Has anyone used the J&s knock control system while using the Power FC as the Fd's main computer? I know that the power Fc has a setup for the knock control, but I have the J&S unit and was thinking of putting it in as a backup. Was wondering if anyone has had this set up in there Fd ? Would either one affect the performanceof the other? Will apreciate any input.

 

I believe the PowerFC can only monitor knock, not react to it - as in, pull timing when it senses knock.

I don't see any reason the J&S wouldn't work, but I'm not sure how the newer ones work. The older ones only pulled timing on leading, and if it pulled enough at the right spot you'd have negative split with trailing - that's a Bad Thing.

Really, I think you'd be better off with a quality, safe tune.

Dale

 

Max leading timing retard on J&S is 10 degrees. Adjust your timing to have a leading/trailing split of 10 or more when on boost to avoid what Dale mentioned. I've used a J&S with PFC for almost 3 years, luckily the J&S has never detected knock/retarded timing.

Jack

 

John at J&S has yet to make a unit for the rotary that is capable of retarding both the leading and trailing. this may happen in 06 however that doesn't mean that the current J&S can't work well on the rotary.

most J&S knock sensor units can retard either 10 degrees or 20 degrees at the maximum. the newer models have a vacuum/pressure line in and can be set so as to only retard at a certain level of boost, say 2 psi...

so you set your split at 12-14 u boost and you never run into the leading firing before the trailing. and you have timing retard on the spark plugs that matter, the leading.

should you wish to further fine tune.... send your unit in and they will change the maximums from 10 + 20 to 5 + 10 for $35.

i am looking forward to tuning my methanol injection w the help of the J&S. i will, BTW, still retain the OEM knock sensor.

howard coleman

 

thanks for the input guys.