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gee, I missed the best part in my post, they were modded HS2's, yes the sm=
all carbs
On =E2=80=8EFriday=E2=80=8E, =E2=80=8EOctober=E2=80=8E =E2=80=8E19=E2=
=80=8E, =E2=80=8E2018=E2=80=8E =E2=80=8E07=E2=80=8E:=E2=80=8E17=E2=80=8E:=
=E2=80=8E27=E2=80=8E =E2=80=8EAM=E2=80=8E =E2=80=8ECDT, Rick Parent <rick.p=
arent@att.net> wrote: =20
=20
What Ralph said............
I have some experience with carbs on Spifires so I will share about 2 cents=
(meaning minimal, I could probably write a book) worth if you don't mind.=
=C2=A0Dual Webers look really cool but will move you up a class or in SVRA =
to the next group, my Dyno says don't do it, it's not worth it. Makuni's? f=
orget it, price and parts are a problem, everyone at the track has Weber pa=
rts on their trailer. 1 1/2 SU's will do 9000rpm on a 1296 I know for sure =
but they are a pain to straighten out the fuel curve throughout the RPM ran=
ge, don't try this one at home boys and girls, you will end up throwing the=
m through the window. The easiest thing to do is purchase a single Weber ma=
nifold and 45 DCOE, a 40 would work as well and maybe better depending on y=
our state of tune. I have a box full of manifolds, 2 are actually within 2h=
p of the dual Webers on the top with way more bottom and mid range one I fa=
bricated and the other was purchased but only runs to 7000rpm. I would be g=
lad to help with jetting when the time comes.
All the best!=20
On Friday, October 19, 2018 4:53 AM, ralph hansen via Fot <fot@autox.te=
am.net> wrote:
=20
gee, my 1147 with HS's puled all the way to 8k with a 4:11 gear - stock b=
ore block, head work, A6 cam - its not the carbs, its either timing or cam
On =E2=80=8EThursday=E2=80=8E, =E2=80=8EOctober=E2=80=8E =E2=80=8E18=E2=
=80=8E, =E2=80=8E2018=E2=80=8E =E2=80=8E01=E2=80=8E:=E2=80=8E13=E2=80=8E:=
=E2=80=8E48=E2=80=8E =E2=80=8EPM=E2=80=8E =E2=80=8ECDT, van.mulders.marcel-=
-- via Fot <fot@autox.team.net> wrote: =20
=20
-"...hitting a wall at that point..." : is it possible this is rather poin=
ting to the camshaft than to the SU's? If it are the carburettors, maybe th=
e 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 a=
bout trying HS6 SU's on your actual manifold?At what maximum rpm is your en=
gine 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 eith=
er Weber or Mukinis. I know this has been done for years and I'd like to ge=
t close the best set up out of the gate.=20
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 fin=
ally 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 ~38m=
m at best.
Recommendations? I've seen all these setups at the track, each with pluses,=
minuses and overkill cause it looks cool.=20
One weber DCOE 40 or 2? what jets, tubes etc for a starting point? Best man=
ifold?=20
2 or 4 Mikuni 40? jet size?
thanksmike
_______________________________________________
fot@autox.team.net
http://www.fot-racing.com
Archive: http://www.team.net/pipermail/fot
arcel@telenet.be
_______________________________________________
fot@autox.team.net
http://www.fot-racing.com
Archive: http://www.team.net/pipermail/fot
com
_______________________________________________
fot@autox.team.net
http://www.fot-racing.com
Archive: http://www.team.net/pipermail/fot
tt.net
=20
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<html><head></head><body><div class=3D"ydp31a22074yahoo-style-wrap" style=
=3D"font-family: Helvetica Neue,Helvetica,Arial,sans-serif; font-size: 13px=
;"></div><div class=3D"ydp31a22074yahoo-style-wrap" style=3D"font-family: H=
elvetica Neue,Helvetica,Arial,sans-serif; font-size: 13px;">
</div><div class=3D"ydp31a22074yahoo-style-wrap" style=3D"font-fami=
ly: Helvetica Neue,Helvetica,Arial,sans-serif; font-size: 13px;">gee, I mis=
sed the best part in my post, they were modded HS2's, yes the small carbs</=
div><div class=3D"ydp31a22074yahoo-style-wrap" style=3D"font-family: Helvet=
