Morbid Intentions
Well-Known LVC Member
so over the course of my involvement with different automotive sites I've really been a big part of the "street and strip" sections the most.... a couple months ago I came up with a rough estimate theory and an early stage mathematical breakdown of just how much a power adder would be helping you at a given elevation and posted it on the mustang site I moderate (I thought I would share this with you guys)... because as we all know, N/A cars suffer the most the higher you go... but just how much more do they suffer on a BHP scale? that is the question I found myself asking when I started this little mini breakdown
turbocharged/supercharged elevation equation... simple steps
#1
figure out your TOTAL PSI @ sea level
(atmospheric pressure + boost pressure = TOTAL PSI)
#2
Figure out your CORRECTED PSI for your elevation and add it to your boost pressure
(2,000ft = -1.1PSI)
#3
Divide TOTAL sea level PSI into CORRECTED PSI
#4
your final product will be a percentage... you need to minus this percentage from 100% and this is your total percentage of BHP lost at given elevation through a forced induction application
#5
now that you have your percentage of power lost through your turbocharged application you need to find out what a N/A car would lose at the same BHP
so take your total PSI @ elevation and divide it into atmospheric pressure (considering there is no boost pressure)
#6
this percentage again, you need to minus from 100% and this is your total percentage of BHP lost at given elevation through a N/A application
now that you have percentages lost from both N/A and F/I application... now you have to figure out the difference in your given BHP between the two
this is how much of a help your forced induction is helping you at your elevation compared to other N/A cars
#7
TEST CAR
bone stock 2003 SVT cobra @ 6,000ft
stock PSI = 8PSI
#8
BREAKDOWN
14.7PSI + 8PSI = 22.7PSI
22.7 TOTAL PSI @ sea level for terminator
now factor in elevation
so...
14.7PSI - 3.3PSI = 11.4PSI
@ 6,000ft atmospheric pressure is 11.4PSI
now that we have corrected atmospheric pressure.... let's do the math
a terminator loses 15% of it's power @ 6,000ft... 15% of it's power is 59BHP, making a terminator into a 331BHP car @ 6,000ft
now let's equate for a naturally aspirated car for comparison to see just how much it's supercharger is helping it at elevation
math time...
seeing as a naturally aspirated engine with the same power output makes 304BHP and the terminator actually makes 331BHP @ 6,000ft we can conclude that 8PSI of boost pressure is helping the terminator make 27BHP @ 6,000ft... a small margin... but as boost pressure and elevation increases, so does this figure
(I know a terminator is under rated from the factory... I was just using the factory BHP numbers as a simple guide for now... this same principle can be used on and horsepower number [RWHP/BHP].. and even your torque if you wish)
again... just like DA factoring, it should be taken with a grain of salt and used as a rough estimate guide
and as everyone knows... bottle fed setups suffer the least, so if you are running gas then this doesn't apply to you at all
EDIT: one of the big reasons I came up with this is because when they tested the ecoboost MKS against all of the european V8 sedans @ 12,000ft and the MKS came in second place... I knew it was a staged BS comparison @ 12,000ft.... at sea level there is good chance the MKS would be dead last, I just needed the math and facts together to show the people that didn't understand why
turbocharged/supercharged elevation equation... simple steps
RULE #1
atmospheric pressure = 14.7PSI
#1
figure out your TOTAL PSI @ sea level
(atmospheric pressure + boost pressure = TOTAL PSI)
RULE #2
2,000ft of elevation = 1.1PSI drop from atmopsheric pressure (14.7)
(@ 6,000ft atmopsheric pressure = 11.4PSI)
#2
Figure out your CORRECTED PSI for your elevation and add it to your boost pressure
(2,000ft = -1.1PSI)
#3
Divide TOTAL sea level PSI into CORRECTED PSI
#4
your final product will be a percentage... you need to minus this percentage from 100% and this is your total percentage of BHP lost at given elevation through a forced induction application
#5
now that you have your percentage of power lost through your turbocharged application you need to find out what a N/A car would lose at the same BHP
so take your total PSI @ elevation and divide it into atmospheric pressure (considering there is no boost pressure)
#6
this percentage again, you need to minus from 100% and this is your total percentage of BHP lost at given elevation through a N/A application
now that you have percentages lost from both N/A and F/I application... now you have to figure out the difference in your given BHP between the two
this is how much of a help your forced induction is helping you at your elevation compared to other N/A cars
#7
TEST CAR
bone stock 2003 SVT cobra @ 6,000ft
stock PSI = 8PSI
#8
BREAKDOWN
14.7PSI + 8PSI = 22.7PSI
22.7 TOTAL PSI @ sea level for terminator
now factor in elevation
so...
14.7PSI - 3.3PSI = 11.4PSI
@ 6,000ft atmospheric pressure is 11.4PSI
now that we have corrected atmospheric pressure.... let's do the math
8PSI + 11.4PSI = 19.4PSI
19.4/22.7 = 85%
100% - 85% = 15%
15% of 390BHP = 59BHP
390BHP - 59BHP = 331BHP
a terminator loses 15% of it's power @ 6,000ft... 15% of it's power is 59BHP, making a terminator into a 331BHP car @ 6,000ft
now let's equate for a naturally aspirated car for comparison to see just how much it's supercharger is helping it at elevation
math time...
11.4/14.7 = 78%
100% - 78% = 22%
22% of 390BHP = 86BHP
390bhp - 86bhp = 304BHP
seeing as a naturally aspirated engine with the same power output makes 304BHP and the terminator actually makes 331BHP @ 6,000ft we can conclude that 8PSI of boost pressure is helping the terminator make 27BHP @ 6,000ft... a small margin... but as boost pressure and elevation increases, so does this figure
(I know a terminator is under rated from the factory... I was just using the factory BHP numbers as a simple guide for now... this same principle can be used on and horsepower number [RWHP/BHP].. and even your torque if you wish)
again... just like DA factoring, it should be taken with a grain of salt and used as a rough estimate guide
and as everyone knows... bottle fed setups suffer the least, so if you are running gas then this doesn't apply to you at all
EDIT: one of the big reasons I came up with this is because when they tested the ecoboost MKS against all of the european V8 sedans @ 12,000ft and the MKS came in second place... I knew it was a staged BS comparison @ 12,000ft.... at sea level there is good chance the MKS would be dead last, I just needed the math and facts together to show the people that didn't understand why