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Eddy current dyno tuning

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  • Eddy current dyno tuning

    Anyone know how to tune timing and fuel on a dyno dynamics dyno?

    This is for an honest spec miata so the only adjustable parts are base timing and fuel pressure.

    Last time I was on such a dyno the owner showed me that flooring it and hitting "page up" and "page down" would change the RPM the dyno was clamping at. Then he ran off.

    How would you guys go about tuning? Get the car to the target coolant temp and clamped at 6,000 rpm and then bravely adjust the timing while the car is at full power at 6k while watching the realtime torque output? Then do the test again at 5,600 and 6,400?
    Last edited by robburgoon; 12-27-2012, 04:16 PM.

  • #2
    Rob,the engine is most prone to detonation/pinging/engine destruction around the torque peak,not peak HP.All "well" boosted engines have a dip in the timing around the torque peak,then the timing ramps up,usually all the way to the redline.
    One of the most important principles in the engine tunning is "least timing for the highest tor the highest torque".What that means practically is that you start raising the timing until the torque numbers go up.Once the torque(power) is not increasing anymore even after the timing was increased you want to go back a degree or so and leave it that way.Continuing to increase the timing at that point wont earn you more power,but will get you closer to the engine destruction.
    If it were me, would adjust the mixture first,at,let's say, 3-4 RPM points between 3500 RPM and the redline.Then continue with finding the best timing points.It is good to have some detonation detection tools,but I dont believe that those engines are detonation limited.
    If you need some more info or help you can PM me.

    Comment


    • #3
      Right, i get the whole add timing until outputput flattens out thing, but my question is more with how to operate the dyno, not how to tune the car.

      Comment


      • #4
        Measure with a dyno run. Shut down and adjust. Remeasure. Shut down and adjust. et al.

        That's how the guys at Bottle Blown Racing in Camarillo did a Spec Miata.
        www.TrackHQ.com

        Comment


        • #5
          Originally posted by ucfbrett View Post
          Measure with a dyno run. Shut down and adjust. Remeasure. Shut down and adjust. et al.

          That's how the guys at Bottle Blown Racing in Camarillo did a Spec Miata.
          There's not an obvious way to do a "dyno run" with an eddy load dyno as you would with an inertial dyno. The dyno decides how long you take to acceleate, not the engine.

          Maybe there's a way to program the dyno to take you from 5k to 7k in 10 seconds and plot it.

          Does anyone know if that can be done or if it will display torque in real time while I adjust the mixture?

          Comment


          • #6
            They used a Mustang dyno, whatever type that is.
            www.TrackHQ.com

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            • #7
              Probably you should hold it on a steady RPM at full load and do the tunning/adjustment,then jump to 300-500 RPMs up and so on.

              Comment


              • #8
                Originally posted by bawareca View Post
                Probably you should hold it on a steady RPM at full load and do the tunning/adjustment,then jump to 300-500 RPMs up and so on.
                Yeah, sounds like it. I can see some advantages to doing it that way rather than separate pulls. I should be able to see if the car is heatsoaking and power is falling, or if it changes right when i turn the wrench.

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                • #9
                  It is hard to compare heatsoaking on the road and on the dyno due to a completely different air flow.Immediate feedback for the changes in the timing-priceless

                  Comment


                  • #10
                    Originally posted by robburgoon View Post
                    Anyone know how to tune timing and fuel on a dyno dynamics dyno?

                    This is for an honest spec miata so the only adjustable parts are base timing and fuel pressure.

                    Last time I was on such a dyno the owner showed me that flooring it and hitting "page up" and "page down" would change the RPM the dyno was clamping at. Then he ran off.

                    How would you guys go about tuning? Get the car to the target coolant temp and clamped at 6,000 rpm and then bravely adjust the timing while the car is at full power at 6k while watching the realtime torque output? Then do the test again at 5,600 and 6,400?
                    I would pay a professional, you know, money.
                    WWW.949RACING.COM
                    SuperMiata

                    Aside from their cost I never understood why people race them.
                    But obviously I just dont get it. -fatbillybob

                    Comment


                    • #11
                      Originally posted by emilio700 View Post
                      I would pay a professional, you know, money.
                      No reason to. I can either figure out this eddy current dyno that's in Escondido, or go to 7's only and tune it the old fashioned way. Either way, the job gets done. It's not like I'm trying to get my car to idle or tune for part throttle fuel economy.

                      Comment


                      • #12
                        Originally posted by robburgoon View Post
                        No reason to. I can either figure out this eddy current dyno that's in Escondido, or go to 7's only and tune it the old fashioned way.
                        This is TrackHQ. There's always the third way... which is that you blow the engine to smithereens trying to figure it out

                        Steve

                        Comment


                        • #13
                          Originally posted by emilio700 View Post
                          I would pay a professional, you know, money.
                          You speekin' langwhich Robbie no understand . . .
                          The deposed former Sheriff of trackHQ . . .

                          2006 Porsche 997 Carerra Coupe 6-MT - daily driver
                          1992 Honda (Acura) NSX 5-MT - classic investment I couldn't resist and occasionally drive
                          2004 Honda S2000 AP2 6-MT - my last track day car (FOR SALE or not, depending on how I feel when I fall out of bed tomorrow morning)
                          2006 Mitsubishi Lancer Evolution IX MR 6-MT - when I need a backseat, 4-doors, or a real trunk, and still want to haul ass . . .

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                          • #14
                            Originally posted by Richard EVO View Post
                            You speekin' langwhich Robbie no understand . . .
                            Be that as it may, it still doesn't make much sense in this case.

                            I also like having a short list of people to blame if things go wrong.

                            Comment


                            • #15
                              Originally posted by robburgoon View Post
                              No reason to. I can either figure out this eddy current dyno that's in Escondido, or go to 7's only and tune it the old fashioned way. Either way, the job gets done. It's not like I'm trying to get my car to idle or tune for part throttle fuel economy.
                              You better figure out the load dyno.After tunning on inertia dyno the car usually needs some fine tune on the street/track.

                              Comment

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