jmead Posted October 22, 2003 Share Posted October 22, 2003 I finally just did it and ordered my megasquirt kit. I'm still planning on a chevy 350 in there soon....but I've always wanted to try megasquirt so it can't hurt to play around with. My real question though is what sensors are people using on their l28 setups? The megasquirt seems to be set up to run the GM coolant and air sensors out of the box, but I'm not sure on the install of these. Does the coolant sensor just swap right in for the datsun sensor? (and the datsun doesn't even have a air temp sensor, does it?). Where would the air temp sensor be mounted then? Any convenient place? I guess thats it for now, though I'm sure I'll have plenty more questions real soon. Thanks (ps, I searched, couldn't find anything on this. Sorry if its been asked before) Quote Link to comment Share on other sites More sharing options...
Bernardd Posted October 23, 2003 Share Posted October 23, 2003 I bought the gm manifold air temp for the GN. And I'm using the stock CHTS. You can regen tables by using easytherm. You can actually use any sensor you want as long as you know three temp=resistances on the curve. Boil the sensor in water, measure temp and resistance. Do the same in the freezer and at room temp. If you're just starting out you should read through all of this: http://members.shaw.ca/megasquirt/MS%20FAQ.htm Quote Link to comment Share on other sites More sharing options...
Xander Posted October 23, 2003 Share Posted October 23, 2003 I used all my sensors from a 86 pontiac fiero v6. Mainly because that was what I had laying around. But it worked out pretty nice. I even used the TB of a fiero. It has the right TPS. For the water temp I unbolted the waterpipe that went to my throttlebodies (carb setup) and screw the temp sensor in there. You will need an adapter because the thread sizes are different. But the adapter is on a fiero block aswel! And there probably isn't a junkyard that doesn't have a couple of fiero's. The air temp sensor on a stock datsun (bosch system) is located inside the AFM. xander Quote Link to comment Share on other sites More sharing options...
DatsunBoy77 Posted October 23, 2003 Share Posted October 23, 2003 The best place to really mount it is before the throttle body though. That will give the best reading of the air temp ctually going into the engine. At least with a turbo car because of an intercooler. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted October 23, 2003 Share Posted October 23, 2003 The best place to really mount it is before the throttle body though. That will give the best reading of the air temp ctually going into the engine. At least with a turbo car because of an intercooler. And even in a non-turbo car, you want to measure the temperature as close to the cylinders as possible; my opinion is you want the sensor in the intake manifold. Quote Link to comment Share on other sites More sharing options...
DatsunBoy77 Posted October 23, 2003 Share Posted October 23, 2003 Yes in the manifold would be best but slightly more difficult than in the intake piping before the TB. i thought about in the intake but i didnt want to chance messing it up, and i figure depending on where in the intake manifold could change temp aslo, like say if the turbo is sitting at the #4&5 it may be warmer there. Probably wouldnt make much of a difference, but i also wanted the inake to be clean looking, thats why i am going to get rid of most things on it. JMEAD, choose which ever one you want and good luck. Oh, yeah, you can use the GM sensor for coolant temp (TSU81 at advance auto that costs like $8) but you have to tap the whole for i belive 3/8NPT which is just slightly larger. Quote Link to comment Share on other sites More sharing options...
Xander Posted October 23, 2003 Share Posted October 23, 2003 most cars I have worked on had the air temp sensor located somewhere in front of the TB. Like in the air filter or afm. I don't believe it is wise to place the air sensor in the intake manifold because this can give problems with heat soak. I other words the manifold will heat up the sensor so that it will read higher than it is suposed too. offcours this is only my opinion. feel free to argue xander Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted October 23, 2003 Share Posted October 23, 2003 What really matters (MO) is the temperature measured is consistant with the actual temperature of the air, not necessarily be the actual temperature. It would be ok to measure 40 degrees if your air was actually 50 degrees if when your air temperature rose to 60 degrees, you measured 50 degrees. So the best place to put the sensor may indeed be before the tb if you do have a heat soak issue in your manifold that affected the sensor. You want a fast and precise response from the sensor when the air temperature changes, and absolute accuracy is not important - it can be calibrated out. Quote Link to comment Share on other sites More sharing options...
Xander Posted October 25, 2003 Share Posted October 25, 2003 yes it can be callibrated out but the reason to go with GM sensors is that you don't have too. Else you could just leave the stock sensor. oh no wait you cant, it is located in the afm and you really want to get rid of that thing. This sort of discussions go on all day at the megasquirt mailing list. To me this is the fun part of the megasquirt project. everyone has there own opinion. It is a lot of work to get a megasquirt up and running but to me it was very educational. xander Quote Link to comment Share on other sites More sharing options...
z-ya Posted October 27, 2003 Share Posted October 27, 2003 I'm running the GM sensor for both air and coolant temp, and it works fine. It not turbocharged though. From what I hear, you want to use a different one for air temp if you are turbocharging it. Air temp sensors should be located in the intake plenum as SleeperZ indicated. It doesn't matter if it is before or after the TB, just that it is as close to the combustion chamber as possible. It is there that it will get the most accurate reading. Pete Quote Link to comment Share on other sites More sharing options...
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