Subject: [Fot] Weber DCOE Question

From: Robert Lang via Fot <[email-masked]>
Date: Thu, 3 Nov 2022 20:54:49 +0000 (UTC)

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Hi,
I've been running 28mm choke tubes in my Weber DCOE40's for a long, long time. It used to be a requirement in the Solo rules!! I can say for sure, that the smaller chokes help low-end torque a lot.
In any case, I switched over to 30mm choke tubes because... well not sure why other than they were sitting on the bench and I had some free time. In any case, the car starts and runs okay and will idle down to roughly 900 RPM with a nice lumpy idle. But I noticed that the carb won't "progress" to the mains like it did with the previous setup. It stumbles a bit coming off idle. I haven't had time to play with the idle mixture yet, but I have a feeling I just need to tweak that to get the carbs to progress properly.

So, my question is - for anyone that's changed choke tubes in a DCOE 40, hopefully on a TR6 (cam, 12:1, etc.): did you have to change anything else to keep the mixture correct? I know I can run the car on a dyno and get real measurements, I'm just looking for applicable experience on same. FWIW, I have the obligatory $3k worth of jets and emulsion tubes.

Side bar - I'm pretty sure I have a good tune on this engine because I dropped around 2 seconds off my best time ever at WGI back in September. That motor was crankin!

:-)Regards,rml

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<html><head></head><body><div class=3D"yahoo-style-wrap" style=3D"font-fami=
ly:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:13px;"><div dir=
=3D"ltr" data-setdir=3D"false">Hi,</div><div dir=3D"ltr" data-setdir=3D"fal=
se"><br></div><div dir=3D"ltr" data-setdir=3D"false">I've been running 28mm=
 choke tubes in my Weber DCOE40's for a long, long time. It used to be a re=
quirement in the Solo rules!! I can say for sure, that the smaller chokes h=
elp low-end torque a lot.</div><div dir=3D"ltr" data-setdir=3D"false"><br><=
/div><div dir=3D"ltr" data-setdir=3D"false">In any case, I switched over to=
 30mm choke tubes because... well not sure why other than they were sitting=
 on the bench and I had some free time. In any case, the car starts and run=
s okay and will idle down to roughly 900 RPM with a nice lumpy idle. But I =
noticed that the carb won't "progress" to the mains like it did with the pr=
evious setup. It stumbles a bit coming off idle. I haven't had time to play=
 with the idle mixture yet, but I have a feeling I just need to tweak that =
to get the carbs to progress properly.<br></div><div dir=3D"ltr" data-setdi=
r=3D"false"><br></div><div dir=3D"ltr" data-setdir=3D"false">So, my questio=
n is - for anyone that's changed choke tubes in a DCOE 40, hopefully on a T=
R6 (cam, 12:1, etc.): did you have to change anything else to keep the mixt=
ure correct? I know I can run the car on a dyno and get real measurements, =
I'm just looking for applicable experience on same. FWIW, I have the obliga=
tory $3k worth of jets and emulsion tubes.<br></div><div dir=3D"ltr" data-s=
etdir=3D"false"><br></div><div dir=3D"ltr" data-setdir=3D"false">Side bar -=
 I'm pretty sure I have a good tune on this engine because I dropped around=
 2 seconds off my best time ever at WGI back in September. That motor was c=
rankin!<br></div><div dir=3D"ltr" data-setdir=3D"false"><br></div><div dir=
=3D"ltr" data-setdir=3D"false">:-)</div><div dir=3D"ltr" data-setdir=3D"fal=
se">Regards,</div><div dir=3D"ltr" data-setdir=3D"false">rml<br></div></div=
></body></html>
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