3.6 power loss at elevation

[Zandcwhite]

The magic of drive by wire.

And an 8 speed. No matter the speed you have the gearing to put the engine at its peak power output instantly.

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[Remorseless]

I still want to get the full dimensions of both grills to see if the shorter 24'+ grill is actually an improvement in volumetric airflow. To me it looks dubious at best. It's shorter for sure, so losing area there, but the slats are removed, so a gain there. But is the gain from slat removal, enough to offset the loss of height? Especially when looking at the cooling pack width vs the opening width. The finned area of the cooling pack is much narrower than the opening of the grill.

I'm not sure if the '24 JT and JL are the same (pre-'24 looked the same, but slightly different dimensionally), but I can compare the JT to the JL maybe and see how the measurements shake out for slot dimension (the one dimension that matters).

 

[jeepingib]

I used common sense.
This is what is behind the grill.

So increasing the width of open airflow will have much less impact than the increase in the restriction of airflow vertically.

The new grill is shorter and even includes another trim piece on the bottom to further block air from going below it and through the radiator. The design of the JL grill is misleading as the outer 2 slats don't really have any substantial airflow going through them. So the only advantage of the new grill vs the old for the middle of the grill where the radiator is mounted is the removal of the 4 bars that separate the middle 5 slats.

Back when this topic first came up I made this post and rough photoshop attempt with my phone.

 

[AnnDee4444]

Back when this topic first came up I made this post and rough photoshop attempt with my phone.

I literally just did this but got different results... Hard to find photos from exactly the same angle so I tried to match headlight size & hood opening gaps.

 

[jeepingib]

I literally just did this but got different results... Hard to find photos from exactly the same angle so I tried to match headlight size & hood opening gaps.

Cool, you definitely did a better job of that than I did. I had a hard time finding the correct pictures and shared angle as well. If yours is more accurate than it looks like it would have gained a bit more. Not a whole lot, but an increase none the less.

 

[YBABRAT]

The issue I see with power or fuel economy is green states that tax petrol or try to limit emissions. Gas stations will place cheaper grade prices as regular. You find out it is E85 or labeled 15% Methanol on the pump. I hate to fill up in CO, Cali, IL and IN. OH, TX, KS, NE, UT, AL, and KY are my choice states.

On a budget looking for real petrol look for Buckey's, Sonoco, Maverick and Casey's. There are other stations like Flying J that are not so common but may be worth while. Never go near a large city, only very few have pure petrol. Country towns and lake areas have what you are looking for.

So all that are complaining about pickup and go, may need to check their fill.

As for air pass through for breathing. Any aftermarket cold air intake will help over the factory grill. If you notice images of cold air intakes in JL models, they have a gap large enough to pull more air.

I will be doing an air mod that should be easy to do. Once I start on my WARN winch install. I noticed the 24 on up upper radiator support plastic cover has vents, while prior years don't.

 

[YBABRAT]

2k feet you'd be talking 6%, high ambient temperatures will cause that amount of loss. VA doesn't have mountains. The desert flatland is higher elevation out west. Make a hard climb at 10k feet and you'll notice the 30%, or at least I do every time. Those that post they don't are kidding themselves or they never use more than 70% of the power the v6 has period. It's scientifically proven. Nobody has a unicorn that magically isn't effected.

I have been in Aspen, Black Hawk, and Denver with similar v6 a 3.5l. Did not see much hit other than filling up with inferior gas before ascending through the mountains.

I lived in Cali half my life. Santa Cruz mountains, Redding up into Trinity Center and Lassen. No difference between Cali and VA mountains and the best CO has to offer. Maybe Alaska, Montana or Canada would help me find altitude limits.

 

[Zandcwhite]

I have been in Aspen, Black Hawk, and Denver with similar v6 a 3.5l. Did not see much hit other than filling up with inferior gas before ascending through the mountains.

I lived in Cali half my life. Santa Cruz mountains, Redding up into Trinity Center and Lassen. No difference between Cali and VA mountains and the best CO has to offer. Maybe Alaska, Montana or Canada would help me find altitude limits.

We aren't driving to the limits of the vehicle running anywhere in the world. When we drive to 10-12k we are losing 30-36% of the peak power period. That's how it works with a NA engine. If you don't feel a 30%+ power loss I'd argue you aren't driving hard at all. Nobody is saying it won't run or will have so little power it won't drive. You'll still have more power at the wheels than the 2.5L TJs had at sea level. Probably more than the 4.0L made to the wheels too. Even down 36% the penstar should be putting out 150hp to the wheels. None of that changes the fact that you are missing a massive portion of the power that you have when not at elevation.

 

[AnnDee4444]

The issue I see with power or fuel economy is green states that tax petrol or try to limit emissions. Gas stations will place cheaper grade prices as regular. You find out it is E85 or labeled 15% Methanol on the pump. I hate to fill up in CO, Cali, IL and IN. OH, TX, KS, NE, UT, AL, and KY are my choice states.

