Reading compressor maps?
02-20-2008 | 03:07 PM
#1
Guest
Posts: n/a
Reading compressor maps?
I thought there use to be a sticky on how to do this? I'm not seeing it and I'm sorry im not digging thru 500 pages that mention the word "compressor map".
Someone help me out here. Anyone have a link or...
Someone please explain this to me, I want to know how to calculate for future references not just a # answer. I need to know the max PSI I can run on my hx-35 while staying in the 76% eff range (thats the island thats ideal, correct?)
Explain it like you would to a retard, i can be a little slow.
Sorry, I feel like such a noob. Flame on.
Someone help me out here. Anyone have a link or...
Someone please explain this to me, I want to know how to calculate for future references not just a # answer. I need to know the max PSI I can run on my hx-35 while staying in the 76% eff range (thats the island thats ideal, correct?)
Explain it like you would to a retard, i can be a little slow.
Sorry, I feel like such a noob. Flame on.
02-20-2008 | 03:13 PM
#2
Guest
Posts: n/a
Re: Reading compressor maps?
PR is ratio of boost pressure to atmospheric.
It looks like the highest point on the 76% island is at a PR of about 2.35.
2.35 * 14.7 = 34.5 psi
That's just talking about boost pressure, you still have to account for the amount of air being moved.
You don't need to stay in the center island to make good power.
It looks like the highest point on the 76% island is at a PR of about 2.35.
2.35 * 14.7 = 34.5 psi
That's just talking about boost pressure, you still have to account for the amount of air being moved.
You don't need to stay in the center island to make good power.
02-20-2008 | 07:20 PM
#5
1.5 BAR
Joined: Apr 2006
Posts: 676
Re: Reading compressor maps?
www.not2fast.com
Compressor efficiency is over rated. Don't worry about it much. You can see how little compressor efficiency matters using the calc on not2fast and varying the compressor efficiency and pressure. You will see running the lowest pressure possible is way better than running at 60% compressor efficiency.
Compressor efficiency is over rated. Don't worry about it much. You can see how little compressor efficiency matters using the calc on not2fast and varying the compressor efficiency and pressure. You will see running the lowest pressure possible is way better than running at 60% compressor efficiency.
02-20-2008 | 07:44 PM
#6
3.0 BAR
Joined: Aug 2003
Posts: 4,666
From: NE-PA
Re: Reading compressor maps?
Originally Posted by jagojon3
PR is ratio of boost pressure to atmospheric.
It looks like the highest point on the 76% island is at a PR of about 2.35.
2.35 * 14.7 = 34.5 psi
That's just talking about boost pressure, you still have to account for the amount of air being moved.
You don't need to stay in the center island to make good power.
It looks like the highest point on the 76% island is at a PR of about 2.35.
2.35 * 14.7 = 34.5 psi
That's just talking about boost pressure, you still have to account for the amount of air being moved.
You don't need to stay in the center island to make good power.
02-21-2008 | 02:44 AM
#8
1.0 BAR
Joined: Nov 2005
Posts: 431
Re: Reading compressor maps?
ok
its easy, i have an ms excel turbo calculator i wrote a while ago to calc this ---- out, and it has heaps of special features and other stuff too. if you want it email me and pm me.
otherwise...
y axis is the pressure ratio generated by the compressor, which jago already said.
x axis is the mass airflow from the compressor, in lbs/min
here's how to convert it.
hope this helps
its easy, i have an ms excel turbo calculator i wrote a while ago to calc this ---- out, and it has heaps of special features and other stuff too. if you want it email me and pm me.
otherwise...
y axis is the pressure ratio generated by the compressor, which jago already said.
x axis is the mass airflow from the compressor, in lbs/min
here's how to convert it.
Originally Posted by rprznt
listen up good noobs, this is the good ----.
works in ideal conditions at sea level. (close enough for hmt)
cfm * 0.069 = lbs/min
lbs/min * 14.49275 = cfm.
so...
100 cfm = 6.9 lbs/min
100 lbs/min = 1449.3 cfm.
works in ideal conditions at sea level. (close enough for hmt)
cfm * 0.069 = lbs/min
lbs/min * 14.49275 = cfm.
so...
100 cfm = 6.9 lbs/min
100 lbs/min = 1449.3 cfm.
02-21-2008 | 05:20 AM
#9
1.0 BAR
Joined: Mar 2007
Posts: 247
Re: Reading compressor maps?
Have you guys ever come across a Turbo, you get the Compressor map and it says its only good for 1.5 bar boost. but it makes postive power all the way to 2.2 bars.
Is this a Common occurance in the turbo world?
Is this a Common occurance in the turbo world?
02-21-2008 | 08:21 PM
#10
3.0 BAR
Joined: Aug 2003
Posts: 4,666
From: NE-PA
Re: Reading compressor maps?
Originally Posted by Inquisition
1.0 PR = atmospheric pressure or 14.7psi absolute
2.0 PR = 14.7psi above atmospheric pressure or 29.4psi absolute
So 2.35 PR is 34.5 psi absolute or 19.845 psi gauge.
2.0 PR = 14.7psi above atmospheric pressure or 29.4psi absolute
So 2.35 PR is 34.5 psi absolute or 19.845 psi gauge.
