3.6 power loss at elevation

[CarbonSteel]

People don't seem to understand that the only thing that makes FI better than a carb is constantly adjusting for optimal air/fuel RATIO. If there's less air it will add less fuel no matter what, and thereby make less power. A perfectly tuned carb will make the same power as the FI, the problem is changing conditions make keeping a carb perfectly tuned impossible. FI doesn't adjust for altitude by adding anything, it subtracts fuel and power to match the air available.

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[Zandcwhite]

Unless you've got the 2.0l...then you're all good BECAUSE TURBO BABY YEAH!!!!

I'm screwed though with my 3.6l. I can't even climb speed bumps. Too much power loss.



This is still a drop in the bucket though...I mean i'm sure you're aware there's like 330M people in this country...but there's also over 50M cars sold every year. We already established that you and I disagree on what is significant power loss, but even if we go with the claim that over 5000ft the loss is bad, it's pretty accurate to say that the vast majority of the population rarely see that altitude.

EDIT: I just did a little googling and found this:

"17 states have NO real estate above 3,000'.
To a first approximation, nobody east of the 100th meridian lives above 3,000'. (E.g., the Berkshires hit 3500', but the towns at their base are at 700'.)

So, to a first approximation, "residents over 3000 feet " is pretty much is limited to the US Mountain States: the residents of Colorado, New Mexico, Utah, Montana, and Wyoming.
You're talking mostly these five states - 12 or 13 million people - plus some loose change.

http://en.wikipedia.org/wiki/Mountain_States

So it's

Colorado 5m,
Utah 3m,
New Mexico 2m;
Idaho 1.5m (and metro Boise isn't over 3000', that removes 0.5m, so really, ~1m in Idaho),
Montana 1m
Wyoming 0.5m,

with
some of Arizona (metro Phoenix is half the population of the state, and under 3,000') ,
and Nevada (metro Las Vegas is half the state, and under; Reno is up there, but only 1/4 of a million people)
and bits of Texas (el Paso, 3/4 million), Wash, Oregon (town of Bend etc), California (Tahoe).
Maybe a handful of folks on the west edge of Nebraska, Kansas, the Dakotas.
Maybe a few more people in southern Cal.
Now you're down to "residents of mountaintop observatories and fire-watch towers"
in places like New Hampshire and Hawaii.

Total: say 16-18 million, tops.
That's about 5-6% of the US."

Again, I didn't say living or even commuting above those elevations. Frequently seeing those elevations are tens of millions of people in CA. Add in the socal high elevation destinations that are popular with skiers in the winter and campers/hikers/ wheelers in the summer and you could be pushing 100
million easy. 30k vehicles per day drive over dinner summit on I80 alone and may of those aren't daily commuters. Big Bear lake sees 6 million visitors per year. Mt whitney area, ski resorts, multiple national forests, etc all being frequented by tourists and many of the states 39 million residents virtually year round.

 

[Ratbert]

FI doesn't adjust for altitude by adding anything, it subtracts fuel and power to match the air available.

Do you mean the amount of oxygen available? I'm pretty sure it's the same amount of air, just less dense / with less oxygen.

 

[TheRaven]

Again, I didn't say living or even commuting above those elevations. Frequently seeing those elevations are tens of millions of people in CA. Add in the socal high elevation destinations that are popular with skiers in the winter and campers/hikers/ wheelers in the summer and you could be pushing 100
million easy. 30k vehicles per day drive over dinner summit on I80 alone and may of those aren't daily commuters. Big Bear lake sees 6 million visitors per year. Mt whitney area, ski resorts, multiple national forests, etc all being frequented by tourists and many of the states 39 million residents virtually year round.

Right but again, you're talking about recreational trips and vacations. Not regular use. The American Heart Association says 100M Americans visit high altitudes every year. "Visit". That's not what I would call "frequent". Even if you're averaging once every two weeks, that's not "frequent" to me...meaning it's not something that's going to weigh in as a major factor in what engine I choose in the vehicle I plan to drive there.

Also an anecdotal aside - i've never in my life heard someone mention "an engine that loses less power at high altitudes" as criteria that's anywhere on their list of things they want in a new vehicle. Was it something you thought of when you bought your JL?

 

[Zandcwhite]

Do you mean the amount of oxygen available? I'm pretty sure it's the same amount of air, just less dense / with less oxygen.

Less dense air in the sane volume would be less actual air would it not? Obviously the oxygen is the important part for this discussion but there are less air molecules per cubic foot of all the things different molecules that mage up the air.

