Bob White wrote:

Hi,

I have just joined the list.  In January, I will be picking up a BD-4
that I purchased without an engine.  My plan is to put a Mazda 13B in
it.  I would like some opinions on turbo-charging vs supercharging
this
engine.  Advantages and dis-advantages of each.

Turbos are more efficient, quieter, more durable.  Supercharging
simplifies the exhaust manifold plumbing and is likely lighter.
Proven (for automotive use) turbo manifolds are cast iron, inexpensive
and heavy.  Of course with enough money and time you could make a
lightweight one that would last.

I think that turbo is the answer, it is just a good fit for the wankel
with its high heat exhaust; with a turbo you recover some of that
energy that is otherwise wasted.

Both will require overboost control, fuel injection and intake air
cooling for most efficiency and durability.

Don't forget the more power you make the more cooling capacity you
need.

If noise is a concern for your installation, some of the weight gain
of the turbo manifold can be made up with simpler exhaust muffling
because the turbine wheel of the turbo spinning around in the exhaust
does a good job of breaking up of the noise impulses.

Wankels have a sound profile that is more irritating to most ears.
That is until you drive/fly one long enough, then everything else
sounds irritating.

People refer to my relatively open exhaust RX-7 as the "angry bee"


Hans

 
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