--===============7668830603560079374==
--000000000000848bfc05789dffc8
Thanks for all the great input. I think I'll stay with the SU's for now and
spend the money on Dyno time to see where the issue may be.
mike h
On Fri, Oct 19, 2018 at 7:13 PM fubog1 via Fot <fot@autox.team.net> wrote:
> These are some words of wisdom...
> Glen
> ps- I've found different size holes in the float valves, also grose jets
> are particularly restrictive.
>
> The SU's are so simple minded and easy to work with I'd want to very
> certain that the was a BIG benifit before changing to jetted carbs that
> need a ton of parts of you are going to make use of the capacity of the
> units.
>
>
>
>
> -----Original Message-----
> From: Kas Kastner <kaskastner@gmail.com>
> To: fubog1 <fubog1@aol.com>
> Cc: Van Mulders Marcel <van.mulders.marcel@telenet.be>; FOT <
> fot@autox.team.net>
> Sent: Fri, Oct 19, 2018 12:32 pm
> Subject: Re: [Fot] Weber vs Mikuni
>
> Lots of times at the higher revs the float bowls of the S.U.'s just run
> out of gas and they need an enlargment of the needle and seat.Many times
> the stock needle and seat j ust does not have enough capacity to flow the
> fuel needed for the much richer needles used and the revvs. The SU's are so
> simple minded and easy to work with I'd want to very certain that the was a
> BIG benifit before changing to jetted carbs that need a ton of parts of you
> are going to make use of the capacity of the units.
>
> If you do not tune for the day and the weather at that time what is the
> point in having all that adustment. With the SU a couple flats adjustment
> up or down and you are done the hour. Bigger machinery does not mean bigger
> power or even more useful power.
>
> BUT, if you are going for the expensive route, get the msot you can get.
> DCOE 45's are the ticket. Start with a small venturi and work up from
> there. Yes, you neeed to buy alterate venturies otherwise you have just
> wasted your money.These same carbs were used on the Sebring and Le Mans
> Spitfire coupes 1147 cc engines and proved 3% more power by tuning. To get
> the benifit you need to work at it.
> *Never be beaten by equipment.*
>
>
> On Fri, Oct 19, 2018 at 9:01 AM fubog1 via Fot <fot@autox.team.net> wrote:
>
> Yes HS4 carbs.
> Glen
>
>
> -----Original Message-----
> From: van.mulders.marcel <van.mulders.marcel@telenet.be>
> To: fubog1 <fubog1@aol.com>
> Cc: fot <fot@autox.team.net>
> Sent: Thu, Oct 18, 2018 5:48 pm
> Subject: Re: [Fot] Weber vs Mikuni
>
> Glen,
> With 1 1/2s carburettors, I suppose you mean HS4? The SU logic is a little
> weird. 1" + 1/2" = 6/8" so you would think it are HS6s, but when talking
> about HS carburettors, 1 + 1/2 = 1 + 4/8 and they took the 4 to name these
> carbs HS4...
> Marcel
>
> ------------------------------
> *Van: *"fubog1" <fubog1@aol.com>
> *Aan: *"van mulders marcel" <van.mulders.marcel@telenet.be>, "Mike
> Harmuth" <ofracer@gmail.com>
> *Cc: *"fot" <fot@autox.team.net>
> *Verzonden: *Donderdag 18 oktober 2018 22:39:39
> *Onderwerp: *Re: [Fot] Weber vs Mikuni
>
> Well I won't speculate on the cause, but I doubt that it's the SUs.
> My small crank 1300 w/1 1/2s on a eurospec manifold w/Stahls header, "big"
> valve head, would buzz easily to 9k, still making power, if I let it.
> Normal shift point 7800-8000.
> FWIW...
