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Solo_S14 Needs Help!! - Tuning Experts??

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  • #16
    Removing the pads should lower your static CR .2 to .3 points. Easy to check before and after. You have both kinds of heads you can measure the CC on right?

    You are misunderstanding me with all of this. I did not say that the perimeter of the piston did not provide for quenching of the air/fuel. They do more than just quench which was the reason for my comment. Had I known my comment about not calling them quench pads would start a flame war then I would have gladly omitted it. You can call them quench pads it does not bother me.

    Yes If you read my original post I do discuss shrouding but not airflow through the valves. I am talking about shrouding of the flame front from the fuel and air in that area. This area is where detonation is occurring. Hmm, fresh air and fuel pocket... descending piston (expanding quench area)... very high heat and pressure...

    I posted to help Solo_S14 not debate. If he tries my suggestion and it helps then he can move on to get some racing done.

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    • #17
      Originally posted by Def View Post
      So quench area = no power? First I've heard of that interesting theory...
      "Quench Pad" the cause of detonation? Ironic right?

      Comment


      • #18
        p00t, you aren't adding anything, you are speculating on something you don't understand and recommending someone change something pretty drastic to solve a problem...that isn't related to what you are inferring.

        And your first post does actually claim the quench pads are not a squish area...thats like saying the beach is not the ocean front...and there is no mention of shrouding.

        the bottom line here is you don't get why the pads are there and you are trying to argue they are doing exactly the opposite of what they do.

        On another note...descending piston doesn't increase the pressure the flame front does...the expectation is that all air/fuel gets burned...when the flame front reaches the edge of the cylinder i would hope that fuel ignites...that's kind of the point.

        Please leave this horse alone or start a new topic, you seem to be the only person supporting your theory and you are mucking up a help thread.


        BTW def was pointing out the irony of your self defeating arguments, not suggesting they had merit.
        I am SKULLWORKS

        Comment


        • #19
          Originally posted by p00t View Post
          Removing the pads should lower your static CR .2 to .3 points. Easy to check before and after. You have both kinds of heads you can measure the CC on right?

          You are misunderstanding me with all of this. I did not say that the perimeter of the piston did not provide for quenching of the air/fuel. They do more than just quench which was the reason for my comment. Had I known my comment about not calling them quench pads would start a flame war then I would have gladly omitted it. You can call them quench pads it does not bother me.

          Yes If you read my original post I do discuss shrouding but not airflow through the valves. I am talking about shrouding of the flame front from the fuel and air in that area. This area is where detonation is occurring. Hmm, fresh air and fuel pocket... descending piston (expanding quench area)... very high heat and pressure...

          I posted to help Solo_S14 not debate. If he tries my suggestion and it helps then he can move on to get some racing done.
          Detonation usually happens before the piston reaches TDC (or at it). So that part of your theory is all wrong.

          Don't confuse seeing detonation damage on quench pads as them CAUSING detonation. They generally improve the quality of combustion by increasing the speed and quality of the combustion due to turbulence in the CC. This function does not increase the possibility of detonation.
          '18 Chevrolet Volt - Electric fun hatch for DD duty!


          DefSport Koni Sleeve and Spring Perch Buy!!!
          http://www.nissanroadracing.com/showthread.php?t=5902

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          • #20
            Detonation usually happens at or after TDC for a number of degrees, as per Heywood.

            Comment


            • #21
              Originally posted by Tower240sx View Post
              ...and there is no mention of shrouding.
              Originally posted by p00t View Post
              You can see that the detonation is originating from under those pads as they hide the fuel/air mix in those regions from the flame-front.
              You can scratch it off the list then. I'm interested in seeing what the fix is for Solo_S14.

              Comment


              • #22
                Originally posted by Jason M View Post
                Detonation usually happens at or after TDC for a number of degrees, as per Heywood.
                That's not what I've seen from combustion videos. I agree it can happen roughly around TDC, but significantly after TDC the clearance volume has opened up in the quench area, and there just isn't much fuel/air to really create another bit of burning.

                I forget the percentages, but quite a bit of fuel/air mixture has burned at TDC for an engine operating at MBT.
                '18 Chevrolet Volt - Electric fun hatch for DD duty!


                DefSport Koni Sleeve and Spring Perch Buy!!!
                http://www.nissanroadracing.com/showthread.php?t=5902

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                • #23
                  Did the original poster ever resolve the issue?

                  Comment


                  • #24
                    Do you have any logs of the knock sensor voltage and how you have the knock retard setup on this car?

                    Also on most turbo cars detonation happens at peak torque where the cylinder pressure is highest. Therefore in this area the timing should be much lower etc.

