Derek,

You are partially correct and partially incorrect.


1)Driving Mrs. Compressor

the compressor is the boss of the system, not the turbine. if you turn the compressor 20k RPM faster you are not going to get more flow...you are going to get more boost!! unless you DRASTICALLY change the flow capability of the engine. the precision TE site is down right now, so i cant say for sure, but if you maintain the the same flow level and increase shaft speed 20krpm you will either be in the surge region, or you will be pushing 15 psi more (30 psi total) boost!!. now if you keep boost the same and turn the compressor 20krpm more you will be out near 55 lb/min @ PR 2.0. but the motor cant physically flow 55 lb/min @ 15 psi....it's just not possible!! that would be a VE of like 1.50!!

2)heat and turbine power and work.

i ran some calcs a while back and at PR 2.0 and 40 lb/min the 82mm 56 trim required damn near 22Hp (thats right 22 Horsepower) to compress that flow of air at 75% efficiency. if you are going to drastically increase the flow of the compressor you are going to drastically increase the work done by the turbine. work is extracted by a change in temp or a change in pressure. the riddle is this tho...the turbine can not extract HEAT energy from the exhaust stream without extracting Pressure energy from the exhaust stream they are linked to gether. you actually get the change in temperature FROM the change in pressure...ever spray compressed air? it's always cold, you are getting work out of your pressure control orifice (air sprayer) thus the air comes out colder. what you are proposing is like saying that an air conditioning system would work without a Thermal Expansion Valve....it's just not possible. temp and pressure are related on the turbine side!! so even though your goal to get the PRE turbine temps as high as possible is a good goal, i dont see it as getting you and real gains, because your POST turbine temps will just be higher. the change in pressure across the turbine will have to be the same.

3) smaller turbine section of yours truly.

if we can now agree that the compressor is the boss of the systemthen there a few other things to discuss. if you are looking to achieve 400 @ 15 psi than that is a fixed RPM and flow on the compressor wheel...no way around that. so both our turbines have to to also turn the same speed...with a BIGGER wheel you need to flow MORE ehxuast gas through the turbine to get the pressure drop through a more OPEN orifice that is your turbine exducer to achieve the same turbien shaft RPM.

I like that you are thinking out of the box....but i'm not sure you are goign to see the results you expect...for the reasons you have listed!

as for your friends honda..the reason you picked up SO much HP was back pressure. the turbien was having to spin at probably 1.5 times the shaft RPM needed to spin a freewheeling compressor. this means more work dotn by the turbine and more Exhaust gas restriction...no flow was being achieved becasue you couldnt get any more air thought the turbine, because you probably had to close th WG down so much mroe to get the boost!!

as usual keep us updated when you go to the dyno!!