Fuel efficiency

[Dahmer]

hey there, I am testing ways to drive efficiently, but of course I have no data because I don't have the funds to fill my tank up consistently.

however here's the situation:

I live in vancouver, and work on cypress mountain, meaning I drive up to the top (2990 ft of vertical) and back down to sea level (approximately 45 minutes of near highway speeds) each day.

I've tried many different ways of getting down the mountain.

Please keep in mind that there's a good chance that I have made a horrendous mistake that probably made serious damage, but it's all in the effort of saving some gas and... I quite literally don't know what I'm doing

first is by chucking the auto tranny into neutral. the engine sits at ~800 RPM all the way down the mountain. obviously I then use the brakes to slow down, and recently I've noticed that braking is stuttery from potential heat warps.

I also believe that using the brakes actually USES gas by further compressing the fluids.

secondly I've tried gearing down (into overdrive and 2, but never further than that)

so obviously I go up to about 3500 to 4000 RPMS coming down the mountain, but find that I brake a fraction of the time.

I presume that because my foot isn't actually on the throttle, there is no change in mixture, and therefore it's still using the same amount of fuel as if I were in neutral at 800 RPM.

[a nifty observation here was that my engine thermometer dropped to almost nothing at this stage]

my next assumption is that gravity is essentially running my accessories, such as radio, defog, and fan. (when I am gearing down)

anyways, like I said before, I haven't gotten any hard data, and I seem to fill up after the same number of km (only about 450???) per tank.

any advice on the issue would be fantastic.

P.S. about 2 months ago, I replaced every fluid in the car, as well as air filter and fuel filter, and change my oil and filter religiously.

thanks a lot

Dahmer

[2RedV's]

Many people with a Scangauge have reported seeing better mpg while coasting, in gear, than in neutral. This is because the throttle is closed and the injectors are turned off. (This neat fact is in the factory service manual). So, letting the engine do some of the braking for you is not only good for fuel mileage, it is MUCH better for your brakes.

Replacing warped rotors just once will cost you way more money than trying to save 1 mpg on every tank of fuel over a year's time.

[Dahmer]

alright so I pose another interesting conundrum.

from the observations I've been making recently, I have some theories of "shifting" on an automatic.

see as a kid I presumed that there were like two separate sections in the tranny of an automatic. ie the actual gears 1-5, and then a separate section for reverse, drive, neutral, and 3-2-1.

now I'm guessing that it's more electronic than that. especially in the CR-V, how it goes:

N
D4
D3
2
1

now I know D3 is overdrive and sits at higher RPMs for more torque, and so is simply an difference in the computer

and based on that, I'm guessing that being in 2 makes the engine sit in the 2nd gear or lower more than any other gear, and 1 shifts down to the first gear.

that makes a ton more sense to me. correct me if I'm wrong.

and then technically, do I have some version of autostick? would it be hazardous to the tranny to have some fun with that?

[2RedV's]

Your V has
1 - first gear
2 - second gear
D3 - Fully auto except locks out 4th gear. Use it provide engine braking while going downhill.
D4 - Fully automatic, all gears, up and down

... and a lock up torque convertor which only locks up when on relatively level ground and in 4th gear and not accelerating. It will drop the rpms about 200 from D4.

While OK to manually shift it, it will not provide any real performance gains since the trans will already shift at redline if the gas pedal is held to the floor and left there.

[Dahmer]

sweet man, thanks for the advise. hopefully I will see an improvement in my gas bills.