Best turbo for 550hp I5

[A80Avant]

Repo,

Have you had any experience to give us some differences between the CT358 and CT458?

although the wheel specs are the same,it seems that the 4inch compressor wheel housing and the 2.5inch turbine wheel housing (as opposed to 3inch and 2inch respectivelly on the 358) gives according to the web page 75hp more! How is that possible?

Also,would it make a difference in spooling if both these turbos had 0.63AR or should they be ordered with 0.82AR instead?

[Bram]

O yes, I have got a new question!

When I would need to choose between the CT355 in a 0.63 or 0.82 A/R, what would be the difference in spoolup Repo? 200 rpm or much more. I do recall that the difference with Garret GT30 0.63 and 082 A/R turbo's is about 500-600 rpm

cheers