 

[Blueliner3]

What does what someone thinks they feel have to do with the math and science of losing ~3% for every 1,000 feet? If your "calibrated butt dyno" can't feel it then that's fine, but that doesn't mean that it's not reality for the rest of the planet.

I'm giving math and science numbers. You're giving Flat Earther-esque "but that's not what I experience" responses. Are you expecting us to simply agree with your personal assessments and just ignore the facts?

Here are the numbers (not opinions) in case you forgot: The Wrangler's 3.6L V6 starts with 285 horsepower. It loses ~3% for every 1,000 feet. Going from sea level to 8k feet is a ~24% loss of power (~64 horsepower).

We frequently wheel at ~11k feet, which is a ~33% loss of power (relative to sea level) in a naturally aspirated engine like the 3.6L. And no, I don't significantly notice the additional drop of nearly 4% when I take my EcoDiesel (fortunately NOT naturally aspirated) from home to those heights.

 

[Zandcwhite]

Right but again, you're talking about recreational trips and vacations. Not regular use. The American Heart Association says 100M Americans visit high altitudes every year. "Visit". That's not what I would call "frequent". Even if you're averaging once every two weeks, that's not "frequent" to me...meaning it's not something that's going to weigh in as a major factor in what engine I choose in the vehicle I plan to drive there.

Also an anecdotal aside - i've never in my life heard someone mention "an engine that loses less power at high altitudes" as criteria that's anywhere on their list of things they want in a new vehicle. Was it something you thought of when you bought your JL?

I don't think anyone claimed it was a factor in everyone who ever drives at altitudes engine choice? 1 guy claimed that most people outside UT and CO don't see high elevations which is categorically false. You and others claimed the power loss is barely noticeable, also false especially when you approach 10k feet. People who live at 5k-6k and frequently drive to 8k aren't gong to notice much, they are only losing an extra 3-9%. A hot day can make that big of a difference on a dyno. I spend over 100 days per year driving above 5k, frequently drive above 10k, and live at 120'. I've owned both a 2019 2.0t and our current 2022 3.6L. Both modded similarly. At sea level performance is very similar, at 10k it's not even close. I'm just stating facts and experiences and some are arguing why? Facts don't have feelings, they don't care why.

 

[TheRaven]

I don't think anyone claimed it was a factor in everyone who ever drives at altitudes engine choice?

And I didn't claim anyone did. I honestly wonder if it's a factor for ANYONE.

1 guy claimed that most people outside UT and CO don't see high elevations which is categorically false. You and others claimed the power loss is barely noticeable, also false especially when you approach 10k feet. People who live at 5k-6k and frequently drive to 8k aren't gong to notice much, they are only losing an extra 3-9%.

Yeah see this is where we disagree. It is certainly true that the majority of the US population don't see high altitudes...note the analysis excerpt I posted...and that was for 3000ft. As you noted, a significant chunk of the population (something like 100M) visits locations over 5000ft, but that's very infrequent, and 100M is not even close to a majority. So I agree with that 1 guy.

And as for the power loss - as you noted in the 5-8k range it's quite possibly unnoticeable (it has been for me) and the majority of people who DO see over 5000ft are in that range (as the altitude goes up, the number of people who see it decreases).

We aren't "arguing facts" we are arguing the conclusions drawn from those facts.

 

[Zandcwhite]

And I didn't claim anyone did. I honestly wonder if it's a factor for ANYONE.



Yeah see this is where we disagree. It is certainly true that the majority of the US population don't see high altitudes...note the analysis excerpt I posted...and that was for 3000ft. As you noted, a significant chunk of the population (something like 100M) visits locations over 5000ft, but that's very infrequent, and 100M is not even close to a majority. So I agree with that 1 guy.

And as for the power loss - as you noted in the 5-8k range it's quite possibly unnoticeable (it has been for me) and the majority of people who DO see over 5000ft are in that range (as the altitude goes up, the number of people who see it decreases).

We aren't "arguing facts" we are arguing the conclusions drawn from those facts.

I absolutely didn't argue that 5-8k is unnoticeable, if you spend most of your time at 5k in Denver, the change from there to 8k may be unnoticeable as it's only a change of 3k feet. Going from 0-8k, like millions of us do regularly iin CA, is massively noticeable. If you don't notice a 25% power loss, you aren't paying attention.

