Truck in my sig. I've read the whole Tuning Twins thread in the drag race section as well as any other threads on topic that I could find. I'm having a hang up here in my thought process when it comes to driving the secondary harder to balance out PRs yet on the contrary wastegating the secondary more to lower overall drive pressure.
This is what I'm currently seeing at full tilt.
80psi at the intake manifold.
45psi between turbos.
90-95psi of drive pressure at the exhaust manifold.
And if I am trying hard, 3rd or 4th up a steep hill with the pedal mashed or a full
WOT 1/4 mile pull; I can peg my 1600* pyro.
I drilled the wastegate out to about 15/16 if I recall correctly (it was is big as I could go with leaving about 1/16" contact surface around the puck. I am running a custom undivided log manifold with the dump between #2 and #3. I recently tightened up my gate (before collecting the above data) because she was smoky and like a dog until 20psi of Boost. My springgate is now set to start opening around 30psi (the only way I have been able to guesstimate this is by listening for "wastegate flutter).
So to me it seems like I should try to get my drive pressures lower? I could go external gate around the WH1C but I will probably try relieving the downpipe flange a little first to make more clearance for the wastegate to swing open.
The problem is that it also seems like I should be driving my secondary harder? My calculations show what I believe is a HIGH 4.61 PR from the primary and a measly 1.6 PR from the secondary. With the high drive pressures I'm seeing, I would expect that secondary to be using up more of the exhaust energy, not leaving much for the primary.
Thoughts?