Weight difference: Power vs manual windows.

[pete c]

why have automakers stopped making cars with those vents? is it because just about every car out there has AC now?

[nemo]

Probably just cost reduction.

[Frank Lee]

Those vents hafta be waaaay cheaper than a/c!

Probably consumer demand for a/c made them redundant; then it was too tough to fit them to only no a/c vehicles, of which there are damn few.

[Thymeclock]

In summer, during the four warmest months of the year, I drive a convertible. If it isn't raining, the top is always down (along with the power windows, and the A/C being off.).

If you really think the weight of a power window motor is going to have any measurable effect on MPG, then this is the wishful thinking list. Or the OCD list. AKA the Ecomodder list<?>

[Fat Charlie]

They already have to have AC available for the higher trim levels. It makes more sense for the manufacturer to slap the system they already have into the lower trim levels than to engineer a system of vents and controls for the lower trim levels because that'll never pay for itself. If it were an "eco" feature that they could charge extra for, then it probably still wouldn't make sense to build.

Weight reduction still makes a lot of sense around town. Doesn't every 100 pounds use 15 hp? With stop & go, you're accelerating all that weight all the time.

[skyking]

Originally Posted by Fat Charlie

They already have to have AC available for the higher trim levels. It makes more sense for the manufacturer to slap the system they already have into the lower trim levels than to engineer a system of vents and controls for the lower trim levels because that'll never pay for itself. If it were an "eco" feature that they could charge extra for, then it probably still wouldn't make sense to build.

Weight reduction still makes a lot of sense around town. Doesn't every 100 pounds use 15 hp? With stop & go, you're accelerating all that weight all the time.

need to move that decimal point over. If 100 pounds = 15 hp
my truck needs more power than a veyron, and about 2000 hp with the trailer

[redpoint5]

Same question, but concerning power and manual seats. Any ideas on the weight difference?

Power seats annoy me because they are way to slow to adjust. The only thing I like about them is the memory ability for multiple drivers (which I don't use yet since I'm not married).

[Fat Charlie]

I had read a magazine article once that casually mentioned it, but I never examined it.

For acceleration it's about power and weight. My car, with a curb weight of 3355 pounds and 250 hp has 13.42 pounds per hp. After I plant my 200 pounds in the driver's seat, each of those poor horses now has to push 14.22 pounds off the line. I'd need to add 15 hp worth of cold air intakes and ricer decals to bring the lb/hp back down to 13.42 again- or I could find 200 pounds worth of interior trim to get rid of. So for accelerating my car, 100 pounds is more like 7.5 hp. On the sporty things that most magazines like to review, 10 or 15 hp per 100 pounds shouldn't be all that unreasonable to see.

Anyhoo, the brisk acceleration that you want in your pulse & glide or stop & go can be more efficiently acconplished by reducing the weight that you are accelerating.

I like power seats because they have more than just a few notches to choose from. Of course they're heavier and if something breaks then they're obscenely expensive.

[some_other_dave]

Originally Posted by redpoint5

Same question, but concerning power and manual seats. Any ideas on the weight difference?

I can tell you that the difference is very noticeable on my wife's car, a 1982 911. We have a power-adjustable "sport seat" that we put in for track days, and the non-power "standard" seat that we put in for daily driving. I can certainly feel the difference when picking the seats up. Probably something around 10 lbs difference, possibly more.

Some of that is due to the sport seat being a bit larger (more bolstering) than the non-sport seat, but some is definitely due to the electric motor and actuators. Those are much heavier than the manual adjusters.

Of course, that is 1980s tech. Electric motors have gotten smaller, lighter, and more efficient since then. I'm not sure what the difference would be these days.

-soD

[redpoint5]

Originally Posted by Fat Charlie

the brisk acceleration that you want in your pulse & glide or stop & go can be more efficiently acconplished by reducing the weight that you are accelerating.

True that acceleration will be quicker with less weight, and I agree about the benefits of reducing it. However, the added weight will also extend the glide portion of the pulse and glide technique. While it may take longer to accelerate, it will also take longer for speed to bleed off.

My motorcycle is terrible at the pulse and glide because it's so aerodynamically inefficient compared to the weight. The instant I'm off the throttle, speed plummets. It takes a heck of a steep down-hill for me to maintain speed at coast. The same hill in my car would produce too much speed.