                    Backpressure can be a problem, but not usually at the lower power levels you are currently seeing. Are you using a

                    Are you using the 24-1 trigger wheel that they recommend with this setup? And also how well is the timing synced?

                    I have had problems in the past with timing "drift" when using the stock trigger wheels. Use a timing light and set a fixed timing map, then rev the car and verify the timing stays where its supposed to.

                    If you need some real tech help pm me and i will send my work phone number.

                    Zack

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                    • #25
                      just realized someone resurrected this thread haha

                      zack

                      Comment


                      • #26
                        Ya Solo, ever get any luck on this one? Do you still think this is ECU related or could engine setup be playing a role?

                        Comment


                        • #27
                          Hey guys!

                          My bad for writing this thread and then disappearing for ....I don't know.....2 1/2 years :P

                          Updates coming for my build thread - I got back at the car over xmas last year and it's now back up and running. A few teaser pics until I can get some time to update that thread.

                          I depinned and rebuilt the engine harness over the winter, and then over the summer I decided to cut everything that wasn't essential out of the main dash harness:














                          Now that I've (hopefully) got everyone's attention - I'll answer the questions that I saw throughout the thread, and post my latest tables and logs - as I'm still seeing the issue......
                          Last edited by Solo_S14; 11-04-2015, 12:07 PM. Reason: Fixed Photo Links
                          In Zipties We Trust....

                          Comment


                          • #28
                            +1 on which CAS disk you're running? I would assume the 24-1 AEM disk given how much troubleshooting you've done, but maybe it's been missed over the years.

                            Actually I'm pretty sure it's stock.......I'm going to find one and get it on order.


                            In addition, I would not rule out the EMS. I know the v1's had some injector driver problems for a long time, and some other circuitry issues as well.

                            I contacted AEM last year to send the unit back and have it tested. They ran through some basic things with me and then said that I'd be wasting my money to send it back. The theory was that either the unit would work, or it would be broken......an RPM bound issue (that isn't random or continuous) wouldn't be attributed to a physically damaged/deteriorating ECU.

                            Long story short, I haven't tried another AEM V1 EMS because I don't know of anybody that has one to try.



                            Damage, is it always on one cyl or on multiple? If on one cyl, is it always on the same cyl?

                            The built motor that I lost in 2009 was due to severe detonation on Cyl #2. 40psi compression on that cylinder before pulling the motor.

                            In 2010, I melted a stock motor - results as follows:
                            - Piston #2 actually melted through the top and side
                            - Piston #3 cracked ring land
                            - Cylinder #2 aluminum build up and scoring on the wall

                            Compression test:
                            #1 - 133.5
                            #2 - 0.0
                            #3 - 91.5
                            #4 - 136.0


                            Coincidentally, when I melted a coil pack harness on the dyno in 2012 (I believe because the ground had been cut off for some reason) - I got a new harness, and haven' had an issue since - In 2012 I was hoping that this was my issue - but apparently not (details in the 1st post of this thread):

                            Details:
                            - We ended up melting the clips on the coil pack harness CYL #2 & #3 - and thought that this may have been causing our ignition / detonation problems, and stopped tuning





                            I'm pretty sure that injectors have been moved around cylinders over the years / while troubleshooting - but never changed out.

                            I wonder if an injector is causing an issue on one cylinder that isn't being picked up on the overall AFR readout?

                            Do you guys think that this could be igniter related? I rebuilt all of the wiring this summer, so I shouldn't have any more damaged wire issues - but I wonder if a damaged igniter could be the issue?



                            Ever shut the motor down as it detonates and read the plugs?

                            No. This might be difficult now that I no longer have access to a dyno and don't want to die on the side of the highway


                            Have you checked that all 4 cyl’s timing is stable from low to high RPM?

                            No, but I will do this tonight - it might point to igniter issues / timing "scatter" on one cylinder, etc.


                            Have you run EGT’s over the 4 cyl’s when on the dyno? Even a hand held infra-red will tell you a lot

                            No.
                            Do you think I'd be able to pick up on temperature differential across cylinders with a handheld unit, after just doing a few pulls on a highway in Mexico, with minor knock, and then pulling over to the side of the road to check? Or do you think this would have to be done basically while on the dyno?


                            Have you got sufficient fuel flow?

                            My AFR's are super rich. I've also got good fuel pressure.
                            If my fuel line was undersized do you think that for some reason I could have flow issues that aren't picked up on in the AFR's or in the pressure? I wouldn't think so, but worth asking the question.


                            What plugs do you usualy run?

