Hello,

Im trying to find the appropreate knock sensor for the rx7, i tried several places and shop but none has any idea of the knock frequency range

Any input, ideas with some information will be helpful

Thanks

 

Contact http://www.jandssafeguard.com/

 

not only they wont pick up the phone that i have been trying to call for 2 months, neither reply my emails, i doubt they will know

 

Bad on them for not replying but they would know. They use some type of Bosch knock sensor as I had one of their earlier units back about 9 years ago.

 

Back from the dead! Looking into getting a new ECU with the Link Knockblock, but wanted to know if anyone had any more information regarding knock frequency on a 13B.

 

what's wrong with the one thats on the engine already?

 

I'll check the model number on my bosch that came with the J&S

 

If you haven't already, read the instructions for the Link Knockblock http://www.linkecu.com/support/docum...4%20Manual.pdf . First you have to set the gain (which seems straightforward), and then you select the frequency filter. If you have a good condition stock sensor in the stock 89+ rotor housing location, the knock frequency is 3.5 khz +/- .3 khz if Mazda technical data is to be believed.



The closest option to that is switch position #3 on the unit. The Link Knockblock is also supposed to have a way of calculating the background noise, just like the stock system does:



I have never personally used the Link Knockblock. However I have significant experience with knock control systems and knock sensor signals on both rotary and piston engine. In practice, there is a LOT of guesswork involved with knock sensors and a lot of trial-and-error. Unfortunately, the "trial" part involves actually experiencing knock, and the "error" part involves risking engine damage. Based on my own experience with high-end (i.e. OEM) knock filtering I am skeptical of the Link's ability to effectively estimate background noise.

I have spent many hours dealing with Subaru OEM knock control systems (STi etc), which are far more sophisticated than anything available to the aftermarket. Even those are very difficult to interpret. Some OEM systems aggressively pick up knock and can be prone to false readings (Subaru) and some are pretty insensitive (Rx-8 is well known for insensitive knock control). In these applications, from the factory the OEM knock system calibration is usually just fine for a 100% stock vehicle. When they are modded you have varying options for adjusting sensitivity in the stock ECU depending on what system you are dealing with. Those systems have multiple layers of timing retard logic and an ability to dynamically adjust ignition timing in response to fuel quality.

On standalones like the AEM EMS you can manually adjust a baseline noise level curve to affect sensitivity, and the ECU will produce a filtered reading. On the Power FC used on most FD's, you get a mostly raw reading without noise learning. This leaves you with a lot of guessing to do.

In the end using knock sensors in this type of application can come down to making frequent judgment calls. I wouldn't call them useless but they're not necessarily going to help you sleep better at night.

 

^ i love you.

 

Now that we've gotten that out of the way, can we skip right to the divorce so I can get half your loot?