That dyno curve is from a Mazda SAE 841017 technical paper published
in 1984. The old is the non dynamic chamber version pre about
1985-1986. Note the lack of the torque peak at 2000 to 3000 RPM in the old
140 HP chart. The dynamic chamber was developed and used post 1986
to enhance the torque at 2000 to 3000 at the expense of peak power.
The 160 HP engine shows that torque hump at 2000 to 4000 RPM.
You are using the stock dynamic chamber and EFI so your engine is 160 HP
at 6500 RPM or so. BTW took me a long time to convince Ed of this fact:)
Paul Lamar
I agree with Paul, if you are using the stock 1988 intake manifold with a
port-port length of approx 47.5" and you also have stock intake port timing,
then 160 HP is what I would expect at 6000 rpm as the HP curve shows. With
the Dynamic Intake Effect (DIE) occuring in the mid 3000 rpm range. Based
on information in the same SAE paper, that Paul sent me a copy of, analysis
shows that changing the intake port timing should have a significant impact
on the RPM at which the Dynamic Intake Effect occurs for a given manifold
length.
Ed Anderson
What Ed is referring too is the opening and closing of the six port valve.
I am assuming you removed that Perry. A part of that valve is what broke
loose, was ingested and destroyed Chuck's engine.
Paul Lamar
Yes, that is scary. I had those inserts in place, with little brackets
locking them open. But that
was during the first 165 hours I think. I removed them completely after
the engine was rebuilt.
And of course they are not there now with the new intake manifold.
Actually, the dynamic chamber was replaced with just a plenum box on my
new intake, but
the [peak] power developed is the same.
--
Perry Mick
Custom Composite Props
mick@bridgingworlds.com
http://www.ductedfan.com
As it should be. That was the gist of my long discussion with Ed on the subject :)
Paul Lamar
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