> Glen
>
>
> -----Original Message-----
> From: van.mulders.marcel--- via Fot <fot@autox.team.net>
> To: Mike Harmuth <ofracer@gmail.com>
> Cc: fot <fot@autox.team.net>
> Sent: Thu, Oct 18, 2018 2:12 pm
> Subject: Re: [Fot] Weber vs Mikuni
>
> -"...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
>
> _______________________________________________
> fot@autox.team.net
>
> http://www.fot-racing.com
>
> Donate: http://www.team.net/donate.html
> Archive: http://www.team.net/pipermail/fot
> Unsubscribe/Manage:
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> _______________________________________________
> fot@autox.team.net
>
> http://www.fot-racing.com
>
> Donate: http://www.team.net/donate.html
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>
>
> _______________________________________________
> fot@autox.team.net
>
> http://www.fot-racing.com
>
> Donate: http://www.team.net/donate.html
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>
>
> _______________________________________________
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>
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>
> Donate: http://www.team.net/donate.html
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>
>
--000000000000848bfc05789dffc8
Content-Transfer-Encoding: quoted-printable
<div dir=3D"ltr"><div>Thanks for all the great input. I think I'll stay=
with the SU's for now and spend the money on Dyno time to see where th=
e issue may be.</div><div><br></div><div>mike h<br></div></div><br><div cla=
ss=3D"gmail_quote"><div dir=3D"ltr">On Fri, Oct 19, 2018 at 7:13 PM fubog1 =
via Fot <<a href=3D"mailto:fot@autox.team.net";>fot@autox.team.net</a>>=
; wrote:<br></div><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .=
8ex;border-left:1px #ccc solid;padding-left:1ex"><font color=3D"black" size=
=3D"2" face=3D"Arial, Helvetica, sans-serif">
<div> <font size=3D"2">These are some words of wisdom...</font></div>
<div><font size=3D"2">Glen</font></div>
<div><font size=3D"2">ps- I've found different size holes in the float =
valves, also grose jets are particularly restrictive.</font><br>
</div>
<div style=3D"font-family:arial,helvetica;font-size:10pt;color:black"><bloc=
kquote style=3D"border-left:2px solid blue;padding-left:3px">The SU's a=
re so simple minded and easy to work with I'd want to very certain that=
the was a BIG benifit before changing to jetted carbs that need a ton of p=
arts of you are going to make use of the capacity of the units.
<div></div>
</blockquote></div>
<div> <br>
</div>
<div> <br>
</div>
<div> <br>
</div>
<div style=3D"font-family:arial,helvetica;font-size:10pt;color:black">-----=
Original Message-----<br>
From: Kas Kastner <<a href=3D"mailto:kaskastner@gmail.com"; target=3D"_bl=
ank">kaskastner@gmail.com</a>><br>
To: fubog1 <<a href=3D"mailto:fubog1@aol.com"; target=3D"_blank">fubog1@a=
ol.com</a>><br>
Cc: Van Mulders Marcel <<a href=3D"mailto:van.mulders.marcel@telenet.be"=
target=3D"_blank">van.mulders.marcel@telenet.be</a>>; FOT <<a href=
=3D"mailto:fot@autox.team.net"; target=3D"_blank">fot@autox.team.net</a>>=
<br>
Sent: Fri, Oct 19, 2018 12:32 pm<br>
Subject: Re: [Fot] Weber vs Mikuni<br>
<br>
<div id=3D"m_-245757380513494367yiv6253483699">
<div>
<div dir=3D"ltr">Lots of times at the higher revs the float bowls of the S.=
U.'s just run out of gas and they need an enlargment of the needle and =
seat.Many times the stock needle and seat j ust does not have enough capaci=
ty to flow the fuel needed for the much richer needles used and the revvs. =
The SU's are so simple minded and easy to work with I'd want to ver=
y certain that the was a BIG benifit before changing to jetted carbs that n=
eed a ton of parts of you are going to make use of the capacity of the unit=
s.
<div><br clear=3D"none"></div>
<div>=C2=A0If you do not tune for the day and the weather at that time what=
is the point in having all that adustment. With the SU a couple flats adju=
stment up or down and you are done the hour. Bigger machinery does not mean=
bigger power or even more useful power.
