| Now I won't go saying everything, everyone else as said here so far. About 25psi, efficiency etc. Know that a turbo of any size has a least efficient area called the choke area. This is where your asking more of the turbo than the compressor side can handle or was made for. Also the pressure ratio depends on the ambient pressure. So not sure where you live, but the pressure reading and turbo efficiency is decreased as the elevation increases (PR increases). Turbos lose performance and become less efficient as elevation gets higher. When the air speed reach sonic speed, the amount of air flow increase is very small as compressor wheel rpm increases. In plain words, the compressor has reached its limit. Turbo Stock = TB02/22 Wheel = T2 map avail Inducer Diameter(in./mm) = 1.57"/40mm Exducer Diameter(in./mm) = 2.02"/51mm Max CFM = 304ea. Wheel = T22 Small turbo's with a very quick response and little lag, but also with a low ceiling of over all flow and quick peak of power. Your manifold pressure will read the overall pressure in the system, but your turbo's are not running a sustained reading of the gauge when their passed their compressors Max CFM and compressor wheel spec's. "From Sparkie's site" You can see by this chart, just how the small stock turbo's at 15psi are under performing to the motors overall flow in the high RPM range just at 15psi. Stock Max CFM = 304ea. x 2 = 608 vise the 761 @ 7000prm redline. 
I wanted to see the Speedo during those runs too, but you focused in on the boost gauge every time. It seemed as you panned back out from the gauge as it dropped, there wasn't a great deal of speed in the car produced from such a high reading in pressure. That again would indicate the flow of the turbo is Max out and is only running a system pressure and having no gains. But then again, the gauge would drop so fast due to him letting off the gas it seemed, that it was hard to tell because it was not a sustained amount of pressure ran for a distance.
 STAGE V++++
Going to XV+ and beyond :) Yellow Z STAGE II
Going to XI+ |
Do you have a list of this cars mods ( i.e injectors ) - 
