ok so my car is a LT1 355, F1A procharger, LT4 heads intake ect.. had the car tuned with the 6 speed in it and the dinky twin intercoolers. i have since put in a fully built 700R4 full manual valve body and a 31x12x4 front mount with 3 inch aluminum piping, car is tuned in speed density. after the new intercooler the car is running at 10.5:1-12.2:1AFR at idle and fouling plugs. is this something the bigger intercooler will cause or should i be looking somewhere else?

 

I just had mine tuned in speed density last week, so I'm still learning about it. However, when I brought it home and unloaded it from the trailer, I had to pull the air filter to clear the ramps. The car idled like crap and I attribute that to the free flowing air. With the filter back on, it ran as tuned. I wonder if your FMIC is flowing better, causing your tune to now be out of whack...? I understand that speed density is touchy. Just a thought, hope it helps.

Ben

 

This is early morning thinking here, but you could be seeing a larger pressure drop across the single big intercooler, thus less air in the motor at idle/ect would equate to a rich condition. Again, I'm not awake, I'm sleep-posting this in case it's out to lunch.

 

we had my fuel pressure turned up to 60 psi so i turned it down to 56-57psi and the idle afr is at 13.1:1 now, it still seems like im popping in the headers though occationaly, its not picking up any knock at idle untill i give it some gas and i get some burst knock, i think at 4-5 quick blips it read 4000 knock which to me thats realy not that much. the timing is jumping between 22 and 28.