Density Alititude Calculator for Flagstaff at 7,000' MSL

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AZRickD
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Density Alititude Calculator for Flagstaff at 7,000' MSL

Post by AZRickD »

My buddy and I took our Rangers to Flagstaff, Arizona to avoid what was predicted to be 111F in Phoenix this weekend vs about 85F in Flagstaff. Ranger Riding around Mt. Elden and Shultz Pass Road to Sunset Crater and back (six hours, followed by margaritas) on Saturday, and dirtbike single-track (with the wives in the Rangers) on Sunday at Munds Park (20 miles south of Flagstaff). Vince on a 2006 Yammi WR 450F.

My buddy has a modded 2005 500 carbo (cam and carb work), while I cam up with my trusty fuel-injected 700 XP ( slightly modded with PowerCommander, 700SP cam, 700SP ECU, throttle mod, red spring).

Both Rangers started easily at 7k feet. The XP like a champ, the 500 carb less so, but adequate. The 500 carbo had plenty of thin-air grunt off the line, but the XP would quickly match and surpass it, with a modest amount of speed betterment as the RPMs climbed.

Here's a cool Density-Altitude calculator to tell you what your elevation and temperature feels like to your Ranger. http://wahiduddin.net/calc/calc_da.htm For "Altimeter Setting" just type in 29.92 -- it should be close enough. For dewpoint, consult http://www.weather.com for your zipcode.

For example, 111 degrees F at 1,100 feet (Phoenix, yesterday), equals 4,658 feet.

Flagstaff at 7,000 feet and 85 F equals... about 10,400 feet.

What did the pressure altitude do to my Ranger's performance? Well, it still had enough juice to hit the rev-limiter -- it just took it a few tenths of a mile longer to do so. Performance from an acceleration standpoint felt like the XP when it was stock, and just broken in.

Also, I had heard some here say that when going to altitude/temp extremes that one shoud turn on the ignition switch but not start it for several seconds on the theory that the ECU is recalibrating. I'd always thought this was bunk, but during the weekend, I kept forgetting to "recalibrate." Finally, on one run (it just so happened that my buddy challenged me to a race) I did the re-cal, allowing 15 seconds before cranking. Seat-of-the-pants seemed to say that it worked... but there's nothing like a race to get your adrenaline up and your judgement down. :) I can't say for sure.

On Sunday I got to test out my new re-jetting (old was 150 Main, DEK-3, and 38 Pilot; new is 148, CEK-3 and 35 Pilot). Down in Phoenix, the new jetting certainly changed the sound of the motor. It went from Bwaaaag to ring-ting-ting-ting. I had misplaced my plug wrench so I didn't get a chance to see how it was burning.

The riding around Munds Park to Mormon Lake ranges in the 7,000 foot range as well. The KDX ran as usual -- still had the 1/16th throttle burble. But I did hear a little high RPM "voop-voop-voop" as if the motor was missing or too lean or too rich. But that was only when it was warming up. Hmmmm.

So now we have some extra data points. Lean runs fine down low in Phoenix, but at altitude (where it is running relatively richer), and during warm-up, I had some voops. Could it be the voops were caused by the combustion chamber not being able to burn the fuel at that RPM? ie, too rich? The voops when cold definately have me wondering.

Anyway, the trails at Munds Park were mostly volcanic and rocky. But we did find some spots that allowed us to stretch out a bit. Problem is, we found them when it was nearing time to head back home.

Here we are up on Mt. Elden's hang gliding launch (9200 feet). We were re-living our old cross country hang gliding days.

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And here is Jolie, begging for a ride on the KDX 220R. Vince's 500 carb in the background

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Oh, and for you Sadists, here I am nearly falling out of the truck bed after my very first time riding the KDX up the ramp. I was foiled by an old car mat that I have in the back of the bed. My front wheel rolled up on it and it slid to the left. Luckliy, the KDX pinned my right leg to the bed wall or I would have fallen off the side. My Moose riding pants protected me from the toasty-warm PC pipe. Not the horrified look on my daughter's face.

