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Old 16-07-2017, 08:16 AM
jondee86 jondee86 is offline
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Join Date: Dec 2015
Location: New Zealand
Posts: 78
Smile Re: Nozzle spray angle...

Small update. Progress has been slow due to numerous small issues that had
to be resolved, and the onset of winter here in NZ. I am investigating why the
s/c is only making 5.16psi @ 7430rpm at the moment, when it should be
making closer to 8.4psi @ 7600rpm.

This engine was sold as N.A. with 10.3:1 compression, and as s/c with 8.9:1
compression. The same camshafts and cam timing were used in both versions.
So I am thinking that maybe there is a little too much overlap for s/c use and
I have retarded the intake cam by 4 deg. This will be tested later in the week
and logged to see if it has any affect on boost.

EDIT: Tested and no apparent change before hitting the limiter.
Bouncing off the limiter did produce another 7kPa and push the IDC up 8% to
80%, but I exclude those values as not representative of a steady pull to
redline.

The other possibility is that the N.A. factory intake/air filter setup has higher
pressure drop now that it is handling greater flow. I am waiting on a new filter
to construct a "free-flowing" intake. This will also be tested once on the car.

And last, when I lifted at 7430rpm the IAT with water only was 54 deg on a
day when the ambient temp would have been no more than 14-15 deg. So if
meth can drop the temp closer to ambient there should be some improvement.

I'd like to get the experimentation over before going to a smaller pulley.

Cheers... jondee86

Last edited by jondee86; 19-07-2017 at 07:28 AM. Reason: Added results of test...
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