Thread: Turbo Compressor Maps

Courtesy of speedjunkie on MSV. I cleaned it up a bit.
Original thread here http://myspecv.com/f/post.php?tid=174779&qid=2004675

I decided I should map out a few compressor maps to see what turbos would be best suited for the qg18de, for this you first have to start out with a few calculations.

First your going to want to find your pressure ratio. Say you wanted to run 10 psi the formula would be:
(10+14.7)/14.7=1.68
so 1.68 is our pressure ratio

Next we need to know our CFM, the formula for that is:
(CID*RPM*VE*PR)/3456
So our formula would look like this:
(109.8*6500*.90*1.68)/3456=312.24

Now we need to convert CFM into airflow, you do that by dividing CFM by 14.27.
312.24/14.27=21.88

So using our Pressure ratio and Air Flow we can now chart points on a compressor map (we also need another point but I am not going to type the calculations for that because it would take too long, but for the second point our Pressure ratio is 1.34 and Air Flow is 8.72)

I have already done a few of the more popular turbos. Do not mind the writing on the paper, I did these a while ago and wrote down the wrong things


gt25r - Ok for low boost but if you wanted to go higher then 10 it would be to close to the choke line



gt28r - Ok Turbo for a street car not looking for more then 220 horsepower, once again if you wanted to run more then 10 psi it would be to close to the choke line



gt30r - This turbo would be good for a drag car, or for someone looking to build later on down the line and who wants to run over 10 psi



gt32r - This turbo actually looks pretty good for 10 psi as it is in the inner most efficiency island, but part throttle boost is too close to the surge line and could damage the turbo in the long run.



45 Trim T3 - Entirely too small of a turbo, it is past the choke line at 10 psi



T3 Super 60 - As I have said many times, the best turbo for a street car, has room for improvement and even part throttle boost is far enough away from the surge line to not cause problems



T3/TO4E 50 Trim - A very efficient turbo for 10 lbs as it is in the inner most efficiency island at 10psi, part throttle boost is closer to the surge line but still far enough away to not cause problems



T3/TO4E 57 Trim - same thing with this one as was with the turbo above. I wouldnt recommend using either of the two previous turbos unless your ready to see what the motor can handle, they will also be sorta of laggy, 3000rpm spool time



T3/TO4E 60 Trim - at first glance this one looks fine but the part throttle boost is to close to the surge line.



Small Wheel 16G (Mitsubishi Turbo) - This turbo is also a good street turbo



Big Wheel 16G (Mitsubishi Turbo) - Even though this is a "bigger" turbo then the small wheel 16g it is only in the 60% efficiency island at 10 psi, i would use this for around 12-14 psi on the street



20G (Mitsubishi Turbo) - Another good turbo for the street, at 10 psi it is in the 72% efficiency island, this one I would use for 10-15 psi.

So out of those turbos, the two that i would reccomend to people wanting good power for a daily driver would be a t3 super 60 or a 20g

good stuff..

Nice ash

everyone saying nice stuff, but can yall break down the graph??

How to read maps: http://www.nycsentras.com/showthread...8318#post68318

Originally Posted by ash

How to read maps: http://www.nycsentras.com/showthread...8318#post68318

ah ha the missing link. sweet i never knew that was on here

here's a easier calculation.. have fun playing with it.
http://www.turbofast.com.au/turbomap.html

What turbo fits you. http://www.turbofast.com.au/TFmatch.html

directly from garret site.. gt2871r


* Ball bearing * Oil & Water-cooled bearing system * Direct replacement upgrade turbocharger for GT2860RS (739548-1) * Comes as a kit; end housings are not assembled onto CHRA * 743347-4 features a low boost actuator adjustable down to 6 psi * T25 turbine inlet flange * Great size for applications w/ packaging constraints * Ideal for smaller displacement engines making up to 475 hp * Ideal for twin-turbo applications on medium size engines making up to 800 hp * Turbine housing option available * Compressor housing kit options available


http://www.turbobygarrett.com/turbobygarrett/catelog/Turbochargers/GT28/GT2871R_743347_4.htm

everyone saying nice stuff, but can yall break down the graph??