SCCAITS

iTrader: (3)

S4 NA TB

The rear secondary plates don't seem to open 100%. They are open, but not perfectly flat like the primary plate. The only way I can find to adjust them is with the idle set screw, but that only adjusts closed position, not open.

I did the TB mod on FC3S Pro and also ported/polished. But, that should not have nothing to do with it. I have a completely stock S5 TB I checked and it does the same thing.

Shouldn't the rear secondary plates open 100% like the primary? If so, where do you adjust them?

HAILERS

This is considered one of my lazy guesses: If memory serves, there is a Tab that can be bent on the throttle linkage. Move the linkage while looking at the linkage and see if my memory serves or NOT.

Look at it this way: At least your thread didn't disappear on to the third or fourth page and now your back on top.

SCCAITS

iTrader: (3)

Thanks, that worked. Bent the link that attaches from the primary linkage to secondary linkage with my thumb which tightened things up and the plates are both perfectly flat. I'd have to imagine this has loosened on many cars, simple fix.

NZConvertible

The way it was is the way it's supposed to be. All FC TB's are like that, and it has little impact on flow. What you've done messes up the sequential operation of the throttles. The secondaries will open earlier than they should, and you'll lose some of the benefit of the primary/secondary design of the whole intake system. Since this is for a race car (I presume) that's no problem, but I wouldn't do this to a street car.