                            BKR7E. In 2013 I dropped my plug gap down from 0.028" to 0.024" while troubleshooting, but didn't notice a big change. I had coincidentally built torque a couple hundred RPM earlier, but I think that's because I dropped the boost down to a more efficient level.


                            Does it do this at slightly lower boost (~14psi)?

                            Yes. I've posted logs below at ~14-15psi from last night.....continuing issue.


                            Have we verified fuel pressure is stable at all RPM's/load...what is the max injector duty cycle?

                            I haven't logged fuel pressure, but I also haven't noticed anything out of the ordinary.
                            I'll record my gauges tonight and play them back / report back. It won't be great data (no real resolution) - but I should be able to pick up on any fluctuation. Since my AFR's are so flat, I've never thought to look deeper. I'll also log my duty cycle and post it up.


                            What turbo, exhaust housing and manifold are you running?

                            GT2871R 0.64A/R. The manifold is a bottom mount Full Race prototype from ~8-9 years ago.


                            Camshaft timing and specs?

                            Tomei Poncams 256.
                            Last edited by Solo_S14; 11-04-2015, 12:15 PM. Reason: Fixed Photo Links
                            In Zipties We Trust....

                            Comment


                            • #29
                              Do you have any logs of the knock sensor voltage and how you have the knock retard setup on this car? Also on most turbo cars detonation happens at peak torque where the cylinder pressure is highest. Therefore in this area the timing should be much lower etc.

                              I don't have logs from the dyno - but I do have logs from last night. Pretty consistently I'm seeing noise start in the ~5500RPM range, and spikes at ~6500RPM. I've posted my timing and fuel maps below, along with (4x) logs.

                              On a related note, I've attached further below a comparison of my 2012 and 2013 dyno charts. 2012 is in bold, and 2013 is the thin line. In both years, torque begins to drop off at 5500RPM, and then there is a noticeable drop-off in torque at 6500RPM (especially 2013). Last night we starting to pick up knock at ~5500RPM and it was usually peaking at ~6500RPM in the logs.

                              My timing map is especially retarded between 5500RPM and 6500RPM @ ~15PSI. I assume that this was done to try to combat the knock that we are seeing.

                              Logs attached for 10:45pm through 11:38pm – with the RPM called out in the titles. It’s sort of tough to see the peaks in knock with the cursor – but my cursor is usually over the peak (you can kind of see it). 11:09pm was the worst spike in knock @ 6500RPM by far.

                              Maybe you guys can make some sense of the patterns against the timing table. To answer the other question, I don't see any timing being pulled on the charts, which tells me that the retard function either isn't set up, or it's not picking it up properly. Need to take a look at this tonight.



                              2012 (Bold) vs 2013 (Thin)






                              Timing Map



                              Fuel Map



                              10:45pm - Spike @ 6200RPM



                              10:46pm - Spike @ 6400RPM



                              11:09pm - Large Spike @ 6500RPM - it shows yellow in the screen capture



                              11:38pm - Spike @ 6500RPM



                              As always - any help is appreciated - trying to make some AutoX racing this weekend - so tonight I'll be troubleshooting what I can.

                              Thanks guys.
                              Last edited by Solo_S14; 11-04-2015, 12:19 PM. Reason: Split post due to excessive photo link length
                              In Zipties We Trust....

                              Comment


                              • #30
                                Hi guys - 3 years on - Again.

                                After the issues documented above, I tore down the motor and it seems that (almost) everything was fine.
                                No damage - with the exception that valves were literally kissing pistons enough to remove some carbon but not enough to damage anything permanently - valves were still sealing.
                                Thinking possible valve float from the stock head / stock valvetrain that I went back to after the last failure, along with the little extra lift from the Tomei 256 poncams.

                                Long story short I've rebuilt the engine - moved back to my full Ferrea valvetrain and ran a thicker HG. Also upgraded fuel system, fully rewired the car, new to me trans, etc.
                                The car is back on the road and engine is breaking in - I need to get in touch with a reputable tuner that knows AEM (V.1) and knows SR20DET's.

                                Looking back I think that my timing in higher RPM's was retarded too heavily - since the car was making more power (with the same "knock" - thinking it was mechanical all along) as timing was added.
                                Who can I get in touch with (ASAP) to pull some logs, e-mail exchange some info, and finally get this thing dialed in?

                                Note - no reputable dyno where I live, however access to a long offroad area - so looking for a "street tune" - pulls in all gears etc.
                                Driveability is already very good, just looking for high load / full throttle tune.

                                Thanks NRR!
                                In Zipties We Trust....

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