Hypermilling an 8% grade?
 

I have a 2000 Honda Civic EX (automatic) and have improved to 46 mpg with mainly highway and nice 45 mph roads using an UltraGauge.

My biggest challenge is a mountain that gains ~1040 feet with upto a 8% grade on my daily commute. It is 3 miles long with average grade of 5.7%! On another side of this mountain they do hill climb races.

I've tried doing it at 40 mph and 50 but it is a mess either way. I loose to much speed to even limit to 2500 rpms and often it hits 3000 rpm. I try to hit the slope with extra speed. Rough estimate is I can only get 22 mpg on this section. The two lane each direction road is 45 mph.

Any suggestions on how to approach this and perhaps do a few test runs?

P.S. Do any websites do eco-routing driving directions?

go as fast as possible before you get to the hill
put your foot in a position that will get you a minimum safe speed at the top of the hill.

70+ at the bottom 45+ at the top

Thanks, I try to do that but as I bleed speed and get to under 50 mph, I see 13-15 mpg on the steep sections. This is a big 1.6 mi mountain not really a hill.

I don't have a good way to go around it :( Perhaps my only solution is an electric assist.

Yeah, try to start the grade with as much speed as possible, hold as much throttle as possible without disengaging overdrive. When it does disengage, reduce throttle and speed to lowest throttle position that will keep you going up the hill without losing momentum.

Gain as much kinetic energy on level ground as possible to then convert it to potential energy. If the kinetic energy isn't enough to get you to the top of the hill, you must expend extra chemical energy.

Just for fun, hour much easier would the grade be if you reduced the mass of your car by removing the spare tire, or rear seat temporarily?

Is there really no alternate route?

try what I said and try different speeds. you might not want to drop too low ect.

cant fight the earth, a hill is a hill. good mpg down bad mpg up. all we can do is try to make the up suck less.


using more fuel to gain momentum on the flat is good.
bleeding speed up hill is good but don't add any speed uphill. try to go 70mph+ at the bottom and decrease the speed so you are a minimum safe speed at the top. what is the speed limit anyways? do you have a mpg gauge? the TPS sensor is good for this technique. DWL

I'm gonna take a wild guess that this is Route 40 just east of Uniontown. The STEEPEST climb by far I have driven in PA. 3rd gear & floored in my Corolla to maintain 45 MPH:eek:

Wait, 8% is not steep lol...(I drive through ridiculous SF streets everyday where I have to climb several hundred feet within 2 blocks)

Going uphill is a great chance to use your engine at high load aka high efficiency. Know when open loop enrichment kicks in and give it enough throttle to be just below that point, there's no way around burning a lot of fuel up the hill. When you go downhill you won't be burning gas.

Oops, I was wrong. Just checked & the grade is 12% on that stretch of route 40.

I've tried to climb a mountain in a 90' Civic DX and I had to drop to 3rd and floor it to get up. I believe it was in PA on the toll road to OH.

I assume you have either a downgrade on the other side or you gotta come back down the mountain. This should cancel it out if you can coast down with your automatic.

I climb a 5 mile grade 2 times every day on my route on I64 in VA. Luckily it is another 5 miles back down on the other side. I've done a bunch of testing and really cant hypermile it. The only thing I have going for me is coasting back down. I dont EOC because of the curves on the mountain.

Here is my data:
Torque app claims I do:
0.30gal used in 10 miles on flat @65mph
0.28gal used up 5 mile grade at 65mph
0.24gal used up 5 mile grade at 55mph
0.016gal used down 5 mile grade clutch in
Below 55mph I'd have to downshift.

Either way I get slightly better FE because of the 5 mile coast. (Before discovering this site I used to run the whole 10 miles with cruise still on. LOL!)

Today I may test 4th gear and follow a truck as not to impede traffic as the speed limit is 65.

Climbing Afton mountain between Charlottesville and Waynesboro in a 1963 Valiant was an adventure, basically the old 170 was floored in 2nd until you got to 55 then 3 rd until you got tired of going so slow 25-30, then back to 2nd.

Still got just under 29 mpg in the old girl, would have been better without the recaps. Radials? maybe 33mpg.

Used to but then 4 years old with gunked up pcv valves, people thought the engines were shot. Clean it out with gas, oil consumption %. 4 year old car for $400.

regards
mech