How about an average of 30 deg F reduction in intake air temp? That's what I found when comparing my truck (w/snorkle) to a friends truck (w/o snorkle). The data on the air temp was taken using the intake air temperature (IAT) data from the OBD2 port. Hwy speeds were 55-70 and city was 0-45.
Ambient temp: 95-97 deg F
My truck 95 w/snorkle
Hwy IAT: 106-111 deg F
City: 115-126
Friends truck 97-no snorkle (factory air intake)
Hwy IAT: 127-140 deg F
City: 147-156
Highest temps for both trucks were when we were stopped in traffic. The only difference in the 2 rigs is that his coolant temp (as measured by the OBD2) is about 5 deg higher than mine, which could result in some increase in the IAT.
Bob
Ambient temp: 95-97 deg F
My truck 95 w/snorkle
Hwy IAT: 106-111 deg F
City: 115-126
Friends truck 97-no snorkle (factory air intake)
Hwy IAT: 127-140 deg F
City: 147-156
Highest temps for both trucks were when we were stopped in traffic. The only difference in the 2 rigs is that his coolant temp (as measured by the OBD2) is about 5 deg higher than mine, which could result in some increase in the IAT.
Bob