MaxxMPG
10-21-2010, 12:57 AM
http://www.cleanmpg.com/photos/data/2/AmericanFlag.jpg The Goodyear Assurance FuelMax teaches an old Voyager a new trick (http://www.cleanmpg.com)
http://www.cleanmpg.com/photos/data/501/FuelMax.jpgChris Bernius - CleanMPG (http://www.cleanmpg.com) - Oct 20, 2010
A friend of mine bought a minivan last May with his tax refund check. It's a 2001 Chrysler Voyager with the 2.4L I4 engine and 3AT. When the Plymouth brand was discontinued, they kept the "Voyager" name under the Chrysler brand to sell lower cost "shortie" vans at the same dealership as the long-wheelbase well appointed Town & Country. EPA numbers are 20/26, and unadjusted numbers are 22/33, so it has some potential if set up "properly" and driven "properly".
When he bought the van, we knew it needed tires. I measured 3/32 on the front tires with my tread depth gauge, and not much more on the rears. After a few thousand miles, a quick penny-test showed the top of Lincoln's head - below the legal minimum.
Three of the tires were Prime Well PS850 and the right rear was a Goodyear Integrity with about 6/32 tread. Considering the Costco cheapies were completely toast, their rolling resistance would already be lower than they were when new. The only tire that had any meat on it was a LRR Goodyear Integrity. So the van was already "LRR-equipped" due to the advanced tire wear. I did not check tire pressure on these tires today, but they were in the mid 30s when I pressed them up back in May. I didn't want to go too high back then because these tires were old (according to DOT code) and badly worn.
Since it's up for inspection in November, it was time for him to make some moves to get the van ready to pass. Phase I is new tires. Phase II will be to get the check engine light issue repaired. It has been on for several months now, and the 3-key-cycle code trick that Chrysler builds into their vehicles revealed a P0455 - a major evap leak - and a code very familiar to many owners of Chrysler products. There is a part that goes bad over time and causes the leak, and that will be addressed in the next couple of weeks.
Tonight, though, was Phase I - new tires. Because of the oddball size (by today's standards), with 15 inch wheels and tall sidewalls, LRR tire brand selection was limited. I decided it was going to be a LRR tire because the owner is unemployed and trying to make every penny count. Looking through the list at Tire Rack, which allows the search of "Only LRR tires" when searching by size, I found my only option in the correct size was the Goodyear Assurance FuelMax. I ordered a set of four on Monday at 1pm and they arrived the next day at 5:30pm.
With the tires here, my friend drove over in the van earlier this evening so we could head over to PepBoys for the familiar mount/balance/valvestem operation.
On the way to the shop, we took "the long way", finding some roads where we could do a couple of coast-down tests. There was no wind, and the roads I picked were about as level as we could get. I explained that I wanted him to drive at a steady 30mph, then take his foot off the accelerator, and watch the speedometer until it dropped to 20mph. Using my wristwatch, I clocked the time it took to coast down from 30mph to 20mph and wrote it down.
As the tires were being installed, we walked down the block to Taco Bell to discuss hypermiling techniques over $15 worth of fast food. I explained the technology and benefits of LRR tires, and how to make the best use of what they offer. The Tire Rack reviews on the tires are a mixed bag, with half the drivers seeing a gain in MPG while the other half notices no difference or fewer MPG.
When he understood the idea behind LRR tires, I noted that only people who "take their foot off the damn gas pedal for more than a second will see much of a difference at all." Why? Because these tires offer the ability to coast long distances without losing as much speed. Then I told him that this was the reason we were doing the coast down test, and that we should see some dramatic improvement with the new tires. He asked why the lower speed was used, thinking that "going faster means you coast farther." I said that the lower speed reduces the effect of aerodynamic drag and wind speed and direction, and that we would be repeating the test on the same day, in the same weather, on the same roads in the same direction, to equalize as many parameters as possible so we could see if these tires really make a difference.
The only changes made between Before and After would be the new tires installed, and the fact that the Before test includes the 88 pounds of new tires (22lbs each, according to the spec sheet) in the back of the van on the way to the shop.
I asked the tech at PepBoys to press the tires up to 42psi. Placard is 35, and sidewall is 51. They usually balk at pressing up beyond placard pressure, but I requested 42, offering the explanation that the outside temperature was 60, and so setting the pressure at 42 meant the tires would be at placard at any temp above zero, thereby avoiding the danger of underinflated tires. They bought the explanation, and set all four at 42. :)
With a new set of shoes, the Voyager was ready to dance. We took the same roads, same direction, sort of going up and around and down again in our trip coming from the opposite direction, in order to replicate the first test to the best of our ability. Temperature was maybe 5 degrees cooler (roughly 54F), but still no wind.
