More power today, why?

[Lin]

We just returned from being away for a week.  The final part of the route home requires we take Hwy 62 off I-10 and head up the hill.  This is at least a 6% grade though it is not marked, and it runs for several miles.  Last time we did it about a month ago, I had to do most of it in 1st gear.  This time, we did the whole thing in 2nd.  The outside temp was about the same above 100.  I am trying to understand why.  Just note, I am not saying we were a full gear higher, because last time we were at the top of first at about 16 mph and this time we ran about 20+ at the worst in second.  One difference is that we got a running start this time, but I do not think that that carries for several miles up such a grade.  Usually, you just get a few more feet before downshifting.  The other difference is the place where I bought fuel.  The first time it was at a Pilot truck stop.  This time it was at a local filling station.  What else could cause this burst of vitality?

[jackhartjr]

Lin, when I hit the bottom of a hill in my truck I get to the top a lot faster than if I had to slow down near the bottom before going up. 
The difference was probably that you hit the hill 'a runnin'!  Makes a big difference.
As far as the fuel...I have bought thousands of gallons over the past two years at literally hundreds of fuel stops, I have seen no difference.
Hope that helps.
Jack

[tekebird]

INERTIA

[quantum500]

Drastic differences in humidity can make a difference?

[Bob Gil]

Drastic differences in humidity can make a difference?

Humidity can make a difference, I agree.

Ask your self how old was the fuel, you are burning that can make a difference.

If you bought the fuel in an area  like the Ft. Worth dallas metro area that has the pollution adjusted fuel it will make a difference too.

My cummins will run better (and it will get better mileage too)  on the fuel I buy in Texacana than it does the fuel I buy in the Ft. Worth dallas metro area.

[WEC4104]

I too, think the running start makes more of a difference than you might suspect and that would be the primary reason.  But as an extra thought, what about a weight difference due to what you had in all your tanks?  The combined weight of full fuel, fresh water, gray, and black tanks can be significant.  If the levels were lower this time, you were huffing a lot less weight up the hill.

[bobofthenorth]

The difference between #1 & #2 fuel can be dramatic.  I always notice a serious drop in mileage in the fall when the dealers up here switch to winter fuel and then it recovers once we get far enough south to start buying real fuel again.

[kyle4501]

Might be the power curve of the engine. It can pull that grade in 2nd gear -IF- you are above a certain speed. Once below that speed, the engine isn't making enough power, so you have to drop back to 1st, then you have plenty of power through out the gear.

If you had more gear ratios, you'd be able to work your way up to 20+. 
This gear overlap is why I want more than 4 speeds. It will allow more choices.    But, there are many who don't see a need for any more ratios than Greyhound used, however, that is another thread. 

[Ednj]

Maybe you had a stuck injector that just started working?

[Lin]

Kyle,
     I've got to agree.  The four speed Spicer leaves a lot to be desired.  When I first got it, I wanted an automatic just to avoid shifting.  Now, I mind the shifting less, but when climbing a hill in first I feel like I am in a do-or-die situation.  When we left the campground yesterday, they had a long hard climb on the way out.   10 mph was the best we could do in first gear, and I was really afraid it would run out of steam.  I did not, but I do not like not having any safety cushion.

To continue on my original post question.  I took the bus out today for some errands.  I went up the same 8% grade I did a couple of weeks ago.  Then, it was at the top of first gear.  This time, it was the middle of second.  I do not think I got any better a start than last time.  Today is more humid, but I seriously think that there could be a difference in fuel too. 

Also, as just mentioned, it is possible that some unknown problem cleared itself up.

[Chariotdriver]

  Had you changed the fuel filters in the interim?
Possibly preventing any restrictions to the engine.

[chazwood]

your getting better at hill climbing.......pretty soon, you'll be good enough to stay in 4th.

[Busted Knuckle]

The more ya "exercise" it, the stronger it gets!   BK