For those with FI, did you change your spark plugs to a step colder and if so which ones did u get? I just got my TT and it is slow to start sometimes and it sounds like backfire when idling. The manual says that one step colder is recommended. ANy info would be appreciated. THanks

 

I have the ATI procharger with 8lbs boost and had to change to one step cooler cooper plugs. I also had to gap them around thirty to prevent the boost from blowing the spark out. I am still experiencing the same type idle problem you are, seems to be cam timing or some other load kicking in at idle.

 

I am gapped at .37 on NGK Copper one range colder; car idles perfectly. When I switch to Irrad's I want to poll everyone for FI gap numbers because this forum has gaps anywhere from .30 to .39!!

The Chicago TS / P.E. tuned car also had to raise the gap a little to idle correctly but had an after market fly wheel.

 

Hmmm, this might be a silly question but is there anything better then copper plugs for FI applications? What about silver coated copper or pure silver spark plugs? Silver is more resistant, transfer heat and current better then copper, but costs maybe 10X as much. So is silver another option here? Thanx.