Here are the results, in seconds, for coasting down from 30mph to 20mph:
Tires|Test#|Time (sec)
PrimeWell PS850 x 3, Goodyear Integrity x 1|1|26
PrimeWell PS850 x 3, Goodyear Integrity x 1|2|29
Goodyear Assurance FuelMax| 1 | 48
Goodyear Assurance FuelMax| 2 | 52
With the FuelMax tires installed, the van rolled for 48-52 seconds before dropping from 30mph to 20mph. As you might expect, the loss of speed becomes more gradual as overall speed decreases, and it takes quite a while to coast from 23mph down to 20mph. Like most heavy vehicles, this van seems like it will coast forever at lower speeds.
During one coast-down, while we were waiting for what seemed to be an eternity for the speedometer to fall to 20mph, I pointed out the red light ahead, and that our coast-down was going to give the light time to change to green before we reached it. Right on schedule, the light went green. I saw his foot move for the accelerator, and I barked out, "No gas! Coast!" My block was just up ahead, and he'd have to slow anyway to turn. We coasted under the green light and made the wide right turn onto my block at about 16mph, with no brake needed. "That", I told him, "is what it's all about. Every time you press the 'go' pedal, you're burning money. Use it only when absolutely needed."
That is how to make the best use of LRR tires - let momentum keep you moving, and don't speed up to the next red light. ...Or up to the corner. Accelerate to your target speed and let the energy-saving technology built into the tires allow you to maintain that speed with an absolute minimum of throttle.
I will see him again soon, around the time we will work on getting the evap leak resolved. After the eye-opening test earlier today, he's ready for another lesson in FE improvement. Next time, I will reinforce the strategy of light timing, DWB, DWL, and if he's ready for it - NICE-on coasting for some more significant improvement.
The Voyager minivan is a must-have for this friend of mine, for family-truckster duty as well as handyman projects and small moving jobs. There is no way to measure actual FE from fillup to fillup because he doesn't have the cash in pocket to fill the tank to first click. He doesn't have a regular daily drive to measure the "$x per week" fuel cost variable. But our informal coast-down test was very revealing, and worth sharing here.
At least one other CleanMPG member is using FuelMax tires, on a minivan, with good results. Now we can add another FuelMax-equipped vehicle to the "thumbs up" column. Whether they live up to the improved fuel economy promise depends entirely on the driver's willingness to take their foot of the tall pedal from time to time. And I think with these new tires on this minivan, we have someone who is eager to explore the capabilities of the new tires and report some encouraging results.
http://www.cleanmpg.com/photos/data/501/FuelMax.jpgChris Bernius - CleanMPG (http://www.cleanmpg.com) - Oct 20, 2010
A friend of mine bought a minivan last May with his tax refund check. It's a 2001 Chrysler Voyager with the 2.4L I4 engine and 3AT. When the Plymouth brand was discontinued, they kept the "Voyager" name under the Chrysler brand to sell lower cost "shortie" vans at the same dealership as the long-wheelbase well appointed Town & Country. EPA numbers are 20/26, and unadjusted numbers are 22/33, so it has some potential if set up "properly" and driven "properly".
When he bought the van, we knew it needed tires. I measured 3/32 on the front tires with my tread depth gauge, and not much more on the rears. After a few thousand miles, a quick penny-test showed the top of Lincoln's head - below the legal minimum.
Three of the tires were Prime Well PS850 and the right rear was a Goodyear Integrity with about 6/32 tread. Considering the Costco cheapies were completely toast, their rolling resistance would already be lower than they were when new. The only tire that had any meat on it was a LRR Goodyear Integrity. So the van was already "LRR-equipped" due to the advanced tire wear. I did not check tire pressure on these tires today, but they were in the mid 30s when I pressed them up back in May. I didn't want to go too high back then because these tires were old (according to DOT code) and badly worn.
Since it's up for inspection in November, it was time for him to make some moves to get the van ready to pass. Phase I is new tires. Phase II will be to get the check engine light issue repaired. It has been on for several months now, and the 3-key-cycle code trick that Chrysler builds into their vehicles revealed a P0455 - a major evap leak - and a code very familiar to many owners of Chrysler products. There is a part that goes bad over time and causes the leak, and that will be addressed in the next couple of weeks.
Tonight, though, was Phase I - new tires. Because of the oddball size (by today's standards), with 15 inch wheels and tall sidewalls, LRR tire brand selection was limited. I decided it was going to be a LRR tire because the owner is unemployed and trying to make every penny count. Looking through the list at Tire Rack, which allows the search of "Only LRR tires" when searching by size, I found my only option in the correct size was the Goodyear Assurance FuelMax. I ordered a set of four on Monday at 1pm and they arrived the next day at 5:30pm.
