Causes of false knocks

K-Series Programmable ECU installation questions / support issues
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kb58
Posts: 81
Joined: Sat Nov 28, 2009 2:53 pm

Causes of false knocks

Post by kb58 »

Had my turbo mid-engine car tuned at Church Automotive last Thursday.

The setup:
  • K24A1 block
    Pauter rods
    9.5:1 CP pistons
    TSX head
    RBC
    2.5 bar MAP
    1000 cc ID injectors
    GT3071 twin-scroll
    91 octane pump gas
    KPro PRB ECU
Don't remember the wastegate spring values but boost came up to 6 psi at 3000, and then it was a straight line to 9 psi at 8000. Torque was 290 across the board, and peak power was 409 whp. Pretty happy with that!

Anyhow, Daniel was seeing a lot of knock; retarding things didn't make a difference. They tried some 109 race gas and it made NO difference either, so the suspicion is that it's seeing false knocks.

Putting on my engineer hat, that seems to mean it's:
1. A wrong knock sensor (I'm using an RSX-S sensor)
2. Defective sensor (it's brand new, but anything's possible)
3. Bad wiring (it's only one wire...)
4. EMI (used the existing shielded wire but shortened it)

Have you guys run into this and what did you do to solve it?

You can read all about it here: http://www.midlana.com/Diaries/Current/

The dip at the high end was due to one of the two wastegates not opening.

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Mid-engine K24 turbo Locost, http://www.midlana.com
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Hondata
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Post by Hondata »

It almost always is 5. Mechanical noise but sometime can be 6. Poor combustion quality.

Usually it is an excessive clearance in the engine, or too much cam acceleration dropping the valves on the seats, or something bolted to the engine transmitting vibration, or a loose accessory.

We've only seen the combustion quality showing knock on the supercharged engines with short / non existent intake runners. In that case, it actually improves with more ignition advance.

You're going to need much more tire.
Hondata
kb58
Posts: 81
Joined: Sat Nov 28, 2009 2:53 pm

Post by kb58 »

Yeah, yeah, those are sticky 275's - not much more I can do short of slicks :P
Mid-engine K24 turbo Locost, http://www.midlana.com
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