Just done the groove on my ford put the throttle body back in and started truck sound smoother and it sound like it idles lower? Haven't done the spark plugs yet. I have closed of the idle air supply to 1/4 "both sides,
Pre mod my vacuum was 17,5 should there be any change post mod not at idle right because the throttle plate is closed ???
Post mod manifold vacuum will be increased by doing two things,
1 - reducing the idle air pathway, which you have done
2 - moving the pcv line off of the intake manifold and capping that port (biggest leak)
and moving that hose to the intake plenum side of the TB in close proximity to the TB inlet.
I've seen vacuum levels of 20" to 21" post mod on some vehicles.
Manifold vacuum is typically at it's highest when the engine is at idle.
Depending on your results, you might consider reducing the IAC pathways down to 1/8" each, but this is also going to depend on the winter temperatures in your area.
The reduction in IAC path to 1/8" is simply a starting point. What I do when I perform this mod is instruct the customer they may have issues with cold starting at first. The computer will generally correct for this within a week or so. If not, then we simply increase the diameter to maybe 3/16" and see how that works.
If the client is resistant, 1/4" will generally be enough. This is the size I use when the client is remote or traveling. That way, there is less likelihood of an issue causing customer dis-satisfaction.
Just finished butting the truck together
I took the TB out again and glued the idle air closed again and reedrilled with 1/8 drill as you guys suggested
Done the spark plugs and rounded of front of TB intake side, and I closed of egr valve
Tomorrow I am going for a test drive see how it does
ITA clued closed
Pic of the groove
Thanks for now Christoph
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