Quote:
Originally Posted by CompFi
Does anyone here have experience with Holley’s Idle Bypass Valve? Holley claims it is a new feature, but I don’t have a sense for what “new” means at Holley. Wondering if I might now be close...
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Once upon a time guys used to drill holes in the primary butterflies to help them idle and transition better with big performance engines. Why would they do that? Because they had a mill that put off a good bit of heat, the air under the hood would thin out, the idle would drop, maybe even stall, and when they "upped" the idle by turning in the idle adjustment screw it opened the primaries up past the transition slot which causes 98% of the carb problems in performance autos.
There are two solutions to the hot idle blues. One is the idle bypass valve and the second is to install a cap screw that lets you open the secondaries a bit for more air. Both do the same thing. Read this thread and you will understand:
Best Way to set the idle mix on a 4160
There's a pic in there of my installation of the cap screw, which you don't need because you have the idle bypass. There's also a lengthy explanation of why setting the primary butterfly properly to the transition slot is so important. Super important. As important as tightening your spinners before you tackle the twisty mountain road.
