Anyone know were it is? Everyone that I've seen ( or someone says that it is) is the big 16g which is not the same.

Evo III compressor map:
http://linux.forcedperformance.net/merchant2/graphics/00000001/footer/evo_ti_map.jpg

An Evo III is not the same as a big 16G:
http://www.turbocarz.com/shapegsx/16g/evo_big.gif

the FP one is too small but the other one is good, just messy with the other map on top of it. Just trying to figure out were this turbo runs at peak effiency.

Fp has the full size one on their site.

OK the second link says TD05HR-16G6 which is the offical name of EVO8 turbos that is not a EVO 3 TD05H-16G

DSMSpyder99 said:

OK the second link says TD05HR-16G6 which is the offical name of EVO8 turbos that is not a EVO 3 TD05H-16G

Click to expand...

I mentioned to Robert @ FP that I thought the Evo III 16G compressor wheel was the same as the Evo VIII 16G compressor wheel, and he agreed.

The VIII is just a reverse image of the III. They are both 16G6 compressor wheels, though.

So the compressor map works for both.

so who cares if the wheel is the same. The EVO 8 is a REVERSE TWIN SCROLL and has a 10.5CM^2 HOUSING. With twin scroll you get better boost response and with a 10.5cm^2 housing you can bet ur ass you get alot more topend. Just use common sense people run 24+PSI on EVO8 16G on pumpgas. You cant push a EVO3 16G that high it will just blow hot air and will fail after a short period of time if you run on pump gas. So saying that the EVO3 and EVO8 have similar compression maps is just wrong.

DSMSpyder99 said:

so who cares if the wheel is the same. The EVO 8 is a REVERSE TWIN SCROLL and has a 10.5CM^2 HOUSING. With twin scroll you get better boost response and with a 10.5cm^2 housing you can bet ur ass you get alot more topend. Just use common sense people run 24+PSI on EVO8 16G on pumpgas. You cant push a EVO3 16G that high it will just blow hot air and will fail after a short period of time if you run on pump gas. So saying that the EVO3 and EVO8 have similar compression maps is just wrong.

Click to expand...

The compressor map displays the compressor wheel effeciency, not considering turbine housing size, etc. Both turbos use the same wheel, therefore their compressor maps will be very similar if not the exact same.

guitarXgeek said:

The compressor map displays the compressor wheel effeciency, not considering turbine housing size, etc. Both turbos use the same wheel, therefore their compressor maps will be very similar if not the exact same.

Click to expand...

Exactly. Robert feels that that compressor map is also valid for the Evo III 16G.

Do you throw out Garrett compressor maps if your turbo has a different exhaust side? No.

Why do you think that you should with a Mitsubishi turbo? The exhaust side has nothing to do with the compressor map. If it did, the engine, the exhaust system, the intercooler, and everything else inbetween would also have to be taken into account in the compressor map. And obviously they are not.

Mike000 said:

http://turbocarz.com/shapegsx/16g/compressor_plot.gif

Click to expand...

Thank you and not to sound anal but I was really looking for one with airflow in cfm on the bottom.I don't understand those other #'s. I'm trying to figure out some things like were i'm ruuuning at with this turbo.

Help me out with this if you can at redline (7500rpms) and 20psi the max the 4g63 will flow is 531cfms, so were on the compressor map am I at? Compressor efficiency? If your wondering were I got the 531 from its

Pressure ratio=14.7+20psi
------------- =2.36 bar
14.7

air flow rate= cid(122)xrpm(7500)x0.5xEv(85%)
--------------------------------- = 225cfm's
1728

Now this is given that Ev is 85% and 85 is the velometric effeciency. Since 1 bar is 14.7. The .5 is due to the fact that a 4 stroke engine fills its cylinders only on one-half revolutions. The 1728 converts ci to cubic feet.

So the 4g63 is flowing 225cfms under N/A conditions. Now factor in 20psi (2.36bar)

Airflow rate=2.36x225=531cfms

Shoot me now if I really FUBAR'd this up and my math is wrong. I got this all from Corky Bells book Maxium Boost.

Why do you care about CFM? Mass airflow is a much better measure. CFM in a vacuum will be infinite. Figure that one out.

Incidentally, the red line on this plot:
http://turbocarz.com/shapegsx/16g/compressor_plot.gif

is the plot of my engine's mass airflow (datalogged) using an Evo III 16G. That was 3rd gear during one of my drag passes.I plotted pressure ratio vs mass airflow. That is actually a useful plot. I can tell what RPM the compressor is turning, and what efficiency the compressor is operating at.

ShapeGSX said:

Why do you care about CFM? Mass airflow is a much better measure. CFM in a vacuum will be infinite. Figure that one out.

Click to expand...

I guess what i'm trying to figure out is what is the best psi to run at with this turbo, and what relationship does mass air flow have to efficiency? Yes it may be infinite but a engine can only pump so much.

here are some forumlas by which I figured out my efficiency. If there are any mistakes please correct them, it's finals week and everything is a blur..... I pulled the formulas from HCI and some of the approximations. I imagine with some different conditions, height above sea level (different air pressures at different heights), actual manifold temp, actual volumetric efficiency, and actual filter drop. The conversion from lbs/min to m^3/sec is my own creation, I did this to agree with Shape's graph.

