knock link

[A80Avant]

ever heard of that before?

http://www.thor-racing.co.uk/Knock_Link-LNK_KNK_LNK.asp

you think it is useful?needed?

[Matt_D]

Yep i had one on my RB5 and it worked well

It basically listens for detonation in the engine, a small 'microphone' bolts onto the engine block but you have to be careful where to mount it so you don't get false readings from ticking injectors etc

[GazzaG60]

a knock link uses a bosch knock sensor same type as vag use. they work yes but its still not gonna stop you blowing it as the sensor that retards the engine is a different one and may not be working.

my mate used to import these for the subaru game. sold loads. the display is around 4 inch by 2 inch but the lights can be removed and fitted to a part of the dash if required.

[A80Avant]

i havent quite understood where the knock sensor itself is mounted and how.I have seen pictures but fail to realise it.Also should it be mounted near the knocksensors that the engine has so as to be as similar as possible to what the oem knock sensor is hearing?

[Matt_D]

Info here on how to fit to a Impreza but fitting is the same:
http://www.rb5oc.co.uk/stephaninstall.asp
...most people mount it here as there is a empty thread available not sure if there is one on the S2

One thing i would say is as the Impreza is a flat-four the knock sensor is mounted pretty much over one of the cylinder heads, on the S2 (not sure where the knock sensor is mounted) i would mount it on the head or top of the block somewhere is possible.

Theres no point mounting it low down on the block when what you want to 'hear' whats going on in the top of the engine, hope this helps

[EspenW]

I have something similar on my Mk2 Golf: http://www.viatrack.ca/
Only one LED as opposed to multiple in the Knocklink.

Costs approx. £ 30 including shipping to Europe.
One advantage with the Knocksense is that it uses one of the stock knock sensors, hooks up in parallel, using the supplied connector.

Works well in the Golf, lots of blinking on 99 Octane, but none on E85
(except at high RPM where the engine makes plenty of noise)

Good think you brought it up, reminded me to get a Knocksense for my RS2

[A80Avant]

if it is blinking on the 99octane then how useful is it?cant it be calibrated?If it is blinking,is there retardation as well?or is it blinking without any reason??

[EspenW]

if it is blinking on the 99octane then how useful is it?cant it be calibrated?If it is blinking,is there retardation as well?or is it blinking without any reason??

It is blinking because it is detecting knock on 99 octane.. The motor has 11:1 compression. No knock sensing ignition on the Golf, so the Knocksense is very helpful.
Running E85 (ethanol), there is no knock (and thus, no blinking), due to the 104 octane rating and cooling effect of the ethanol.
The sensitivity of the Knocksense can be adjusted.
Note: just remembered that the Knocksense is built around a two terminal knock sensor, while Audis use three terminal sensors.
Don't feel like cutting and splicing the sensor wires on the RS2, so I'll see if I can find a place to mount a standalone knock sensor for the Knocksense

[A80Avant]

i have contacted them myself for an individual sensor and instructions.Lets keep contact to see if we can get any results out of this!

[EspenW]

I searched a bit more, and found that there is another unit on the market, the Knocklite, by Turbo XS. This one takes rpm into the equation as well, adjusting the sensitivity based on that.
Available for approx. $ 100 off Ebay.
http://www.turboxs.com/more_info.php?ID=212

(the graph on the bottom of the page supposedly compares it to the Knocklink)

I don't think that we need a standalone knocksensor. I was hesitant about splicing into the knocksensor signal wire in the engine compartment (rubber coated wire, etc), but it will be easy to splice into the signal wire where it enters the ECU.
For the KnockLite, splice into knock and tach signal, for the Knocksense, splice into knock signal only.
I will do a little more reading, but I think that I will try the KnockLite, as it seems more sophisticated, more able to filter knock from engine noise. It works as a shift light too.

[A80Avant]

im hesitant a bit about splicing the existing sensors...
for 50$+shipping i can try the knocksensor with the led to see how it does.It can be calibrated as i am told to specific Hz where the detonation occurs.Originally it is calibrated depending on the engine bore and sound i guess,so im thinking that none of all those items will perform adequatelly unless you calibrate them correctly.But to do that,you must make the engine knock,at least in low rpm in order to make the calibration...

[A80Avant]

does the knocklite come with the sensor and wiring?

[EspenW]

No, the Knocklite does not come with the sensor and wires.
I will check the wires going into the ECU tonight. Did you order a Knock Sensor from Boris (Knocksense), or are you getting one locally?

The knocksense works fine on my Golf, it is just that it seems quite sensitive to engine noise, so it lights up at high rpm.
However, knock is most likely at low to mid rpms, where the torque (cylinder filling) is at its peak, thus temps are the highest, and knock has time to occur. Knock sensitivity decreases with increasing rpm, since the knock events have less and less time to occur.
Strangely, my Golf tends to ping at part throttle, probably due to the vacuum timing advance. With E85 in the tank, there is no ping/knock at all. I've even programmed the injection to 15.3 A/F at part throttle for better fuel economy on E85.
Advantage of the knocksense is that the LED is easy to integrate. Put it in a blank switch, next to your alarm LED, or some other place that is easy to view.

[A80Avant]

i havent ordered yet but will probably go for knocksense along with the sensor,yes.
how can you calibrate the module in order to avoid engine noise?

also where would be a suitable place for the sensor on the RS2 engine?

[EspenW]

The knocksense is calibrated, but you are also supposed to calibrate it at idle.
Another option is to put some low octane gas in the tank, and adjust the sensitivity so that it lights up when it detects knock.
The reason why I want to try the KnockLite is that it seems more apt at distinguishing engine noise from knock.
I will have a look at the RS2 block tonight and see if I can see a suitable spot for the sensor. The 4 cylinder block has plenty of spots with holes with the right thread, so I guess the I5 at least has one..