TOPIC: Groove positioning

After putting the groove on three vehicles, a 2BBL carburetor, a 4BBL carburator (Edelbrock) and a throttle body on a 1999 Hyundai Accent, one of the things that I have noticed and developed a curiousity about is the following.

On each Groove mod the throttle plate was at a different angle which brings up the question of, Has anyone noticed any specific characteristics that seem to be consistent with the angle of the throttle plate relative to the groove position?

One of the things that I have noticed, physically on the throttle body groove, the throttle plate being about 10 degree in the closed idle position and that the air opening as the plate moves across the groove is close and the sweep across the groove is only about 15 degrees of sweep before the throttle plate starts moving away from the groove.

On a mechanical throttle (cable actuated) I cut the groove right after the throttle plate (TP). You don't need to wary about idling. The air for idling mode goes on a separate path thru the idle valve and a system of channels that avoid the plate.
On electronic throttles there is no Idle valve or separate way for the air. Now ,if you cut the groove the same way , you'll have a problem with idling. To avoid that, the groove need to be cut about 3/16 away from the TP. You can achieve that by putting a business card between the TP and TB (throttle body) on the opposite side . ( Ron's method) It works most of the time. Personally , I use a more precise method to establish the groove position on electronic throttles. On an OBD2 scanner, I read the TPS (%) value at cold start. After I take of the TB of the intake , I leave the electrical connector on the TB , and key on/ engine off (how else?!), I mark the position where the TP matches the TPS(%) reading on the scanner. Some TP's get stuck once you turn the key to on position, so be creative, use different spacers before you turn the key on ,until you achieve the same reading for TPS(%).Once you get it, live the spacers on and do the grove.
I am not worried about the low angle of TB, after passing the groove. The groove makes a difference even after the TP passes (within some limits), and we do most of the driving at low TB angles any way.

Titus