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Which SU needle?

sparkydave

Jedi Knight
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Probably a question that's been asked many times, but most of the info I find online is how to convert the needle dimensions into a needle type. I have an HS-4 carb, type AUD465, which corresponds to one of the two used on a 1971 MGB. I'm thinking of using it (trying it, at least) on the 1500. Unfortunately, since it falls under the heading of a non-standard use of it, how would one go about trying to find a suitable needle? Would this be a better question for Joe Curto?
-Dave
 
Thanks Mark, that WinSU program looks like it might be worth a try. If that doesn't work, Joe seemed to think the single HS4 would work pretty well on the 1500, so hopefully he'll have some thoughts on what needle might work.
-Dave
 
thats interesting. i plan on twin hs4 on my 1500 so i will be hoping to hear how you make out.

mark
 
I raced a 1500 Spit with a single modified HS4. The needle I was using was a KW, but probably would be too rich for a street engine.
Jeff
 
Hello Mark,

"i plan on twin hs4 on my 1500",

Burlen list a twin HS4 set up for the Midget (but not the single)
74 model with carburettor id AUD 665 F and R, needle, ABT, and the 78 model with carburettor id FZX 1122 F and R, needles, ADN.

Alec
 
I converted my 1500 over to the dual HS 4 setup after having trouble with the ZS setup and after trying to go with a single HIF6 setup. I learned a lot about the SU and needles trying to figure out what to use with the HIF6. One thing to do is get some good manuals like the Weber Carb Manual by Hayes and the How To Build & Power Tune SU Carburettors by Des Hammill. If you get these two you will have a good working knowledge to make educated guess. I found I could make them just as good as Joe on the 1500 with a HIF6. By the way the HS4 dual setup is really sweet!

There is a web based needle selection site that seems pretty good. The WinSu is great to but I found this one just as good and doesn't require a download so I'm including the link here:
https://www.mintylamb.co.uk/suneedle/

Get a list of possible needle sizes from the "Weber carb manual by hayes". It's in the back of the book. It list cars, engine sizes and carbs placed on that motor. I found similar models and setups, then took the list to the mentioned website and saw how each needle would perform at any given range. Then make a choice and try it out. The How To Build & Power Tune SU Carburettors by Des Hammill will give you the knowledge how to make refined improvements.

Good luck and let us know how you make out.
 
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