ica Neue,Helvetica,Arial,sans-serif; font-size: 13px;"><br></div><div class=
=3D"ydp31a22074yahoo-style-wrap" style=3D"font-family: Helvetica Neue,Helve=
tica,Arial,sans-serif; font-size: 13px;"><br></div><div class=3D"ydp31a2207=
4yahoo-style-wrap" style=3D"font-family: Helvetica Neue,Helvetica,Arial,san=
s-serif; font-size: 13px;">
=20
</div><div class=3D"ydp3d2ead4cyahoo_quoted" id=3D"ydp3d2ead4cyahoo=
_quoted_0220153929">
<div style=3D"font-family:'Helvetica Neue', Helvetica, Arial, s=
ans-serif;font-size:13px;color:#26282a;">
=20
<div>
On =E2=80=8EFriday=E2=80=8E, =E2=80=8EOctober=E2=80=8E =
=E2=80=8E19=E2=80=8E, =E2=80=8E2018=E2=80=8E =E2=80=8E07=E2=80=8E:=E2=80=8E=
17=E2=80=8E:=E2=80=8E27=E2=80=8E =E2=80=8EAM=E2=80=8E =E2=80=8ECDT, Rick Pa=
rent <rick.parent@att.net> wrote:
</div>
<div><br></div>
<div><br></div>
<div><div id=3D"ydp3d2ead4cyiv3809709404"><div><div style=
=3D"color:#000;background-color:#fff;font-family:Helvetica Neue, Helvetica,=
Arial, Lucida Grande, sans-serif;font-size:16px;"><div id=3D"ydp3d2ead4cyi=
v3809709404yui_3_16_0_ym19_1_1539949984130_7456"><span id=3D"ydp3d2ead4cyiv=
3809709404yui_3_16_0_ym19_1_1539949984130_9159">What Ralph said............=
</span></div><div id=3D"ydp3d2ead4cyiv3809709404yui_3_16_0_ym19_1_153994998=
4130_7456"><span><br clear=3D"none"></span></div><div id=3D"ydp3d2ead4cyiv3=
809709404yui_3_16_0_ym19_1_1539949984130_7456" dir=3D"ltr"><span id=3D"ydp3=
d2ead4cyiv3809709404yui_3_16_0_ym19_1_1539949984130_10854">I have some expe=
rience with carbs on Spifires so I will share about 2 cents (meaning minima=
l, I could probably write a book) worth if you don't mind. </span>Dual=
Webers look really cool but will move you up a class or in SVRA to the nex=
t group, my Dyno says don't do it, it's not worth it. Makuni's? forget it, =
price and parts are a problem, everyone at the track has Weber parts on the=
ir trailer. 1 1/2 SU's will do 9000rpm on a 1296 I know for sure but they a=
re a pain to straighten out the fuel curve throughout the RPM range, don't =
try this one at home boys and girls, you will end up throwing them through =
the window. The easiest thing to do is purchase a single Weber manifold and=
45 DCOE, a 40 would work as well and maybe better depending on your state =
of tune. I have a box full of manifolds, 2 are actually within 2hp of the d=
ual Webers on the top with way more bottom and mid range one I fabricated a=
nd the other was purchased but only runs to 7000rpm. I would be glad to hel=
p with jetting when the time comes.</div><div id=3D"ydp3d2ead4cyiv380970940=
4yui_3_16_0_ym19_1_1539949984130_7456" dir=3D"ltr"><br clear=3D"none"></div=
><div id=3D"ydp3d2ead4cyiv3809709404yui_3_16_0_ym19_1_1539949984130_7456" d=
ir=3D"ltr">All the best!</div> <div class=3D"ydp3d2ead4cyiv3809709404qtdSep=
arateBR"><br clear=3D"none"><br clear=3D"none"></div><div class=3D"ydp3d2ea=
d4cyiv3809709404yahoo_quoted" style=3D"display:block;"> <div style=3D"font-=
family:Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-siz=
e:16px;"> <div style=3D"font-family:HelveticaNeue, Helvetica Neue, Helvetic=
a, Arial, Lucida Grande, sans-serif;font-size:16px;"> <div class=3D"ydp3d2e=
ad4cyiv3809709404yqt8722674958" id=3D"ydp3d2ead4cyiv3809709404yqt24051"><di=
v dir=3D"ltr"><font face=3D"Arial" size=3D"2"> On Friday, October 19, 2018 =
4:53 AM, ralph hansen via Fot <fot@autox.team.net> wrote:<br clear=3D=
"none"></font></div> <br clear=3D"none"><br clear=3D"none"> <div class=3D"=
ydp3d2ead4cyiv3809709404y_msg_container"><div id=3D"ydp3d2ead4cyiv380970940=
4"><div><div class=3D"ydp3d2ead4cyiv3809709404ydp154784e8yahoo-style-wrap" =
style=3D"font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size=
:13px;"><div></div>
<div>gee, my 1147 with HS's puled all the way to 8k with a 4:11 gea=
r - stock bore block, head work, A6 cam - its not the carbs, its either tim=
ing or cam</div><div><br clear=3D"none"></div>
=20
</div><div class=3D"ydp3d2ead4cyiv3809709404ydpe7e79603yahoo_quoted=
