<html><head></head><body><div class="yahoo-style-wrap" style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:13px;"><div dir="ltr" data-setdir="false">Hi,</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">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.</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="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 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.<br></div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">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.<br></div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="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 crankin!<br></div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">:-)</div><div dir="ltr" data-setdir="false">Regards,</div><div dir="ltr" data-setdir="false">rml<br></div></div></body></html>