:::RHMT::: Real Home Made Turbo

General Category => Engine Management => Topic started by: turbohf on January 28, 2013, 01:07:31 AM

Title: air temp sensors?
Post by: turbohf on January 28, 2013, 01:07:31 AM
so every time i see someone add an air temp sensor to convert a car to speed density or custom setup i see GM threaded IAT sensors. cheap and available i know.

but how reliable are they? how accurate are they?

i have Honda IAT sensors and plugs. those rarely go bad. they make threaded ones, or you can just cut the brass off a coolant sensor....

what spawns this question would be putting SD AEM EMS in the GVR4 that doesnt have an IAT sensor, and would need one added. i know that AEM has a Honda IAT programmed in it already, cuz well my Honda runs it lol.



learn me? lol
Title: Re: air temp sensors?
Post by: snm95ls on January 28, 2013, 02:41:12 AM
I can't recall ever replacing a faulty GM IAT sensor.

Title: Re: air temp sensors?
Post by: PhilStubbs on January 28, 2013, 08:06:13 AM
I'd just use the Honda sensor. Drilling 3 holes and tapping 2 of them isn't difficult. Although, I have never replaced any iat sensor on any brand. They just work
Title: Re: air temp sensors?
Post by: Joseph Davis on January 28, 2013, 09:01:38 AM
It doesn't matter, AEM's air temperature correction is horribly broken.  Use whatever.

FYI, the open element or even non-Honda IATs shouldn't be used with an OBD1 Honda ECU.  They double as a MAT by design, and position, so they shouldn't be put in the charge piping/intake arm either.
Title: Re: air temp sensors?
Post by: turbohf on January 28, 2013, 10:50:40 AM
well my question would be specific to a Galant VR-4, and a K-swapped vehicle.


on the current  homo 'engine management' that is in the Galant there isnt an IAT sensor and the voltage is clamped at 74° or someshit... and i have seen setups that run them free air in the engine bay... so i would assume it can be tuned around or not at all.
Title: Re: air temp sensors?
Post by: Joseph Davis on January 28, 2013, 10:54:35 AM
You asked an AEM specific question, my answer applies.

Your VR4 has an IAT in the MAF.  Sliderbarzzz clamps it because it has sliderbars that you can slide, yo!
Title: Re: air temp sensors?
Post by: turbohf on January 28, 2013, 11:05:10 AM
you made a comment about obd1 honda.


its got a maf-translator 2.06...  :-X  and hopefully it will be gone before the new motor starts up, or shortly after, and i probably wont drive far on it...
Title: Re: air temp sensors?
Post by: bigdaddyvtec on January 28, 2013, 12:08:51 PM
JD:

Thoughts on cutting the plastic off the IAT Honduh SLow ass sensor... Located in the plenum... Using teh Mefth?
Title: Re: air temp sensors?
Post by: Joseph Davis on January 28, 2013, 03:37:01 PM
you made a comment about obd1 honda.

I made a FYI in a Honda-centric forum after I told you AEM's IAT comp is worth one stale - but not too stale - dog turd.




JD:

Thoughts on cutting the plastic off the IAT Honduh SLow ass sensor... Located in the plenum... Using teh Mefth?

No.  Not only is that a bad idea, but the Honda sensor is not slow.  The temp changes neatly from MAT to IAT at the first sign of appreciable airmass.  Nothing wrong, don't fix it.
Title: Re: air temp sensors?
Post by: snm95ls on January 28, 2013, 03:49:49 PM
Interdasting.

Title: Re: air temp sensors?
Post by: turbohf on January 31, 2013, 10:42:52 PM
(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Fi276.photobucket.com%2Falbums%2Fkk32%2Fefssuck2%2FGVR4%2FIMG_20130131_180859.jpg&hash=a1ed247ea83c2a023cbfd878bbbf266e2d028f98)

legit?
Title: Re: air temp sensors?
Post by: rawr on February 01, 2013, 01:41:12 AM
Find out the thermocouple type and just use some damn tc wire.


How accurate is it? Probably +/- 5 deg f. Tc wire can be more accurate but i doubt the ecus ability to compensate for icepoint.

Most temp shit is off.
Title: Re: air temp sensors?
Post by: turbohf on February 01, 2013, 01:49:35 AM
btw that pic i posted is of a ECT sensor, with the brass piece cut off the end.
Title: Re: air temp sensors?
Post by: rawr on February 01, 2013, 08:10:14 AM
you made a comment about obd1 honda.

I made a FYI in a Honda-centric forum after I told you AEM's IAT comp is worth one stale - but not too stale - dog turd.




JD:

Thoughts on cutting the plastic off the IAT Honduh SLow ass sensor... Located in the plenum... Using teh Mefth?

