Since atmospheric pressure is 14.7 at sea level and more like 11.7 at 5,000 Ft elevation, would'nt the first 3 PSI of boost go to waste? Well, not go to waste, but if you're somewhere where the atmosphereic pressure is 11.7, would'nt the first 3psi of boost do nothing but fix the elevation differeance (while adding power)

I have another question, theres this 'rule of thumb' I heard about that says you lose %3 of power for every 1000FT of altitude, do you guys think this is true?

My third question, let's say you have a 100 HP all motor engine and you go to a really high altitude, high enough that your engine makes more like 70 HP... if you boosted your motor to add only 30 HP and ended up having 100 HP at that high altitude, would the engine be reliable as stock since it's making only 100 HP?

EDIT: I'm not 100% sure if atmospheric pressure at 5000FT is 11.7, so if you know the correct pressure, please correct me.

I'm not sure what the exact pressure it at that altitude, but you can probably check the local weather stations to see what it is at any given day.

The biggest difference at higher altitudes is the lack of air to compress compared to low altitude areas. You'll have to run a higher boost level to make the same power there as you would at sea level. It also depends on what type of gas you can get - I know in Colorado the normal "premium" was 91 octance. That plays a huge part in detonation.

It makes sense that you should be able to run higher boost at higher elevation since say if you were running 10psi and you were 5000ft up and you ran 13psi the same ammount of air would be getting to the engine? I might be wrong i have never thought about that but it makes sense. So id assume a motor would be just as reliable as before you cranked up the boost. I might be wrong though.

It makes sense that you should be able to run higher boost at higher elevation since say if you were running 10psi and you were 5000ft up and you ran 13psi the same ammount of air would be getting to the engine? I might be wrong i have never thought about that but it makes sense. So id assume a motor would be just as reliable as before you cranked up the boost. I might be wrong though.
You have to watch out at higher evelations because the air is less dense - you can easily detonate at higher PSI. Most people run less, but "yes" to your question about running higher boost to obtain the same power.

That's an interesting question... but I'm good cuz I'm only about 500ft. above sea level