Definitely reducing fuel (heat, drive energy)will do exactly that but you are seeing similar power with both high and low fuel loads which is why I ask about drive pressure . If drive pressure and inlet temps are good and your pump can maintain timing at high rpm 1 afr point makes 30-40 degrees difference to egt's ( nothing drastic)
Knowing that u got the boost increase with more fuel only and no boost controller adjustment but with little power increase points to the turbine choking(high emp, high drive pressure) counter productive to power . Each turbine housing and turbine has its own sweet spot for efficency. usually with a drive pressure ratio below 1.5:1 the closer to 1:1 the better. It's a handy thing to measure and u don't have to guess when u have all the data . And with some fine tuning, the boost controller you have will allow slightly higher drive pressure on spool up (earlier, faster spool) but then allow the the gate to progressive open more to control emp and help make power efficiently .
I'm not knocking what you've done, just trying to confirm if the turbine and wastegate was actually choking or just the turbine with gate closed to much. Initially I though you may have adjusted the boost controller holding the gate shut to much which made it seem like the turbine was choking. I like big power and if I see someone unsure why their adjustment didn't yield the gains expected I'll try to help .
Thing are easier with all the data . Tap your exhaust manifold and measure emp, you might get a shock . It will also help setting and fine tuning your boost controller .
Looking foward to seeing your prototype's results !
