Turbo Questions>>>>??

[Brian]

Ok, I now know how to read compressor maps, so i've been doing research on turbo sizing ect. I have a couple questions though. How do you figure out how soon the turbo will spool up on a given engine? I would assume the A/R ratio would play a part in figuring this out. From the research i've done it looks like a TO4E .50 seems to be a good match as far as my target power and efficiency ect. Any opinions?

[stu]

The bigger the A/R number is, the slower it will spool. One way to do it would be to get a graph of how much CFM your car will flow at what rpm and match that up to the corresponding numbers on a compressor map, if this would work the way I think it would you would be able to see at what rpm the turbo would reach full boost. Check out Ted's thread about the $2000 budget for more info on this.