The TT uses Hybrid Turbo's, based on the T25 but with slightly smaller Impeller wheels ?

 

Whats the Max boost before they become innefficient..and unreliable ?

 

The reason I ask is that I have a friend looking to buy an Alpina B10 bi-turbo, which uses a Pair of T25 tubs.

 

They come with an In-car boost controller as standard for adjusting boost from 20psi - 26psi.

 

And this is stock, from the factory.

 

Was very suprised.

I think previous discussion has had the theoretical limit of 18psi but 16psi being the upper limit before fuel runs out and 14psi being the highest most people should realisticly run

I actually saw a reduction in MAF reading going from 15 to 17psi, so suggest about 15 is the limit on the sort of flowrate of a 3l.