i have a MPT70 with the .96 on my 6l and it spools very quick. I tried the .68 and didn't like it, it was always boosting when i didn't want it to and was harder to tune.

 

STS = T60-1

 

T76

 

Here is a great write-up on how to read compressor maps
http://www.turbomagazine.com/tech/03..._map/t04e.html

 

Im dont know much about turbos, but im tryin to learn.
I went ahead and got a MPT76 from Kyle. We shall see how it does.

 

That sounds like a good choice to me. What size turbine did you get T4 .96 A/R? What boost are you planning to run, what are your shift points and still running the LQ4? Check out the consumption chart from Forced Inductions for a 364 LS1/LS6.

1.) Calculate your Pressure Ratio = (Boost + Atmospheric)/ Atmospheric

ex. (10psi + 14.7) / 14.7 = 1.68 ~ 1.7

2.) Determine your consumption say 10 psi and 6000rpm = 59 lbs/min from consumption chart.

3.) Plot this on the T76 Compressor Map and you end up between 75 - 70 % efficiency island. Not bad since max. efficiency is 78%.

4.) As a comparison on the T 60-1 you would be completely to the right of the islands in a totally inefficient area and making lots of hot air.

5.) On a T70 you would be on the outer line or just to the right of it and out of the efficiency range as well with no room to grow.


The image of the chart does not seems to be showing up try:
http://www.forcedinductions.com/consumption364.htm

 

When I want to see compressor maps, I just take some LSD, and I see them in the carpet and the curtains. They make the same amount of sense to me as the ones I see posted here.

 

LOL...you prolly like the colored ones better.


Another thing the maps will show you is the rpm required to make a given PR (pressure ratio). A T60-1 requires almost 96000 rpm per the example above. Think heat.

A T76 only requires ~ 60000 rpm. Cool runnings...