F8L

So in your example the overall difference to own is $12 per tire between the two examples. So clearly the FuelMax would be the winner as the FuelMax is more than $12 per tire less than the Energy Savers. I would probably venture to say the Michalen Defenders are one of the least expensive to own. They are LRR tires but they have 80,000 - 90,000 mile treads.

As with most things in life, when you are getting to the top of the line you pay a ton of money for only a slight increase in performance. Top of the line is very rarely the most efficient to own.

No, the Energy Saver A/S would be then in winner despite the higher initial price. Rebate specials also mess with the numbers because Goodyear didn't run rebates often whereas Michelin and Bridgestrone did. I see the $80 Goodyear rebate more often now. Still, the Energy Saver A/S is a better tire all around than the Fuel Max except regarding snow traction.

 

The Defender ranks up there but it is much less efficient than the Energy Saver A/S so the savings come from longevity instead of fuel economy. If you don't care about using less fossil fuel then they are a great choice. You will also have to factor in the cost of mounting, balancing and taxes. Those fees also favor a long lived tire.

Don't forget about the Atkinson cycle of these engines.

Agreed. My only experience with Atkinson engines is based on my 3 Prii and only one of them did I drag race and play around with filter configurations. Slow is slow no matter what kind of filter you use. lol

I understand that, but adding a high-flow AF isn't doing anything without an unrestricted outlet from the engine.

It's like adding a cam to a hot rod and keeping the same stock intake and exhaust. It's a waste of time and money.

 

Opening the exhaust flow will make the AF flow better. Sure, you might gain something, but until the other end is

matched it's an unbalanced setup and your not getting the full affect.

The only cautionary note here is that we know next to nothing about the airflow in or out of this vehicle. So I don't think we can say with any degree of confidence that you NEED to replace the exhaust system to benefit from a high flow filter or that a high flow filter will even help. Besides, would you really want your nice CMax to sound like a fart-can equipped ricer from 1999? lol

 

I postulate that it will work like most other import cars in that it will make slightly more HP in a particular part of the curve but over a very short portion of usable RPM. This is compared to a clean OEM filter. Obviously a dirty filter is going to be worse. A simple drop in K&N probably wouldn't even make a detectable difference on a chassis dyno. The run variance would probably create too much "noise" in the data. That's based on my experience dynoing hundreds of LS1 equipped cars and trucks, more than a few Mustangs and selling import performance parts. Still, that doesn't mean I know anything about the CMax. :) 

I replaced the OEM's with something else and mpg dropped from 43.5 to 37.5.  

 

I hate the stock tires - the darn things slipped on the paint stripes on a dry road.  As a result, it was only moderately bad news when my son hit a curb (10 mph) and the darn thing blew out the sidewall.  (Again, I have no respect for that stock tire.)

 

My wife hates the idea of ever being stuck someplace, and bought a set of run-flats - the Bridgestone "Drive Guard".  The traction is good, but the car feels "draggy", and even with a fuel-efficient driving style I see the mileage at 37.  I'll keep looking for a solution, but right now it is not the OEM's and not this Bridgestone.  is there anything in the Kumho family?

No. Kumho doesn't make a good LRR tire IMO. Go have a look at the tires I recommended in the post above yours. For the best mix of safety (handling and stopping distance in wet and dry), longevity and fuel efficiency the Michelin Premier A/S and Continental PureContact are tough to beat right now. They are less efficient than the Energy Saver A/S but better in all other regards.

Here is a new test from TireRack with a couple of the tires CMax owners would be interested in.

 

http://www.tirerack.com/tires/tests/testDisplay.jsp?ttid=188&cid=

 

Summary:

You missed my point. I said I would not buy them "based on any of the data I see at Tire Rack."

 

Your statement may well be true, but the available data included only 1 manufacturer's low CRR tire line, which is how you stack the deck. Had the test included Energy Saver/AS or Ecopia models, one could reach rational conclusions regarding relative CRR. It didn't, so no rational conclusion can be reached.

 

The real issue I have with your posts is a propensity for confusing opinion with fact. Repeat baseless opinion long enough and folks will start believing it. I live in a fact-based world whenever possible, and will identify baseless opinions as such whenever possible.

 

And I'll note that I have a long-standing bias against Michelin summer tires, and for all types of Conti's, but personal bias is just another baseless opinion!

 

HAve fun,

Frank

Well all I can say to your rebuttal is go buy the tires and test them yourself. I have and my experience with these tires closely resembles the information posted by TireRack during their testing. Furthermore, not every top shelf LRR comes in the same size as close rivals. This is especially true for low profile 17" tires which are usually in the Grand Touring or performance categories instead of passenger tire. E.g. the Prius comes equipped with 15" or 17" tires but the Energy Saver A/S is only available in a 15" size that is appropriate for this vehicle. So a customer searching for the most efficient 17" tire for the Prius is out of luck with regards to the Energy Saver A/S. In this instance does it matter that the ESAS is more efficient? Nope. 