" id=3D"ydp3d2ead4cyiv3809709404ydpe7e79603yahoo_quoted_0115294811">
<div style=3D"font-family:'Helvetica Neue', Helvetica, Arial, s=
ans-serif;font-size:13px;color:#26282a;">
=20
<div class=3D"ydp3d2ead4cyiv3809709404yqt7631504929" id=3D"=
ydp3d2ead4cyiv3809709404yqt02256"><div>
On =E2=80=8EThursday=E2=80=8E, =E2=80=8EOctober=E2=80=
=8E =E2=80=8E18=E2=80=8E, =E2=80=8E2018=E2=80=8E =E2=80=8E01=E2=80=8E:=E2=
=80=8E13=E2=80=8E:=E2=80=8E48=E2=80=8E =E2=80=8EPM=E2=80=8E =E2=80=8ECDT, v=
an.mulders.marcel--- via Fot <fot@autox.team.net> wrote:
</div>
<div><br clear=3D"none"></div>
<div><br clear=3D"none"></div>
<div><div id=3D"ydp3d2ead4cyiv3809709404ydpe7e79603yiv47835=
38815"><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 carburettors, maybe the power would decrease more gradually a=
bove 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 HS6 S=
U's on your actual manifold?</div><div>At what maximum rpm is your engine s=
till reliable?</div><div>Marcel</div><div><br clear=3D"none"></div><hr id=
=3D"ydp3d2ead4cyiv3809709404ydpe7e79603yiv4783538815zwchr"><div class=3D"yd=
p3d2ead4cyiv3809709404ydpe7e79603yiv4783538815yqt3904850125" id=3D"ydp3d2ea=
d4cyiv3809709404ydpe7e79603yiv4783538815yqt49846"><div><b>Van: </b>"fot" &l=
t;fot@autox.team.net><br clear=3D"none"><b>Aan: </b>"fot" <fot@autox.=
team.net><br clear=3D"none"><b>Verzonden: </b>Woensdag 17 oktober 2018 1=
5:49:45<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 i=
nto switching out my twin HS4s on the 1296 race engine to either Weber or M=
ukinis. I know this has been done for years and I'd like to get close the b=
est set up out of the gate. <br clear=3D"none"></div><br clear=3D"none"><di=
v>I don't think the SUs are up to the task of moving enough air with the ne=
w ported head and Stahl header. I've worked on the SUs and gotten them to f=
inally 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 flo=
w calculator link appreciated)<br clear=3D"none"></div><div>Biggest gate I =
suspect is the intake valve, 1 3/8" head (~35mm) HS4 is ~38mm at best.<br c=
lear=3D"none"></div><br clear=3D"none"><div>Recommendations? I've seen all =
these setups at the track, each with pluses, minuses and overkill cause it =
looks cool. <br clear=3D"none"></div><br clear=3D"none"><div>One weber DCOE=
40 or 2? what jets, tubes etc for a starting point? Best manifold? <br cle=
ar=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">fot@autox.team.net<br clear=3D"none"><br clear=3D"none">http://ww=
w.fot-racing.com<br clear=3D"none"><br clear=3D"none">Donate: http://www.te=
am.net/donate.html<br clear=3D"none">Archive: http://www.team.net/pipermail=
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tions/fot/van.mulders.marcel@telenet.be<br clear=3D"none"></div></div></div=
></div></div><div class=3D"ydp3d2ead4cyiv3809709404ydpe7e79603yqt3904850125=
" id=3D"ydp3d2ead4cyiv3809709404ydpe7e79603yqt23489">______________________=
_________________________<br clear=3D"none"><a href=3D"mailto:fot@autox.tea=
m.net" target=3D"_blank" rel=3D"nofollow" shape=3D"rect">fot@autox.team.net=
</a><br clear=3D"none"><br clear=3D"none"><a href=3D"http://www.fot-racing.=
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</div></div></div><div class=3D"ydp3d2ead4cyiv3809709404yqt76315049=
29" id=3D"ydp3d2ead4cyiv3809709404yqt39579">_______________________________=
________________<br clear=3D"none"><a href=3D"mailto:fot@autox.team.net"; ta=
rget=3D"_blank" rel=3D"nofollow" shape=3D"rect">fot@autox.team.net</a><br c=
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get=3D"_blank" rel=3D"nofollow" shape=3D"rect">http://www.fot-racing.com</a=
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_______________________________________________
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http://www.fot-racing.com
Archive: http://www.team.net/pipermail/fot
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