Barry Gardner wrote:

Paul, let me ask a dumb question. I understand the reasons for controlling intake
manifold length and exhaust pipe length for naturally aspirated Mazdas. However,
if one has a turbo, aren't these both moot? After all, the intake side no longer
depends on sucking in the mixture but relies on the positive turbo pressure
instead. And on the exhaust side, the turbo gets in the way of improved
scavenging of the exhaust, making the exhaust pipe length immaterial.

Russell Kent wrote:

It is unclear to me whether tuned exhaust pipes downstream of the turbo is even
possible (what would one be tuning for?).  Tuned exhaust pipes upstream of the
turbo would seem to be deleterious to the turbo, in that it would promote surging.
Tuned intake upstream of the turbo, like the tuned exhaust downstream, does not
seem possible.

That leaves the intake downstream of the turbo.  In that case, it seems that the
pumping action from the intake port opening and closing would still exist.  I think
that section of intake pipe should be analyzed for the proper length.  Make it
exactly wrong, and the turbo has to fight the pumping action; make it exactly
correct and the turbo gets the benefit.

Regards,
Russell Kent

The AirCraft Rotary Engine NewsLetter.              Powered by Linux.

http://home.earthlink.net/~rotaryeng/            http://www.linux.org