 

[yokramer]

I absolutely didn't argue that 5-8k is unnoticeable, if you spend most of your time at 5k in Denver, the change from there to 8k may be unnoticeable as it's only a change of 3k feet. Going from 0-8k, like millions of us do regularly iin CA, is massively noticeable. If you don't notice a 25% power loss, you aren't paying attention.

Yea but only millions of people do that every year the sample size isnt big enough.

 

[TheRaven]

NOTE: I edited this post because I changed my mind about how I wanted to respond after thinking about it.

I absolutely didn't argue that 5-8k is unnoticeable, if you spend most of your time at 5k in Denver, the change from there to 8k may be unnoticeable as it's only a change of 3k feet.

Its irrelevant - power loss is power loss whether you are used to it or not. Those people living at high altitude are still down on power...the fact that they don't notice it is exactly my point. No one in Denver is complaining that their cars are too slow. There are race tracks and drag strips at altitude and racing is still awesome.

So this sounds like you are obsessing over the fact that you lose power as you go up, not actually complaining that your JL isn't powerful enough up there. If that's your point, then I don't disagree, I just feel differently - I don't obsess over the numbers until I see what they translate to in real life. I don't care if I lose half my power as long as I still have enough to do what I need/want.

Going from 0-8k, like millions of us do regularly iin CA, is massively noticeable. If you don't notice a 25% power loss, you aren't paying attention.

And I would argue that if you have to be "paying attention" to notice it, it's not that bad.

 

[AnnDee4444]

the only thing that makes FI better than a carb is constantly adjusting for optimal air/fuel RATIO.

Fully electronic fuel injection, yes... but mechanical, not really (at least those without a lambda sensor)

 

[JeepinJason33]

I don't think anyone claimed it was a factor in everyone who ever drives at altitudes engine choice? 1 guy claimed that most people outside UT and CO don't see high elevations which is categorically false. You and others claimed the power loss is barely noticeable, also false especially when you approach 10k feet. People who live at 5k-6k and frequently drive to 8k aren't gong to notice much, they are only losing an extra 3-9%. A hot day can make that big of a difference on a dyno. I spend over 100 days per year driving above 5k, frequently drive above 10k, and live at 120'. I've owned both a 2019 2.0t and our current 2022 3.6L. Both modded similarly. At sea level performance is very similar, at 10k it's not even close. I'm just stating facts and experiences and some are arguing why? Facts don't have feelings, they don't care why.

Please prove that most people in the US see high 5,000'+ elevations on a regular basis. Running up to the mountains for the occasional day trip is not regular, and even if you included the millions that visit above 5,000' each year, you will still not get to 170 million people see above 5,000' even on a yearly basis! There are 341 million people in the US. Show me any statistic from a accredited source that says 170 million people/51% see high altitudes on a regular or even yearly basis. You can include everyone that lives in Colorado and Utah in your research. However, it will not matter, you simply can't prove what you are stating is factual because it is "categorically false" as you like to put it.

You continue to say "I'm just stating facts" but you aren't!

 

[GoatHerder]

Read the entire thread, need a aspirin,

learned high octane 91 high altitude, under load, if can afford it, if own a Jeep affording should not be a determinant.

still don’t know what a straw man is, former knowledge of straw man was in the wizard of oz.

 

[Zandcwhite]

Please prove that most people in the US see high 5,000'+ elevations on a regular basis. Running up to the mountains for the occasional day trip is not regular, and even if you included the millions that visit above 5,000' each year, you will still not get to 170 million people see above 5,000' even on a yearly basis! There are 341 million people in the US. Show me any statistic from a accredited source that says 170 million people/51% see high altitudes on a regular or even yearly basis. You can include everyone that lives in Colorado and Utah in your research. However, it will not matter, you simply can't prove what you are stating is factual because it is "categorically false" as you like to put it.

You continue to say "I'm just stating facts" but you aren't!

Not that it matters, but 61 million snow skiers, 15 million lake Tahoe visitors, 6 million yellowstone visitors, 4 million Yosemite visitors, 5 million big bear visitors, 30 million plus hikers, there's 120 million just in activities/ destinations I could think of off the top of my head. Add in 10s of millions of vehicles that cross I-80 from NV, I-5 from OR, tens of millions of tourists traveling to/ through ID, Montana, Wyoming, etc and I'm confident in saying that more than 170 million people see 5k feet or higher every year. It's not like it's a statistic that easily searched, but virtually everyone that drives out west be it truck drivers, tourists, etc all see 5k. It's not at all rare.

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