four corner idle

[flyinlow]

What is the advantage of four corner idle in a carb?

Does it idle with the secondaries slightly open?

[Ghoste]

More even, balanced fuel flow under idle conditions which is even more beneficial with many high performance cam grinds where idle quality has already been compromised. 

[firefighter3931]

  Better idle quality and tunability. Using 4 venturies to adjust idle mixture often means you don't have to run on the main circuit when setting the idle speed & mixture. Cam profiles that produce low manifold vacuum readings allways benefit from a carb with 4 corner idle. The carbs that have a 4 corner idle syatem also have a more agressive fuel curve which makes further tuning much easier. 

Often with 2 corner idle carbs and big cams you need to mess around with air bleeds and PVCR's to get them to run right. 



Ron