[melgish]

What's the best car wax to use. Does teflon based wax really increase MPG by reducing friction?

 

[john1701a]

Don't forget, you'll get a different answer from someone that lives in the north than someone in the south... because having to reapply during the winter is totally unrealistic.

And have you noticed how the underside of boats are not smooth anymore? It was proven that the rough skin of a shark really did provide it with the ability to slide through the water easier. I wonder if that is true with air too. Hmm?

 

[melgish]

And have you noticed how the underside of boats are not smooth anymore?

I don't spend a lot of time on the underside of things... But that's interesting. I suspect if it were true for air, planes would have shark-skin on them

And big teeth painted on the front just for show

 

[DAVID]

Melgish,
I have wondered about which wax is best from the coefficient of drag perspective, too. I wonder if there are any pilots out there who have input about it. Pilots wax their small aircraft. Anybody out there?

 

[melgish]

Well, I remember a job interview at a Rainbow Polish outlet back 'round 1989. The guy mentioned a pilot that used their polish on his plane and claimed better fuel economy.

So I figure there must be some 'best mix' out there, and if I'm going to wax the car anyway... I might just as well pick a wax that will pay for itself through MPG

 

[jfschultz]

Well, I remember a job interview at a Rainbow Polish outlet back 'round 1989. The guy mentioned a pilot that used their polish on his plane and claimed better fuel economy.

So I figure there must be some 'best mix' out there, and if I'm going to wax the car anyway... I might just as well pick a wax that will pay for itself through MPG

Because air resistance goes up the square of speed, this is much more significant for planes than cars. My airline pilot father mentioned back in the 60's that a dirty DC-8 used about $2,000 more fuel than an clean DC-8 in a trans-atlantic flight. I doubt any car would see that big of a hit.

 

[AgentElrond]

An SUV might, if you could get it moving fast enough; then again, by the time it got up to that kind of speed, the tank might be empty. :lol:

 

[ehurtley]

In a similar vein, I've always found it funny when people put those monstrous spoilers on little imports. The two big reasons:

1. Spoilers only matter if you're going over about 100mph. (Higher if the car isn't very aerodynamic.)

2. Spoilers provide DOWNWARD pressure. Most of the cars they are put on are front wheel drive, meaning you are taking grip AWAY from the tires, because you are causing a downward rotational force around the rear axle, providing lifting power on the front end of the vehicle.

As for waxing? I don't think any wax will provide enough of a difference to warrant hunting down 'the perfect wax'. Merely keeping the car clean will be enough. And you'll probably get more of a mileage boost by simply not keeping heavy objects in the car. (So, for example, if you were to replace the tires with run-flat tires, and get rid of the spare.)

(I have an aerospace engineering bachelors degree with an emphasis on aerodynamics, so I *should* know what I'm talking about. That doesn't automatically mean I'm right, though, since I haven't worked in aerospace since leaving college, so my knowledge is starting to get rusty.)

 

[BIF]

It's my understanding that runflat tires have more mass, because of the stiffer sidewall. So wouldn't that extra rotating mass be a direct drag on engine and electric motor performance?

And if this is true, would the rotational drag be less or more when compared to the lower-mass tires plus the weight of a lightweight "donut" spare tire in the trunk?

A question beyond my own ability to answer.

 

[ehurtley]

It's my understanding that runflat tires have more mass, because of the stiffer sidewall. So wouldn't that extra rotating mass be a direct drag on engine and electric motor performance?

And if this is true, would the rotational drag be less or more when compared to the lower-mass tires plus the weight of a lightweight "donut" spare tire in the trunk?

A question beyond my own ability to answer.

Good question. I had never really paid much attention. I'll have to do some research now.

 

[melgish]

My airline pilot father mentioned back in the 60's that a dirty DC-8 used about $2,000 more fuel than an clean DC-8 in a trans-atlantic flight. I doubt any car would see that big of a hit.

In the 60's fuel was $0.20 a gallon. So $2000 = lots of gallons. If all other factors are equal, than any improvement would be better than none at all.

So I'm back to..if I'm going to wax anyway...which wax is best

and ehurtly: I'll also go back on my diet to reduce the heavy objects in the car

 

[ehurtley]

My airline pilot father mentioned back in the 60's that a dirty DC-8 used about $2,000 more fuel than an clean DC-8 in a trans-atlantic flight. I doubt any car would see that big of a hit.

In the 60's fuel was $0.20 a gallon. So $2000 = lots of gallons. If all other factors are equal, than any improvement would be better than none at all.

