Originally posted by 400HP930
Force fed is saving himself some embarasment by stating that a way undersized turbine housing can restrict your exhaust flow to get you any crazy pressure ratio you want. Unless someone is looking to get high boost at very low RPMs and screw themselves at the high RPMs doing so is sheer stupidity.
These weren't rolling abortions I'm talking about. First was a 300zx with a 57 trim T04E with a stage 3 turbine in a hogged out stock housing, a VERY common turbo on a variety of apps. The other that I mentioned is a big block Ford that had a single Y2k (I think 91 or 100mm) but he was choking the motor so bad that while on the transbreak it saw a 2:1 ratio, as soon as the button was let go it jumped to 3:1 during the run, all this with 30psi intake pressure so you do the math :o
There are many other examples but these two are the ones I'm most familiar with. Again I ask you Tony, have you ever measured exhaust pressure in your Porsche? This may sound stupid, but physics class is one thing and the real world is another.