[Fewman]

I'm a newbee here (take delivery on a new '12 CT when it arrives from Portland next week) and have only test driven a CT for a short duration last week. First time driving a 'hybrid' so that experience is all new too! Been lurking ever since I joined and apologize if I missed a post on this subj while searching here.

In anticipation of delivery, I'm curious about driving techniques people are using in acheiving MPG figures and whether it was from driving in 'normal', 'sport' or 'eco' modes; Seems like some report <40 and others mid 40's to mid 50's with few clues as to how (maybe a poll?). I've been viewing a lot of data on the Prius -3rd Gen on this subject and am curious if the same Prius techniques apply to a CT. I was told by my salesman that the CT drivetrain is a newer generation from the Prius ("7th Gen"?) so if true, what are the differences? I've read that one should stay within the "efficiency mound/curve" of a 1.8L Atkinson 'BSFC' chart; which for a Prius is stated (some will argue) somewhere above the centerline and just below the power mark on a Prius Indicator. So does that translate (some will surely argue) to a slightly above 9 o'clock position and slightly below the 'power' position on a CT Hybrid Indicator? As popular as "pulse and glide" is, I'm not sure this technique is for me (and where should the indicator be on the "pulse" and on the "glide"?). The fact that the CT has very limited EV mode, especially compared to the Prius, makes me believe there are differences in driving techniques between the two. The Prius info gets pretty deep so before I drown in all that, I need my CT and also would appreciate the opinions of the forum membership here on better gas mileage techniques?

Thanx in advance

 

[emejay]

I also did a lot of research on MPG techniques, including Prius forums.
-First, the salesman doesn't know his product (huge suprise), as the drivetrain on the CT is the same as the current Prius (Generation 3). The EV mode is the same as the Prius.

-Driver technique is just one of the many variables to high MPG. The worst I have gotten in 15000 miles is 52 MPG (per computer), but I have great conditions for good mileage.
Some of the variables are:
-weather (cold REALLY kills mileage), I notice worse mileage when it is 50F, much better when it is 90F (even with a/c on)
-longer trips (driving the car when the engine is not fully heated kills mileage too). I have a 60 mile commute.
-higher tire pressure is good for another 1-2 MPG. I set them to 50 psi
-higher speeds increases aero drag HUGE! Traffic where I live doesn't usually allow 70mph.
-like a traditional internal combustion car, quick acceleration sucks up the fuel. I don't drive like grandma, but rarely floor the car
-I find normal or sport or eco mode makes no discernable difference in mileage whatsoever
-after the car "breaks in" (8K to 10K miles), it just uses less fuel. Part of that may be gaining experiece in driving it.
-big, long hills followed by big long downhills uses more gas net than the same distance all flat terrrain (no hills on my usual commute)

You will love this car....

 

[xxxxxxxxxxxxxxxxxxxhookah66]

One new coined word I learned from these threads is "hypermilling", which is what you are describing. I really do not know its true meaning. I guess I was doing that all the way along without realizing it was hypermilling. I am getting about 47.5 mpg on my CT which got about 577 miles.

Few other things will increase mpg by minimal amount but with compromises: an oil impregnated air filter element such as one by K/N will give immediate gratification, but the oil particles will fowl the MAF sensor in the air intake; nitrogen filled tires will also help, nitrogen is a dry moisture free gas, thus it inhibits dry rot in the internal tire wall preserving the softness of rubber and roundness of the tire; and of course tire over inflation which will reduce rolling resistance. I read a thread written by someone else saying that Toyota Motors pre-fill Lexus tires with nitrogen prior to shipment.

However, I would not over inflate any passenger car tires to 50 psig. The recommended placard spec's for a 215/45 R17 set of tires are F: 33 psig / R: 32 psig. I would over inflate the front by no more than cold 2 psig and stay at spec for the rear. The reason being is that CT200h is a FWD and inherently it got over steer. You also got a sensitive electrical rack pinion steering up front sensitive to jarring of harsh tires. If you grossly over inflate the front tires you will create unstable condition for everyday driving. The bushings of CT200h were not designed for 50 psig tires. Besides, grossly over inflated tires will cause premature wear in the center section of the contact surface, the most vulnerable section of a steel belted radial; unlike bias ply, radial tires needs to flex its wall. Over inflated tires is prone to aquaplaning and it will render you useless if the roads are covered with minimal amounts of ice/snow. Under inflation is dangerous and unsafe; so is over inflation.

