Ah...good to know about the plugs !! I wonder if for some reason the throttle blades of some sleds tend to be adjusted a tad on the open side, then if they set the tps to that in order for the idle to be correct, this then would cause higher than normal idle with the turbo now increasing the low level air pressure in the airbox. Cause we are now drawing off of a "closed" system regulated by flow through the turbo.
It would be nice to have a spec on the throttle blade opening in thousands of a inch and check yours now to see if its correct as far as what is called for.
Figure the little screw is fine thread, probably around 32 tpi so 1 turn is .030" movement of the lever, I have a set of throttle bodies on the shelf right now and i'll look into this a bit.
It would be really nice to know, lets say, that .005 was the correct blade opening for the turbo so as to check and set this when throttle body was on the bench.
I know on my porsche Fi motors the opening is critical and once you set it its a done deal as the ecu sets idle rpm, but if its off either way , you have real problems as it can't compensate.
On the dragon 1/2 turn made a big difference in the idle.(300 rpm)