Intake air temp data (Stillen Gen 3, need stock)

Modshack

Yup...I was in a store the other day and left the car off sitting in the sun...60 degree day. Switch on and the IAT temps read 156 degrees!

Within an eighth of a mile it was down to 100 degrees and continued to drop as the car aired itself out.

I have an intake system on my Vette that runs IAT's at ambient as long as the car is moving. On that car, timing starts getting pulled when it hits 86 degrees. Wonder what it is on the Z??

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juld0zer

i relocated my IAT sensor to the pre-airbox duct (aircon compressor side). it's mounted about 2 inches from the mouth of the duct. My IATs and fluctuations are very similar to wstar's findings.

However i do notice this sensor responds very fast and as soon as i come to a stop, IAT starts rising quite quickly. Once moving again, it drops fairly quick and i've gotten it to within 1*c of the onboard ambient sensor temperature reading.

Car is stock with heat shielding tape wrapped stock airboxes & airbox outlet pipes wrapped in heat resistant mitt material. Filters are stock Nissan ones.

I'm attributing the standstill IAT climb to radiant heat from the radiator. Stick your hand thru the front grille when she's full warmed up and u can feel the heat radiating without sticking your hand in too far.

This is probably why motoIQ quoted a higher dyno output with the front fascia removed.

With the factory sensor, the IAT climbed slower when standing still and dropped slower so i'd say it's quite slow to respond or that may be due to distance from the intake mouth. When testing with hairdryer aimed into the airbox (filter holder removed, it seemed to respond quite quickly though.


NB: sensor is one from a Mazda3. @ 20*c air, it has the same resistance as the factory IAT sensor. I have it mounted in this duct because someone on the forum said the ecu takes IAT readings from the (US) driver's side bank. This is incorrect. According to the FSM and my own hair dryer test with scanguage to monitor, the ecu does indeed take IAT readings from bank 1. ie the side closest to the alternator. Either way, the coolant hose on bank 1's side seems to be radiating a lot of heat while bank 2's side seems cooler without this hose nearby.

SouthArk370Z

What are you calling the "airbox" - the box with the filter or the box on top of the engine? Ie, are you measuring temp at the inlet to the ductwork (near the radiator) or after the throttle body?

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juld0zer

hi there, i have the sensor inside the inlet duct to the air filter box. (the bit that gets removed during a Gen 3 intake install.

Putting it inside the plenum (that's what it's called right?) would get you a pretty good idea of air temps almost immediately before it enters the cylinder. but that would be heatsoak galore... and i'd need a different sensor capable of being in the hostile conditions of this region (vacuum, oil blowby, heat) which would be a covered sensor, ie one which reacts slowly compared to the bare bulb style type.

Plenty of debate over the effectiveness of IAT sensor relocation, where is the 'ideal' place to mount it etc but let's leave that to the GM guys. concept is the same though - reduce bogging to improve driveability & improve standing starts whether simply keeping up with civics or at the drag strip.

I dont have the gear to measure air temps using an independent sensor/device but i'd be interested in getting an idea of how much the air gets warmed as it passes thru the blazing hot pre-throttle body pipes. Does plastic really radiate less heat into the air inside? Does the air inside get heated at all due to the velocity it travels thru en route to the cylinder?
If the heating is minimal then i'd say mounting the sensor outside of the engine bay is a great idea on a n/a engine. FI guys would most benefit from a post intercooler mounted sensor though

SouthArk370Z

I'm experimenting with the same thing. I bought a spare set of ducts (from radiator support to TB on both sides) and am in the process of insulating the spares and hunting down an inexpensive multi-channel thermometer. You can check on my progress at this thread.

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