But didn't we pay premium for our Lexus? We already got the Michelin Primacy a LRR tire! So why are going through the trouble of over inflation?

 

[emejay]

One new coined word I learned from these threads is "hypermilling", which is what you are describing. I really do not know its true meaning. I guess I was doing that all the way along without realizing it was hypermilling. I am getting about 47.5 mpg on my CT which got about 577 miles.

Few other things will increase mpg by minimal amount but with compromises: an oil impregnated air filter element such as one by K/N will give immediate gratification, but the oil particles will fowl the MAF sensor in the air intake; nitrogen filled tires will also help, nitrogen is a dry moisture free gas, thus it inhibits dry rot in the internal tire wall preserving the softness of rubber and roundness of the tire; and of course tire over inflation which will reduce rolling resistance. I read a thread written by someone else saying that Toyota Motors pre-fill Lexus tires with nitrogen prior to shipment.

However, I would not over inflate any passenger car tires to 50 psig. The recommended placard spec's for a 215/45 R17 set of tires are F: 33 psig / R: 32 psig. I would over inflate the front by no more than cold 2 psig and stay at spec for the rear. The reason being is that CT200h is a FWD and inherently it got over steer. You also got a sensitive electrical rack pinion steering up front sensitive to jarring of harsh tires. If you grossly over inflate the front tires you will create unstable condition for everyday driving. The bushings of CT200h were not designed for 50 psig tires. Besides, grossly over inflated tires will cause premature wear in the center section of the contact surface, the most vulnerable section of a steel belted radial; unlike bias ply, radial tires needs to flex its wall. Over inflated tires is prone to aquaplaning and it will render you useless if the roads are covered with minimal amounts of ice/snow. Under inflation is dangerous and unsafe; so is over inflation.

But didn't we pay premium for our Lexus? We already got the Michelin Primacy a LRR tire! So why are going through the trouble of over inflation?

Please note the tire manufacturer, Michelin, states on the sidewall the maximum pressure is 51PSI. 50 PSI is not overinflation. Most automobile manufacturers recommend a lower amount primarily for the softer ride which many people demand (have you noticed the # of posts on this site of people complaining about the "harsh" ride?). I have kept my tires on all of my cars inflated to the higher end of the tire manufacturers suggested range for many years (close to a million miles of driving) and have never experienced any of the problems you describe. I am not criticising you for following Lexus' suggestion, but don't obfuscate the facts.

In the interest of factual clarity, the primary function of using nitrogen in tires is to keep a consistent tire pressure, as the nitrogen molecules are slower to seep out. Most people don't even own a tire pressure gauge, let alone use it. I have never heard of a tire "internally rotting" and "preserving the softness of rubber and roundness of the tire".

Also, you got it wrong on the oversteer/understeer thing. FWD cars such as ours will inherently understeer, not oversteer as you state. Changing the tire pressure to your suggestiion would theoretically make the car understeer more, but probably not even be noticeable to most drivers.

Lastly, K and N filters were most popular years ago, but people find there is an increase of dirt in the engine oil when the used engine oil is analysed. Hold one of these filters up to the light and you can see tiny holes in them! I had used them in the past on a few cars, but found the only performance noticeable (and barely noticeable) was at wide open throttle. The increased noise was annoying. Concerns about MAF sensor fowling when the filters are overoiled are valid too. I had never seen any change in MPG when using these filters.

