Jump to content
jalexquijano

when to replace SU CARBURETORS SM NEEDLES?

Recommended Posts

Ztherapy refurbished both of my 3 sscrews roundtop SU Carbs and install Brand new SM Needles on them. My car engine is not stock it has been upgraded to 2.6 L with oversized pistons and a Shneider 274F Camshaft. Should i consider changing the needles to another type to get a better performance at idle?

Share this post


Link to post
Share on other sites

Idle is Idle is Idle.  The only thing to worry about is too rich a mixture that stinks and fouls plugs.  Anything from 13 to 16 usually works. 14 to 15 is the least stinky.  13 is  more tractable and sounds better.

Share this post


Link to post
Share on other sites

Nice! But quite expensive! im using the gunson colortune. Ill let the car warm up and race the car for 10 to 15 mins and then pull the plugs out to see if i can achieve the dark Brown color on the plugs.

Edited by jalexquijano

Share this post


Link to post
Share on other sites

I had a colortune and it was nice at idle but couldn't see what was happening while driving on the street. Also with modern unleaded gas it's difficult to base everything on the color of the plugs.


Sent from my iPhone using Classic Zcar Club mobile

  • Like 1

Share this post


Link to post
Share on other sites

That's not expensive...especially if you consider how long you have been chasing drive ability problem s and the associated mechanics fees!

  • Like 2

Share this post


Link to post
Share on other sites

anyone else bought this a/f sensor?  i want to see which is the correct spark plug color i must achieve

Edited by jalexquijano

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Recently Browsing   0 members

    No registered users viewing this page.

  • Who's Online   26 Members, 0 Anonymous, 172 Guests (See full list)

  • Search Engine Meta Tags:
    classic, z, datsun, 240z, 260z, 280z, zcar, zed, s30, classiczcars.com, 240z.org, fairlady, 240, 260, 280, nissan, 240 z, 260 z, 280 z, zx, turbo, classic z, 280z cars, cars 240z, car forums, datsun, nissan, cars datsun, car club, 280zx, car, nissan zcar, classic z car
×