Aerocivic - how to drop your Cd from 0.31 to 0.17

[elhigh]

Hey, Basjoos,

I just went back and looked at #1 and noticed where you said LED replacement headlights "are several years off."

That was in 2007. It is now several years later. Any thoughts on that score? You had stated that you guesstimated the headlight use (due to considerable nighttime driving) was costing you around 2-3mpg, rather a noticeable dip into the results, and only noticeable because your fuel consumption is otherwise very low. It might be one of the few vehicles where the headlights' signal is clearly discernible against the noise of other loads.

Lots of LED headlight options out there now, and some of them don't suck. Thoughts?

[basjoos]

If I still had my old job where I had to do a lot of night driving, I would likely have done it when a bulb burned out. But if the LED's actually do outlast several replacement sets of halogen bulbs, then the conversion becomes cost effective. I currently do very little night driving now, but whenever a bulb does burn out, I might consider it.

Just passed through 600,000 miles on my odometer.

[freebeard]

I swapped my H-4 halogens for LEDs with cooling fans. The light is whiter but the pattern gets lost because the LEDs are not all at the same focal point. I applied a field expedient fix, but they make better DRLs than night-time lights.

[basjoos]

I made a trip up to the NC mountains a few weeks back and saw the effect that altitude has on mpg. At 400 feet elevation at 55mph, 15" of manifold pressure, and 85 degrees my SuperMID shows 100mpg. At 2100 feet elevation those same parameters show close to 120mpg. The mpg improvement would be due to a combination of reduced aero drag in the thinner air and the 15" of manifold pressure at 2100 feet elevation resulting in a wider open throttle plate for reduced pumping losses. I wonder what it would show at 6000 feet, not that there are any flat, straight road stretches to try this on in the eastern US.

[COcyclist]

Originally Posted by basjoos

I made a trip up to the NC mountains a few weeks back and saw the effect that altitude has on mpg. At 400 feet elevation at 55mph, 15" of manifold pressure, and 85 degrees my SuperMID shows 100mpg. At 2100 feet elevation those same parameters show close to 120mpg. The mpg improvement would be due to a combination of reduced aero drag in the thinner air and the 15" of manifold pressure at 2100 feet elevation resulting in a wider open throttle plate for reduced pumping losses. I wonder what it would show at 6000 feet, not that there are any flat, straight road stretches to try this on in the eastern US.

I have a stretch of road between Steamboat Springs and Laramie WY where the elevation is over 8,000 feet for much of the trip. In that thin air I can hit 70@70 where mpg and speed are the same. At lower elevations I have to drive much slower to come close to those numbers. And the diesel doesn't have a throttle plate like a gas engine.

[Tahoe_Hybrid]

What we need is a after market boat tail that is pretty much made for the main stream cars/ SUV with high sales esp trucks/SUVs as they have a hitch to plug into and use..

I would only pay like 2-300 dollars for a clear plastic item because i know its only going to last 2-3 years(and turn yellow)

[mpg_numbers_guy]

Originally Posted by Tahoe_Hybrid

What we need is a after market boat tail that is pretty much made for the main stream cars/ SUV with high sales esp trucks/SUVs as they have a hitch to plug into and use..

I would only pay like 2-300 dollars for a clear plastic item because i know its only going to last 2-3 years(and turn yellow)

Problem there is that no one would build them because pretty much no one would buy them except for a few of us extremist ecomodders, and since most of us all drive different cars, they might sell 2 or 3 of each kind, and in order to produce any kind of quality and improvement in aerodynamics they would have to spend hours in the wind tunnel. That is, unless they charged $100,000 or something ridiculous for each unit.

[Xist]

I recognize your issues, but aside from Metro moving his boat tail from one vehicle to another, I really do not think this is a one-size fits-all proposition, unless it were adjustable for different makes and models, which would make it cost more.

However!

How often do you see roof storage (pointed the wrong way)? If they marketed an alternative to roof boxes that were easily accessible and actually slightly increased your fuel economy, while the traditional method made it a bit worse, they probably would not sell very many, but it should appeal to people.

You can invent an easier method and sell some, but people seem pretty determined to keep doing the same thing.

[freebeard]

Make them collapsible.

[Xist]

Everything is collapsible if you Hulk-smash hard enough.