fishtaco

Sorry if this has been asked before, I did try a search but I didn't find what I was looking for.

J&S Knock Sensor seems to be the recommended one from the posts that I've read. In what areas is it better than the factory one?

Thanks a lot...

cewrx7r1

iTrader: (2)

You can adjust it's sensitivity so it starts retarding sooner than the stock one. Stock really does not seem to work from all the evidence given over the years.

Warning: if you get the model that retards only the leading and have a PFC, make sure your timing split for boost is at least 15 degrees.

The old only retard the leading model isn't worth the trouble to put it in. Many of us have tried it and taken it out as it caused more problems than it solved.

fishtaco

Thanks for the info.

So it is worth it then to get the J&S knock sensor over the factory one. But seems like you need to get someone to tune it.

Sonny

The J&S isn't really tuneable. It has one adjustment **** (sensitivity). As Chuck mentioned, the old unit was a single channel unit that could only retard timing on the leading plugs. People had trouble with it because you can choose between 10 or 20 degrees of maximum retard. With 20 degrees, it's possible for the J&S to pull enough timing out that you end up with 'negative split' (leading plug fires AFTER trailing)...a big no no.

I have one in my car now and have used the J&S on several piston motors since 2000. It's a great tool, but the rotary is a little different. I feel comfortable with it and I am glad that I have it...especially on 91 octane pump gas.

There is a 2 channel version out now that you can use to retard timing on the trailing plugs. Better yet is the 4 channel version that would retard timing on the leading AND trailing plugs. I have yet to convince John to let me play with one of those.

It's about half the price of the Power FC. The Power FC is a better buy for the money, but like anything, knowing how to use it is important.

Sonny

EVLFD

Heres a dumb question but i got to ask. Is it necessary to replace the knock sensor?

Sonny

You only need to replace it if you damage the stock one. The ECU will throw a Check Engine light if it detects a problem with the stock sensor.

Sonny