Reading compressor maps to select compressor to hp needs and calculate outlet temps

[Tippy]

First off, let me say I am not a turbo expert. I was just trying to simplify the "art" of compressor map reading. If I have a mistake in my presentation (especially the math part!), please let me know as I don't want to put out bad information.

My goal was to use the standard 1-bar using a K27 on a 930 as an example. I am attaching other compressors maps from a 60-1 (60mm) and a Holset HX40 6-blade (60mm) for reference.

Stock K27 (60mm - not HF, etc.)


100 degree ambient temps


60-1 (60mm)


HX40 6-blade (60mm)

[smurfbus]

It would be nice to know how our typical 3.3 liter engines with NA cams fit in there (curves) at around one BAR. Someone with MAF and EFI could log airflow and then using VE calculations to figure how different points are placed. I did that with my audi and another diesel way back and it was good for deciding what boost/turbo to run for optimum results. Theory and practice might differ though as has been proved time after time.

What is our VE for starters? Low CR/2valves must mean low VE but boost will fix that a bit.

There are calculators over intardnet and this is one of those:
http://www.lovehorsepower.com/joomla/index.php?option=com_content&view=article&id=35:compressor-flow-map-calculator&catid=8:mr2-helpful-stuff&Itemid=49

And for another reference here is a map for the holset40super where I used the above online calc to determine the curve. I used 85% for VE.

[Tippy]

Let me take a look at my datalogs (have EFI) and see what I come up with.

[fredmeister]

Originally Posted by Tippy

Let me take a look at my datalogs (have EFI) and see what I come up with.

Cory, that was a very good presentation.

thanks for posting.

Fred---

I would like to see the actual values for your engine laid in on the compressor maps like you mentioned above.
Could you provide more detail on your engine build, ie cams and porting and other info to make a good baseline for the chart?

This is helpful info. Do you have any compressor maps for the k27S turbo?....I have this on my 3.4 liter turbo and would love to have the info and its hard to get when i was serching awhile back.

[Tippy]

Fred, if you're asking me, I have a 3.4 from a base Carrera 3.2. 3.2 cams are the same profile as SC.

I am running an Holset HX40 8-blade which flows a tad less than a 60-1 at 1-bar but runs far more efficient at higher boost than 1-bar. Previously had a 60-1.

I do not have a K27S map but Squirrel Performance where I sourced the stock K27 map may have one.