Thumper Posted October 17, 2005 Share Posted October 17, 2005 73turbo240z and I were having a discussion about where we are going to install our IAT sensors. I was thinking in the intercooler pipe after the intercooler. He's planning to install his in the intake manifold right after the tb in the cold start injectors hole. His way would probably give more accurate results because of the contributing exhaust manifold heat. Although from what I've read most people install it in the intercooler pipe. What is best? Thanks Quote Link to comment Share on other sites More sharing options...
evildky Posted October 17, 2005 Share Posted October 17, 2005 the megamanual recomends against installing directly in the intake due to excessive vibration shortening the life of the sensor, I put mine in the pipe about 3 inched before the tb, as far as I know everyone else mounted theirs outside the intake and have not had any issues Quote Link to comment Share on other sites More sharing options...
Guest ON3GO Posted October 17, 2005 Share Posted October 17, 2005 i put mine right after the t-body in the jsk spacer.. but i have microtech. mike Quote Link to comment Share on other sites More sharing options...
Kraker_Jax Posted October 17, 2005 Share Posted October 17, 2005 Mine is in the protruding pipe on the 280zx stock j pipe. Welding teacher put it there for me, rather than having to cover the hole anyways. Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted October 17, 2005 Share Posted October 17, 2005 Mine is in the protruding pipe on the 280zx stock j pipe. Welding teacher put it there for me, rather than having to cover the hole anyways. Are you gonna run an IC? If so, you will have to move it. My IC lowers temps somehwere in the neighborhood of 100 degs, oh, I used that hole for my BOV. Mario Quote Link to comment Share on other sites More sharing options...
akeizm Posted October 17, 2005 Share Posted October 17, 2005 Mines in the cold start injector hole. But I would want it as close as I can to the motor cause whats the point in taking the temp of the air else where, when its going to be a different temp when it get into the engine. Quote Link to comment Share on other sites More sharing options...
midnightzxt Posted October 17, 2005 Share Posted October 17, 2005 To be a little more technical on this issue.. here's some fun facts. You want the IAT sensor after the intercooler obvoiusly. The "don't install on the intake" is not always correct. The CLT sensor is on the intake and nothing's wrong with that.. It's really easy to place anywhere if you have a 3/4in drill, welder or even jb weld and a bung or nut that fits the pipe thread on the sensor. All up to you Quote Link to comment Share on other sites More sharing options...
Thumper Posted October 17, 2005 Author Share Posted October 17, 2005 So it seems like the most accurate place to put it is on the intake manifold. And the better looking and convienent way is on the ic piping. Since there are so few sensors with megasquirt might as well get as accurate readings as you can. Thanks Quote Link to comment Share on other sites More sharing options...
Nismo280zEd Posted October 17, 2005 Share Posted October 17, 2005 I'm gonna be like Mike and put mine in the cold start after the TB. -Ed btw... is the correct MAP sensor i need to order ? MPX4250 MAP Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted October 17, 2005 Share Posted October 17, 2005 Why do you need to order a MAP sensor? Is it a higher boost one? If so, see which ones are compatible with the firmware. I think these are all the most common replacements, and I believe MSnS-E is comaptible with all of them: http://www.megasquirt.info/v22manual/3bar.htm MPX4250AP showld have come with your kit. Mario Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted October 17, 2005 Share Posted October 17, 2005 Mine is before the TB =) Quote Link to comment Share on other sites More sharing options...
jkube Posted October 18, 2005 Share Posted October 18, 2005 I've put my IAT in the air inlet to the turbo. Seems to work well. I can setup the car to start and run well during warmup in colder weather, without a cold air valve. When I had it located after the intercooler just before the TB the air temp seemed to be "off" all the time. I also had trouble getting a consistant fuel setting, I think it was because the different ambient temps under the hood had a big affect in the higher temp ranges depending on how I drove the car. http://www.execulink.com/~jkube/Brians280z/280turbopage%201.html Quote Link to comment Share on other sites More sharing options...
Guest 73Turbo240z Posted October 18, 2005 Share Posted October 18, 2005 I've put my IAT in the air inlet to the turbo. Seems to work well. I can setup the car to start and run well during warmup in colder weather' date=' without a cold air valve. When I had it located after the intercooler just before the TB the air temp seemed to be "off" all the time. I also had trouble getting a consistant fuel setting, I think it was because the different ambient temps under the hood had a big affect in the higher temp ranges depending on how I drove the car. http://www.execulink.com/~jkube/Brians280z/280turbopage%201.html[/quote'] so wait.. you put it on the inlet side of the compressor housing plumbing? an all vacuum source? and a source that reads the ambient temps of what the turbo is sucking in, with no reference what so ever to what is going on pre or post intercooling? that doesn't seem like it should work... at all.. Quote Link to comment Share on other sites More sharing options...
midnightzxt Posted October 18, 2005 Share Posted October 18, 2005 I'm going to agree with 73turbo240z... if you've got that before the turbo, it's definitely in the wrong place. You need to be measuring the air going into the cylinders, which is a lot hotter than the ambient. IF it doesn't run right.. that's in the tuning, not the sensor placement. From the megamanual: Note: A few early installations using the open-cage MAT sensor experienced vibration induced failure of the sensor. The thermistor bulb is supported only by two thin wire legs. These can apparently fatigue and break when installed in high vibration environments, such as occurs when you screw it directly into an intake manifold. Several people solved the problem by "potting" the legs of the thermistor with O2-sensor-safe silicone (most silicone sealer/adhesives destroy O2 sensors, so pay attention!), squeezing it down inside the sensor body but leaving the bulb exposed. IAT sensor - this should be located in the intake system somewhere after the compressor and intercooler. It needs to sense the temperature of the air going into the cylinders. You can put it before the throttle body or in the intake plenum, either location will be fine. Your intake temperature sensor must be the “open-element†type. Regular closed sensors are shielded within a brass housing, and will respond too slowly to the rapidly rising intake temperatures that occur when boost comes on. See the Sensors and Wiring section for more details. Just a little reading at http://www.megasquirt.info Quote Link to comment Share on other sites More sharing options...
