Intake Air Temp

[rjwest]

I am considering adding a Intake Air Temp Gage.

1. What temp range do I need ?

2. Would a Oil temp gage and sender work.
I have one that goes up to 300 Deg F.

May be a water cooler in my future....

[BuffaloGuy]

I did this mod. a few months ago. I drilled and tapped the lower half of the intake manifold on the drivers side in the center between the two ports. I chose this location because I thought it would be out of the extremely high velocity air and as such would protect the sensor from wear and failure.

I used a mechanical trans temp gauge. It reads from 135 to 300+. It works fine, albiet a little slow to react. It would also be nice to know the temp. below 135 but not that big of an issue.

When pulling this is a VERY interesting gauge to watch. I really think it is as important if not more than the exhaust temp. I guess GM must agree since on the computer trucks they use an intake sensor but not an EGT to sense motor conditions and scale back fuel to protect it.

Go for it!

[gmctd]

For best results, the probe sould be thermally isolated from the aluminum intake manifold casting, such that only the temperature of the flowing air is indicated.

[rjwest]

Thanks All.
GMTD, understand Thermal isolation, but that presents a problem on type sender, Any suggestions. I can use a fiber washer under remote sender but the threads still connect to
intake...How much in accuracy ?

Do you have any idea at what temps fuel gets cut back.

OR SHOULD I install it and use as referance only.?

[kowsoc]

Maybe the temperature would respond quicker with the probe right after the turbo. The amount of metal is much less than the whole intake manifold. Also, to thermally insulate....maybe a PVC bushing screwed to intake and the sensor screwed into it? Just about .02.. smile.gif

[gmctd]

Apologies for the delayed response. Was on a run for further data after retarding timing (-1.5 to -0.78 TDC Offset, headed for -0.5 to get a pre-upgrade baseline). Results are being analyzed even as we speak (type?).

So - good ideas, Kowsoc. Hi temp pvc\abs insulator bushing, closer to the compressor outlet if using a slow-reacting (water, oil, etc)thermo-probe.

If the charge-air is to be cooled, mist or radiator, choose location so the probe will be post-cooling.

My setup is for both pre- and post- probes, for future upgrade.

Added gages - IAT, EGT, ECT, etc - give an accurate pulse on how the engine is reacting to the driver's input.

Without a charge-air cooler, Intake Air Temps can climb rapidly when modifications are installed.

Temperature spikes can be problematical, but sustained hi temps result in lower performance from identical boost levels.
Hot air contains much less oxygen per volume than cool dense air.

These temps were noted in 60* to 80* weather, no a\c, coolant temps 180*, 50 to 85 mph, flat to deep Texas hill country hiway.
Maintained IAT under 200*.
No sustained IAT over 200* - observation only.

Factory-level 4 to 8psi boost temps run in the 160* to 180* range, and will climb under demand.
Boost to 10psi hits 200* quickly, and climbs from there under demand.
Boost to 15psi, and 200* is just a memory.
20psi, and it's Katie, bar the door!

Coolant temps, normally at 180*, quickly reflect hi boost temps and EGT.

Your results may vary.

'87-style 8500lb drw truck, automatic, 3.00 final drive, stock OBD-I PCM L65 with GM-8, no charge-air cooler, 3.5" Ford P/S exhaust.

There are further problems with boost levels over 12psi with the GM-X series turbos, but I've been getting some reference info before hot climate sets in.

Yesterday was cool and humid-to-sprinkling, ideal for some a\c-not-required power-testing.
Meaning, only rear-wheel power demand, no added heat from the a\c condensor.

[ 03-27-2004, 02:36 PM: Message edited by: gmctd ]

[rjwest]

Thanks!!!! Think I'll just tap a hole in the
heavyest part of the casting and try to get all of probe in air flow. Use temps as Referance.

Plus I'm becoming a bit of a gage " wacko "

Running out of places to put things,

I wish there was 1 1/2 or 1 inch automotive gages..

Did install Heath turbo master, really like it
running empty, plan to keep it at 10 psi and below
if it will run that high....