3 screw Su needle advice needed.

[Yamahacam]

Just freshened up a set of su's and fitted them on a stock 240k with extractors, 2 1/2 exhaust and 240z airbox. Adjusted and sync ed them as best I can and it runs pretty well but a can't get the idle mixture leaner than about 11 without making the rest of the rev range too lean. No markings on the needle but I have measured the stations with verniers to give me an idea of what is happening. 1 and 2 are about .0950 and .0940? Can anyone recommend a needle for me before I buy sw, SL ? Thanks.

Edited May 3, 2019 by Yamahacam
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[aircobra]

did you ever get a source for the needles? do you know what is supposed to be stock for  a 240?

[1600dave]

SU Midel in Sydney sell a huge range of SU needles, about $10 each last time I got some.

You won't get stock 240Z needles from SU Midel (or any SU carb shop) as 240Z carbs aren't "real" SU's - you would have to get genuine Nissan if they are still available. Otherwise, you'll have to work out what the needles in the zed "Hitachi copies of SU's" equate to in the "genuine british SU" needle range.

Edited May 18, 2019 by 1600dave

[gav240z]

On 5/18/2019 at 9:00 AM, aircobra said:

did you ever get a source for the needles? do you know what is supposed to be stock for  a 240?

Original needles are N27's, but as stated above are difficult to find. It also depends on mods you have done to your car (running L24 vs L26 vs L28). No point running N27 needles with an L28 bottom end. It will be lean out.

[Yamahacam]

I have made some progress with the tuning. I do have a wideband sensor but only at the end of the extractors. I contemplated moving the sensor up further so I could split between the carbs but ended up just getting a Colortune. I have managed to get them really close and now in the stages of really fine tuning for the best overall performance. Adjusting and test driving is just taking a while to do. From the measurements I found on some forums I suspect my needles are pretty close to N27. I think the tune is close enough now for this motor and will probably wait on buying needles for my other motor.