Petrol? All states tax gas and I don't see any correlation to "being green" or any other color, unless you're talking about money (subsidies for corn). Tests have been inconclusive on E85 emissions.

# 1 hate: Colorado $0.22/gal.​

# 1 choice: Ohio is $0.3851/gal.​

From: https://en.wikipedia.org/wiki/Fuel_taxes_in_the_United_States



Pure gasoline is around 114,000 BTU/gal.
E10 is 111,836 BTU/gal. (98.1% of gasoline)
E85 is 81,800 BTU/gal. (71.75% of gasoline) but can't be used in any JL without a tune

From: https://en.wikipedia.org/wiki/Gasoline_gallon_equivalent#Gasoline_gallon_equivalent_tables


I doubt the 1.9% lower BTUs of E10 is noticeable vs. the ~3% power loss for every 1000 feet of altitude...

 

[Ratbert]

The issue I see with power or fuel economy is green states that tax petrol or try to limit emissions.

Are there really states that don't tax petrol?

 

[YBABRAT]

BTU equals energy. Limit burn BTU drops. Numbers prove E85 burns less. To compound the issue lack of oxygen. Everybody who knows such things will try to refrain from Methanol for best fuel economy and performance. Until I see an issue, there is one way to help that will add power easily. A 50 wet shot of NOS.

I know a few people who have flex fuel cars and trucks. They wont fill with e85 in the mountians.


As for taxes, i saw the opposite on my fill ups. Go figure.

 

[Ratbert]

BTU equals energy. Limit burn BTU drops. Numbers prove E85 burns less. To compound the issue lack of oxygen. Everybody who knows such things will try to refrain from Methanol for best fuel economy and performance. Until I see an issue, there is one way to help that will add power easily. A 50 wet shot of NOS.

You'll use NOx whenever in the mountains? And if you lived at altitude?

As for taxes, i saw the opposite on my fill ups. Go figure.

And I have no idea what you meant by this. Maybe you're saying that very few states have taxes on petrol? I'm pretty sure every single one taxes petrol, but Georgia has temporarily suspended them.

Maybe you just didn't notice that Virginia (where you're apparently from) charges over 30 cents for every gallon?

 

[Zandcwhite]

You'll use NOx whenever in the mountains? And if you lived at altitude?


And I have no idea what you meant by this. Maybe you're saying that very few states have taxes on petrol? I'm pretty sure every single one taxes petrol, but Georgia has temporarily suspended them.

Maybe you just didn't notice that Virginia (where you're apparently from) charges over 30 cents for every gallon?

It is really only peak power situations that you notice the loss anyway, so I could see the 50 shot wiring rather well in that line use.

 

[AnnDee4444]

BTU equals energy. Limit burn BTU drops. Numbers prove E85 burns less. To compound the issue lack of oxygen. Everybody who knows such things will try to refrain from Methanol for best fuel economy and performance. Until I see an issue, there is one way to help that will add power easily. A 50 wet shot of NOS.

Fuel economy, yes... anything with less BTU/gal. = less MPG (assuming E10 or E15, as E85 won't work in a stock JL). But for performance? A tuned JL will make more power on E85 than 93 octane

So if E10 has 98.1% of the BTUs as gasoline, and you lose ~3% power loss for every 1000 feet of altitude, this should mean that an engine at sea level on gasoline should produce the same power as E10 at 633 feet (assuming tune doesn't account for ethanol content).

 

[YBABRAT]

I assumed by how much at idle the 3.6 L V6 seems rich. It has been a common thing to do for high compression engines to run rich. The draw back is altitude. A rich tune will worsen the higher the altitude. Probably the main reason why some complain. Basically the richness allows what would normally be a 92 or higher octane engine to operate safer than to rely on complex computer management.

Again taxes at the time seemed less so. Just before 9/11 I was able to fill with pure gas at 99 cents per gallon, in IL. All that changed within a year and the big push to Ethanol. Taxes there were climbing and until Corona, the governor stated he would not raise gas tax... nor did he try and lower it when travel was at a stand still.

As for high VA tax.... don't see it in the prices. TX, AL, KY, NC and VA all had fair prices ranging around $2.90 to $3.25 a gallon.

As for Cali ... $6.59 in the mountains. $7.00 in the city and $5.35 at towns in between.

One thing VA is doing that some states are following. Anti Cali mandates. One thing is taxing fuel efficient vehicals big time. My road use tax is low because my Rubicon has a Hwy/city average MPG below 24MPG. Above that you get hit with a tax.

Any way... what looks good on paper may not look so good when face to face on taxes.

I admit I left the comment as if some states are petrol tax free, when I shortened and over simplified wording.

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