OKM centre frequency and HW setup

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OKM centre frequency and HW setup

Postby Mazi on Wed Apr 28, 2010 12:14 am

Is it the same for Mitsubishi and Subaru? Any details available?
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Re: OKM centre frequency and HW setup

Postby Martin on Wed Apr 28, 2010 3:49 pm

Definately not.


Ive done subaru`s that have different centre frequencies. Even a modification to the engine will change it.

Its quite easy to get the centre freq on a subaru since it pings quite easily when hot.
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Re: OKM centre frequency and HW setup

Postby PeteS on Fri Apr 30, 2010 8:03 am

Mazi wrote:Is it the same for Mitsubishi and Subaru? Any details available?


Hi Mazi
Subaru's using factory knock sensors are usualy quite easy to set up.
The signal is generaly fairly quiet and the sensor is of the wide band type.
Center frequency settings of 14 and 16k usually work well how ever this is only a true statement for an untouched engine. That said most engine modification noises that may creep in usually occur down at frquencies below 6k.

Mitsubishi is another thing altogether
EVO 4-9 utilise a narrow band sensor where most of the back ground noise and knock all occur at 12-13k
The signal amplitude at this setting is too high so a frequency choice well away from this is required.
Trouble is the more you go away from the narrow band frequency the less the knock shows up.

I have found in the past settings of 6k to be good however this setting can sometimes be over shadowed by excess background noise occuring from fordged pistons etc which usually occur at 3-6 k

there is no magic answer
You should use goldwave to capture a recording of knocking then analyse the results.

It also helps to review the knock manual which is stored on our website.

Regards

Pete
MoTeC Research Centre, Melbourne Australia
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Re: OKM centre frequency and HW setup

Postby Mazi on Sat May 01, 2010 4:26 am

Mea culpa, mea culpa! I just have to buy new glasses... Or microscope...

Frequencies, gain and dm pads are on the bottom side of the OKM TCK pcb.
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