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ECMlink Knock on e85

Posted by jed344, Jul 24, 2019

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  1. jed344

    jed344 Proven Member

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    Waterville, Iowa
    I have been running into a strange issue on my new build. I have been tuning dsm's and with e85 for at least 5 years and am no stranger to them. The car has a 1/2 filled split thrust 7 bolt built loose, 10:1 pistons, cams are BC 288s degreed to motor. 62mm hx40 in .82AR housing. The e85 tested at 87%, currently on 20psi and only 12 deg of timing I seem to be picking up .4-1.5 counts of knock retard 5500-6500rpm. It seems no matter what I do it shows up, could it be the 1/2 filled block is cause the knock sensor to pick up motor noise? I have a new knock sensor on the way and new plugs so might try to disable knock sensor and read the plugs after a pull too see. Just seems strange as I have tuned cars with much much more timing without issues on e85. 7,000 rpm + seems to not pick up any knock and the car really feels like it wants the timing.
     

    844  26

    1997 Mitsubishi Eclipse GSX
    awd · manual · 2G DSM
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  2. motomattx

    motomattx Proven Member

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    wampum, Pennsylvania
    I wouldn't do that if its really knocking, E85 goes straight to detonation quickly from knock and can do some real damage! You almost need a dyno to see if its knock limited at this point.
     

    Drag Race Build 3K  24

    1995 Mitsubishi Eclipse GST
    fwd · manual · 2G DSM
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  3. jed344

    jed344 Proven Member

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    Waterville, Iowa
    How so? Would be easy enough to put a new set of plugs in and do a pull. Then pull the plugs and look at the insulator for signs of detonation. I know reading plugs is a dying art but when done correctly can tell you a lot about what is going on. I find it hard to believe it is knocking around that rpm then randomly goes away as rpm goes up and even more timing is added. Normally it will continue to knock and even worse. I find is hard to believe my motor is already knock limited when buddies 6 bolt I built with 9:1 pistons on e30 we are at 28psi on bolt on hx35 and 19 deg with zero signs of knock.
     

    844  26

    1997 Mitsubishi Eclipse GSX
    awd · manual · 2G DSM
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  4. ist dwa

    ist dwa Proven Member

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    Centerville, Ohio
    Post a log, but that is very little knock, almost not enough to even worry about.
     
  5. 1990TSIAWDTALON

    1990TSIAWDTALON Moderator

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    Independence, Kansas
    I bet the half fill in the block is resonating somewhat, maybe transferring the knock noise a little easier BUT as @ist dwa says, that is very little knock. Now I disabled my sensor one time and did ONE PULL and melted a piston and burned 2 valves. Car ran GREAT but I couldn't believe that I couldn't run 4* on pump gas, boy was I wrong. Limped home on 2 cylinders.
    I always run my DSM's on E85 also, its the bee's knees' for fuel, I just hadn't gotten to the transfer over yet on that car.
    I would add a degree or 2 and see if it pulls that much more out or stays at .4-1.5. Pulling the plugs is a good idea too. You for sure know that with E, we can usually run 14-19* and not see knock, or at least that is my experience.
     

    Street Build 4K  28

    1992 Eagle Talon TSi AWD
    awd · automatic · 1G DSM

    683  14

    1990 Mitsubishi Eclipse GSX
    awd · manual · 1G DSM

    511  18

    1967 Chevrolet Camaro RS
    rwd · automatic · Misc Vehicles

    Street Build 716  7

    1998 Eagle Talon TSi
    fwd · manual · 2G DSM

    Street Build 5K  11  25

    1990 Eagle Talon TSi AWD
    13.620 @ 108.460 · 1G DSM
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  6. jed344

    jed344 Proven Member

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    Waterville, Iowa
    I tried that. Ran 8-13 degrees and it would sometimes show some knock and sometimes clean. That’s why I think I will add more timing, disable the sensor, read the plugs. I can only think the 1/2 filled block is transferring a sound the knock sensor is picking up.
     

