HP loss at high altitudes

[lukeh]

But I wasnt joking, i seriously though that is what the thread is about !!

When you come onto ucp you have to change the way you think you have to put on your car thinking cap. HP is no longer hewelt packat it is now horse power.

[fpv_gtho]

I hate it when someone takes my beautifully crafted, researched and worded engineering analysis of an issue and it's solution and THEN summarises in in ONE sentence -- especially when THAT sentence conveys the message best

I suppose thats 30 years of knowledge difference then

[taz_rocks_miami]

But I wasnt joking, i seriously though that is what the thread is about !!

Due to the title, I can see how you might have thought I'd lost my HP Laptop while climbing a mountain or something like that.

[Matra et Alpine]

I suppose thats 30 years of knowledge difference then

I didn't know you were 77 years old

[lukeh]

I didn't know you were 77 years old

his not.

[Matra et Alpine]

his not.

hint, lukehow, the smiley conveys JOKE.

Note no smiley !!!

[fpv_gtho]

I didn't know you were 77 years old

I'd be doing pretty good if was 77

[Matra et Alpine]

I'd be doing pretty good if was 77

not with the women though





So that'll be nothing different then !!


OUCH Sorry coudlnt' resist

[fpv_gtho]

Oh well, cant hide from the facts im afraid.....

Heffner manages to keep it going though

[lozmoss]

Is there any way to calculate how much power a normaly aspired engine losses at higher altitudes? For example: Denver Colorado or Mexico City, they're both about a mile above sea level.

Hey don't know if anyone told you but the calculations

HP loss= Elevation in feet
--------------- X0.03
1000
X sea level HP

For example a car driving at 8325 feet and rated at 255hp @ 5200rpm

HP loss= 8325
------ X 0.03 X 255
1000
=63.69 - 255hp
= 191.31hp


hope this helps you

[clutch-monkey]

^ that's quite interesting to know. good first post, thanks!

[CapnBoost]

I also have a question about hp. Is it that every degree above 100 degrees (air temperature) the engine losses 1 hp for every 1 degree over. don't know if this statment is correct.

It's hard making a solid distinction like that. It depends on too many things.

FWIW, I've heard 1% loss for every 7 degrees(F) over ambient.

[azizajalal]

But I was not joking, i seriously though that is what the thread is about !!

Tinting

[stian1979]

Is there any way to calculate how much power a normaly aspired engine losses at higher altitudes? For example: Denver Colorado or Mexico City, they're both about a mile above sea level.

I also have a question about hp. Is it that every degree above 100 degrees (air temperature) the engine losses 1 hp for every 1 degree over. don't know if this statment is correct.

Hp is not lost because of increased temperatures or because of increased hight.
It's lost because of reduced air densety. If you drive on a hot summer day with low barometic preshure in the lowlands it could give the same output as a cold day with nice wather and high barometic preshure in the montains.

It all com down to how much particles of air (mass) you can get into the cylinder.

So to cut it short, forced induction has to work harder to make the same numbers, but since its forced induction theres less loss overall?

If you run a supercharger you will expereince the same % of loss as with a NA engine.

If you run a turbo it depends on the wastgate. Is the wasgate working with barometic preshure as reference it will experinece the same loss in % ,but if it use absolute preshure as reference it will compensate for the reduced air densety.

[Sid447]

I also have a question about hp. Is it that every degree above 100 degrees (air temperature) the engine losses 1 hp for every 1 degree over. don't know if this statment is correct.

Oldish thread,

But relevant question. The hotter the engine runs (within reason) the lower the emissions and engine cylinder wear.
The C5 ZO6 Vette for example had the 1st cooling fan set to come on at 108c and the 2nd one at 113c!
(See attached thumbnails for detailed explanation).

Most car computers are set to pull timing as a protection measure if the ECT (Engine Coolant Temp) goes too high.

Running hotter can run you closer to detonation, but with decent fuel it shouldn't be a problem.

It's Intake Air Temp that can and does cause loss of power as it increases....

Intake Temp.........Power Loss.......Example Power Output

20oC......................... 0%................... 400hp
40oC......................... 3.5%................ 386hp
50oC......................... 5.3%................ 379hp
60oC......................... 7%.................. 372hp
80oC......................... 10%................ 360hp
100oC....................... 13%................ 348hp