Mythbusters dimpled a Taurus

Mr. Pancake · #31 10-30-2009, 07:09 PM

Quote:

Originally Posted by SD3_Driver

i saw that episode twice and as far as i remember the clay added about 800 extra pounds, so i'm not that convinced of the benefits of dimples.. maybe they got better mpg, but used more fuel, so, where's the advantage??? the idea is to use less fuel, or not???

The clay was used as an easy way to go from a smooth car to a dimpled one, they weren't advocating using the same method at home for better FE.

jim isbell · #32 10-31-2009, 11:04 AM

Quote:

Originally Posted by SD3_Driver

i saw that episode twice and as far as i remember the clay added about 800 extra pounds, so i'm not that convinced of the benefits of dimples.. maybe they got better mpg, but used more fuel, so, where's the advantage??? the idea is to use less fuel, or not???

I dont see how they could get better mileage and use more fuel. Can you explain that to me??

I watched the show two nights ago after hearing about it here. being a scientist, I was very skeptical that they had done a well run test. But after seeing the show and that they actually carried the clay from the dimples in the back seat, I feel they did a good job. I dont know if they considered wind and temperature, but since they carried the dimples in the back seat, I assume they covered all the bases. Doing 5 @ 1 mile runs and averaging the results was good. AND the 11% increase was so huge that even if they made some errors, it overshadows any small errors.

But as someone else said, I think the clay was used as a good test, not as a recommendation. There are other ways to do it I am sure.

SD3_Driver · #33 11-02-2009, 02:26 PM

Quote:

Originally Posted by jim isbell

I dont see how they could get better mileage and use more fuel. Can you explain that to me??

I watched the show two nights ago after hearing about it here. being a scientist, I was very skeptical that they had done a well run test. But after seeing the show and that they actually carried the clay from the dimples in the back seat, I feel they did a good job. I dont know if they considered wind and temperature, but since they carried the dimples in the back seat, I assume they covered all the bases. Doing 5 @ 1 mile runs and averaging the results was good. AND the 11% increase was so huge that even if they made some errors, it overshadows any small errors.

But as someone else said, I think the clay was used as a good test, not as a recommendation. There are other ways to do it I am sure.

yes sir i would explain, they used two tanks, one to get to 65mph and then switch to the other at the start of the run, so the fuel used to get to 65mph with 800 additional pounds is not taken into account. if they consider that fuel ( about a 4% loss), i'm sure it will lower mpg to the same value as without the dimples or maybe to a lower value... the test was good, but only at that speed under very specific conditions...

PaleMelanesian · #34 11-02-2009, 02:59 PM

Weight doesn't matter for aerodynamics. That's why they did a control test with smooth clay before dimpling it, to remove the weight factor. If you want the aerodynamic benefit, you can achieve it in other ways than adding a bunch of clay. That's what Mitsubishi did with the previous-gen EVO with the row of shark-fin vortex generators at the back end of the roof.

I keep trying to think of how they messed up the test. All I can come up with is engine warmup and weather conditions. Even with those, 11% is at least worth considering.

jim isbell · #35 11-02-2009, 07:33 PM

Quote:

Originally Posted by SD3_Driver

yes sir i would explain, they used two tanks, one to get to 65mph and then switch to the other at the start of the run, so the fuel used to get to 65mph with 800 additional pounds is not taken into account. if they consider that fuel ( about a 4% loss), i'm sure it will lower mpg to the same value as without the dimples or maybe to a lower value... the test was good, but only at that speed under very specific conditions...

But those of us that drive Insights know that the acceleration is roughly compensated for by the deceleration...or were you meaning to leave them at 60mpg forever? Also, by carefull management of the throttle, acceleration is not that bad on fuel mileage. AND more importantly, the CLAY was not the point of the test, it was the dimpling. There are many ways to dimple a car without using 800 pounds of clay!!!

JusBringIt · #36 11-02-2009, 07:42 PM

800lbs is a LOT of extra kinetic energy at 65mph. This WILL affect your glide distance due to momentum. Imagine if they had tested the fuel used for acceleration only. It would be significantly higher with the 800lbs of clay.

GaryG · #37 11-15-2009, 07:36 PM

I'm not one that keeps a car washed and waxed all the time and I somehow knew washing and waxing never improved my mileage. I wasn't aware that a dirty car improved mileage until I saw mythbusters last night. I've been putting off washing my '09 FEH because a month or so ago I was ask to be in a documentary on Hypermiling the BMW X6 ActiveHybrid. They said they wanted to include footage of me and my '09 FEH so I put off washing it till I had to drive to Miami for the shooting on 11/6/09. The FEH got real dirty during this time but my mileage was increasing. About 3pm on 11/5/09 I took the FEH to the car wash and had it detailed and hand waxed. Since that time I noticed a decrease in MPG of about 10%. I've never noticed that big of a drop in just washing the FEH but waxing it really made a difference for the worst. No question in my mind that a dirty FEH gets better mileage than a waxed FEH.

GaryG

woodkie · #38 11-16-2009, 05:23 PM

There is a dimpled car video / animation inspired by the discussion here: http://www.vimeo.com/7651196

jim isbell · #39 11-17-2009, 10:43 AM

Quote:

Originally Posted by woodkie

There is a dimpled car video / animation inspired by the discussion here: http://www.vimeo.com/7651196

I am not sure what is supposed to happen, but it doesnt. I click on the video and nothing happens.