    844  26

    1997 Mitsubishi Eclipse GSX
    awd · manual · 2G DSM
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  7. 97gsxIA

    97gsxIA Proven Member

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    Mount Vernon, Iowa
    You'll know if it is real knock if you add timing or up boost and it gets worse in the same spot respectively.
    When I run into a small count of knock that pops up, I'll push it a couple degrees or another psi to confirm its real.
    Without risk, where's the fun?
    5500-6000 for an HX40 is real close to where it kicks up to peak torque. Add a half filled block and 10:1 pistons... it wouldn't terribly surprise me. But saying that- I've pulled 14*adv at 38psi on almost the exact same turbo in a different housing, I would say push it a couple more degrees or psi and see how it responds.

    Keep in mind theres nothing explicitly wrong with retarding a couple degrees at peak torque for 500 rpms, and then come back up a few when the curve plateaus.
    I'd rather push a few more psi, then worry about a couple degrees of timing.
    Different strokes for different folks.
     

    3K  10

    1997 Mitsubishi Eclipse GSX
    11.316 @ 131.63 · 2G DSM
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  8. jed344

    jed344 Proven Member

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    I’m going to try some fresh plugs to read too and see what they say. Worst case it will just be soft in that area and back half. The car pulls out past 8,000rpm with zero drop off in power.
     

    844  26

    1997 Mitsubishi Eclipse GSX
    awd · manual · 2G DSM
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  9. Steve93Talon

    Steve93Talon Proven Member

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    Look up knock ears or det cans
     

    Drag Race Build 1K  24

    1991 Eagle Talon TSi AWD
    369.5 whp · 403.2 lb/ft · 1G DSM

    2K  7

    1993 Eagle Talon TSi
    11.784 @ 115.120 · 1G DSM
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  10. Ben-Stian

    Ben-Stian Proven Member

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    If you pull timing, do you still get the same knock?
     
  11. jed344

    jed344 Proven Member

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    Pulled the plugs and going off the timing mark burned on the ground strap the car needs more timing. Heat looks correct distance up threads. Will try a fresh set of plugs and look for knock.
     

    844  26

    1997 Mitsubishi Eclipse GSX
    awd · manual · 2G DSM
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  12. jed344

    jed344 Proven Member

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    0B2C6A33-B93D-49F6-91C7-A66B14722622.jpeg
     

    844  26

    1997 Mitsubishi Eclipse GSX
    awd · manual · 2G DSM
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  13. donniekak

    donniekak DSM Wiseman

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    Surprise, Arizona
    You can only read brand new plugs. Do a wide open 3rd gear pull and shut the engine off at the end of the pull.
     

    Street Build 4K  0

    1991 Eagle Talon TSi AWD
    manual · 1G DSM
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  14. 1990TSIAWDTALON

    1990TSIAWDTALON Moderator

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    Agreed......1 pull per set to read them.
    Good call Donnie!
     

    Street Build 4K  28

    1992 Eagle Talon TSi AWD
    awd · automatic · 1G DSM

    683  14

    1990 Mitsubishi Eclipse GSX
    awd · manual · 1G DSM

    511  18

    1967 Chevrolet Camaro RS
    rwd · automatic · Misc Vehicles

    Street Build 716  7

    1998 Eagle Talon TSi
    fwd · manual · 2G DSM

    Street Build 5K  11  25

    1990 Eagle Talon TSi AWD
    13.620 @ 108.460 · 1G DSM
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  15. jed344

    jed344 Proven Member

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    Waterville, Iowa
    Sounds good I have a bunch. Laptop is almost dead so need to charge it. But I richened it up from 12.0 to 11.7 and the knock went away. I’ll try new plugs and add some timing and see what it says.
     

    844  26

    1997 Mitsubishi Eclipse GSX
    awd · manual · 2G DSM
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  16. 1990TSIAWDTALON

    1990TSIAWDTALON Moderator

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    Independence, Kansas
    Glad you made some "progress" at least. Hope that it all turns out for the good for you and Mr Knock stays away!
     

