S50: lot's of powa when cold, less powa when warm

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  • arsevader
    E30 Enthusiast
    • May 2005
    • 1025

    #16
    Originally posted by aeryk7
    Yeah that just your intake ,hot air in your engine equals less horsepower . Cold air into your engine equals more horsepowe its just that easy .

    Many times when people replace a stock airbox with a cone filter right on to a Air flow meter without a heatshield or air duct it will feel like they lost horsepower when the engine warms up because they are sucking much hotter air than they were before . When the car is first started the engine bay is still cool ,once at operating temp you are screwed and are forced to listen to your cone sucking air but with a nice horsepower loss.
    How much HP does one really need at idle, which is the only time you are really sucking warm air in?

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    • 1991 318is
      Mod Crazy
      • Dec 2005
      • 786

      #17
      Hotcha...

      Put the outside air temp sensor in your engine air intake right after the filter. This will give you the temperature of air going into the motor and costs zip. The computer compensates for air temp by adjusting the fuel. When you swap motors, injectors and who knows what else, the opportunities for a screwup are increased. My bone stock 318is runs without a stutter or slip from startup to 105 degree Texas stop and go traffic. The variation in horsepower is almost imperceptible and that's how it should be. The goal should be to have an S50 that runs as good as it did in the original car(excepting mods). BMW's are good at this stuff.

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      • Ryan Stewart
        I Love Miatas
        • Oct 2003
        • 8978

        #18
        My car is still controlled by the factory controller.

        I have actually noticed the same little hesitation in the M3 but its just less noticable. I think the heavier car and taller gearing masks it.

        Mine only does it around the vanos changeover point when the engine is really cold. Once it gets near running temp its fine.
        Im now E30less.
        sigpic

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        • kylebes1
          R3VLimited
          • May 2004
          • 2804

          #19
          Did you get this handled? I will say when I had my e30m50 I made the mistake of switching the two plugs on teh front part of the head under the intake... one is the coolant temp sensor for the engine... It ran like shit until warm, then ran a little better. I realized what I had done, and everythingw as hunky doory...

          I would say replace the coolant temp sensor, and the eBay heat shields are decent and should work with the swap...

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          • static
            E30 Addict
            • Oct 2005
            • 501

            #20
            can these temp sensors really go bad? what happens when they do?
            Is there a manifold air temp sensor? (sorry, still a newb)

            what else could cause my particular scenario?

            Thanks
            Alex

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