With the tires here, my friend drove over in the van earlier this evening so we could head over to PepBoys for the familiar mount/balance/valvestem operation.
On the way to the shop, we took "the long way", finding some roads where we could do a couple of coast-down tests. There was no wind, and the roads I picked were about as level as we could get. I explained that I wanted him to drive at a steady 30mph, then take his foot off the accelerator, and watch the speedometer until it dropped to 20mph. Using my wristwatch, I clocked the time it took to coast down from 30mph to 20mph and wrote it down.
As the tires were being installed, we walked down the block to Taco Bell to discuss hypermiling techniques over $15 worth of fast food. I explained the technology and benefits of LRR tires, and how to make the best use of what they offer. The Tire Rack reviews on the tires are a mixed bag, with half the drivers seeing a gain in MPG while the other half notices no difference or fewer MPG.
When he understood the idea behind LRR tires, I noted that only people who "take their foot off the damn gas pedal for more than a second will see much of a difference at all." Why? Because these tires offer the ability to coast long distances without losing as much speed. Then I told him that this was the reason we were doing the coast down test, and that we should see some dramatic improvement with the new tires. He asked why the lower speed was used, thinking that "going faster means you coast farther." I said that the lower speed reduces the effect of aerodynamic drag and wind speed and direction, and that we would be repeating the test on the same day, in the same weather, on the same roads in the same direction, to equalize as many parameters as possible so we could see if these tires really make a difference.
The only changes made between Before and After would be the new tires installed, and the fact that the Before test includes the 88 pounds of new tires (22lbs each, according to the spec sheet) in the back of the van on the way to the shop.
I asked the tech at PepBoys to press the tires up to 42psi. Placard is 35, and sidewall is 51. They usually balk at pressing up beyond placard pressure, but I requested 42, offering the explanation that the outside temperature was 60, and so setting the pressure at 42 meant the tires would be at placard at any temp above zero, thereby avoiding the danger of underinflated tires. They bought the explanation, and set all four at 42. :)
With a new set of shoes, the Voyager was ready to dance. We took the same roads, same direction, sort of going up and around and down again in our trip coming from the opposite direction, in order to replicate the first test to the best of our ability. Temperature was maybe 5 degrees cooler (roughly 54F), but still no wind.
Here are the results, in seconds, for coasting down from 30mph to 20mph:
Tires|Test#|Time (sec)
PrimeWell PS850 x 3, Goodyear Integrity x 1|1|26
PrimeWell PS850 x 3, Goodyear Integrity x 1|2|29
Goodyear Assurance FuelMax| 1 | 48
Goodyear Assurance FuelMax| 2 | 52
With the FuelMax tires installed, the van rolled for 48-52 seconds before dropping from 30mph to 20mph. As you might expect, the loss of speed becomes more gradual as overall speed decreases, and it takes quite a while to coast from 23mph down to 20mph. Like most heavy vehicles, this van seems like it will coast forever at lower speeds.
During one coast-down, while we were waiting for what seemed to be an eternity for the speedometer to fall to 20mph, I pointed out the red light ahead, and that our coast-down was going to give the light time to change to green before we reached it. Right on schedule, the light went green. I saw his foot move for the accelerator, and I barked out, "No gas! Coast!" My block was just up ahead, and he'd have to slow anyway to turn. We coasted under the green light and made the wide right turn onto my block at about 16mph, with no brake needed. "That", I told him, "is what it's all about. Every time you press the 'go' pedal, you're burning money. Use it only when absolutely needed."
That is how to make the best use of LRR tires - let momentum keep you moving, and don't speed up to the next red light. ...Or up to the corner. Accelerate to your target speed and let the energy-saving technology built into the tires allow you to maintain that speed with an absolute minimum of throttle.
I will see him again soon, around the time we will work on getting the evap leak resolved. After the eye-opening test earlier today, he's ready for another lesson in FE improvement. Next time, I will reinforce the strategy of light timing, DWB, DWL, and if he's ready for it - NICE-on coasting for some more significant improvement.
The Voyager minivan is a must-have for this friend of mine, for family-truckster duty as well as handyman projects and small moving jobs. There is no way to measure actual FE from fillup to fillup because he doesn't have the cash in pocket to fill the tank to first click. He doesn't have a regular daily drive to measure the "$x per week" fuel cost variable. But our informal coast-down test was very revealing, and worth sharing here.
At least one other CleanMPG member is using FuelMax tires, on a minivan, with good results. Now we can add another FuelMax-equipped vehicle to the "thumbs up" column. Whether they live up to the improved fuel economy promise depends entirely on the driver's willingness to take their foot of the tall pedal from time to time. And I think with these new tires on this minivan, we have someone who is eager to explore the capabilities of the new tires and report some encouraging results.