So I'm back to..if I'm going to wax anyway...which wax is best

and ehurtly: I'll also go back on my diet to reduce the heavy objects in the car

hehe.. No wax will make enough of a difference to 'pay for itself'. Choose based on how nice it makes your car look, how infrequently you have to reapply, how much it costs, or other esoteric things. Don't even worry about its effect on mileage. (Waxing in general will make a SLIGHT improvement, but again, not enough to pay for itself, and no wax is *SO* much better that it pays for it's price increase over normal wax. Cheaper wax will provide better 'drag reduction for the money' simply because it's cheaper.) Water has significantly more resistance than air, that is why wax makes more of a difference in water. (Boats, surfboards, etc.)

 

[patrickg]

Most folks I know wax the top of the surf board for traction for their feet not to make the board slipery. If the bosrd went faster you'd just have to angle more to avoid outrunning the wave.

Some airplanes do have little "bumps" on them to create turbulent flow (typically on wing near root).

The small orthodontocete whales (dolphin-porpoise-pilot wtc. have lower drag than sharks due to the wrinkles that form on their skin at higher speeds and go away at low speed, dynamically configurable.

Even gravity powered soap box derby entries wax their ride.

Golf balls have little dimples and hence less drag than a similar smooth ball. Maybe you should take a small ball pein hammer and or a small punch or awl and make little dents all over your car.

Tires would only have to be increased a bit in weight or diameter to result in poorer performance than carrying a spare. Of course the performance hit would be mostly in acceleration and deceleration so highway performance would not take as much of a hit as would stop and go.


pat

 

[AgentElrond]

Golf balls have little dimples and hence less drag than a similar smooth ball. Maybe you should take a small ball pein hammer and or a small punch or awl and make little dents all over your car.

LOL! I think I'll just live with what I've got. :lol:

 

[patrickg]

Maybe you could just go to "Earl Scheib" and have them apply a topcoat. They usually end up with an orange peel surface that looks like a model of moon craters. This will simulate golf ball dimples closely enough. Be sure to pay the extra $5 so they use a clean mop and bucket to apply the paint and you won't get so much included debris.

Alternativelytakek it to the beach and spray it with spray cans of clear and then throw sand all over it. Remember it is the mileage that counts, not looks.



Pat

 

[melgish]

Alternatively take it to the beach and spray it with spray cans of clear and then throw sand all over it. Remember it is the mileage that counts, not looks. Pat

And contribute to beach erosion.... never! ;-)

 

[patrickg]

Melgish, But beach erosion is nature's way. All up the east coast as errosion would denude a beach the local authorities would construct a groin or other anti-errosion thingy sticking out in the water transverse to the lateral sand transport. This would preserve their sand but down current the natural sand transport would still carry sand away that was no longer replaced. This ruined the next door neighbor's beach who would then construct an anti-erosion device and pass the problem to the next community. Eventually everyone who would build them did build them and status quo resumed as regards coastwise sand transport with beach erosion much as it was before anyone built the anti-erosion thingies.

I don't think your minor impact in beach erosion will be significant or noted from overhead satellite imagery. Besides, in the quest for maximum PRIUS mileage, TRUE GRIT might be just the thing.

Pat

 

[melgish]

Acutally it's the accellerated erosion cause by ripping up the dunes and installing resort hotels I'm against.

It's funny how I'll get fined for digging up a sea-grape but a condo developer does not

 

[patrickg]

Melgish, Ironically it is often developer money spent to build the "STICK OUT IN THE OCEAN TO TRAP SAND THINGIES" to preserve their beach that holds back the sand from the next stretch of beach down current.

I know lawyers have a bad PR situation about on a par with used car salesmen but develppers deserve a lower rating.

Pat Enjoying driving way too much.

 

[ehurtley]

Melgish, Ironically it is often developer money spent to build the "STICK OUT IN THE OCEAN TO TRAP SAND THINGIES" to preserve their beach that holds back the sand from the next stretch of beach down current.

Which is why I like Oregon. Every inch of coastline is public property. Yes, there are hotels on the beach, but they don't own the beach itself, and can't do anything to the beach without government permission. (Like installing 'sand trap thingies'.)

Of course, when the water is 50 degrees, max, in the middle of Summer, the beach isn't as fun as in California, Florida, or Hawaii. (And the air temperature is usually below 80, even in the Summer. In fact, last week, while Portland was having its record 100+ degree weather, most of the coast was only 80, and *THAT* was a record.)