knock knock
Turbo Mini Forums

anyone seen this? Knocksence diy kit, even plugs into the MegaSquirt too :)

http://www.viatrack.ca/

any use to us A series users?

...............................//tumbleweed/..............

I think there have been threads on this before. The basic config of the a series (e.g. 3 main crank) means there is going to be a lot of background 'noise' making accurate knock detection difficult........

There is always a first to make it work though....

Mike, why not be the innovator and report back?

ok, sod it, i'll be the one that gets laughed when u all turn round and say 'told you you couldnt do it'!!!

n, seriously, i'm going blind into this, i'll order a kit after i've spoken to the guy selling them and we'll see what comes of it.

Hey, that's the way to do it!

I had the same feeling when I first went over to Weber Alpha in '99 (?)... Learnt a lot since then!

Keep us informed!

err, what do i reply with?!?! i know f-all about knock sensing!

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Mike,

Without seeing the engine close up it would be hard for me to guide you where to mount it. I am also little confused with your mention of the crank and its relevance on the knock sensor location. Perhaps I am missing something.
Generally the knock sensor goes on the upper side of the block, centered near the intakes. Two pin Bosh sensor is recommended and it has a hole for 8mm bolt.

"good idea boss"

"Mike,

I looked at the pictures but it is hard to see if there is a convenient spot.
Sound conduction propagates well throughout the block so if you center it somehow it should work Knocksense has adjustable threshold to compensate for different signal levels. "


so i need a hole drilled and tapped at the top of the block and it should work, its not a bank busting project so have ordered one.

Could you use one of the alternator mounting bosses cast into the block perhaps??

is that central enough? would save the posability drilling into a gallery tho i suppose.

Don't know. It has the main advantage of being already there though........

Isn't there knock sensor on the MPI mini? where is that mounted?

Team Racing

I didn't think they used one? But I could be incorrect there?

I could be wrong too

Team Racing

MPis dont have one


You need it mounted between cylinder 2 and 3 about half way up the bore.


Alex

AlexF

any prefs on front or back? Are there any 'safe' areas away from water galleries? I guess i only need 10mm deep.

I'd go with the front, or it will BBQ under the turbo!

It doesnt need to be very deep at all.... its only a piezo electrical microphone that listens to the sounds of combustion ringning through the block.

Alex

AlexF

k, any pointers on wheres safe?

just use the casting marks on the outside to miss any oil galleries...

You can use a length of welding wire down th inside of the coolant passages to trace their route through the block.

Other than that just suck it an see. You can always seal the hole with with a plug or just some ptfe on the bolt thread.

Alex

AlexF

would the distributor screw be a decent place? thats on the front half way down?

I have not seen a Knock sensor DIY kit before, however I am running a knock sensor on my ECU system and this detects knock within a certain freqency band (learnt from running an A series into the ground) and retards from the base map until the knock stops, this works on a per cylinder basis, so it is possible. But it is part of an ECU system not a plug in/standalone.
It has been running well for over a year and on various RR sessions has been seen to be detecting knock and generally doing it's job.

y i've got a megasquirt ecu, and this knocksence has been built to work with the megasquirt. i'm sure there probably another/better/different/cheaper way to do it but hey!

hi guys, i have a similar knock detection unit from www.turboxs.com on my subaru wrx and will be fitting one to my mini conversion, i personally think its brilant and works and looks great here's some info about the turboxs KnockLite from the website.

The task of detecting knock is to detect the characteristic sounds of knock above the background engine noise. By filtering out the engine noise, it allows the detection of knock at the earliest stage possible. The task of filtering out the noise is no simple task as the level of engine noise changes with RPM. Thus for a knock detection system it is important to be able to vary the sensitivity over RPM. If you only have one setting then the knock detection will be sensitive to knock at high engine noise (high rpm) but there will be a reduced sensitivity at low RPM.



The KnockLite system connects to a broadband frequency knock sensor such as a Bosch knock sensor, but it can also be connected to a suitable factory sensor. It is very important to carefully position the knock sensor on the engine as you are trying to detect the ringing of the cylinder and so this has a major effect on the performance of any knock detection system. The actual mounting of the knock sensor and the torque setting of the mounting bolt is important as well to provide the best contact for the knock sensor. Under normal operation the KnockLite measures the RPM and adjusts its sensitivity to suit. It then measures the engine noise and determines whether knock is present. If knock is detected it will determine how severe the knock is and flash either an amber or a red LED. The KnockLite initially needs to learn the characteristics of the engine and this is done by activating the KnockLite program mode. In program mode you rev the engine to three separate RPM points and capture the engine noise levels from the knock sensor using the Program pushbutton. This is done over three points in the RPM range so that the KnockLite can determine an engine noise profile. Once calibrated the KnockLite sensitivity can be increased or decreased using the Program button. The KnockLite uses a RISC processor (which is a fancy name for a small micro-controller) to process the knock signal, determine the RPM and store all the calibration information in its non-volatile memory.



As a bonus, a shift light function has been added which is easily programmed by revving the engine to half the desired shift light RPM point and pressing the Program button. If the engine RPM exceeds the shift light RPM point it will turn on a green LED. The KnockLite requires power, ground, knock sensor signal and an RPM signal. The RPM signal can be taken from either a tach signal, which is common on most cars, or even from the points on an older car. The KnockLite is packaged in a machined billet aluminium case and comes with full instructions for fitting and calibrating.

it retails for around $120USD which i thought was'nt a bad price for peace of mind, i will be fitting one to a mates turbo mini when i get back from holidays in 2 weeks will let you know how it goes.

cheers

wayne