HFS-4 Q&A, application for your engine...

[Richard L]

I wouldn't use the restrictors if you are running two 1mm jets. The restrictor just improves the linearity of the system. At those rate, it is not as important. It is much much imnportant when you are using one 0.8mm or smaller.

The difference in flow will be warrant a retune.

The reason behind the restrictor is to match the flow characteristics of the valve's inlet to the jets. It is liken to control the flow out of a small hole on a large water tap.

I don't mind questions if you it helps you to make better use of the system.

[makro86]

Hi Richard,

I was just reading your last reply.

If I am using 1 x 1.2mm jet, should I be using any of the flow restrictors?
My calculated WMI flow should be around 570cc.

Going by page 9 of the manual, I put the 0.7mm restrictor in to cover flows of 0 - 680cc. Would this be correct?

Cheers.