No.  Not only is that a bad idea, but the Honda sensor is not slow. I love dongs.  The temp changes neatly from MAT to IAT at the first sign of appreciable airmass.  Nothing wrong, don't fix i

The mass around the tc wire will also create a smoothing effect and cause the wire to be less spastic
Title: Re: air temp sensors?
Post by: snm95ls on February 01, 2013, 12:09:20 PM
Unless I am missing something here, ECT, and IAT sensors are typically thermistors not thermocouples.  Not to mention they operate totally differently since a thermistor changes resistance with temp and thermocouples generate voltages with varying temps.

Dealing with cold junction compensation on a thermocouple adds even more bullshit that isn't needed.

Title: Re: air temp sensors?
Post by: rawr on February 01, 2013, 01:40:39 PM
Almosr every tc reader ive used compensates for cold junction comp. If not thry can be pretty wrong if you plug one into a dmm and check it. Jd told me most cars run k type tcs. Rtd is more accurate typically, but i rarely see anyone use rtd to monitor any process. I only use rtd to cal a2la ovens, dry wells, baths etc. Shrug. Send me an iat and ill tell you what it is and chart the values.
Title: Re: air temp sensors?
Post by: DmC on February 01, 2013, 09:50:27 PM
Evo8 ecu maf a jumper harness?
Title: Re: air temp sensors?
Post by: turbohf on February 01, 2013, 11:20:33 PM
Evo8 ecu maf a jumper harness?

or...ill just run AEM. ive been fucking with it and running it in the CRX and i like it. i will be running it in my EKK, i can get it for same price/cheaper than the other options...
Title: Re: air temp sensors?
Post by: snm95ls on February 02, 2013, 12:59:52 AM
Almosr every tc reader ive used compensates for cold junction comp. If not thry can be pretty wrong if you plug one into a dmm and check it. Jd told me most cars run k type tcs. Rtd is more accurate typically, but i rarely see anyone use rtd to monitor any process. I only use rtd to cal a2la ovens, dry wells, baths etc. Shrug. Send me an iat and ill tell you what it is and chart the values.

Pulled this off Alldata for a 1994 GSR.

(https://realhomemadeturbo.com/forum/proxy.php?request=http%3A%2F%2Fwww.alldatapro.com%2Falldata%2FPRO%7EV314675216%7EC19109%7ER0%7EOB0%7EP3R0H%7EN%2F0%2F41746445%2F56621960%2F56621961%2F56621962%2F34853741%2F34857029%2F100410262%2F100410263%2F34857031%2F34849463%2F56650568%2F42171873&hash=ba494c2e3930887019ff358cbf0e4432dc1469b2)

I just can't see a thermocouple as a good solution for most automotive applications when it comes to inlet air and coolant temp.

Shrugs.

Unfortunately I don't have a spare IAT or ECT to pull apart.
Title: Re: air temp sensors?
Post by: rawr on February 02, 2013, 04:35:42 AM
Thats actually suprising to me. Tc can be accurate to like .5 deg c in real world conditions. I havent noticed aby real difference between the two as far as traversivity goes except on the higher end 4 wire comp rtd shiz. Submerged in coolant, the reading is almost instant.  I guess it doesnt matter too much, its interesting to think about, but irrelivant at the same time.
Title: Re: air temp sensors?
Post by: HiProfile on February 03, 2013, 12:51:08 AM
Most temp shit is off.

Probably because it doesn't pay to be dead accurate in most applications. If your MAP is off 5psi, yeah it's a prob, but with a sensor that's 5F off nothing bad is going to happen. More than likely your injectors are mismatched to a greater percentage than your IAT is off, and I mean air density.
Title: Re: air temp sensors?
Post by: Joseph Davis on February 03, 2013, 12:17:40 PM
Jd told me most cars run k type tcs.

LOL, no.


btw that pic i posted is of a ECT sensor, with the brass piece cut off the end.

Most F-series and CRV motors have a screw in type IAT. 


Evo8 ecu maf a jumper harness?

or...ill just run AEM. ive been fucking with it and running it in the CRX and i like it. i will be running it in my EKK, i can get it for same price/cheaper than the other options...

98-99 DSM or Evo8 ECU is a better option, IMO.
Title: Re: air temp sensors?
Post by: Joseph Davis on February 03, 2013, 12:18:38 PM
And for the EKK, you should convert to DBW and run a '06-11 Si ECU.  That's the most affordable way to run any K-series, if a bit labor intensive.
Title: Re: air temp sensors?
Post by: rawr on February 03, 2013, 12:44:45 PM
Bish please
Title: Re: air temp sensors?
Post by: snm95ls on February 03, 2013, 01:28:52 PM
Fuck.  Should have hosted that image myself.