89RS_82Z

iTrader: (2)

ok, i seen this up before, it has alot of different views on it so i want to get an updated opinion, for us who go with a custom breather (or people who may be interested in the "HP gain" if there is any) and are wondering if we should put the stock IAT in the breather, or put it near a fresh air source or use a resistor that makes it think its getting a cool charge all the time (what should make it run richer and advance the timing some)... or use an potentiometer set up to go from about -40 to 120 F, and adjust it in the ball park area according to outside air temp, i found a chart

temp in F~~ohms
5~~~~~~~21450
14~~~~~~16180
23~~~~~~12300
32~~~~~~9420
41~~~~~~7280
50~~~~~~5670

i know this is very limited but it can give you an idea of the temp to ohms,
dont want this to get into a big fight of whats better but i would like to a few opinions on it and what people think of the set up they are using

the cost is nothing to do a potentiometer or resistor, rat shack has resistors in 5 packs for 99 cents and potentiometers, plus a case to mount it in costs like $6

Tbi-MAX

its easy, for simplicity i would use a POT... i did the same thing you are atempting on my Buick Lesabre... instead i series 2 resistors for the optimal ohm load, soldered them, and bent them like a paper clip U shape.. then i inserted that into the harness, and taped it up... worked like a charm! the car was lot more peppier... but in the summer time and heat, it would lag.. the other 3 seasons it was good, especially winter..

this is not really safe for longterm, and its really tricking the pcm... a custom tune will be tons better.. and more power.

but if you dont know what resistors you need to get, just use a POT measure out the ohm load you need for optimum engine temp, and solder some wires to the POT, and the ends of the wires, just push them into the harness.. and run your CAI...

you will be happy... IMO

89RS_82Z

iTrader: (2)

yea got a pot now and seems to work good, also got a custom tune to the chip, so i try to keep the pot at out side air temp, just wodering if i should go back to stock, being a got a custom tuned chip

icarus402001

I have mine in the CAI bonnet. Why mess with the location and take a chance? You're not running right following a tune up,right? Try it in the CAI bonnet and see if it runs better

studdmstr

Why mess with it? The IAT sensor is simply a thermistor placed in the vehicle's air intake system used to calculated the temperature of the incoming air charge. As the temperature of the air changes, the resistance of the sensor changes. The computer measures this resistance by comparing the voltage drop across the resistor. Based on what the computer calculates it adjusts the air / fuel ratio accordingly. If the computer senses that the air is particularly cold it will add more fuel to compensate for the denser air. The theory behind this modification is that by placing the IAT sensor closer to the air filter and further away from the hot engine, a "more accurate" reading will be obtained and more horsepower will be created. Unfortunately this theory is fundamentally flawed. GM didn't just throw the IAT sensor somewhere and forget about it. The computer is calibrated to provide the proper air / fuel ratio based on the IAT being exactly in it's stock location. By placing the IAT in a colder location the computer will effectively see a cooler air charge than what is actually entering the engine, this results in a rich mixture which costs horsepower and fuel economy.

BMmonteSS

You shouldn't mess with it for a multitude of reasons, the biggest being that you are wasting your time. The 746' ecm does very little compensation with the IAT and what little changes it makes is only fuel related if my memory serves me correctly.

ON top of that you are trying to change the AFR when you don't even know if your rich or lean. Most stock tunes are too rich, which means you should tell the ECM that it's hotter than it is. Even then I don't think you can make enough of a change in the AFR to even tell. Keep in mind that at part throttle the ecm will self trim itself using the O2 sensor, so messing with the IAT will just result in the ECM tuning around your gizmo.

89RS_82Z

iTrader: (2)

yea i been at the same thought to intall it back into my breather, i dont have a stock breather so i will have to figure out as way of hooking it up, should be no problem.... drill a hole or something, i just hope i can find my factory breather with the IAT and plug on it LOL if not i will have to raid the U-Pull-It yard.......has anyone else put one in a aftermart cleaner and if so how did you mount it?? although its been doing good with the POT set up, been getting 20+ MPG (mix of city and highway) and had tons of more power than it ever did stock, i want to go back with the IAT, see if its better, worse, or no difference. i really dont think i need the rice boy mod since i got a custom tuned chip in it, but at the time of putting the breather on it, i didnt want to drill into the base and mess with it at the time so i just used the pot..... maybe i need to hook up that air fuel gauge i got sitting around the house and see what it says

studdmstr

I have a flat base open element air cleaner setup and I just made a hole in the base. Installed the IAT sensor and was good to go.

Pablo

iTrader: (1)

Don't bother with it. There is nothing you will accomplish that you could not accomplish with fuel pressure or base timing adjustments. IIRC the IAT does very little in the 746 anyway. BMonteSS is right, these cars run rich from the factory to begin with. You don't need more fuel right now.