Can someone explain compressor maps?
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From: Sierra Vista, AZ
Can someone explain compressor maps? Hopefully this will stay in the FI section.
I am trying to figure out how to read a compressor map and how it relates to sizing selection.
TIA,
Charlie
I am trying to figure out how to read a compressor map and how it relates to sizing selection.
TIA,
Charlie
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From: Sierra Vista, AZ
Lots of great stuff, but without knowing my **** about turbo stuff then its going to be hard inputing required info. There was a book mentioned about FI, think it was by Yunick, not sure, but does it have the compressor maps in it maybe?
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This will help to understand it a little better. At least it did for mew. Now I know what the lines mean. LOL
http://www.turbobygarrett.com/turbob..._techinfo.html
http://www.turbobygarrett.com/turbob..._techinfo.html
You have to sit down with a calculator and formulas. Most of the formulas can be found in Corky Bells Maximum boost. That, together with all you motor and turbo info, projected efficiencies of the intercooler and so on, and you can plot it on the map I can not leagally post the entire map, but email me if you would like to see mine...
Last edited by Jammer; Apr 5, 2004 at 01:15 AM.
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Dude, no offense but if I gotta do maff, nope, someone else can the map for me. hell with that. no wonder the ricers are all over this ****.
For real, Corky Bells book, not Smokey Yunick (although he has some good read out too!). Thanks guys. Will start with the link from F8L... and try to get this Max Boost book before I leave for Afghanistan as I am sure its not a best seller over there.
Charlie
For real, Corky Bells book, not Smokey Yunick (although he has some good read out too!). Thanks guys. Will start with the link from F8L... and try to get this Max Boost book before I leave for Afghanistan as I am sure its not a best seller over there.
Charlie
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The gannis go fast with water injection, not turbos. Watch those camel fockers run!
Good Luck when you go and THANKS. We got your back....way back...
Seriously, bring the book...it'll tke your whole tour to undertand it. But bring a calc and do maff...or the ricers will take over.
Good Luck when you go and THANKS. We got your back....way back...
Seriously, bring the book...it'll tke your whole tour to undertand it. But bring a calc and do maff...or the ricers will take over.
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Pick up corky bell's book. It's an excellent read.
So I guess I'm the "import" guy??
heh
You first need to figure out the air flow rate of your engine N/A
CID * RPM * 0.5 * VE / 1728
So for a stock displacement 346 this would equate to...
346 * 6500 * 0.5 * 0.85 / 1728 = 553 CFM (at 6500rpm)
Next you need to know your desired pressure ratio.
14.7psi (1 bar) is one atmosphere. You need to add the desired amount of boost to this base amout. We'll pick 13psi which is .89 bar. Your pressure ratio for 13psi will be 1.89
you then multiply your desired pressure ratio against your N/A CFM.
1.89 * 553 = 1045 CFM (boosted)
For many compressor maps you'll need to convert cfm to lbs/m.
The general consenses seems to be multiply by .069
1045 * .069 = 72 lbs/m
So now we'll look at a compressor map...
The pressure ratio is marked vertically on the scale and your air flow (lbs/m) is marked horizontally.
pin point where the two meet on the compressor map. You want to stay within 60% of the compressors effieciency and never hit the surge limit at any rpm.
To calculate where you will be on the compressor map at different boost and rpm levels, change the formula above as needed.
Make sense?
So I guess I'm the "import" guy??
hehYou first need to figure out the air flow rate of your engine N/A
CID * RPM * 0.5 * VE / 1728
So for a stock displacement 346 this would equate to...
346 * 6500 * 0.5 * 0.85 / 1728 = 553 CFM (at 6500rpm)
Next you need to know your desired pressure ratio.
14.7psi (1 bar) is one atmosphere. You need to add the desired amount of boost to this base amout. We'll pick 13psi which is .89 bar. Your pressure ratio for 13psi will be 1.89
you then multiply your desired pressure ratio against your N/A CFM.
1.89 * 553 = 1045 CFM (boosted)
For many compressor maps you'll need to convert cfm to lbs/m.
The general consenses seems to be multiply by .069
1045 * .069 = 72 lbs/m
So now we'll look at a compressor map...
The pressure ratio is marked vertically on the scale and your air flow (lbs/m) is marked horizontally.
pin point where the two meet on the compressor map. You want to stay within 60% of the compressors effieciency and never hit the surge limit at any rpm.
To calculate where you will be on the compressor map at different boost and rpm levels, change the formula above as needed.
Make sense?
Last edited by 1point3liter; Apr 9, 2004 at 11:00 AM.
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The majority of what I typed above is what I learned from corky's book. I started reading it earlier this week (time permitting). I had to poke around on the net to find how to properly convert from cfm to lbs/min and a few other things, but for the most part, it's in the book.
Today I'm reading chapter 6: intake manifold design. cool stuff. :thump:
$27 shipped from Amazon.com
http://www.amazon.com/exec/obidos/tg...books&n=507846
Today I'm reading chapter 6: intake manifold design. cool stuff. :thump:
$27 shipped from Amazon.com
http://www.amazon.com/exec/obidos/tg...books&n=507846
Last edited by 1point3liter; Apr 9, 2004 at 01:53 PM.
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btw...
for a wide range of compressor maps check out.
http://www.turbocalculator.com/compressor-maps.html
If you guys don't want to do the math this website also sells software to help plot your engine and boost requirements against available compressor maps.
