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Re: [Fot] Weber vs Mikuni

To: Mike Harmuth <ofracer@gmail.com>
Subject: Re: [Fot] Weber vs Mikuni
From: "van.mulders.marcel--- via Fot" <fot@autox.team.net>
Date: Thu, 18 Oct 2018 08:49:35 +0200 (CEST)
Cc: fot <fot@autox.team.net>
Delivered-to: mharc@autox.team.net
Delivered-to: fot@autox.team.net
References: <CAO0FjVYfGvEsvs5F_EyKQ921wCN+x0Z7+Y4=GGV8OATiQY+GfA@mail.gmail.com>
Thread-index: GoTmMKXuczj6VYEwD6VQTec/+H9GNQ==
Thread-topic: Weber vs Mikuni
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-"...hitting a wall at that point..." : is it possible this is rather pointing 
to the camshaft than to the SU's? If it are the carburettors, maybe the power 
would decrease more gradually above 6500 rpm. 
-In general one choke per cylinder is better, and 2 Webers 40 DCOE isn't 
overkill I think 
- what about trying HS6 SU's on your actual manifold? 
At what maximum rpm is your engine still reliable? 
Marcel 


Van: "fot" <fot@autox.team.net> 
Aan: "fot" <fot@autox.team.net> 
Verzonden: Woensdag 17 oktober 2018 15:49:45 
Onderwerp: [Fot] Weber vs Mikuni 

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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<html><body><div style=3D"font-family: Verdana, Arial, Helvetica, sans-seri=
f; font-size: 10pt; color: #000000"><div>-"...hitting a wall at that point.=
.." : is it possible this is rather pointing to the camshaft than to the SU=
's? If it are the carburettors, maybe the power would decrease more gradual=
ly above 6500 rpm.</div><div>-In general one choke per cylinder is better, =
and 2 Webers 40 DCOE isn't overkill I think</div><div>- what about trying H=
S6 SU's on your actual manifold?</div><div>At what maximum rpm is your engi=
ne still reliable?</div><div>Marcel</div><div><br></div><hr id=3D"zwchr" da=
ta-marker=3D"__DIVIDER__"><div data-marker=3D"__HEADERS__"><b>Van: </b>"fot=
" &lt;fot@autox.team.net&gt;<br><b>Aan: </b>"fot" &lt;fot@autox.team.net&gt=
;<br><b>Verzonden: </b>Woensdag 17 oktober 2018 15:49:45<br><b>Onderwerp: <=
/b>[Fot] Weber vs Mikuni<br></div><br><div data-marker=3D"__QUOTED_TEXT__">=
<div dir=3D"ltr"><div>I'm looking into switching out my twin HS4s on the 12=
96 race engine to either Weber or Mukinis. I know this has been done for ye=
ars and I'd like to get close the best set up out of the gate. <br></div><b=
r><div>I don't think the SUs are up to the task of moving enough air with t=
he 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 othe=
r flow calculator link appreciated)<br></div><div>Biggest gate I suspect is=
 the intake valve, 1 3/8" head (~35mm) HS4 is ~38mm at best.<br></div><br><=
div>Recommendations? I've seen all these setups at the track, each with plu=
ses, minuses and overkill cause it looks cool. <br></div><br><div>One weber=
 DCOE 40 or 2? what jets, tubes etc for a starting point? Best manifold? <b=
r></div><br><div>2 or 4 Mikuni 40? jet size?</div><br><div>thanks</div><div=
>mike<br></div></div>
<br>_______________________________________________<br>fot@autox.team.net<b=
r><br>http://www.fot-racing.com<br><br>Donate: http://www.team.net/donate.h=
tml<br>Archive: http://www.team.net/pipermail/fot<br>Unsubscribe/Manage: ht=
tp://autox.team.net/mailman/options/fot/van.mulders.marcel@telenet.be<br></=
div></div></body></html>
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