 

http://priuschat.com/threads/bridgestone-ecopia-ep422-review-17-tire.118328/

 

http://priuschat.com/threads/michelin-primacy-mxm4-review.120027/

 

http://priuschat.com/threads/yokohama-avid-ascend-review.105546/

 

http://priuschat.com/threads/michelin-energy-saver-a-s-review.110038/

 

http://priuschat.com/threads/installed-lexus-ct200h-17-wheels-and-205-50-17-tires.115411/

The issue is comparisons are unclear when no tires or vehicles are common between tests, and Tire Rack doesn't make it easy to find. Clicking the tire links in a test should bring you to that tire, but not so... right to "tires by brand."

 

The Conti test is particularly useless as there are no other LRR tires; Potenza, Primacy and P7 are not expected to equal Energy Saver/AS or Ecopia tires. I also see minimal difference; 0.33% and 0.1 mpg to second place, and only 0.7 mpg best-to-worst, a 2.33% range. The Prius used in the LRR test had a 3.8mpg range, a 7.5% difference.

 

I have owned may Conti tires over the years, but I would not buy them for a LRR applicatoin based on any of the data I see at Tire Rack.

 

Frank

The tests are actually fairly controlled in that the same cars are used in the single test and often across multiple tests. In this case it is usually a 3 series BMW. However, tire size differences can and will change some characteristics. For example, the Energy Saver A/S may be the most efficient tire in a 195/65/15 but it may not be the most efficient in a 225/55/17. Since we only have the TireRack data to go by it is difficult to make a truly informed decision. If we had EU LRR ratings standards to go by this would be a lot easier.

 

I disagree with your assessment of the Contis. They are actually quite a bit better in terms of LRR than a lot of other regular tires and they compete well against other LRR tires. I would suggest choosing a tire based on your typical needs and safety and use LRR performance as a tie breaker. I.e If the Bridgestone Serenity Plus and the Continental PureContact look very appealing to you then you can use the lower rolling resistance of the PureContact as a tie breaker. My point is, max fuel economy is a great goal to aim for but make sure you take your safety and driving patterns (fast, wet, snow, slow etc..) into consideration. 

Noticed today on TireRack that they have two Michelin Energy Saver A/S 225/50-17, one 93V UTQG 480 AA 51psi MAX(tires our cars came with) and 94V UTQG 480 AB 44psi Max for $9 less. I wonder if they are going to discontinue our tires for cheaper ones. :)

 

Paul

 

You are likely seeing the difference between the OE version of the tire and the aftermarket version. The OE version is designed to specs required by Ford. The aftermarket version doesn't have to use those same exact specs so Michelin tweaks the design to fit their criteria which usually means a better performing tire and longer lasting but likely less efficient since they are not held accountable to CAFE standards. There are many other tires out there that exhibit this dual nature, the Goodyear Assurance  Fuel Max and Bridgestone Ecopia EP422 are notable.

Yesterday we did several short trips as you describe--AC likely was working 100% each time as the trips were short and the car never got cooled down.  Very interesting info  Thanks.

No problem. :)

 

For low speed driving I just roll the windows down. For higher speed driving I use the flow through technique where you crack your driver side window about 4" or so and crack the rear passenger side window about 2-3".

 

Keep in mind that if you are uncomfortable then your battery probably is too. In those cases it is better to just run the AC and promote longer battery life as well as your own. ;)

FWIW, we see similar effects in the Prius. AC current draw can be as high as 1,800 watts at startup when temps are much higher than your climate setting (100F ambient vs. 76F setting).

 

Monitoring via Scanguage and Torque app has shown a 7-10mpg instant drop in FE when the AC is turned on and the load is high. This drop is sustained until the cabin finally cools down and the compressor winds down. This can take 10min or more in really hot temps.

 

Now imagine making many short trips where the AC is working 100% during each trip because you don't drive long enough to cool the cabin down. That is a true mileage killer. :(

You crazy! :p

 

Congrats!

As PWBarret mentioned above, the CMAX has more vertical stacking height whereas the Prius has more horizontal length. The Prius v is even larger still. It just goes to show you can't just look at total cubic feet! :)

I am on my way to a 630 mile tank. Warm weather is one major thing to consider. I am dertermined to hit 700 on a tank sometime this summer.

Do it! :)

Good. Now I KNOW who you are.

 

Watch it guys, he's trouble.... :p

Thanks, not making a whole lot of sense to me right now but I'll look into it further. How does one get to plotting out such a chart, scangauge?

Nah, they are usually put out by the manufacturer. The engineers come up with this stuff while desiging the engine. Then they test it on an engine dyno and output a map. In essence anyway. lol

Not all downhill. Airport to the CalTrans yard before Crowley. Past Crowley up to Tom's Place are a bunch of up and down till you reach the lookout of Sherwin grade and then it's truly downhill. Last time I tried this, it was way over 100+ before the airport and then it slowly sucked the MPGs out. By the time I clocked the mpg just past down Sherwin, it dropped like 70 something. So no, not truly all contiguous downhill but it was fun though...better in a hybrid than a gas guzzler  :)

 

By the way, whats a BSFC chart?

