I
apologize for lack of clarity, causing you to have to re-invent this theory.
Al
(Also running TWM TB)
That's now the old theory
Al. The latest theory is that you and I are just kidding ourselves, and
the restriction is real. I just wish people like Bill and Bernie would
have the decency to lie to me about their readings :-)
Our intake designs are different; so
perhaps the concerns are as well. I have very short runners downstream
from the TB, so the MAP reading is very close to what is seen at the ports. It
would be interesting to know what the MAP reading is near the intake port in a
setup like Tracy’s. Whether the MAP reading at
the TWM ports is accurate or not, I don’t know. My 44mm diameter
barrels (1 per rotor) may be a bit smaller than I’d like; but I don’t
think they are causing a significant performance penalty. The MAP reading
is, of course, not the full measure of the charge into the chamber. There
are the pulses and momentum (velocity) to consider.
It might be good to have the TB barrel
x-section area roughly matched to the port area. I can’t find my calcs
now, but I think the combined primary and secondary ports on my engine is over
3 sq. in., like maybe 3.5; and the TB barrel is 2.34 sq. in. So maybe a
20% larger diameter would give better high end performance, at some expense to
throttle response.
I am anxiously awaiting your definitive data
on performance vs TB barrel diameter. J
Al