Modification: Warm Air Intake

[SVOboy]

Originally Posted by diamondlarry

On my Saturn, I just unplug the air temp sensor and stick some resistors in the end of the plug. On this car it is around 110 ohms or so. This way I can easily return everything to stock when necessary.

I'm not really an electrical wiz, so do you think your could explain a bit of the theory behind this?

[dfoxengr]

just makes it think it is one temp when its not.

[SVOboy]

So then would 110 ohms work for all cars or is it something I need to figure out differently for my honda? That makes sense, I just wonder what temperature I should try to trick it into thinking it is.

[dfoxengr]

no clue

[Flatland2D]

Well the temperature is calculated by measuring the voltage drop across the sensor. The voltage drop changes with resistance of the sensor, and the sensor's resistence changes with temperature. It's a temperature controlled variable resistor of sorts.

You could use a potentiometer in place of a resistor (also a variable resistor, but controlled by a knob) so you could test a range of resistences easily.

[SVOboy]

That makes sense, I learned this last year. So then do you think there is anyway to ballpark what is too much or too little resistance or should I just get a knob and then try it out? Seems like something for your afr tweaker/instantaneous mpg gauge also.

[diamondlarry]

I was looking in my Hayne's manual for my Saturn about how to test the air temperature sensor for proper operation. That's how I found out that the sensor's resistance varied with temperature. I had a variable resistor laying around so I hooked it into the plug that went onto the sensor. I found that the potentiometer was very difficult to control but I did notice that, according to my Scaguage, when I varied the resistance to the equivalent of anything over about 250 degrees or so that the "check engine" light came on. I went to Radio Shack and bought some 1/4 watt resistors and started putting them together until the light came on. The combination I came up with was 1-100 ohm resistor in series with 2-22 ohm resistors in parallel. This is actually 111 ohms. It's hard to say whether this would be the same for all cars but it's worth checking out.

[SVOboy]

Well that solves a lot of my questions about intake stuff, haha, I'll have to try it out one of these days, mehbe since I've only got 92 hp I could wire the knob inside and then just heat it up a lot when I'm cruising and not when I am accelerating. Unless it makes no difference really. How much mpg difference was there on the scan gauge?

[diamondlarry]

I will have to get back to you on the mpg difference. I made the change back in April and forgot what the mileage was before the change. I'll do some runs with and without the mod to get the mileage difference. I'll do some runs on my favorite test route. It's a 10 mile trip on a county road(5 miles out and 5 back) with not too much traffic. I'll do 2 with the mod then 2 more at stock.

[SVOboy]

That sounds great, I'm interested to hear the results. By your method you'd have it running just under 250 degrees, right?