Brake Specific Fuel Consumption chart. It shows the efficiency profile of a particular engine. http://en.wikipedia.org/wiki/Brake_specific_fuel_consumption

 

Here is an example for the Prius GenIII

One of the key points about pulse & glide is how it can be used to boost overal average FE. I don't think anyone is saying you should go out and pull a marathon P&G session. Instead, focus on the techniques used and use them when appropriate and when you feel like it. I.e. toss in a few pulse & glide cycles when traveling through residential areas or long boulevards (with little traffic) with stop signs.

 

Most people traveling through a residential area (35mph speed limit) will pull away from a stop sign rather quickly and get up to cruise speed and just stay on the throttle until they reach the next stop sign at which point the brake hard. This is extremely inefficient.

 

Instead, pull away from the stop while maintaining the RPM or power display sweet spot. Get up to speed then glide to the next stop or if the next stop is quite a distance then P&G your way there. Do this once or twice a day and your overall tank average will climb. Evtually it becomes second nature. This is how you trounce the EPA rating without turning into a full on hypermiling menace to society. :p Same goes for freeway offramps. If no one is directly behind you then lift off the throttle and glide to the exit.

I swear I've seen one but don't recall where.  I'm thinking Bob Wilson showed one but you know that guy, he's all about charts and graphs, so it could have been something else.  LOL   :drool:

I've seen the Prius ones for both 1.5L and 1.8L but not one for the CMAX. :( Bob will find it. I'll PM him. lol

Nah...too much hard work. I'll drive to The Mill and take it EV all the way down just past Sherwin Grade (after bypassing 10 CHP and their lasers)....that ought to do it...and not a drop of sweat  ;)

 

ps it was not quite 109 but a good 70+ and thats a fair stretch of road as well...

Downhill doesn't count. :p

Great post!

 

Is there a CMAX engine BSFC map floating around the web yet? This would be very helpful in determining your target acceleration RPM.

 

While not directly applicable to the CMAX, I will briefly detail my P&G method for the GenIII Prius because it is instructive despite the difference in vehicle.

 

My pulse ends at 45mph and my target RPM for the pulse portion is 1,500-1,800rpm. Once I hit 45mph, I lift off the throttle then reapply just enough pressure to cancel regen yet use very little HV battery power. I continue to glide until my speed reaches 25mph at which point I pulse back up to 45mph. Then the process begins again. I've practiced this method with slight variations for over 6hrs one day. I was rewarded with a total trip of 233 miles and 95mpg. Don't ask why I was doing it. A month or so later I went back out for more testing and 2hrs and 62miles later I had nailed 109mpg.

 

I used the accumulated knowledge from professional hypermilers like Wayne Gerdes and bestmapman at CleanMPG.com as well as folks at Priuschat. The BSFC map was invaluable as it saves a lot of testing time while trying to find the sweet spot.

 

The OP laid everything out nicely. I think further refinements could come in the form of mph limits and RPM/load sweet spots. Also a disclaimer about not using P&G in heavy traffic or at high speeds. LOL

It is more efficient to use the vehicles kinetic energy and coast than it is to regen brake to put energy into the battery. There are way too many conversion losses for the later to be as efficient as the former. Coasting (with no regen) is the hypermiler's first rule. Drive like you have no brakes.

 

Now you obviously have to balance this with the traffic around you. With no traffic you can lift off the throttle 1/4mile out and coast to a stop. With traffic you just have to drive with the flow and suffer worse fuel economy but you're allowed to curse about it and post angry things on hybrid forums.:)

Thanks for the reference. I was also considering the Continental ExtremeContact DWS, have you evaluated the driving dynamics of this tire.

 

 

 

A lot of Prius folk use the DWS because it is one of the only affordable long lasting 18" tires available in the size we need. I'm not sure how they compare to the PureContact but I would expect the PureContact to be more fuel efficient and better in the wet due to it being a much newer design and utilizes new compounds not found in the DWS. This is purely speculation on my part.

 

I would contact Continental for clarification. Their tech people are very reachable. :)

I've got a white SEL in Sacramento

Not a ton in our area yet. Maybe I've seen you on the freeway. I'm always on the lookout for cool hybrids an EVs. With my Woodland to Auburn commute I feel like I live on the freeway. :)

 

Anyway, good to see some NorCal folks buying something other than a Prius!

Aye, the first of this annual event will be held this year on June 14-16th in Riverside, CA. :)

 

http://www.togobefore.com/

 

http://www.greencarreports.com/news/1083531_first-toyota-prius-hybrid-national-car-meet-announced-for-june

 

After Toyota flew 40 of us out to Detroit for the unveiling of the 2010 Prius we've all been looking forward to another big get together. So Danny and Russell decided to create one. :)

I'm highly skeptical of their claims.

 

In my experience, a lighter wheel does not significantly affect fuel economy in a measurable way unless you go to extremes and shave off 20lbs per wheel. I've tried 24lbs wheels and 15lb wheels (17x7") on two of my Prii and the difference was not noticeable. I used the same tires to reduce errors.

 

We all know that lighter is better BUT how many years will it take you to recover the cost of those expensive wheels with a 1mpg gain? How about a 3mpg? Honestly you would be looking at 15+years to recover your costs. LOL