eddyboy

Hello,

I'm making a attempt to read the compressor map for my turbo, but I think my math is a off. I used BlueShadow's Post on READING COMPRESSOR MAPS, as my guide.

https://honda-tech.com/zerothread?id=142398

Part one Pressure Ratio
1-left side, PRESSURE RATIO(14.7 + amount of boost) / 14.7 = PR

My calculations

(14.7 + 10psi)/14.7 =1.68

Part two Airflow Rate
2-bottom side, AIRFLOW RATE UNDER BOOST (LB/MIN on this map)
This is the part i'm having trouble figuring out but, it looks like i need to find out the Engine Flow Rate in Cubic Feet per Miniute/CFM then convert that to Pounds per Minute(Lb/min)

Here is what i've done

Using this equation from this site http://www.gnttype.org/techare....html
Engine Volumetric Flow Equation
volume of air (cu ft/min)= engine rpm x engine cid/(1728 x 2)


Using a link from D-MAN i was able to figure out my Displacement in CC.
Displacement Cubic Centimeters=1611.8629468903425
Displacement Cubic Inches = 98.3619116
I plug this info in to equation and I get

volume of air (cu ft/min)= 7000 x 98.3619116 / (1728 x 2)

I get = 199.22840891203703703703703703704 CFM

Convert it to LB/Min using BlueShadow's equation which is
@ 48 degrees F : (CFM * 0.078125) = LB/MIN
@112 degrees F : (CFM * 0.070318) = LB/MIN
@175 degrees F : (CFM * 0.06251) = LB/MIN

@112 degrees F: (199.23 * 0.070318) = 14.00945514

Does this sound right?

Here is the compressor Map for my turbo

http://www.atpturbo.com/root/maps/gt28rs.htm

Thanks for all your help

edit: btw this is for a D16z6 motor


Modified by eddyboy at 1:27 PM 9/12/2004


Modified by eddyboy at 1:58 PM 9/12/2004

eddyboy

bump for info

eddyboy

Late nite bump

b18cls1

your math is right but i always use the industry standards when i do the math and standard temp is 60 deg f or 520 rankine, but i would look at your engine lets say at 6000 rpm you will be moving 12.92 lbs/min now plot that at a pr of 1.6 and see that your getting close to the surge line

becuse remember that is good to have a turbo be able to flow enough air at top rpm its also good to look at some of the lower rpm just my input
good luck

eddyboy

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b18cls1 &raquo;</TD></TR><TR><TD CLASS="quote">your math is right but i always use the industry standards when i do the math and standard temp is 60 deg f or 520 rankine, but i would look at your engine lets say at 6000 rpm you will be moving 12.92 lbs/min now plot that at a pr of 1.6 and see that your getting close to the surge line

becuse remember that is good to have a turbo be able to flow enough air at top rpm its also good to look at some of the lower rpm just my input
good luck </TD></TR></TABLE>

That is exactly why I think i'm doing something wrong. Cause I am barely on the map even at near redline. If I do a another calculation at lower rpms i'll practically fall off the map. If that makes any sense?

From what i've read the gt28rs aka Disco Potato woud be a great match for a D series motor. From the compressor map it doesn't look to promising

b18cls1

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by eddyboy &raquo;</TD></TR><TR><TD CLASS="quote">

That is exactly why I think i'm doing something wrong. Cause I am barely on the map even at near redline. If I do a another calculation at lower rpms i'll practically fall off the map. If that makes any sense?

From what i've read the gt28rs aka Disco Potato woud be a great match for a D series motor. From the compressor map it doesn't look to promising </TD></TR></TABLE>

to use thart turbo imho youll need to up the displacement of the motor a little in order to flow a little more air,