Image

Rick
Last edited by AZRickD on 08:41 pm Jul 18 2006, edited 1 time in total.
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quailchaser
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Post by quailchaser »

That is the sole reason I picked up the 3 rail trailer. I've been hurt more so far loading and unloading my bike from the pick up bed than I have from riding. Luckily for me...NO ONE EVER GOT A PICTURE! :lol:

You've used the term "voops" many times...I'm still not sure what that means? As far as how the KDX runs when "COLD"...yes, it is a cold blooded machine and will take some time to warm up before it runs clean. More so in conditions that would make the jetting more on the rich side..ie. at altitude. How it runs when not warmed up all the way is not an issue so long as it runs as it should once warmed up. For me: once jetted good for our elevation down here. Up one clip and down 1 main worked well for 5500 to 8500. Although, your jetted 1 main and 1 pilot leaner than worked for me for our elevation of 1600 ft.

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AZRickD
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Post by AZRickD »

NO ONE EVER GOT A PICTURE!
I consider it a community service, as well as comic relief.

I just found my plug wrench (deep in my Camelbak) and will have to see how lean I've actually made it.

I still haven't learned to use the RPM band of the KDX 220R, so as a result, I'm bogging at low RPM quite a bit and letting the KDX torque out of the situation I got it into. That's partially why I've leaned it out.

As far as what a "voop" is, its just the sound the KDX makes when it's not firing well at high RPMs. Whether it is due to lean or rich or spark, I don't know. But the fact that it did it at altitude (and only during warm-up) makes me go away from the thought that it was a lean problem. Possibly a spark plug issue? I did swap out your old plug for one frome the same manufacturer, although the electrode is considerably fatter. Perhaps it's a colder plug? I'll have to check.

Rick
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fuzzy
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Post by fuzzy »

What the heck is ranger?
'91 KDX 200 Project $300 KDX
'95 KDX 200 Project $600 KDX
'94 WR 250 Always a project
AZRickD
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Post by AZRickD »

What the heck is a "Ranger?" You don't get out much, dood. (for a moderator) :lol:

That's "Ranger," Polaris Ranger, with a capitol R.

http://www.polarisindustries.com/en-US/Ranger/

It's what these two cool camo guys are riding in.

700 EFI twin. 40 HP from the factory... (but I've modded mine with a cam from the Polaris quad and a PowerCommander module for extra fuel). It climbs hills like a billygoat and has enough cargo capacity for two dressed elk and riders. :supz:

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Indawoods
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Post by Indawoods »

Why not just buy a Jeep!? :shock:
*** Administrator //***
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"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
AZRickD
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Post by AZRickD »

When I was flying hang gliders in cross country comps some would ask me why I just didn't fly a sail plane. After all, a sail plane is faster and has a better glide-ratio.

They didn't get it. It's not the same. It would be like someone asking me why I didn't get a real bike like a KTM 200 or Yammi WR450.

And, besides... :butthead:

Rick
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fuzzy
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Post by fuzzy »

I figured it was that thing in the background :mrgreen:

Yeah, I'm a moderator of a KDX motorcycle forum and should be ashamed for not knowing what an oversized 4-up quad is :lol: :lol:
'91 KDX 200 Project $300 KDX
'95 KDX 200 Project $600 KDX
'94 WR 250 Always a project
AZRickD
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Post by AZRickD »

Kwad ?!!? :blink:

Them's fightin' werds.

This site will edify you. http://www.utilityoffroad.com/

More on why not a Jeep. Triple the price, quadruple the weight. Six-times as much for insurance.Too wide, too tall. Mopar.

Anyway, back on topic --

I'm thinkin' spark plug, you?

Rick
I done KX-ed QuailChaser's KDX220R
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