If you molest google.com enough, I imagine you could find a couple websites that will do the calculations for you.
for a wide range of compressor maps check out.
http://www.turbocalculator.com/compressor-maps.html
If you guys don't want to do the math this website also sells software to help plot your engine and boost requirements against available compressor maps.
If you molest google.com enough, I imagine you could find a couple websites that will do the calculations for you.
Staging Lane
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From: South of Boston, Ma
Originally Posted by 1point3liter
Pick up corky bell's book. It's an excellent read.
So I guess I'm the "import" guy?? heh
You first need to figure out the air flow rate of your engine N/A
CID * RPM * 0.5 * VE / 1728
So for a stock displacement 346 this would equate to...
346 * 6500 * 0.5 * 0.85 / 1728 = 553 CFM (at 6500rpm)
Next you need to know your desired pressure ratio.
14.7psi (1 bar) is one atmosphere. You need to add the desired amount of boost to this base amout. We'll pick 13psi which is .89 bar. Your pressure ratio for 13psi will be 1.89
you then multiply your desired pressure ratio against your N/A CFM.
1.89 * 553 = 1045 CFM (boosted)
For many compressor maps you'll need to convert cfm to lbs/m.
The general consenses seems to be multiply by .069
1045 * .069 = 72 lbs/m
So now we'll look at a compressor map...
The pressure ratio is marked vertically on the scale and your air flow (lbs/m) is marked horizontally.
pin point where the two meet on the compressor map. You want to stay within 60% of the compressors effieciency and never hit the surge limit at any rpm.
To calculate where you will be on the compressor map at different boost and rpm levels, change the formula above as needed.
Make sense?
So I guess I'm the "import" guy??
hehYou first need to figure out the air flow rate of your engine N/A
CID * RPM * 0.5 * VE / 1728
So for a stock displacement 346 this would equate to...
346 * 6500 * 0.5 * 0.85 / 1728 = 553 CFM (at 6500rpm)
Next you need to know your desired pressure ratio.
14.7psi (1 bar) is one atmosphere. You need to add the desired amount of boost to this base amout. We'll pick 13psi which is .89 bar. Your pressure ratio for 13psi will be 1.89
you then multiply your desired pressure ratio against your N/A CFM.
1.89 * 553 = 1045 CFM (boosted)
For many compressor maps you'll need to convert cfm to lbs/m.
The general consenses seems to be multiply by .069
1045 * .069 = 72 lbs/m
So now we'll look at a compressor map...
The pressure ratio is marked vertically on the scale and your air flow (lbs/m) is marked horizontally.
pin point where the two meet on the compressor map. You want to stay within 60% of the compressors effieciency and never hit the surge limit at any rpm.
To calculate where you will be on the compressor map at different boost and rpm levels, change the formula above as needed.
Make sense?
Originally Posted by 1point3liter
Pick up corky bell's book. It's an excellent read.
So I guess I'm the "import" guy?? heh
You first need to figure out the air flow rate of your engine N/A
CID * RPM * 0.5 * VE / 1728
So for a stock displacement 346 this would equate to...
346 * 6500 * 0.5 * 0.85 / 1728 = 553 CFM (at 6500rpm)
Next you need to know your desired pressure ratio.
14.7psi (1 bar) is one atmosphere. You need to add the desired amount of boost to this base amout. We'll pick 13psi which is .89 bar. Your pressure ratio for 13psi will be 1.89
you then multiply your desired pressure ratio against your N/A CFM.
1.89 * 553 = 1045 CFM (boosted)
For many compressor maps you'll need to convert cfm to lbs/m.
The general consenses seems to be multiply by .069
1045 * .069 = 72 lbs/m
So now we'll look at a compressor map...
The pressure ratio is marked vertically on the scale and your air flow (lbs/m) is marked horizontally.
pin point where the two meet on the compressor map. You want to stay within 60% of the compressors effieciency and never hit the surge limit at any rpm.
To calculate where you will be on the compressor map at different boost and rpm levels, change the formula above as needed.
Make sense?
So I guess I'm the "import" guy??
hehYou first need to figure out the air flow rate of your engine N/A
CID * RPM * 0.5 * VE / 1728
So for a stock displacement 346 this would equate to...
346 * 6500 * 0.5 * 0.85 / 1728 = 553 CFM (at 6500rpm)
Next you need to know your desired pressure ratio.
14.7psi (1 bar) is one atmosphere. You need to add the desired amount of boost to this base amout. We'll pick 13psi which is .89 bar. Your pressure ratio for 13psi will be 1.89
you then multiply your desired pressure ratio against your N/A CFM.
1.89 * 553 = 1045 CFM (boosted)
For many compressor maps you'll need to convert cfm to lbs/m.
The general consenses seems to be multiply by .069
1045 * .069 = 72 lbs/m
So now we'll look at a compressor map...
The pressure ratio is marked vertically on the scale and your air flow (lbs/m) is marked horizontally.
pin point where the two meet on the compressor map. You want to stay within 60% of the compressors effieciency and never hit the surge limit at any rpm.
To calculate where you will be on the compressor map at different boost and rpm levels, change the formula above as needed.
Make sense?
Also, With my engine computed it comes out to 94 lbs/m....how would I get in the good efficiency range?
Thanks,
Andy
Last edited by andy98Z; Apr 22, 2004 at 04:24 PM.
That's a lot of motor you got there... 