This may be a little long,but bear with me. In the process of tuning my BLM I have noticed that after driving, when I let the car idle my BLM would decrease drastically from the 128 during my driving monitoring down to as far as 110. After searching through my log data I believe this is being caused by a rise in temperature reading of the IAT sensor. There is a 30 degree plus change from low speed driving to idle. Now I know that I can set the "BPW injector constant multiplier vs IAT" table values all to a value of 1 to test my theory and see if my BLM holds constant at the end of my drive, but long term I was wondering what others have experienced with IAT for their setups.
This way maybe I can find a better solution for when IAT compensation may be required due to ambient temperature changes.

I am current using an open element air filter (14x3). The IAT sensor is mounted in the air cleaner base. I have a 427 vette style scoop molded into the original hood. The scoop is open at both the front and the cowl. The hood is opened up (about 3/8 inch clearance all the way around) to allow the air cleaner to extend about 1/2 inch above the hood into the scoop.

THe last run I made was stop and go driving of about 30 mph. The IAT temp ran about 112 average. When I parked the car at the end, within a little over a minute the IAT temp went to 147 and my BLM went from 128 to 110. Out side temp was about 75 degrees and my coolant temp was between 190 and 200 degrees. I am running a 170 thermostat and an adjustable fan controller set to come on at 185 degrees.

I guess this scoop is really providing quite a lot of intake cooling.

So, i was wonder how much IAT variation is typical with the stock setup? Is there a better was to mount the IAT sensor for this application? Will I also need to change some spark tables if I am seeing this much temp rise at idle?
Any comments of what you have experienced in this area are welcome at this point.

 

I have attached a picture so you can see what the scoop setup looks like.

Al

 

Just a quick update.

Last night I set all the multipliers in the "BPW injector constant multiplier vs IAT" table to 1.00 and made a monitor run. BLMs looked great. After I returned home I let it idle and watched while the IAT rose to about 147 degrees. The BLMs at idle remain solid.

I guess this thing doesn't want any IAT temperature compensation for the fueling system.