MAT sensor on Ram Jet 350?

Discussion in '40- & 55-Series Tech' started by DomSmith, Oct 25, 2007.

  1. DomSmith

    DomSmith SILVER Star

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    Finalizing the wiring on a 350 Ram Jet install on my 40 and cannot figure out the MAT (Manifold Absolute Temp) sensor crap. It mentions it in the instructions but not in the service book. There is a wiring loom for it but I cannot find it on the engine! There are no pictures with it or listing of where it is...

    :confused: (Maybe this is for Big Block applications only?...)

    Anyone installed this? Oh yeah, MEFI4 Computer.

    These GM instructions could use an overhaul...
     
    Last edited: Jul 8, 2010
  2. cruiser boy

    cruiser boy

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    it goes in the air intake tube...at least thats where we put em on ours
     
  3. cruiser boy

    cruiser boy

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    you can buy the sensor at your local gm dealer, not a big deal
     
  4. DomSmith

    DomSmith SILVER Star

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    I'm not running a tube, just straight air cleaner... :confused:
    ramjet01.jpg
     
  5. nocents

    nocents

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    The sensor plug on mine only fit certian areas.... MAP is just behind you air cleaner, top "fitting" in you photo. Oval plug 3 wires on mine. I have not got mine running and the harness is still in a box, but that what the lables indicate.

    Nocents
     
  6. DomSmith

    DomSmith SILVER Star

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    Nocents-

    Thanks, I've got the MAP sensor plugged in, it's the MAT sensor I can't get straight. The connector is on the loom and the instructions (if you can call them that) SAY it comes with it, but I didn't receive one unless it's somewhere already installed...
     
  7. DomSmith

    DomSmith SILVER Star

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    Found this online from a HotRod website... Looks like I need to do some more work. Maybe a short tube between the Throttle Body and filter threaded to fit the MAT.
    0602sr_22_z+fuel_injection+air_temp_sensor.jpg
     
    Last edited: Oct 26, 2007
  8. cruiser boy

    cruiser boy

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    Thats what we do is build a real short metal tube,( we used 3 inch exhaust tubing swelled to the right size) welded in a bung and then used rubber inbetween the pieces, works great. I don't know why they call that a mat sensor because it is actually an AIT sensor (air intake temp). All it needs to see is the air temp going into motor. At least this is what my local G.M. guru tells me and he's pretty darn sharp. ...I'll call mike this A.M. and get a part number for you. I would send a pic but the closest one I've done is in Fresno right now. ( I'm in Idaho).... Hope this helps......Rod ( bandito's rock racing) a little plug hehe...:beer:
     
  9. DomSmith

    DomSmith SILVER Star

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    Thanks for the info Rod. I guess that's where I'm, getting confused. Here are the sensors I have (less the O2 sensor on the exhaust).

    IAC: Idle Air Control
    TPS: Throttle Position Sensor
    MAP: Manifold Absolute Pressure
    ECT: Engine Coolant Temp

    The IAT (Intake Air Temp) sensor is mentioned in the instructions although not where to install it, but not the service manual. To make things more confusing I didn't get one, AND the wiring harness says "MAT" sensor. So I suppose those that are running the air filter straight to the throttle body are using the MEFI 3 stuff? :confused:

    Let me know if you get a part #. My GM dealer hates when I come in w/o a specific year/model...
    ramjet01-copy.jpg
     
  10. cruiser boy

    cruiser boy

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    So I called my chevy guru's here today and this is the part number you need gm# 2506751.. This is the one we are using in our builds and works perfectly....If you have any questions or need them to order call Shad or Brian at Tyler-Kelley Chevrolet @ 208-746-9801 Have a great day!......Rod p.s. thats in Lewiston Idaho .
     
  11. cruiser boy

    cruiser boy

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    Hey by the way if you are running an automatic with that baby make sure you pull the brass pilot bearing out of the rear of the crankshaft.......most of them have one installed for some crazy reason....Just might save you a headache....Rod
     
  12. DomSmith

    DomSmith SILVER Star

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    Rod-

    Thanks for the part #. A buddy of mine here that builds motors knew exactly what I needed and gave me one. The part # will be essential when replacement time arrives! :)

    Running a 5 speed manual so I actually had to add a bushing but thanks for the tip.
    :beer:
     
  13. genesmith5720

    genesmith5720

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    I just bought this IAT. The correct part number is: 25036751
     
  14. DomSmith

    DomSmith SILVER Star

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    Thanks for the post Gene!
     
  15. Sharp38

    Sharp38

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    Dom

    We do this engine all the time. Assuming we have room between the end of the factory RJ350 air cleaner and the radiator/fan combination, we drill a hole and put the sensor in the metal end of the air cleaner. It's a NPT sensor, so we have historically got a bung of some sort to supply threads on the inside. Works fine.

    Don
     
  16. DomSmith

    DomSmith SILVER Star

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    Don-

    Thanks for the suggestion. Here's where I ended up putting mine:

    [​IMG]

    :beer:
     
  17. Sharp38

    Sharp38

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    Dom

    Looks like you got the serpentine belt system and changed the compressor. Are you able to keep that thing cool with the radiator that you have.

    Don
     
  18. DomSmith

    DomSmith SILVER Star

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    Yes I put the serpentine kit (without air) in initially, and then added the OBA compressor that I had been running on my old SBC. I wanted to get it up and running and then took my time swapping the OBA back in.

    I have not had a problem with the stock radiator and Taurus fan but I have gotten her up to 215-220 on a warm day up a long grade at 70-75 MPH. Nothing too concerning but I live in SoCal so not much heat to deal with here. I doubt it would cut it in AZ.
     
  19. Sharp38

    Sharp38

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    Dom

    This is what I put in my personal 65 fj40. 350 SBC with TBI. The radiator is 32 in wide Griffin, 2X1.25 tubes. Two 12 in spal fans, driver's side on engine temp switch, pass side on adjustable temp switch in water outlet of radiator. I don't have a bunch of miles on it, but haven't gotten it to go over 170 yet. I would have put 2X1.5 tubes, but I have an FJ60 PS box on the frame and that was as thick as I could go.

    Don
    1014111519.jpg
     
  20. Sharp38

    Sharp38

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    Spectre makes an air cleaner that is recessed in the front that will fit the RamJet. Gives you a location for the sensor in the front. The Spectre part number is 8138. Photo attached.

    Don
    1017111546.jpg
     
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