<div><br clear=3D"none"></div>
<div>BUT, if you are going for the expensive route, get the msot you can ge=
t.=C2=A0 DCOE 45's are the ticket. Start with a small venturi and work =
up from there. Yes, you neeed to buy=C2=A0 alterate venturies otherwise you=
have just wasted your money.These same carbs were used on the Sebring and =
Le Mans Spitfire coupes 1147 cc engines=C2=A0 and proved 3% more power by t=
uning. To get the benifit you need to work at it.<br clear=3D"all">
<div>
<div class=3D"m_-245757380513494367yiv6253483699gmail_signature" dir=3D"ltr=
">
<div><strong><font color=3D"#000099">Never be beaten by equipment.</font></=
strong></div>
</div>
</div>
<br clear=3D"none"></div>
</div>
</div>
<br clear=3D"none">
<div class=3D"m_-245757380513494367yiv6253483699gmail_quote">
<div class=3D"m_-245757380513494367yiv6253483699yqt4822778474" id=3D"m_-245=
757380513494367yiv6253483699yqtfd10159">
<div dir=3D"ltr">On Fri, Oct 19, 2018 at 9:01 AM fubog1 via Fot <<a rel=
=3D"noopener noreferrer" shape=3D"rect">fot@autox.team.net</a>> wrote:<b=
r clear=3D"none"></div>
</div>
<blockquote class=3D"m_-245757380513494367yiv6253483699gmail_quote" style=
=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div class=3D"m_-245757380513494367yiv6253483699yqt4822778474" id=3D"m_-245=
757380513494367yiv6253483699yqtfd33561"><font size=3D"2" face=3D"Arial, Hel=
vetica, sans-serif" color=3D"black">
</font>
<div> <font size=3D"2">Yes HS4 carbs.</font></div>
<div><font size=3D"2">Glen</font><br clear=3D"none">
</div>
<div> <br clear=3D"none">
</div>
<div> <br clear=3D"none">
</div>
<div style=3D"font-family:arial,helvetica;font-size:10pt;color:black">-----=
Original Message-----<br clear=3D"none">
From: van.mulders.marcel <<a rel=3D"noopener noreferrer" shape=3D"rect">=
van.mulders.marcel@telenet.be</a>><br clear=3D"none">
To: fubog1 <<a rel=3D"noopener noreferrer" shape=3D"rect">fubog1@aol.com=
</a>><br clear=3D"none">
Cc: fot <<a rel=3D"noopener noreferrer" shape=3D"rect">fot@autox.team.ne=
t</a>><br clear=3D"none">
Sent: Thu, Oct 18, 2018 5:48 pm<br clear=3D"none">
Subject: Re: [Fot] Weber vs Mikuni<br clear=3D"none">
<br clear=3D"none">
<div id=3D"m_-245757380513494367yiv6253483699m_-3204379643218842764yiv75571=
79423">
<div>
<div style=3D"font-family:Verdana,Arial,Helvetica,sans-serif;font-size:10pt=
;color:#000000">
<div>Glen,</div>
<div>With 1 1/2s carburettors, I suppose you mean HS4? The SU logic is a li=
ttle weird. 1" + 1/2" =3D 6/8" so you would think it are HS6=
s, but when talking about HS carburettors, 1 + 1/2 =3D 1 + 4/8 and they too=
k the 4 to name these carbs HS4...</div>
<div>Marcel</div>
<div><br clear=3D"none"></div>
<hr id=3D"m_-245757380513494367yiv6253483699m_-3204379643218842764yiv755717=
9423zwchr">
<div class=3D"m_-245757380513494367yiv6253483699m_-3204379643218842764yiv75=
57179423yqt0596148954" id=3D"m_-245757380513494367yiv6253483699m_-320437964=
3218842764yiv7557179423yqt61649">
<div><b>Van: </b>"fubog1" <<a rel=3D"noopener noreferrer" shap=
e=3D"rect">fubog1@aol.com</a>><br clear=3D"none"><b>Aan: </b>"van m=
ulders marcel" <<a rel=3D"noopener noreferrer" shape=3D"rect">van.m=
ulders.marcel@telenet.be</a>>, "Mike Harmuth" <<a rel=3D"no=
opener noreferrer" shape=3D"rect">ofracer@gmail.com</a>><br clear=3D"non=
e"><b>Cc: </b>"fot" <<a rel=3D"noopener noreferrer" shape=3D"r=
ect">fot@autox.team.net</a>><br clear=3D"none"><b>Verzonden: </b>Donderd=
ag 18 oktober 2018 22:39:39<br clear=3D"none"><b>Onderwerp: </b>Re: [Fot] W=
eber vs Mikuni<br clear=3D"none"></div>
<br clear=3D"none">
<div><span style=3D"color:black;font-family:Arial,Helvetica,sans-serif;font=
-size:small">
</span>
<div> <span style=3D"font-size:small">Well I won't speculate on the cau=
se, but I doubt that it's the SUs.<br clear=3D"none">
</span></div>
<div><span style=3D"font-size:small">My small crank 1300 w/1 1/2s on a euro=
