No air pressure help from mother nature. I even dropped to a 14cm3 housing and had it ceramic coated, still having a hard time spooling the 62/84mm.
Maybe it's time for NOx.

 

Tell us more about that 84mm turbine wheel. I have the GDS 62mm compressor side driven by the stock H1C turbine wheel which I think is 60mm and a 16cm housing. I am having no spooling issues and with my fueling it takes it straight to 45psi.

 

Actually I think it is a 62/86, 7 blade Gillett H1C hybrid based off my Stage4 original 60mm 6 blade.
This new wheel and housing require so much more drive pressure it's crazy. Now I'm still pulling hard at 90 when I shift into 5th. Crazy top end, runs cooler, but takes a lot of fuel to get it to spool. May have to go compound.

 

A common misbelief is that the exhaust flow is what turns the turbine. It isn't so much that as it is the temperature. You have to burn more fuel to spin it up. Then the compressor side brings in more air to burn the fuel more efficiently. No spooling without some smoke.

Look at your AFC mechanism to see why you're not getting enough fuel when you romp on the go pedal.

Edwin

 

I'm getting enough fuel, turn day into night if I don't roll into it.

 

My experience is different. I sucked my BHAF into my 6 blade 60mm wheel, so I sent the turbo off to Gillett who upgraded the wheel to 7 blage 62/86mm and machined housing, but same 16cm3 exhaust housing and turbine that I had before.

No other change on the turbo or fueling. All the sudden I didn't have enough drive pressure for the bigger wheel. I dropped from the 16cm3 to a 14cm3 and it helped a little, but I think I will need a 12. The issue is I don't want to restrict the top end performance, so I am thinking about ways to make it work with the 14cm3. I have plenty of fuel.

 

IMO, Yes its important to keep heat in the exhaust, but the flow absolutely does drive the turbine. Its why you swap turbine housings to change flow characteristics/turbine back pressure.