Walter, Dan, et al,

 

In my airplane, the temperature probe was placed away from the exhaust pipes, but measuring the total temperature of the air used to cool the ENGINE and OIL cooler exit air (TOTC) - that is, the probe is located aft of all 4 cylinders rather the ahead of the cylinders where the induction air might be drawn from.  Remember that I am talking about injected Lancair 235/320/360s with the throttle body mounted on the forward face of the oil sump.

 

Baro 30.18, OAT 86F, Airport is 710 MSL, Palt 450, Dalt 2400:

 

8 min after start, TOTC 176F (90F rise)

 

During 135 KIAS climb (WOT, 2600 RPM) TOTC went from 167F to 158F when the OAT was about 81F or a rise range of 86F to 77F.

 

Level at 4500 MSL, 25 squared, 180 KIAS, 194 KTAS, OAT 75F, (TAT 68F), CHTs 360F-380F, TOTC 149F (rise from OAT of 74F)

 

On taxi in after landing, Oil temp 200F, TOTC 190F to 203F for a rise of 104F to 117F above OAT.

 

So....Take off and climb might indeed see a difference from OAT of under 100F, but actual induction air temps of 150F to 175F.  Is that bad?  Oh, I forgot the impact of passing thru the oil sump and then hitting the hot cylinders........

 

I then went to move the probe to the air exiting the heat muff (just like carb heat air) and in doing so I finally broke my probe.  Maybe it wouldn't matter because the display is limited to 210F (99C) although I would have liked to show that the "carb heat" air is always hotter than the lower cowl air.  I am looking for an independent probe and meter.

 

Maybe someone with an actual carburetor would make this measurement to help out this poor soul (in a Lancair, not a Bonanza and with a digital gauge) along with lower cowl air temps.  Huh? Huh?