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View Full Version : Stage 3 turbo compressor map question


phillysrt4
07-01-2020, 02:23 PM
Im having trouble getting someone to get me the compressor map for the stage 3 turbo. What I have found is compressor maps for the TD05-14G and the TD05-16G small wheel. Is it safe to assume I can use these maps to interpolate a good guess for the TD05-15G, i.e. the S3 turbo?

I did a preliminary analysis of the compressor maps to see if my guesses are verified, and so far, maximum boost at 6500RPM based is fairly close to my interpolated guess.

My rationale is that since the 15G wheel is in between the size of the 14g and the 16g the map for the 15g wheel should fall somewhere between the 14g and the 16g with respect to flow.

Comments? Does anyone have the compressor map for the S3 turbo?

slow4dr
07-01-2020, 10:44 PM
I don't think one has been released. I would guess it to flow around 38 lbs-min of air.

phillysrt4
07-02-2020, 08:41 AM
then its time for me to use ninja tactics to get a map :owned:

phillysrt4
07-02-2020, 01:19 PM
I got some data on my turbo performance. I am going to use it to try and interpolate a compressor map if mopar and mitsubishi decide that for some reason a simple compressor map is a trade secret.

Today I did some testing outdoors on 3rd gear pulls to get an idea of what it would flow. Given the fact that it was 90 degrees out with a heat index of 93 and a baro pressure of 30.00 in., it was a good thing I had an intercooler sprayer at my disposal. The first run I scrubbed because the PCM was pulling boost due to the heat of the charge. For example, as the rpms climbed above 5000 rpm, the boost would bounce between about 16 and 18. I ran the intercooler sprayer on subsequent attempts and the boost readings were far more stable.

Using a passenger in the car to call out boost numbers as I called out RPM numbers, we found the PCM using the intercooler sprayer was solidly holding the following boost numbers at various RPMs:

5000 RPM - 21 lbs
5500 RPM - 19 lbs
6000 RPM - 18 lbs
Redline(*) - 18 lbs

(*=as close to 6500 as I could get and avoid fuel cutoff... its probably about 6400 RPM in reality)

Given that when my car is off my 30/30 autometer gauge rests on the low side of the "0" block, I think its safe to say that I get 18 lbs of boost at redline.

Im going to use this in various flow calculations to make a guess at the TD05-15G compressor map should my contacts fail to procure one. Based on the way that boost fluctuated without intercooler spraying, the 18 lbs must be in a relatively crappy area of the efficiency range, so I'll take that into consideration when I "guess" at my flow map.

Comments welcome...

blackbird
07-03-2020, 04:44 AM
Interpolation may get you in the ballpark for overall airflow, but for that you might want to just back compute the airflow requirements from the horsepower produced by S3 instead. It might be just as accurate as guessing from two completely different wheels. And just guessing won't tell you about surge characteristics and efficiency anyways.

The S3's TD05HR-15GK uses a similar wheel to that on one of the older Evo's we never got stateside (special limited edition model like around an Evo V-VI timeframe). You might want to dig around on some Mitsu sites but I don't think you'll have good luck finding anything exactly for this compressor.

phillysrt4
07-03-2020, 09:04 AM
hmm ok i'll have to see what I can find on mistu sites.

mind you my first guess is not going to be my only guess. your thoughts on using horsepower to backcalc is a good one as well, but its going to be a while before I am going to be able to get on the dyno.

In any event, I'm sick of mopar treating the compression map as a secret of national security, and Im going to get some results one way or another.

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