PatriotTA

Ok, so I was reading in my shop manual that the IAT will read a maximum of 2.7k ohms when the air is at its coldest. So, could I just unplug it and put a resistor in it? Or would it be better to relocate it to a colder location so it can actually monitor the air? I would rather put a resistor in it (so it can provide maximum spark advance) and tuck it out of the way. Even if it doesn't help performance very much at all, it'll still clean up the look of the engine some. Would 2.7k ohm be the correct resistor to use?

teke184

of the two things i would say you would be better off relocating it closer to the air box for a "cleaner" reading.

things to be cautioned about. there are mods available from SLP (air temperature module...link in my sig) that you plug in between the sensor and the plug. it is basically a resistor that fools the computer into thinking that the incoming air is something like 40degrees. by doing this it advances the spark as you mentioned.
however
there is a real world test of this mod and it found that Yes it did advance the spark, but in doing so it started to pick up about 2* of knock. obviously this increase in knock would negate any increase in hp gained from the spark advance. therefore i would be very carefull how you mess with these things.

teke184

found the link:

install university

PatriotTA

Thanks for the info. Do you think using an LT4 knock module could get rid of the knock that was seen? Also, in the shop manual, it says the IAT reads 2.7k ohms at 70 deg. F. In that experiment, they were tricking it into reading a LOT colder. Do you think that could have something to do with it?

teke184

i have no idea as to whether the really cold "false" reading is the culprit. it very well could. i have known lots of guys who put a resistor in the sensor (don't know how...but i'm sure someone does), and the particular resistence one they use is supposed to give a reading of 55* or something, instead of the 36* that the SLP unit produces. maybe a reading of 55* doesn't give so much hassle.

i have tried removing the SLP unit and have not been able to feel a sotp difference. i wish i had a scanner to monitor knock. i actually have the lt4 km on order from gmpartsdirect right now. it should arive in a few days. hopefully this will eliminate any false knock from the IAT module and maybe i'll be able to feel a difference.

best i can say is ...i'll keep ya posted.

these reasons are why i say to just relocate it. that way you are just getting a truer reading of the actual incoming air.

PatriotTA

Thanks again for the info. My car's in storage now, or else I'd be experimenting too. If this post ends up getting buried, you can just PM me.

maximumvelocity

so wait, does anyone know if a lt4 knock module will give back the lost or hidden hp from the slight knock produced from the slp iat module? I have one of these and did not notice any sotp increase in performance. Still have yet to get a lt4km, saving up for one after the headers though.

teke184

like i said, i'll let you know next week...hopefully the module will get here monday.

maximumvelocity

ok I was just wondering if anyone else has done it

DaveW 396ci

uh... The IAT is not used except in Speed density mode which is all '1993s or those later years in limp home mode with a bad MAF.

So relocating it or replacing it with a resistor is a waste of time if you are in Mass Air mode (using your MAF). If you want to change your timing why wouldn't you get your PCM tuned (on a dyno of course)? That way you know your timing will be optimized for your motor.

DaveW

P.S. the LT4 KM is not a solution. It is at best a band aid which in my case did nothing. I still am running the LT1 KM after finding the LT4 KM did nothing.

PatriotTA

If the IAT is only used in speed density mode, then how was the timing affected when Install University tested the SLP unit? I'm not being an ***, I'm just wondering.