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Thread: Knock Retard

  1. #1
    Join Date
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    Default Knock Retard

    Hi guys,

    Have had my dash hawk on for a while now and have set up KR alarms on it.
    The alert threshold has been set for anything greater than 0.0 (any).

    Have been noticing this a bit and was wondering how much is bad (if any at all) and wanting to know how much and how often the rest of you notice this.


    Cheers!

  2. #2

    Default

    i get concerned about anything over 1.0

    Meth fixes a lot of these issues.. even if its not spraying, because it cleans all the carbon hotspots responsible for some of the KR..

    which would normally be cleaned away in a port injected motor, but not with the DISI..

    Above 1.0 i let off the throttle

  3. #3
    Join Date
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    Default

    You'll always see a bit of part throttle, low rpm KR, its only really an issue if you see it at WOT. I have my screen set to change to a bright blue at 2.0, brighter blue at 3.0, and alarm at 4.0.
    Mine will quite often flash blue (briefly) when moving off from a set of lights, or slowly punting around in traffic at about 70.

  4. #4

    Default

    I never used to think small temperature differences made much of a difference with knock. My thinking was due to the hundreds of degrees generated by the motor, why would and extra 10 or 20 degrees make a big difference? But when my IATs and BATs are running 40 and 50 degrees (usually 30s and 40s), I notice a lot more KR at the low and mid ranges.

    Yesterday I switched over to Denso 1 step colder and cleaned my MAF, and while it's too early to tell, I haven't had a single warning of KR since. Previously I would get at least one warning of KR per drive. I've got my Dashhawk setup to beep over 1.0, 2.0 and 3.0 KR.

    I'm pretty sure my old plugs were one of the contributors to knock in my car. Looks pretty black and I'm not liking those pink spots. My car has done only 8200 km (still new!).


    Nuliaj: Hatches are only really half a car anyway.
    shinslinger66: And you forgot to add that they are also a girls car!

  5. #5

    Default

    Quote Originally Posted by Nuliaj View Post
    I never used to think small temperature differences made much of a difference with knock. My thinking was due to the hundreds of degrees generated by the motor, why would and extra 10 or 20 degrees make a big difference? But when my IATs and BATs are running 40 and 50 degrees (usually 30s and 40s), I notice a lot more KR at the low and mid ranges.

    Yesterday I switched over to Denso 1 step colder and cleaned my MAF, and while it's too early to tell, I haven't had a single warning of KR since. Previously I would get at least one warning of KR per drive. I've got my Dashhawk setup to beep over 1.0, 2.0 and 3.0 KR.

    I'm pretty sure my old plugs were one of the contributors to knock in my car. Looks pretty black and I'm not liking those pink spots. My car has done only 8200 km (still new!).


    The ECU will make timing adjustments depending on IAT and BAT..

    Thats why KR is tied in with temps..

  6. #6

    Default

    KR is essentially the opposite of Timing Advance. If the ECU is doing it's job properly it shouldn't be advancing timing to the point of knocking due to the increased temps. The fact that the knock happens so regularly suggest that there's some other issue rather than just OEM tune being wrong.

  7. #7

    Default

    After installing my DashHawk today I saw KR hit 4.0 under WOT. It hit 2.5 to 3.0 a few times as well. I can't actually hear any pinging/knocking though. The car ran a little rough this morning on startup, as if it had to relearn all my modifications again, so I'll drive a few more km's to see if things settle down.

    But I'm a little concerned about this.

    I have a CAI, TIP and SU TMIC. Ive read up on KR but there are alot of theories/suggesitons floating about. Some suggest checking all intake hoses and clamps for leaks, so i'll try this tomorrow. Should I go colder plugs? Could it be 'fake' KR? Should the dealer have a look at it?

    Ive read any KR above 1.5 on WOT is a worry.

  8. #8
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    Default

    Go one colder Nick, if its still happening get the car into a performance shop for dyno and diagnostics. I wouldnt stress too much.

  9. #9
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    Default

    Revival!

    So the cars had its 40k service and since I have not put my mazdaspeed intake back on just to see how it was going, though I do have an ETS on.

    Today I saw KR flash up of 8! I want to get to the bottom of this and find the cause.. Im thinking of booking the car in with mazda to see what they think, reason being I have a bit of a knocking/clicking noise which I think *may* be timing chain.
    Ive got a sound clip of it but it makes it sound much worse than it does.

    Any ideas/input? - as soon as something is wrong it drives me bonkers.
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  10. #10
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    Default

    Here is a run from the other night.. not as bad as today though

    Click image for larger version. 

