The stock cast iron manifold would be suspect at a 100% duty cycle. It
would be unusual to operate a street turbo car at full throttle for more than a
few seconds. Cast iron does not perform well when over heated and stressed at
the same time. It is easy to cast, and the cheapest material that will work in a
car engine.
A small blast tube directed at the header tubes works wonders to make non
turbo headers last to TBO.
Once quit using .125" wall SAE 1010 tubing my normally aspirated
racer, and went to .135 Wall SAE 1010 tubing, I had no more header
problems. Even the thinner wall on the outside of bends holds up. The same wall
or thicker in stainless would be fine, it seems to me. Easy to make from
Handrail pieces. The turbo must be braced to the engine
in every case, to lower stress on the headers and turbo parts.
Lean mixtures are easy on the pieces in piston engines. Lower EGT, lower
head temps, fewer exhaust valve heads falling off, Longer TBO and much lower
fuel flows. Used on every round engine to cross the Atlantic. In the rotary the
same things, however, less fuel flow means less seal lubricant if you
premix.
A real ignition system will light a far leaner mixture than a Kettering
system. A Mallory High Fire or MSD6AL
or similar, at least on the leading plugs. So any fuel setting will run
smoother.
You can run rich at 1600 degrees or a bit less at take off and climb, then
switch to lean to 1600 degrees at cruise, same as piston engines. Piston engine
use the excess fuel for cooling and detonation protection at low altitudes. Both
over lean, and over rich mixtures burn more slowly, and the richer mixture
limits available oxygen, and cools the chamber.
Detonation is charge temperature dependant.
Over lean mixtures can stand more ignition advance than ideal (Best power)
mixtures, so leaning also reduces ignition adjustment requirements. Moving
ignition timing is done to keep highest cylinder pressure at about 50
degrees after top dead center (ATDC). Adding boost increases effective
compression ratio, and moves the highest cylinder pressure point around. More
boost, higher pressure, faster burn rate, Higher pressure closer to TDC, lower
pressure further from TDC.
So the ideal advance will be different on each day.
You might tune the B controller for cruise, and the A controller for take
off and climb.
Lynn E. Hanover