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Wastegates and MBC's

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  • Wastegates and MBC's

    My current build ia a KA-t, and has both a tial 38mm WG and a Greddy Profec Spec b 2 million or whatever it is, my question is, do I need an MBC if I have an adjustable WG? Doesn't that control it? Or is an MBC just for setting the psi wherever you want it from the cockpit.

    If the latter is true, and all I have is a tuned ecu, couldn't that be kind of pointless? Seeing as how each psi requires a different tune.

  • #2
    You already have an electronic boost controller so there's no need for a manual one.


    • #3
      Each psi does not require a different tune either
      Between rides...unless you count a WD21...


      • #4
        When you get tuned, you tune for the highest boost you'll ever run.

        Then you turn it down a bit for normal driving.

        Your high boost tune should work for lower boost levels - as your tuner likely covered that portion of your map when he was tuning. If uncertain, make sure he makes a clean tuned pull at your desired boost level as well as your 'high boost' setting.
        1990 240sx - Aristo 2JZGTE, R154, GT37, Defsport Wilwood kit, KTS coilovers - daily driver
        1991 civic si - B18C5 / toda / ATS / hytech - autox
        2001 integra type R - Greddy td05-18g - garage queen


        • #5
          Well its a jim wolfe and was done before I owned the car so I have no idea what its set too.

          Speaking I can't find specs on this turbo anywhere.


          • #6
            Come on now... pull cover off ecu, copy down text written on eeprom and call/email JWT, it's that easy.

            JWT build the programs for the ECU's based off of CR, injector, and MAF... nothing else.


            • #7
              I did that, I have the specs.

              So you are saying that psi doesn't matter.

              It has to, doesn't it? I'm confused.


              • #8
                And what is written on the specs? I've used JWT for 10 years on several different vehicles, ranging from 7psi on a T25 to 16psi on a T28... the ECU tune never changed as I used the same MAF/Injectors on all these setups.

                On a basic rom tune (like JWT) the psi only matters when you max out the injectors or MAF, ignoring the turbo and detonation.


                • #9
                  the tune is set up so that everything in the airflow range defined by the MAF selected is correlated to the appropriate pulsewidth for the Injector specified, aslong as you aren't exceeding either of those limits with the PSI you select you will be within the Map.

                  It's a Mass flow system not pressure driven, ecu doesn't know manifold pressure
                  I am SKULLWORKS


                  • #10
                    Well its a turbonetics t3/4 hybrid with a .63 A/R. I have no idea on the specs of the turbo but its definitely a small frame. the injectors are 720cc and thats what the tune actually calls for I guess.


                    • #11
                      Is it being said that no matter the psi the ecu compensates for it? Is that what a ECU tune consists of?