Has anybody found an equivalent match to the  n27 needle in an SU needle? The n27 needle does not show up in in the SU reference charts. Any help will be greatly appreciated.

C

I did some research and found 2 Needles close to the N-27 stock ones......    See my write up....    Hope this helps .... Good Luck...

I compiled some data to share (all from this site) on Needle comparisons for anyone's interest to use.   There are 2 Needles that come close to the N-27 profile during working ranges and I went with one that is a slightly richer at Stations #3 through #6, but leaner than "SM" ...   I am currently testing the "SR" Needle that is close to the N-27 (but slightly richer through all stations when compared to Idle Diameter), have set the Mixture Screws on the SUs back to 2-1/4 Turns Out and it's idling rock sold again... put about 100miles on these needles and the car is running real well and will stick with them for now. 

The closest Needle profile to the N-27 is actually the "SL" , and may work better for those with a more Stock Like engine configuration.  

I used pages 10 & 11 for Needle Profile testing during driving from attachment:   SU Needles - Tuning_SU_Carburetors.pdf

I purchase my 0.100" Needles from SU Midel:   http://www.sumidel.com/shop/category/-0100-fixed

Data table in the last attachment..............................

  

SU Needle charts pp 47 to 49.pdf SU Needle profiles vs N27 Stock.pdf SU Needles - Tuning_SU_Carburetors.pdf

Edited May 10, 20195 yr by moritz55