jkube Posted October 18, 2005 Share Posted October 18, 2005 I agree with you guys on the location (just before the TB). It makes sense to me too, and thats how I had it set at the beginning of my tuning sessions. I read the manual and located between the intercooler and TB. I moved it because of the trouble during tuning, to see if it would fix my inconsistant cold weather operation and it seemed to. I know the coolant sensor adjusts the fuel flow in cold weather, but I cant seem to find anohter explanation as to why it works. What can I say. Maybe I've tuned around it somehow??? I also routed my piping to go from the turbo outlet..across the rad.. into intercooler on the passenger side .. and then out and around to the TB. I did this because I didnt want the cooled air to be reheated again by the rad. http://www.execulink.com/~jkube/Brians280z/000_2393.JPG The IAT I've used is a GM sensor used on the LT1 corvette. Its an open sensor unit surrounded by a plastic cage and is mounted in a rubber bushing to isolate it from vibration. I used Easytherm to adjust the temps/resistance values table. Maybe this is why the car starts so well in the cold weather now?? Quote Link to comment Share on other sites More sharing options...
Guest 73Turbo240z Posted October 18, 2005 Share Posted October 18, 2005 I agree with you guys on the location (just before the TB). It makes sense to me too' date=' and thats how I had it set at the beginning of my tuning sessions. I read the manual and located between the intercooler and TB. I moved it because of the trouble during tuning, to see if it would fix my inconsistant cold weather operation and it seemed to. I know the coolant sensor adjusts the fuel flow in cold weather, but I cant seem to find anohter explanation as to why it works. What can I say. Maybe I've tuned around it somehow??? I also routed my piping to go from the turbo outlet..across the rad.. into intercooler on the passenger side .. and then out and around to the TB. I did this because I didnt want the cooled air to be reheated again by the rad. http://www.execulink.com/~jkube/Brians280z/000_2393.JPG The IAT I've used is a GM sensor used on the LT1 corvette. Its an open sensor unit surrounded by a plastic cage and is mounted in a rubber bushing to isolate it from vibration. I used Easytherm to adjust the temps/resistance values table. Maybe this is why the car starts so well in the cold weather now??[/quote'] sounds like the sensor i'm using... got your GM part number? cause the Gm sensors are supposed to work w/ stock values... no tweaking of easy therm. Quote Link to comment Share on other sites More sharing options...
Sean 83ZXT Posted October 18, 2005 Share Posted October 18, 2005 This post talked about the IAT sensor location a while back: Link Quote Link to comment Share on other sites More sharing options...
jkube Posted October 24, 2005 Share Posted October 24, 2005 Sorry 73turbo240z, I cant find the package that the sensor came in, and there is no part number on the sensor itself. As for using easytherm, I did this because I didnt really know if the resistances were the same as encoded into MS. I didnt want to take a chance. So I measured the resistance settings at 3 different temperatures. First in the ice box (35F), then in room ambient(77F) and then in the oven (200F). I used a room thermometer to record the temps, and a multimeter to measure resistances. The way I knew the numbers would be accurate. Now, on this problem with location. I really dont thnk putting the IAT in the intake to the turbo is all that bad. Heres why, this spring I put a turbo into my son's B13 Sentra, and it uses the MAF to read incoming air temps. It's located in the turbo intake side. The ECU seems to handle these readings with out a problem. All these type of tuner cars seem to use the same setup, and the cars run very well. I took my car for a hard run this weekend and there is no signs of problems with the current setup. Maybe I just lucked out on this one. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted October 24, 2005 Share Posted October 24, 2005 I really dont thnk putting the IAT in the intake to the turbo is all that bad. I just going to list one example of when this would be bad for someone else that reads this thread and wonders where to locate the IAT. These numbers where measured on my car so this isn't made up. If you place the IAT before the turbo and don't run an intercooler your computer will read intake air temp of 70 degrees (on a 70 degree day), but at 10psi of boost you air temp in the intake manifold will be 180 degrees. On my car is was just as much work to put the IAT before turbo, before TB, or in the intake. I put it before the TB just to avoid the heat soaking issues. Do I ever want the computer reading the wrong intake air temps by hundreds of degrees, no way. The bottom line is that we run EFI to give us the advantage of being able to measure many aspects of the engine accurately and as close the combustion chamber as possible. Get your moneys worth from the computer and put the sensors as close the cylinderhead as is practical. Quote Link to comment Share on other sites More sharing options...
jkube Posted October 29, 2005 Share Posted October 29, 2005 Dont know if anyone is still interested, but I found the GM number for the GM sensor I"m using. #12160244 Here is a link to a pix of it. http://album.hybridz.org/data/500/medium/000_2414.JPG I'm going to take Mobythevans advice and give move the IAT back to intake of the TB just after the Intercooler. I should have time this weekend to retune MS. I'll post my air temp readings after I'm done Quote Link to comment Share on other sites More sharing options...
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