Name:	DHKR.jpg 
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ID:	1137

    I put the yardstick (red mesurement tool) over the KR so you can see the values at that time.
    Last edited by Jmac; 19-08-2009 at 10:47 PM.
    MY16 WRX STi Crystal White Pearl
    -= Rally Armour Flaps - 2XS Muffler Delete =-

    FG FPV F6 MKII Vixen - SOLD
    -= Bluepower SRI - ID1000 Injectors - Venom Cat - XCAL3 - ProcessWest Stg2 Intercooler - 359 RWKW=-

    CX9 Grand Touring Stormy Blue
    -= The rolling armchair =-

    6 MPS Velocity Red - SOLD
    -=Cat Back Exhaust - Pirelli PZero=-

    3 MPS Aurora Blue - SOLD
    -=PG SRI - PG Inlet - ETS TMIC - GFB Hybrid BOV - Best Mufflers DP - Eibach Pro - AccessPort STG2 - Autotech HPFP - ITV22 - Michelin PSS=-

  11. #11

    Default

    under what sub menu is the KR situated on the dashhawk. any could anyone tell me the main things u should have set up on the DH?

  12. #12

    Default

    not good jus.....maybe switching to another dealer......

  13. #13
    Join Date
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    Default

    Hey Stealth, try this link for some DH profiles that are MPS based.

    DASHHAWK Datalogging PID Profiles: - Mazdaspeed Forums

  14. #14

    Default

    Looking at that plot I'd say it's genuine KR and not some other rattle causing a spurious detection. It's that classic low-rpm high-load transition that MPS's hate. We can see that the throttle partially opened for about a second, then opened further which brought on some boost immediately followed by KR.

    Had you been doing any steady speed highway style driving leading up to this?

  15. #15
    Join Date
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    Default

    On 80 km/h road, winding it up basically.
    Alfords point road actually
    Last edited by Jmac; 20-08-2009 at 08:53 AM.

  16. #16

    Default

    If you log your ignition timing as well as knock retard, it will be more useful. One of the things you'll notice when you monitor your ignition timing while doing steady driving, is that it slowly creeps up until it hits the mid-high 40s. This is the way Mazda tries to achieve fuel economy. The side effect of this is the temperatures get much higher which is usually what leads to the knock.

  17. #17
    Join Date
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    Default

    Cheers, ill try that.
    I was just a bit spooked after last night.. after reading on MSF a bit it seems to be normal.
    Only problem is the car hesitated a bit and the DH flashed 8.5 KR, I still dont think that can be good though.

    Too bad I wasnt logging at the time, I dont think I was WOT at the time.

  18. #18
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    Default

    What are the normal parameters for advance or retard out of curiosity?

  19. #19

    Default

    I don't believe there is such thing as normal parameters for our car, but this is why long distance highway cruising are commonly mentioned when talking about knock and thrown rods. If you cruise at a constant speed, ignition timing starts to advance, as the higher your ignition timing, the more fuel efficient the car is. Now whether this is in increments of 0.5 or just what my reader shows, but I could be at say 100km/h with a timing of 20 and within a few minutes I'll be up in the 40s because I'm cruising, the ecu tries to use as little fuel as possible and advance the timing all the way up.

    Think of knock retard (as oppose to actual knock) as the opposite of advance timing. The ecu has a balancing act of trying to optimise timing for maximum fuel efficiency without causing knock. It uses both advance and retard in this balancing act. Knock retardation in of itself is not bad, it's the knock that is bad, and there hasn't been enough conclusive evidence to say that everytime we get KR it's due to knock.

    Now all this goes out the door when you go WOT as ignition timing drops to almost 0 and sometimes goes negative depending on your car and driving patterns.
    Nuliaj: Hatches are only really half a car anyway.
    shinslinger66: And you forgot to add that they are also a girls car!

  20. #20

    Default

    Just to further complicate the issue: the knock sensor is a microphone that listens for the sound of detonation - which is the spontaneous explosive burning of the air/fuel mixture rather than the progressive and controlled burning of normal combustion.

    However there are many other sounds that to an ECU sound like detonation. Try tapping the engine with a screw driver while its running and see what happens.

    Another example of eliminating false knock detection is the large black piece of foam under the inlet manifold. If you remove it, the knock sensor will hear the banging of the injectors and pull timing for no reason.

    That's why you first need to determine if it really is detonation before taking action to deal with it.

    I don't have any answers for you, but hopefully you have a better understanding of the issue.
    Last edited by kmh001; 21-08-2009 at 12:02 PM.

    Gone to Volvo


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