I have an aftermarket knock sensor that came off an old car. I can't remember where the sensor should be mounted to the engine. It's going onto and from a version 2 sti. Would this replace an original knock sensor already on the engine, (or do they not have one as standard???) or does it simply bolt on in a new location? Thanks in advance for any help.

 

I have bolted mine near the engine number on my newage, not sure if the holes are there on the classic.

 

Thanks for quick reply, is it just a matter of bolting it to the engine somewhere then?

 

What's this being connected to, a KnockLink (or similar "approximate" device) or a good digital knock detector? The obvious location is the unused M8 boss right at the back of the block - next to the engine number like 360ste says. However, this isn't ideal, especially with a KnockLink, as it will pick up a hell of a lot of unwanted noise from the transmission.

The better location, if your car doesn't have aircon, is the unused M10 fine boss above the #2 cylinder - but you will need an adapter to fit a regular knock sensor there. And, as above, it's occupied on an A/C equipped car.

 

Thankls splitpin. It is a black box knocklink sensor (are these not very good then?). Just thought I would make use of it as I had it. No aircon as its going on a track car.

 

Do you mean an adapter to bolt it to the block?

 

KnockLink is better than nothing and was a boon in its day (when there were no commercial alternatives), but it is very imprecise. It doesn't accurately detect knock, it merely gives you an indication of the overall noise level emanating from the engine, with the theory being that any sudden increase in level should be considered as "knock".

In reality it can pick up false readings from all sorts of sources - from a noisy transmission to a "loud" or bumpy road surface. However, as above, it's better than nothing once you know how to set it up and read it.

And yes, if you're building a track car without aircon, you will need an adapter to mount it to the spare boss above #2. The hole there is threaded M10 x 1.25, and your knock sensor will have an 8mm bore, so you need something that screws into the engine, with an 8mm shaft and M8 thread on the top - so you can screw a nut onto the whole thing and tighten the sensor down.

 

Brilliant, thanks for your help. Will soon be runnning a power fc so maybe not worth the hassle as the fc reads knock I think. Anyone want a cheap knocklink?