In my airplane, the temperature probe was placed away from the exh= aust=20 pipes, but measuring the total temperature of the air used to cool=20 the ENGINE and OIL cooler exit air (TOTC) - that is, the prob= e is=20 located aft of all 4 cylinders rather the ahead of the cylinders where the=20 induction air might be drawn from. Remember that I am talking about=20 injected Lancair 235/320/360s with the throttle body mounted on the for= ward=20 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=20= the=20 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),=20= CHTs=20 360F-380F, TOTC 149F (rise from OAT of 74F)

On taxi in after landing, Oil temp 200F, TOTC 190F to 203F for a r= ise=20 of 104F to 117F above OAT.

So....Take off and climb might indeed see a difference from=20 OAT of under 100F, but actual induction air temps of 150F to 175F. = ; Is=20 that bad? Oh, I forgot the impact of passing thru the oil sump and the= n=20 hitting the hot cylinders after being cooled by fuel vaporization........&nb= sp;=20 In any event, software from Sacramento Sky Ranch calculated a loss of 5% - 8= %=20 power if the induction air temperature is raised by these amounts.

I then went to move the probe to the air exiting the heat muff (just li= ke=20 carb heat air) and in doing so I finally broke my probe. Maybe it woul= dn't=20 matter because the display is limited to 210F (99C) although I would have li= ked=20 to show that the "carb heat" air is always hotter than the lower cowl=20 air.

>>>>>>>>>>>>>>>>>>= ;>>>>>>>>>>>>>>>>>>>= ;>>>>>>>>>>>>>>>>

OK, I replaced the temperature probe and put it where the heat muff air= =20 exits. This is the same air that would be "carb heat" air.

Baro 29.89, OAT 72F:

8 minutes after startup, 167F (95F rise)

Runup, 198F (126F rise)

During 135 KIAS climb (WOT, 2600 RPM) in excess of 210F (probe display=20 limit), OAT 68F, rise > 142F.

Level at 6500 MSL, 25 squared, 174 KIAS, 196 KTAS, OAT 66F, CHTs 360F-3= 90F,=20 203F (rise of 135F)

The heat muff air is quite a bit hotter.

I believe the carb air temp probe is located after the fuel has been mi= xed=20 with the air - thus lower temps from the vaporization process are seen=20= on=20 the cockpit display. The same thing happens after the injectors in an=20= I/O=20 engine.