I've been reading about led's and I've come up with an approach to wiring a second IAT sensor to monitor IAT's for readout by resisted led's on the dash or other spot.

This is theoretical and not bench tested, try at your own risk, as I have not tested it at all.
Ohms law v= I*R or R=v/I
R=(12v-3.4v/.020) R=430 ohms

Led's light at about 3.4v for the colors I'm using (red, green)
and the IAT sensor has known resistor values, ie 467 ohms at 160*F, so if you wire a second IAT sensor off a 12v source ( and tap a port for it ofcourse) At 160*F the R lowers enough to light an otherwise unresisted green LED in the circuit. A second green LED wired parallel with another 80 ohms would light at 175*F. a third green with 170 ohms would light at 195*F, a fourth, red LED with 275 ohms would light at 212*F. A fifth red with 340 ohms would light at 230*F, a sixth red with 385 ohms should light at 250*F

I'm going to test this before I start drilling my dash but I think it's viable.

You don't like guages?

Lights are purdy-er.

You don't like guages?
Do you have a line on a gauge that will read ohms as *F or similiar?

How 'bout a remote thermometer maybe? Either mechanical, or electronic?

get one of those fancy mirrors with the compass/temp in it

Not exactly cheap, but check out these IAT guages from Autometer:

http://www.egauges.com/vdo_mult.asp?Type=Intake_Temp&Series=Sport_Comp&Cart=

The second one is a 2 channel guage for pre and post intercooler measuring.

get one of those fancy mirrors with the compass/temp in it

I like it. You could get the led temp gauge to read the stock IAT sensor as long as it reads above 199 *F.

Another less expensive option would be to buy a used digital thermometer such as a Fluke 52 dual channel (or 51 single channel), get one of the probes for measuring air temperature, extend the wire into the cab, and measure it that way.

Your local computer emporium has THERMALTAKE digital temperature LCD display module, with separate adjustable controller for a small fan for 35 bucks.

Reads to about 195f max, range is -35deg to ~ , good for a vehicle with charge-air cooling.

Cast aluminum frame mounts in 5.25" disk drive slot, but LCD thermometer module is about 1" x 3", pops out of frame, has remote sensor, runs off +12v, iirc.

Try it - you'll like it..............

Tell me why IAT temp is so important. And if it gets to high, the ECM does what? I havent thought much about it.

QM - before you go overboard on this project, try turning your LED's on with 3.4vdc and see what happens. An LED is just a diode and generally a diode runs on 0.7 - 1.0vdc. It's a semiconductor device and 0.7vdc are the general specs that most consumer diodes are manufactured to. When you purchase your diodes, get a manufactures spec sheet with it if you can. It will more than likely work, but be prepared to possibly replace them every so often.

Just looked it up through a local electronics specialty store (not RadioShack) and for a standard 5mm round bright green LED, the forward voltage is 2.0-2.4vdc. You can use a higher voltage but you will have to use current limiting resistors to due this.

To bad you couldn't just tap into the ecm as it has most of the things we want to monitor except egt.

Just Intercool it and you would only need a range of 30-140*...

Tell me why IAT temp is so important. And if it gets to high, the ECM does what? I havent thought much about it.The higher above ambient the intake chargeair the higher the EGT's. Intercooling recovers lost efficiency from the turbos heat.
I have three IC's to install. The 30-140F range makes sence.

The ECM will lower fuel delivery if IATs read too high. It is not like limp mode where you loose timing advance and fueling but it will seem sluggish until temps drop back.