West TX RX-7

They worth the money? I'm putting around 12k in my engine ATM for a rebuild turboupgrade and getting it done right. I talked to the builder and he suggested a J&S Knocksensor. Says it'll save your engines *** and with that kinda investment in it sounds like a good idea.

Anyone have any experience with them? They work? What exactly do they do? They kinda high, Jason has em for 525.00 i think.

RETed

Waste of money, unless they have a 3 channel system that can handle both the leadings and the trailings.&nbsp Installing the J&S on just the leadings defaults it as an expensive knock sensor monitor.&nbsp MSD sells one for a fraction of the J&S price.


-Ted

Wankel7

Spending that much coin get your self a wideband kit

James

West TX RX-7

wideband kit?

I'm not sure of it does leadings and trailings or not. Supposed to retard the timing when it hears knocking and you can adjust the sensitivity.

I had been looking into 3 hi-6's so I guess it could do leading and trailing with em all hooked up but thsat would get real expensive.

What does MSD make?

RETed

As far as I know, they are all still one channel models.&nbsp I actually run one on my FC, but it's nothing but a $500 light show.&nbsp We actually managed to blow up a 13B-REW on an FD with a J&S.&nbsp Why?&nbsp The stock ECU eliminates the trailing spark ignition difference to zero, so basically the leadings and trailings are firing at the same time under heavy load.&nbsp So, you can retard the leadings all you like, but the trailings will happily fire the motor.&nbsp Try this trick - remove the leadings and run the car, I bet you can hardly tell the difference.&nbsp The trailings are more than enough to blow the engine up when you run into detonation.&nbsp About the only thing that will save the engine is a quick foot.&nbsp The J&S (when calibrated correctly) can light up with is "sees" light detonation.&nbsp How fast you get off the gas pedal is directly related to if you can save your motor or not.




-Ted

Wankel7

A wideband oxygen sensor, controler, and display. That would allow you to see your exact air/fuel ratio

James

West TX RX-7

I've got an E6K installed, car is at marvelspeed atm, engine us back together and ready to go in just waiting on the FMIC to get in.

I was thinking the knocksensor ( retarder) was supposed to retard the timing or something to help keep the engine from self destructing or driver destruction.

It tells about it here but it doesn't really mean anything to me. I know jack when it comes to ignition and computer controlled timing and spark.

http://www.rx7.com/cgi-local/2catalog.cgi?cat=6&part=5

RETed

Correct - since the J&S is typically installed on just the leadings on our cars, the leadings eventually fire behind the trailings.&nbsp It's the trailings that will kill the engine.


-Ted

rx7freddie

thank u i was gona get this for my 87 turbo 2 but f that i`ll just try my best to make sure everythign is tuned right and if something happins then yeah id ont wanna think about it .

zkeller

iTrader: (47)

Wouldn't it be safe as hell to run zero split and use the J&S? I am running an E6K, Autronics wideband for air-fuel, and a J&S is being added to the family of gadgets.

Scott 89t2

that's great.... too bad this topic is about timming and not air/ fuel.

NZConvertible

You've missed Ted's point. External of the ECU you basically have three seperate ignition systems; one leading and two trailing. An add-on like the J&S can only control one system, so even if it retards the leading coil, the trailings will still be firing with normal timing, so if it's detonating then it will keep doing so. You could buy three sperate units, but that's a tad pricey...