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Mixture setting on triple CD's

Started by _gtrtorana_ , Feb 11 2006 02:17 PM

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6 replies to this topic

#1 _gtrtorana_

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Posted 11 February 2006 - 02:17 PM

HI, I have a set of 1 3/4 inch triple CD strombergs on the side of my motor. According to the XU-1 book I have, base mixture setting is 2 1/4 turns out. This seems to be a very rich mixture and fouls the plugs when not driving car flat out. Just wondering what other mixture settings people are running on their strombergs. Thanks

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#2 Litre8

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Posted 11 February 2006 - 02:30 PM

Are the CD's still running the standard needles? At what number of turns out do you get best idle quality?

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#3 _gtr161s_

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Posted 11 February 2006 - 02:33 PM

buy yourself an airflow meter. I noticed one at the american autos store in syd. This is the most accurate way to balance each carb for air flow then providing your running the correct needles and springs they should tune up fine.Also make sure you can easily lift each damper with your finger.

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#4 _gtrtorana_

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Posted 11 February 2006 - 02:53 PM

At the moment they have 6D needles. I have made a custom linkage set up so there is no slop and all buterflies open in sink. I still idles well at 2 turns out but I have not taken it for a drive with this set up yet. All dampers lift and fall with no tight spots.

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#5 warrenm

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Posted 12 February 2006 - 07:32 AM

These needles should be ok, from memory I think they are std as fitted by Holden. The book lists 2 1/4 turns as the base setting, this is a starting point so the engine will run, then tune from here.

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#6 _gm3300_

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Posted 12 February 2006 - 11:08 AM

with the engine running and the air filters removed, use a small screwdriver to raise the piston about 1/8", if the setting is too lean the idle will drop off and try to stall, if the setting is too rich the idle speed will increase, when the setting is correct the idle should remain the same and then slowly drop away. The LC 150CDs have a lift pin underneath the diaphram for exactly this purpose, on the 175CDs this pin was deleted.
This technique will work providing all the other settings are correct ie, the jet is central to the needle, the float level is correct, and the needle has been installed correctly with its shoulder flush with the base of the piston,
hope this helps
grant

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#7 _gtrtorana_

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Posted 12 February 2006 - 03:16 PM

Thanks. I will try these steps. I spent a lot of time bench tuning carbs before instulation. I set jets central to needles, needle shoulder flush with piston, correct float level and used a dial gauge to find my zero mixture setting before going 2 1/4 turns out so hopefully tuning should be easy. Thanks again