 

[2012CTinSD]

I have been searching for the sweet spot(s) so thought I would resurrect this thread.
I have had my 2012 CT for less than 2 months, but have enjoyed trying to maximize fuel efficiency. So I have been studying information on hypermiling and on Prius efficiency.
According to the photos I am posting, the sweet spot is from about 1300-2300 RPM, with the sweetest spot at about 2000RPM. Climbing hills and accelerating the sweet spot is apparently below 4000 RPM, the lower the better, up to a point.
While trying to learn how to optimize my driving, I found myself sometimes using the Hybrid System Indicator(in ECO mode), and sometimes using the Tachometer(in Sport mode). Today I got out my wireless OBDII device and hooked my iphone up to it to act as a tachometer and did some test runs.
It would have been nice to have a co-pilot do the readings, but I found that the 1300 RPM corresponded roughly to the line between ECO and POWER on the Hybrid System Indicator. It was not consistent, probably fluctuating plus or minus a couple hundred RPM. THE 2000 RPM SWEET SPOT was usually at about the "P" in POWER. AND the 3650 RPM power spot was just about at the end of the "R" in POWER. Most of testing was done in ECO MODE. Interestingly, I found that the RPMs were correspondingly higher in NORMAL and SPORT modes, but I could not confirm exactly how much. I'd guess 200 RPMs higher in NORMAL and 300 RPM higher in SPORT. It was difficult to hold the throttle fixed at a spot on the Hybrid System Indicator, and glance at the tiny tachometer on the iphone.
Having determined this, I am now more comfortable using the Hybrid System Indicator, rather than the Tachometer.
So, my throttle targets on the Hybrid System Indicator gauge will be the line right between ECO and POWER for light accelerating, the P in POWER for medium accelerating, the R in POWER for heavy accelerating, higher when I have to, and just above CHARGE for gliding, maybe higher for "warp stealth". Great read on Warp Stealth, here: http://techno-fandom.org/~hobbit/cars/warpstealth.html
To get more accurate readings, I might do these tests again with my iPad, at night, with an iPad cradle...but not sure when I'll get around to that.
Also, I have been doing some crude hill climbing tests. I'll try to publish them later.
Here are a couple pictures of Prius 1.8 Liter (gen 3 like our CT, I believe.)

 

[stormchaser]

Thanks for the interesting finds. I will use this method too.


Sent from my iPhone using Tapatalk

 

[Pete44]

Please note the tire manufacturer, Michelin, states on the sidewall the maximum pressure is 51PSI. 50 PSI is not overinflation. Most automobile manufacturers recommend a lower amount primarily for the softer ride which many people demand (have you noticed the # of posts on this site of people complaining about the "harsh" ride?). I have kept my tires on all of my cars inflated to the higher end of the tire manufacturers suggested range for many years (close to a million miles of driving) and have never experienced any of the problems you describe. I am not criticising you for following Lexus' suggestion, but don't obfuscate the facts.

In the interest of factual clarity, the primary function of using nitrogen in tires is to keep a consistent tire pressure, as the nitrogen molecules are slower to seep out. Most people don't even own a tire pressure gauge, let alone use it. I have never heard of a tire "internally rotting" and "preserving the softness of rubber and roundness of the tire".

Also, you got it wrong on the oversteer/understeer thing. FWD cars such as ours will inherently understeer, not oversteer as you state. Changing the tire pressure to your suggestiion would theoretically make the car understeer more, but probably not even be noticeable to most drivers.

Lastly, K and N filters were most popular years ago, but people find there is an increase of dirt in the engine oil when the used engine oil is analysed. Hold one of these filters up to the light and you can see tiny holes in them! I had used them in the past on a few cars, but found the only performance noticeable (and barely noticeable) was at wide open throttle. The increased noise was annoying. Concerns about MAF sensor fowling when the filters are overoiled are valid too. I had never seen any change in MPG when using these filters.

I agree wholeheartedly. I cannot attest from data that I am not damaging my suspension components, but I drive very easily and always avoid the rough spots in roadways. I pressure my tires to very close to 50psi because I like the efficiency. I compensate when roads are wet or snowy, however, as there is a noticeable difference is traction. Glad to know the "why" of the nitrogen. I'm glad I don't really need to mess with that!