Newton is costing me MPG - The hills thread

[Arragonis]

Like most here I'm keen to tune my technique given my environment and routes - but hills are killing me. There is one climb of about a mile on my "to" work route which costs me 3-6 MPG (my trip is only 20 miles or so) as it is quite steep. So I would like some advice on the best method to handle it...

- take a run at them and bleed off speed
- P&G, even with reduced G
- steady throttle and ignore the beeps
- DWL and ignore the increasing beeps
- get em over with asap.
- something else

And maybe include advice based on vehicle size, engine type, turbo or not, even driver weight maybe.

If I can crack this then 80 MPG is mine.

Mine I tell you, all mine....

[Daox]

What does the LOD read on your SG while climbing this hill at the speed limit?

The absolute best way to do it is to still P&G even with the real short glides. I'd recommend just leaving the engine on since they'll be so short. However, if your LOD is high enough I'd just stick to the speed limit and climb up em.

[320touring]

funny you should mention this..

was thinking to myself today on the way home about that ******* of a hill between harthill and junction 5 on the m8..

seems to me best option is to climb it at a constant load (60mph, 30mpg indicated on econometer) as having a speed of 60 at the top lets me glide nearly a mile down the other side..

short ones i just try and time the end of a pulse to be at the peak

[Arragonis]

Originally Posted by Daox

What does the LOD read on your SG while climbing this hill at the speed limit?

The absolute best way to do it is to still P&G even with the real short glides. I'd recommend just leaving the engine on since they'll be so short. However, if your LOD is high enough I'd just stick to the speed limit and climb up em.

At roughly 65 MPH (limit is 70 but traffic got in the way) -
5th (~3000 rpm) LOD says 43 at WOT
4th (~3700 rpm) LOD says 60 at WOT

Didn't try 3rd due to traffic.

Held on to 4th and noticed power increase at 4500, may need to explore the positions on the rev counter beyond 11 o'clock...

I've tried P&G before but the glides are really only lasting about 1/2 the time of the pulse if that.

Glides at anything over 45 don't seem to last long even on the flat - maybe thats pushing me towards aero mods. And I promised I wouldn't before he is 1 year old at least

[Daox]

Meh, it looks like your LOD reading isn't the % of load available at that specific rpm but rather the % of load that the engine is capable of putting out. Unfortunately, this is much less useful. I'm almost positive, but the car has a MAF not a MAP sensor, right? If it had a MAP you could use the manifold pressure as a more accurate load gauge. Otherwise a vacuum gauge does the same thing.

Anyways, as I said before, even with the really short glides, P&G is still the best technique. However, if the hill is real steep at all I'm sure just puttering along at the speed limit (or whatever) is going to load the engine up enough to put it in an good area for BSFC.

[PaleMelanesian]

I agree with Daox. If you're not at peak BSFC efficiency, press the pedal harder until you are. Then use micro-glides to control speed.

I would use 5th. Even running 3000 rpm is a killer to mpg, and anything higher (4500! ) is even worse.

75% LOD should correspond with about 12 psi MAP if your car reads that better than LOD. Edit: I saw Daox's comment about MAF. Not sure what advice to offer there.

[NeilBlanchard]

I am still working at getting better at hills -- I try to do something I call "swooping" when there is a downhill before an uphill. New England has a fair number of these...

I find it is much better to slightly accelerate before you hit the nadir of a valley between hills, and then try to carry the speed up the hill.

[California98Civic]

I have a similar situation. Mile long hill right at the end of my commute in the morning--though I get to ride down it in the afternoon. I get into fifth and carry it to 70-80% load (ultragauge). I adjust throttle to keep load near 80% as the car decelerates up hill. I shift down to 4th when it becomes necessary. I get off the throttle entirely and coast up the last part of the hill, seeking to roll, off, to the appropriate left turn speed. I'm still not satisfied.

BTW, the car is about 2000lbs dry. 5 speed manual, 4 cyl, no turbo, 87 octane gasoline. And I'm a light 144lbs.

[euromodder]

Climb it at the same steady speed in 4th and 5th - but reset the OBC or the SG right when you hit the bottom of the slope. That'll show which gear is most efficient.

[Arragonis]

Originally Posted by Daox

Meh, it looks like your LOD reading isn't the % of load available at that specific rpm but rather the % of load that the engine is capable of putting out. Unfortunately, this is much less useful. I'm almost positive, but the car has a MAF not a MAP sensor, right? If it had a MAP you could use the manifold pressure as a more accurate load gauge. Otherwise a vacuum gauge does the same thing.

Anyways, as I said before, even with the really short glides, P&G is still the best technique. However, if the hill is real steep at all I'm sure just puttering along at the speed limit (or whatever) is going to load the engine up enough to put it in an good area for BSFC.

Apologies, I have gained business in the past day or so. No idea of MAF vs MAP, I will google and ask in appropriate places.

I plan to try (traffic allowing) the steady speed approach, in 4th and 5th (although George will do it in 3rd - screaming...) and reset the SG "trip" before each one. This depends a lot on traffic as the bypass is only 2 lanes and the main McMotorway joins it just before this hill - so it can be solid in both lanes.

I'd still be interested in how others tackle gravity.