Horsepower Loss At Elevation

[JLARSH]

Is there some kind of formula to roughly estimate horsepower at elevation on a non boosted sled? Say for example a sled making 190 hp at sea level would make what at say 6000'? Thanx for any help guys.

 

[bigdawg]

Is there some kind of formula to roughly estimate horsepower at elevation on a non boosted sled? Say for example a sled making 190 hp at sea level would make what at say 6000'? Thanx for any help guys.

190 HP@ sea level BUT would be 155.8 HP @ 6000 ft

 

[ferniesnow]

190 HP@ sea level BUT would be 155.8 HP @ 6000 ft

and the formula is? just asking....:d:d:d

 

[JLARSH]

What about boosted sleds? Say 190 hp again?

 

[RUDY]

ft-----% hp lose
_______________
0 0%
1000 -3%
2000 -6%
3000 -9%
4000 -11%
5000 -14%
6000 -16%
7000 -19%
8000 -21%
9000 -24%
10000 -26%
11000 -28%
12000 -31%

 

[storch]

190 HP@ sea level BUT would be 155.8 HP @ 6000 ft

My figures show 155.7654663738383888888888 hp or I could just say
156 HP ....LOL

 

[Pro-Am Chris]

What about boosted sleds? Say 190 hp again?

If you keep the air pressure equal going in you will have a 0% loss. So just turn up the boost.

 

[steveo10]

bingo!

approx 3% lost per 1000ft. damn NA sleds!

ft-----% hp lose
_______________
0 0%
1000 -3%
2000 -6%
3000 -9%
4000 -11%
5000 -14%
6000 -16%
7000 -19%
8000 -21%
9000 -24%
10000 -26%
11000 -28%
12000 -31%

 

[Zar]

bingo!

approx 3% lost per 1000ft. damn NA sleds!

X2 I heard the same approx 3% for every 1000 ft of elevation

 

[Pistonbroke]

And of course remember that all the "brochure" numbers are from sea level measurements.

 

[Bogger]

WOW can you imagine how fast a phazer would be on the ocean floor.....

 

[senorjeem]

If you are developing 190 HP at sea level, then you are probably running a 1000 AC, so you needn't worry about getting too high!!

Just screwin with ya'll

 

[allrevsrule]

So what will the loss be in compression ratio if you have 14:1 at sea level what do you have at 7000 feet or if cranking is 175 psi at sea level 7000 feet would be _____ ?

 

[beeonaplug]

If you are developing 190 HP at sea level, then you are probably running a 1000 AC, so you needn't worry about getting too high!!

Just screwin with ya'll

Ha, that's funny. So hall the 1000 AC down a 2 km. below sea level mine shaft and keep up with the turbos way above. Not much snow down there though. Just a stupid thought!

 

[overkill131313]

so a 200 HP NA at say 8000 feet, lost 42 hp! so 158 hp is all it will make up on the hill. .....and my turbo will stay at 310 hp if I turn my booooooost up!

I didnt think it was that much but yes I just did the math! turbo all the way!

 

[Ancient Sledder]

So what will the loss be in compression ratio if you have 14:1 at sea level what do you have at 7000 feet or if cranking is 175 psi at sea level 7000 feet would be _____ ?

Your compression ratio does not change. The compression "pressure" looses the same 3% per 1000 feet. The engine just can't get enough air into it and that is why the HP drops. As stated before, a turbo will make up the power lose because it forces air in at higher than atmospheric pressure.

 

[allrevsrule]

Ancient Sledder

So does cranking pressure decrease? 175 psi at sea level and say 145 at 6000 feet about?

 

[Longhairfreak]

So if my sled has 162 HP at 7000 ft it should only take about 8 lbs of boost on an Apex to spank me? Interesting.

 

[JLARSH]

So if my sled has 162 HP at 7000 ft it should only take about 8 lbs of boost on an Apex to spank me? Interesting.

No it will only take 6lbs of boost on my M6 to spank you.:d

 

[Ancient Sledder]

Ancient Sledder

So does cranking pressure decrease? 175 psi at sea level and say 145 at 6000 feet about?

Yes. The compression tester will read lower at higher elevation. It will be the same 3% decrease. It still has to do with the lack of air to compress. If you could theoretically get the engine up to 18000 feet, it would barely run.