Subject: [Fot] Weber vs Mikuni

From: Mike Harmuth via Fot <[email-masked]>
Date: Wed, 17 Oct 2018 09:49:45 -0400

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I'm looking into switching out my twin HS4s on the 1296 race engine to
either Weber or Mukinis. I know this has been done for years and I'd like
to get close the best set up out of the gate.

I don't think the SUs are up to the task of moving enough air with the new
ported head and Stahl header. I've worked on the SUs and gotten them to
finally deliver a good AFR , 12.6, at 6500 RPM under load but I seem to hit
a wall (figuratively) at that point. I suspect that the openings just
aren't big enough to deliver the mass of air required. (spreadsheet or
other flow calculator link appreciated)
Biggest gate I suspect is the intake valve, 1 3/8" head (~35mm) HS4 is
~38mm at best.

Recommendations? I've seen all these setups at the track, each with pluses,
minuses and overkill cause it looks cool.

One weber DCOE 40 or 2? what jets, tubes etc for a starting point? Best
manifold?

2 or 4 Mikuni 40? jet size?

thanks
mike

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<div dir=3D"ltr"><div>I&#39;m looking into switching out my twin HS4s on th=
e 1296 race engine to either Weber or Mukinis. I know this has been done fo=
r years and I&#39;d like to get close the best set up out of the gate. <br>=
</div><div><br></div><div>I don&#39;t think the SUs are up to the task of m=
oving enough air with the new ported head and Stahl header. I&#39;ve worked=
 on the SUs and gotten them to finally deliver a good AFR , 12.6, at 6500 R=
PM under load but I seem to hit a wall (figuratively) at that point. I susp=
ect that the openings just aren&#39;t big enough to deliver the mass of air=
 required. (spreadsheet or other flow calculator link appreciated)<br></div=
><div>Biggest gate I suspect is the intake valve, 1 3/8&quot; head (~35mm) =
HS4 is ~38mm at best.<br></div><div><br></div><div>Recommendations? I&#39;v=
e seen all these setups at the track, each with pluses, minuses and overkil=
l cause it looks cool. <br></div><div><br></div><div>One weber DCOE 40 or 2=
? what jets, tubes etc for a starting point? Best manifold? <br></div><div>=
<br></div><div>2 or 4 Mikuni 40? jet size?</div><div><br></div><div>thanks<=
/div><div>mike<br></div></div>

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