy schmancy navigation screen that tells me what I am getting, but have to rely upon the little diagram above my steering column. I hope that with the disappearance of the arrows at the "sweet speed of 40" I am doing things right.
BTW, is there a cheaper way to get the NAV system for the HH than by going straight through Toyota? there has to be an OEM store out there that supports our 06 models at a fraction of the current $2000 range.
John
I meant to say we needed to stay in D, Drive, when gliding so the wheels can charge the battery. N, Neutral, cuts off all charging. Thanks to a reader for pointing that out.
To get a feel for your instant MPG number, you can bring up the "Bar Graph MPG Indicator" to replace the "Engine Flow Diagram". I use that bar graph to show me what MPG I am getting at various speed on the freeways.
Whenever the graph reaches the middle between 20 and 40, I know I am getting close to 30 MPG and something good is happening
The "game" is to keep the bar extended way beyond 20 for as long as possible (safely) through all driving conditions. If I can do that, the average MPG cannot be that bad.
We are finally up into 28+ now.
They drove the care with a computer attached and gave me a printout of results...
It showed that my vehicle was achieving 35 mpg hiway and 55 city ????
With this inconslusive result, I drove home Iand decided on an impulse to check the tire pressure.
Found the left front tire was down to 22 Lbs....all tires should be at 32 lb.
I have driven through 1/2 tank and have noticed markedly improved gas mileage.
I will run this tank close to mt and will report back.
BTW I asked the dealer about the fuel 'bladder' and their techie said the HH did not have one...so if you are filling up with 19 gals (as was reported on this site) then it must be going down your pants leg....
I have used a varianrt of the Prius Pulse n' glide, but found that my non-ltd 4wdi HH
has different thresholds.
Most of my 'electric' traction motor only glides can only be accomplished after driving for some 15-20 minutes.
I accelerate per the P&G directions to 48-50 then ease off the pedal and monitor the horizontal bar graph gauge. I also search for the 'sweet spot' which on my HH seems to be just at the top part of the dashed (white) portion of the analog KW gage.
I use this same 'sweet spot' while on the x-way when I release the accelerator pedal. Of course I dont P&G very often on the x-way.
At the end of day, when returning to my home, I can accomplish an electroglide up several hills here in the Dunes, until I hit my driveway when the ICE does kick in due to the slope.
I have 1600 miles on my HH and word is that the mPG will improve as I'm told the ICE only works half as hard as a 'normal' ICE and it takes longer to 'break-in.'
In closing take heed of my previous post on tire pressure. I do not have a leak or damaged tire and the pressure on the left front was 22 Lb oinstead of 32lb...evidently has been ever since I picked it up from the dealer. :mad:
mmreid
My calculated and computer indicated mileages are as follows
27 --- 29.5
28.05 ---30.4
28.54 -- 30.3
I have been extremely happy with the HH but would like to increase fuel economy. I understand and have done the glide. But need much more detial on other techniques.
Would also be very interested in a plug in charger to start each trip with max battery and a solar panel charger.
Interesting report at http://www.cnn.com/2005/TECH/08/15/hybrid.tinkerers.ap/index.html
titled "250 miles per gallon? They're doing it" on the Prius
For those who take this car off pavement onto dirt trails where there may be jagged rocks, you may want to consider increasing pressure to 35 PSI or change to tougher truck tires.
We visited Mt. Shasta (CA) base camp for a day hike and lost a tire on the seemingly flat and easy dirt trail. Lucky thing was we reached the trail head and parked before it went flat. Our best guess is that at 32 PSI, the sidewall bulges out and reaches too low for dirt tracks. The Goodyear Integra seems to have weak sidewall so at the right angle and right pressure, a well embedded sharp rock on the road surface can puncture or cut the bulging, low reaching side wall.
At 35 PSI, the sidewall bulges significantly less so there is less chance (still possible!) of a rock embedded in the road surface cutting the sidewall. Of course, if you get too close to one portruding from the side, that is a different story.
Our dealer emphasized that Toyota is very strict with warranty. If we touch the electrical system on the car, changing it in non-Toyota approved manner, they will void the warranty. Charging the traction batteries could mean "changing" the electrical system.
You may want to contact your dealer and find out what they say.
We have a solar powered trickle charger with automatic cut-off for charging normal car battery, it will work for the normal 12V in our HH. After reports of how HH sometimes will not start due to the 12V running low, we plan to use the solar charger in the winter when 12V are more likely to run low.
Whoever came up with that instant mpg screen I think was on crack. Who wants to know the "instant" mpg you are getting? To me it is a pretty screen, but otherwise worthless. On the limited edition, I think you get the "actual" mpg on the screen. I would have preferred that anyday. Or if they would have changed it to a number other than a graph, it would have made more sense. I hate guessing the numbers especially when I am running on electric. That way you can still get bragging rights on the little screen.
The Ltd NAV screen does show the actual MPG but we do not use that when driving, too dangerous to look that way when driving.
In electric, the bar will fill the entire line out to 60 MPG but you must do what is most comfortable for you. The bar is just an alternative that may or may not work.
The type of driving I had to do should be done by the cruise control. It take a lot of attention and not to the road. I can pretty much feel when the engine kicks in and back off now but I wish the computer could do this on its own.
I know for the 2001-2003 Prius, if you maintain the Toyota recommended pressure, you see classic signs of underinflation wear. Pump them up 5 psi and handling and wear improve dramatically, and you get a bit stiffer ride. I run my 2001 Prius 9 psi above Toyota's recommendation (8 psi below the maximum allowable pressure) and get record tire wear on the OEM tires (over 36,000 miles). I'm close to that with the 04 Prius. I'm running the HH at 38 psi, with an improvement in handling and steering stability with each vehicle.
Aside rom a stiffer ride, do you see any mileage improvement with higher pressure ?