Will somebody please develop a way to explain how to read compressor maps in english. I have looked into many ways and still don't fully understand what the vertical and horizontal lines mean together. I just get confused on the conversions of ? to cfm and so on. Is it possible in ENGLISH? I think this would help many of our "Which turbo should I use" people.

 

i shall do a write up.

give me some time aiite?

 

Heres my 20am, just got home from the bar, grossly over simplified explanation:

y-axis: pressure ratio. 1=0psi, 1.5=7.35psi, 2.0=14.7psi etc
x-axis: air flow expressed in lbs/min. (the cool thing about lbs/min is that is roughly translates into HP potential. 100hp = 10lbs/min, 250hp = 25lbs/min, etc...)
The large area circles with %'s on them are efficiency islands that express the compressors efficiency at a given plot point.

By looking at dyno sheets from similar engines/setups as your own, you can realistically guess hp potential, and apply it to a turbo's compressor map.

A ZC at 7psi applied to a T3 map:

x-axis airflow lbs/min= 17 (170ish hp)
y-axis pressure ratio= 1.47 (14.7+7)/14.7



Plotting this point puts you on the 70% 'island'. This compressor is 70% effecient at feeding a ZC at 7psi. (roots superchargers blush at these #'s...heheheh)
Turn the boost up to 10-12 and the compressor approaches the 74% island.

Heres a more indepth example that google came up with:
http://shingles.no-ip.com080/cars/crx/turbo/compmap.asp

'Maximum Boost' has a simple layout on compressor maps as well.

HTH,
Dave

 

Wow Dave,
Thanks alot. It took me like an hour on that link, but I think I figured out my flow rates and stuff. That's alot of damn math. Thanks
Shortyz- If you could put that into English for others, that would be great. I mean, we shouldn't be here to have people tell us what we should do, we should want to understand it ourselves. Thanks.
P.S. I was just ------' with you in the chat room, I promise.

 

Ok, I went on turbonetics.com and started plotting my points on all the compressor maps. I found that the t3 60 trim was the best. Question- when trying to spot a t3 to buy, how do I know/find out if it is the "60 trim". Maybe you guys know what factory turbo is similar. Please help.