Driving steep grades with large elevation gains
03-22-18, 08:19 AM
#16
Moderator
The power mode does not boost power. It simply moves the shift point a bit higher in rpm to give you reduced economy for a bit more power at high rpms.
Has any one pushed a vehicle on an upward incline?
Sitting in the vehicle the road appears flat, but the attached graph shows how much the altitude is changing. Human's need acclimation as they change altitude and with the computers the vehicles have built in memory. Amount of oxygen molecules per volume intake impacts the energy being consumed. [output = consumed - loss]
Salim
Has any one pushed a vehicle on an upward incline?
Sitting in the vehicle the road appears flat, but the attached graph shows how much the altitude is changing. Human's need acclimation as they change altitude and with the computers the vehicles have built in memory. Amount of oxygen molecules per volume intake impacts the energy being consumed. [output = consumed - loss]
Salim
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murphysf (03-22-18)
03-22-18, 01:18 PM
#17
Pit Crew
Thread Starter
As you go higher, your engine is consecutively receiving less oxygen. hence, reduced power. This is why super and turbo chargers are norm on airplane engines. To pump more oxygen through.
That said, you need to do one thing:
ditch your air filter and replace it with high air flow one. Septre, for example. No need to pay grossly for K&N. I also just bought HAF filter on Amazon for $16 for my NX. Same difference as K&N or Septre. Fraction of cost.
Also, you may consider a higher octane for trips like this.
That said, you need to do one thing:
ditch your air filter and replace it with high air flow one. Septre, for example. No need to pay grossly for K&N. I also just bought HAF filter on Amazon for $16 for my NX. Same difference as K&N or Septre. Fraction of cost.
Also, you may consider a higher octane for trips like this.
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murphysf (03-23-18)
03-23-18, 07:45 AM
#19
Pit Crew
Thread Starter
what HP value did you use to get the 45 HP loss,
or maybe I am missing something
03-24-18, 03:12 PM
#20
Lexus Test Driver
220 HP X (7 (thousands of feet of elevation) X .03 (percentage of air pressure lost per 1K feet) = 46.2 HP
With 272K miles, there's absolutely no way it's making 220 HP at the power peak. Probably more like 180, if you're lucky.
When we lived in Colorado, at about 9K feet of elevation (it's not altitude if you're touching the ground), the V8 '94 Grand Cherokee I had felt like the 318/5.2L had been swapped for a slant-6.
The only way to make up for this is to bring your own atmospheric pressure with you in the form of a turbo- or supercharger. Our coach, at elevation, feels the same as it does at sea level because of the Cummins turbodiesel. Still almost a 60 second 0-60 time (55 seconds), but at least it's consistent.
With 272K miles, there's absolutely no way it's making 220 HP at the power peak. Probably more like 180, if you're lucky.
When we lived in Colorado, at about 9K feet of elevation (it's not altitude if you're touching the ground), the V8 '94 Grand Cherokee I had felt like the 318/5.2L had been swapped for a slant-6.
The only way to make up for this is to bring your own atmospheric pressure with you in the form of a turbo- or supercharger. Our coach, at elevation, feels the same as it does at sea level because of the Cummins turbodiesel. Still almost a 60 second 0-60 time (55 seconds), but at least it's consistent.
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murphysf (03-26-18)
03-26-18, 03:50 PM
#22
Pit Crew
Thread Starter
Update
I just did the drive this past weekend... I purchased a new air filter a high flow Spectre. I didn't reset the computer.when I got to the grade I turned over drive off and help my foot into it, I didn't floor it but had the rpm between 3500 and 4000 rpm made it up doing about 65mphThen I had another pass to go over which is call Brockway Summit pass which goes from to 7,200 feet at 10% grade, did the same thing keeping the rpm between 3,500 and 4k rpm but this time was only able to do 45 mph.
so I guess its not the car but my driving habit in the past where I didn't keep the rpm and momentum up
I just did the drive this past weekend... I purchased a new air filter a high flow Spectre. I didn't reset the computer.when I got to the grade I turned over drive off and help my foot into it, I didn't floor it but had the rpm between 3500 and 4000 rpm made it up doing about 65mphThen I had another pass to go over which is call Brockway Summit pass which goes from to 7,200 feet at 10% grade, did the same thing keeping the rpm between 3,500 and 4k rpm but this time was only able to do 45 mph.
so I guess its not the car but my driving habit in the past where I didn't keep the rpm and momentum up
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