    Street Build 4K  28

    1992 Eagle Talon TSi AWD
    awd · automatic · 1G DSM

    683  14

    1990 Mitsubishi Eclipse GSX
    awd · manual · 1G DSM

    511  18

    1967 Chevrolet Camaro RS
    rwd · automatic · Misc Vehicles

    Street Build 716  7

    1998 Eagle Talon TSi
    fwd · manual · 2G DSM

    Street Build 5K  11  25

    1990 Eagle Talon TSi AWD
    13.620 @ 108.460 · 1G DSM
    Loading...
  17. jed344

    jed344 Proven Member

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    Joined Jan 10, 2008
    Waterville, Iowa
    The car felt much stronger when richer too. So this might be a odd case where my set up just likes richer on e85 then some. I will add i think this set up is going to make some power at a peak of 20.2 psi and 11 deg of timing i logged 40lb/min.
     
    Last edited: Jul 26, 2019

    844  26

    1997 Mitsubishi Eclipse GSX
    awd · manual · 2G DSM
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  18. jed344

    jed344 Proven Member

    563
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    Joined Jan 10, 2008
    Waterville, Iowa
    Update looks like bad knock sensor was issue. Old one was oozing out. Put new one in and ran 15 deg of timing with zero knock retard.
     

    844  26

    1997 Mitsubishi Eclipse GSX
    awd · manual · 2G DSM
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    1990TSIAWDTALON likes this.
  19. jed344

    jed344 Proven Member

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    Waterville, Iowa
    Update again. Car is now on 26-27psi running 7 deg at peak tq and around 13 deg at 8,000 rpm. Knock sensor still picks up minimal knock, I pulled some plugs today and did infact see very minimal speckling on the plugs showing the knock is real. More interesting the timing mark looked to be in a good place on the ground strap. Car is logging 56lb/min at 26psi, maybe its time to have to go to e98? Intake temps where around 91-95 deg at end of pulls.
     

    844  26

    1997 Mitsubishi Eclipse GSX
    awd · manual · 2G DSM
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  20. kenuwine4g63

    kenuwine4g63 Proven Member

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    Thats kind of crazy to see knock at that amount of timing with medium boost. Try running a reach plug instead of a standard plug. BR8ces.
     
    kenuwine4g63

    401  0

    1995 Mitsubishi Eclipse GST
    000.0 whp · 000.0 lb/ft · 2G DSM
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  21. jed344

    jed344 Proven Member

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    Waterville, Iowa
    Possibly. I have been in contact with a few people and we are almost wondering if my camshafts are partly to blame. Old school brian crower 288's. I almost feel the motor is detonating before it reaches MBT.
     

    844  26

    1997 Mitsubishi Eclipse GSX
    awd · manual · 2G DSM
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  22. jed344

    jed344 Proven Member

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    Waterville, Iowa
    Update. Lowered boost to 18psi ran into knock again 6500 rpm + at 10 deg. I lowered timing to 8 deg and it pulled clean and car felt like it picked up power by lowering timing. Tested fuel 87% so that’s good. I’m out of ideas.
     

    844  26

    1997 Mitsubishi Eclipse GSX
    awd · manual · 2G DSM
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  23. jed344

    jed344 Proven Member

    563
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    Joined Jan 10, 2008
    Waterville, Iowa
    Last update for the season. Took the car out for 1 last rip. I ended up this summer at 26psi and 4-5 deg at peak tq and 11-12 deg up top. Car logged 58lb/min. Tried to go farther but stock ignition seems to be holding me back aswell as single walbro 450 is about tapped out. I think the knock issues are due to the old school BC 288 cams and there specs and due to them being degreed very far retarted. Plan to switch to gsc S2, Add a ARC 2, and run 2 more walbro 450's in a surge tank for next year. Think turbo I think is more then capable of getting up to if not over 700 wheel being I am logging almost 60lb/min at under 30psi.
     

    844  26

    1997 Mitsubishi Eclipse GSX
    awd · manual · 2G DSM
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