How can a turbo be to small for a B16A (ie T25), I thought when the waste gate opened the turbo spun at roughly a constant rate to produce a regulated output pressure. So wouldn't said turbo spin at a constant rate once the wastegate is actuated regardless of engine rpm over max boost.

Someone kindly explain this to me please.

 

The wastegate keeps the compressor flowing at a certain pressure, say 8 psi. This is different than keeping the turbo at a certain rpm. The actual amount of air being flowed by the compressor, and the rpm of the turbo, increases as engine rpm increases. A small turbo like a t-25 will be very inefficient at 8,000 rpm on a B16 because it is not meant to flow that much air.

 

If you ever take the time to look at a compressor map, it would make sense. If a small turbo that is effecient at say 10psi while flowing onle 200cfm is asked to flow over 400cfm (like a B16 at 7-8k) is will 'fall' off its effeciency map and heat the air considerbly more than a larger turbo.

(BTW im drunk

 

haha, lee