GIXRMAN if you wanted to figure out what PSI you would get your best efficiency at that would require some serious rearrangement of the equations and back substitution. I would just try 3 or so points a high, low and medium and then estimate.

Second pic is where my calculations landed me on Shape's Graph.

Ok so maybe I have no life
Here are the figures that I came up with, again they are based on the approximations that I previously stated. I just threw the information into Excel and it spit out everything. I then threw it on the graph. Notice that the Efficiency is only at 7500 RPM.

Wow, thanks for all of that. I called slowboy yesterday(they sold me my evo16) and asked if they had a compressor map for the turbo and they stated that Mitsu does'nt release comp. maps to the public. :thumbdown

On the 2nd map the way you have it graghed out looks like at 20-22psi the evo3 is running into or should i say out of efficiency(64%) quickly, flowing that much air. Yes,no? So basiclly your pumping hot air.
I ordered the "Turbo Calculator" off the internet, and in it should be a 16g compressor map. I post my findings when I get it.

Well I wouldn't analyze the plots that I made too critically. I mean all of the calculations, as I stated before, are total approximations. If we lived in an environment in which everyone lived at sea level and had the exact same temps year round then analyzing the map would be much more possible. Take intake manifold temp for instance. If you have an efficient intercooler then the intake air should be much cooler, closer to ambient temperature. This intake temp approximation might hold true if you live in CA where it frequents 110* then this approximations would be true because it is a bit higher than the ambient temperature; but in PA where it gets in the high 80s this temp would be a bit too high. The density of air increases and decreases with temperature and elevation. Higher elevations would probably see a lower atmospheric pressure. This would change the Pressure ratio, A higher atmospheric pressure will yield a lower pressure ratio which would drop all of the points on the graph down a bit.
What would need to be done would be a log that recorded intake temps (via GM Maft) and lbs/min flow. Your intake temperature would be taken close to the throttle body so they would probably be a much better approximation. The airflow will also be very close to what the engine is actually seeing.
Don't forget that this is at redline, your EVF will be at it's highest at this point. As you get into a more normal RPM band you will see that the EVF will decrease. With this decrease you will consequently get a decrease in lbs/min.
Your best bet is to take the car out, do a pull log, log intake temp, lbs/min airflow and RPM, once you have these you can get an idea of where your boost is landing you on the map. I will try this next spring, I will then have a GM Maf setup, this is necessary because your intake temp with a regular MAS will be read before the turbo not after where it is much more important. Full boost will come on way before redline, so I would think that calculations within the 4K to 7K band would be way more useful then that at 7500. After all not all of us wait until we hit rev limiter to shift.

Just some food for thought.

You do realize that the red line on the original plot is a plot of my mass airflow vs my pressure ratio in 3rd gear on one of my 11 second passes, right? I sortof rode the line between 70% and 68% efficiency. Which isn't bad at all at that pressure.

Miteclgst- I understand that there are alot of variables that can change airflow and o2 content by enviromential influences. I'm still learning about turbo tunning and after doing some reading about forced induction I was trying to apply what I have learned run this turbo at peak effiency.


I was looking at what this turbo is capiable of from a mathmatical standpoint given the data available. What is the max boost(effiency) without over-run? At what rpm, boost, airflow am i able to keep it in the sweet spot. Stupid geeky stuff like that. I am sick of hearing people post stuff like i'm running a t-25 at 30psi on 89 octane without the data to back it up.

I just want to know the hard facts about this turbo. I plan on doing some serious datalogging on this turbo.

Thank you guys for your responces, they have helped me understand compressor maps better.

gixrman said:

I called slowboy yesterday(they sold me my evo16) and asked if they had a compressor map for the turbo and they stated that Mitsu does'nt release comp. maps to the public. :thumbdown

Click to expand...

Well here's a website that lists just about all of the popular Mitsu turbos (evo3b16g is not included, though)... http://not2fast.wryday.com/turbo/maps/

guitarXgeek said:

Well here's a website that lists just about all of the popular Mitsu turbos (evo3b16g is not included, though)... http://not2fast.wryday.com/turbo/maps/

Click to expand...

Does this show the small 16G wheel as more efficient than the big16g? If you look at airflow on bottom (.25) at a pressure ratio of 2.2 the small is over 74% efficient while the big is between 60 and 65%? Am I reading this right?

Talonman said:

Does this show the small 16G wheel as more efficient than the big16g? If you look at airflow on bottom (.25) at a pressure ratio of 2.2 the small is over 74% efficient while the big is between 60 and 65%? Am I reading this right?

Click to expand...

It sure looks that way. I do recall hearing a while back that the small16g wheel was in fact more efficient than the big16g wheel. I never really looked at the two maps comparatively, but it does seem that the small16g really is more efficient!

The units on the bottom of the small 16G map are different than the rest. Hence why everyone has thought for so long that the small 16G was more efficient. It is not. The small 16G map is not nearly as wide as that picture shows.

here is an actual analysis proving what ShapeGSX said is absolutely true. Using the same Pressure Ratio as calculated in my previous post and coverting from lbs/min into kg/s you end up with a point that lands on the included graph. This point is nearing the choke line, the specific choke line isn't shown on this graph but it does reside to the right of the physical map. The choke area is where RPMs increase dramatically and air temps rise rapidly. Being on the wrong side of this line will result in a damaged turbo. In the very best case the turbo will be less than 60% efficient in this region