Is my hill climb theory sound?

[brucey]

I do about 60~65 up the steepest of mountains, making sure the torque converter stays locked and the transmission stays in top gear. When I get to the crest, I put it in neutral so it will coast down to about 50 before it starts accelerating from going down again. Then I will let it coast up to as fast of a speed as I am comfortable with (true speed limit) before putting it back in gear to get DFCO and control my speed. I never ever brake through the mountains.

I plan to do a test using this method with my car empty, and my car with 500 lbs of extra weight in it, and see what kind of differences there are.

[evilskillit]

Originally Posted by redpoint5

I am without a scangauge because my ODBII port is already being used by Progressive's My Rate device.

I had never heard of Progressive Myrate, so I googled it. How is that working out for you? Sounds a bit scary to me to have my insurance company know all of my driver inputs. I wonder how they use them to determine what (if any) discount you get.

I assume you have to have it on as long as you want the discount? I would imagine I could hook one up for a few months and exhibit really good behavior. But there is no way I could be good forever, one of those would eventually get me in more trouble than it would save me I imagine.

[basjoos]

Originally Posted by redpoint5

It follows that if the most efficient way to climb a hill is as slow as possible while over 1200 rpm, then doing it in 1st gear would be most efficient. I find this difficult to believe.

In general, I get my best mileage when I climb the hills as slow as I can (in 5th gear) while still keeping the rpm over 1200, usually at around 70% to 80% throttle. That translates into a speed of 40 to 45mph. Impossible to do 40 to 45mph in 1st gear and it wouldn't be efficient at a screaming rpm even if I could. Below 1200 rpm in 5th gear the motor gets less efficient when pulling much of a load and on steeper grades I'll have to run at a higher rpm to have enough torque to maintain speed on the hill.

[redpoint5]

Originally Posted by evilskillit

I had never heard of Progressive Myrate, so I googled it. How is that working out for you? Sounds a bit scary to me to have my insurance company know all of my driver inputs. I wonder how they use them to determine what (if any) discount you get.

I assume you have to have it on as long as you want the discount? I would imagine I could hook one up for a few months and exhibit really good behavior. But there is no way I could be good forever, one of those would eventually get me in more trouble than it would save me I imagine.

It's working out quite well, especially on my truck which is rarely driven. I get nearly the full 20% discount on that. I just bought a new car, so it's too soon to tell what sort of discount I will get, but the minimum is 5% just for reporting. I got something like an 8% discount with my old Subaru, mostly because I was working a shift which made me drive at high risk hours (1am).

You have to weigh the benefits of lower premiums with the downside of having Big Brother watch your driving habits. In fact, the device can even be subpoenaed by law to determine the driving conditions which preceded a crash. This could either exonerate or condemn you.

I heard that keeping below 75mph 99.9% of the time results in an extra discount, so the effect has been that I now drive slower (72ish). This improves my fuel mileage and reduces my chance of being pulled over. Overall, I think the program is great because it saves you money and creates an incentive to be mindful about how you drive.

[gone-ot]

...keep the ENGINE operating within its best BSFC curve area...in the highest gear possible, and "...speed be damned."

...that's where the vacuum gauge and SG really help!

[Weather Spotter]

If you port is used, get one of these
Amazon.com: Cable, J1962M to 2-J1962F, Splitter Cable, 1ft (145802): Automotive

from Amazon for $12.95. then attach both divices

[cfguy2000]

It seems to me that the effects of wind drag would be more dramatic on a vehicle trying to go uphill. I know my car (1997 Toyota Corolla 1.6L) can get 40 mpg in 2nd gear (3 speed automatic) but I have to go 25 mph. On a steep incline I would have to go pretty slow and downshift to 2nd just to make it up the hill. I think extremely slow in a lower gear would give the engine a better mechanical advantage, but you would have to go pretty slow.

[redpoint5]

Originally Posted by cfguy2000

It seems to me that the effects of wind drag would be more dramatic on a vehicle trying to go uphill. I think extremely slow in a lower gear would give the engine a better mechanical advantage, but you would have to go pretty slow.

I can see no reason why aerodynamic drag would be more severe just because one is going up hill.

Mechanical advantage does not imply better use of energy (efficiency). On what principle of physics would going as slow as possible up a hill be the most efficient?

As far as I know, the only significant downside to driving fast is aero drag (assuming an engine at optimal rpm and throttle setting).

[fidalgoman]

The more work you do the more energy is needed. Pulling a hill at fifty takes a great deal more energy than at thirty five. Also any time the engine is running the gas is flowing. As RPM increases the greater the piston speed and internal drag. There are lower engine speed efficiency limits as well so don't go too slow. Your instantaneous readings on your Scangage should reveal a great deal of information. Some cars have fuel shutoffs if the RPM is much above idle and the throttle position is zero so in this case shutting off the engine and riding the brakes might not be worth it wear and tear wise.

It's farly simple to create a graph and the killer app wil be when somebody makes a dynamic one for a flat panel to graphicly see how you're doing and what you should be doing for optimum economy.

[tumnasgt]

Work = force x distance. The only added force needed for higher speeds will be aero as far as I can work out. The main problem with hills is trying to accelerate up them. If you are going 60mph at the bottom, you're way better to give enough throttle to keep your car from going too slow than you are to have to try speed back up.