spec manifold w/Stahls header, "big" valve head, would buzz easil=
y to 9k, still making power, if I let it.</span></div>
<div><span style=3D"font-size:small">Normal shift point 7800-8000.</span></=
div>
<div><span style=3D"font-size:small">FWIW...<br clear=3D"none">
</span></div>
<div><span style=3D"font-size:small">Glen</span><br clear=3D"none">
</div>
<div> <br clear=3D"none">
</div>
<div> <br clear=3D"none">
</div>
<div style=3D"font-family:arial,helvetica;font-size:10pt;color:black">-----=
Original Message-----<br clear=3D"none">
From: van.mulders.marcel--- via Fot <<a rel=3D"noopener noreferrer" shap=
e=3D"rect">fot@autox.team.net</a>><br clear=3D"none">
To: Mike Harmuth <<a rel=3D"noopener noreferrer" shape=3D"rect">ofracer@=
gmail.com</a>><br clear=3D"none">
Cc: fot <<a rel=3D"noopener noreferrer" shape=3D"rect">fot@autox.team.ne=
t</a>><br clear=3D"none">
Sent: Thu, Oct 18, 2018 2:12 pm<br clear=3D"none">
Subject: Re: [Fot] Weber vs Mikuni<br clear=3D"none">
<br clear=3D"none">
<div id=3D"m_-245757380513494367yiv6253483699m_-3204379643218842764yiv75571=
79423">
<div>
<div style=3D"font-family:Verdana,Arial,Helvetica,sans-serif;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 carb=
urettors, maybe the power would decrease more gradually above 6500 rpm.</di=
v>
<div>-In general one choke per cylinder is better, and 2 Webers 40 DCOE isn=
't overkill I think</div>
<div>- what about trying HS6 SU's on your actual manifold?</div>
<div>At what maximum rpm is your engine still reliable?</div>
<div>Marcel</div>
<div><br clear=3D"none"></div>
<hr id=3D"m_-245757380513494367yiv6253483699m_-3204379643218842764yiv755717=
9423zwchr">
<div class=3D"m_-245757380513494367yiv6253483699m_-3204379643218842764yiv75=
57179423yqt0105059393" id=3D"m_-245757380513494367yiv6253483699m_-320437964=
3218842764yiv7557179423yqt73080">
<div><b>Van: </b>"fot" <<a rel=3D"noopener noreferrer" shape=
=3D"rect">fot@autox.team.net</a>><br clear=3D"none"><b>Aan: </b>"fo=
t" <<a rel=3D"noopener noreferrer" shape=3D"rect">fot@autox.team.ne=
t</a>><br clear=3D"none"><b>Verzonden: </b>Woensdag 17 oktober 2018 15:4=
9:45<br clear=3D"none"><b>Onderwerp: </b>[Fot] Weber vs Mikuni<br clear=3D"=
none"></div>
<br clear=3D"none">
<div>
<div dir=3D"ltr">
<div>I'm looking into switching out my twin HS4s on the 1296 race engin=
e 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. <br clear=3D"none"></=
div>
<br clear=3D"none">
<div>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 gotte=
n them to finally deliver a good AFR , 12.6, at 6500 RPM under load but I s=
eem 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. (spreadshe=
et or other flow calculator link appreciated)<br clear=3D"none"></div>
<div>Biggest gate I suspect is the intake valve, 1 3/8" head (~35mm) H=
S4 is ~38mm at best.<br clear=3D"none"></div>
<br clear=3D"none">
<div>Recommendations? I've seen all these setups at the track, each wit=
h pluses, minuses and overkill cause it looks cool. <br clear=3D"none"></di=
v>
<br clear=3D"none">
<div>One weber DCOE 40 or 2? what jets, tubes etc for a starting point? Bes=
t manifold? <br clear=3D"none"></div>
<br clear=3D"none">
<div>2 or 4 Mikuni 40? jet size?</div>
<br clear=3D"none">
<div>thanks</div>
<div>mike<br clear=3D"none"></div>
</div>
<br clear=3D"none">_______________________________________________<br clear=
=3D"none"><a rel=3D"noopener noreferrer" shape=3D"rect">fot@autox.team.net<=
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57179423yqt0105059393" id=3D"m_-245757380513494367yiv6253483699m_-320437964=
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</blockquote></div>
</div>
</div>
</div>
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/mailman/options/fot/ofracer@gmail.com</a><br>
<br>
<br>
</blockquote></div>
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