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Join Date: Oct 2000
Location: agoura hills, ca 91301
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pedal to the floor or lower gear

Stupid question:

Going uphill and trying to maintain the same speed .....am I better off using a lower gear to maintain speed or a higher gear but with the pedal to the floor?

I am looking for input (pros and cons) with regard to:

1. Gas Mileage?
2. Engine wear and Tear?

Thanks!

Old 04-26-2002, 06:26 AM
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Location: Zaventem, Belgium
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A lot does depend on initial velocity of the vehicle, gear in which the vehicle is engaged, and gradient of the slope.
I'm not an expert, and perhaps others will be more precise in explaining, but
-don't stay in 5th, pedal to the floor, at less than say 3000 rpm
-don't either stay any time in 1st, even 2nd gear
-stick to medium rpm's in 3rd or 4th gears, that should in actual practice cover most slopes you would in actual practice encounter
-this would be valid for less than VERY steep gradients, in which case you need to limit your speed as well as remain in middle-range rpm. of any practical gear
-try a Cayenne
I would consider, for average gradients, to stay in a medium gear with medium rpm's as better policy than low revs in high gear.
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Old 04-26-2002, 06:58 AM
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This is a non-technical explanation, but I liken it to a bicyclist choosing gears. There's a certain pedalling pace where a cyclist is most efficient and he gears up or down with different grades to maintain the rate at which he pedals. Two things you want to avoid are over-revving and "lugging." Over-revving is obvious as indicated by the tach. Your power train will tend to buck and lurch and the engine will sound strained when you're "lugging." It's being asked to produce more torque than it's capable of, like a cyclist who is "standing" on the pedals to go up a hill in too high a gear. It's a strain, and both the cyclist and the car will be much better off with a down shift.

In general, Porsches seem happiest at higher revs, and I would err on that side. A healthy 911 will run all day at higher revs, as proven by their track record in endurance races. I got "tuned" into my engine when my radio was kaput. After listening to her sing with no other distractions for awhile, I learned what makes her happy. At around 3,800-4,000 rpms you can also feel an extra little kick in the seat of your pants that tells you it's a sweet spot, and that sweet spot seems to go right up to redline.

I'm sure someone else can chime in with an analysis of torque curves and such, but my advice is turn off the radio and listen to the engine .

Old 04-26-2002, 07:39 AM
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