Can somebody point me in the direction of info on the IAT mod, i.e. putting a resistor in the IAT sensor harness? Is it really worthwhile, or not? TIA

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Kevin-87 Firebird 2.8 A4
Ported Intake, K&N, !Cat, Cutout coming soon...
Best 0-60 10.26 seconds...for now

 

It's not really worth it... your best bet would be to relocate the IAT so it picks up air in a cooler location... as in the case of your firebird, you could take it out of the metal air filer can (plug the hole!) and "hang it" in front of the air filter intake hole, which is under the lid. If you want the MAT values the computer uses to figure out intake air, here they are, in a chart I did a while ago. You'll have to scroll down a bit to see it; don't ask me why

<table BORDER=3 CELLSPACING=3 CELLPADDING=3 >
<tr><td>Temp F</td><td>Temp C</td><td>Ohms</td></tr>
<tr><td>210</td><td>100</td><td>185</td></tr>
<tr><td>160</td><td>70</td><td>450</td></tr>
<tr><td>100</td><td>38</td><td>1,600</td></tr>
<tr><td>70</td><td>20</td><td>3,400</td></tr>
<tr><td>40</td><td>4</td><td>7,500</td></tr>
<tr><td>20</td><td>-7</td><td>13,500</td></tr>
<tr><td>0</td><td>-18</td><td>25,000</td></tr>
<tr><td>-40</td><td>-40</td><td>100,700</td></tr>
</table>

So, if you want your computer to think it's sucking in 20 degree air, remove the MAT connector, stick a 13.5 k-ohm resistor in there, and tape it up.

[edit] Oh there's also something else you could do. Note how higher resistance = colder air temp. If you wired a 1k-ohm resistor in series with the MAT sensor, you'd be adding 1000 ohms to the actual MAT readout. So for instance if you did that, and the MAT was "really" reading 450 ohms (for 160 degree air temp), the computer would see 1450 ohms, and figure the incoming air's closer to 100 degrees.

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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!

[This message has been edited by TomP (edited April 25, 2001).]

 

Thanks, Tom! When I posted, I was gonna ask if there was any way to augment your IAT signals, rather than replacing the sensor with a resistor. That's exactly what I was wanting! Now, next question, if you're tricking the computer into thinking the air is colder, it'll add more fuel because it assumes denser air, so wouldn't you be running a bit richer than normal? Isn't lean the way to go? I already have the IAT sensor hanging beside the air intake (K&N) and haven't noticed any real difference. Thanks again!

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Kevin-87 Firebird 2.8 A4
Ported Intake, K&N, !Cat, Cutout coming soon...
Best 0-60 10.26 seconds...for now

 

I have a 4.7 Ohm in i think but im gonna take it out and hook it to my air box when im not lazy ne day. Didnt notice one damn differnece.