Al Gietzen wrote:

According to David Atkins; dyno tests done by Mazda engineers years back
showed his short (4") manifold had only 1 to 2% less power than Mazda's
tuned manifold.  I'm going for the 'packaging' advantage.  When (if) we

get

it done, I'll post a picture.

Did I mention that patience is not my strongest attribute?

Al

That data is pure BS. I have lots of that kind of data in various SAE

papers

published by Mazda and there is a very good reason that all late Mazda

manifolds

have long runners. I saw your manifold or one that looked like it at

Arlington

and I was not impressed. Here is a picture. I think Paul Yaw will agree

that

this manifold is not what you need for good power at 6000 RPM.

Actually I have talked to Paul Yaw, and he thought the short manifold could
be very little different than the "so-called" tuned version because it
BREATHES.  We'll see what the dyno says.

That was before Paul actually saw the 13B version. I have his email response and I
will look
it up later. Paul Lamar

The manifold you pictured is like the one I rejected; except the one they
made for me had the runners welded to the wrong side of the flange, giving a
mirror image of the correct port layout.  We're making one with tubular
runners.

Al

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