From: William Blount Arthur Date: Thu, 22 Apr 1999 01:10:42 -0400 (EDT) To: dakota mailing list Subject: IAT sensor info Ok, I tried to send this before, but it didnt make it. I am a bored Mechanical Engineer who will be graduating very soon so I went to town on this IAT thing today. Heres what I have. First, using a thermo program, I have a way of telling what temperature air the computer should think is coming in to make up for increased flow. Now, if someone could tell me some acutal flow numbers, like before and after, like a massair through the TB, I could get this way more precise. I will have to do some trial and error when I get my A/F meter. Anyways, what I did is I used the stock TB could flow 580 cfm and a F&B stage I could flow 650 cfm, I think thats right. - as an aside, my calculations show that a 650 can support upto 6250 rpm or so on a 360 and like 7000 rpm on a 318, so I dont think you need much more than that..anyways- just for the calculation I said flow went from 580 to 650 cfm. then I used the densitys and stuff to find the temperature of the 580 cfm that would have the same mass as the 650 cfm at actual temperature. Then I used Quattro pro and the chart in haynes to make a curve of resistance vs temp and then the ammount of resistance that needs to be added to the sensors resistance to make it appear colder to give the stochiometric mixture or whatever the computer would give it stock. What I am finding is that I think 15 kOhms might be too much if you are just using the resistor trick, I cant tell with out actual flow numbers. Also, this whole think is temperature dependant. The colder it is outside, the more resistance you need to add. Anyways, none of this may even be right, but its something to think about. I am going to try it out. I hooked up some quick connects into the IAT sensor today and I have a 0 to 20 kOhm potentiometer that I can connect quickly. I plan to dial in and tune it some and see what happens. This will be easyer when I get my A/F meter. The idea of this graph is that you can measure the resistance when you get to the track, then either select the appropriate resistor, by adding the sensor resistance and the resistance to add, or get a potentiometer and hook it up in series like me and dial in what you need. good luck! PS write me if you have any ideas on this. Who wants to hook up a separate computer and a mass air meter and really get this on.... Bill '97 SS/T