coolrotaries

anyone using the j&s set up with the haltech E6k? How to set it up?

RETed

Which version?
Did they make a 3-channel one yet?

If you're talking about the single-channel one, it's a waste of money.


-Ted

sillbeer

I've been thinking about picking up a J and S knock sensor. I just started looking around today. Could you split the one chanel up to 3 seperate sensors? Also what is a waste of money about it? I've been told it's one of the better units out. Is there another alternative?

-Destin

RoadRaceJosh

The single channel unit will only work for a vehicle with one coil. Unless you have a distributor you have 3 coils. If you do have a distributor you're very likely to have two ignition coils. Without being able to control the timing of all your engine's ignition events you're wating your money. Clear enough?

sillbeer

I found there website. It's around $500 a unit and more if you want the bosch sensors.

http://www.jandssafeguard.com/orders.html

They offer 1, 2, 3, and 4 chanel units.

-Destin

GUITARJUNKIE28

i wouldn't say waste of money.
just make sure your split > max retard

Claudio RX-7

iTrader: (1)

Ive seen the J&S on a couple of 3rd gens in miami, it really does work. Provided you know what you are doing.

RETed

Tell that to the owner of the FD who killed his motor on the DynoJet cause the J&S didn't work...
With the single-channel J&S on the leadings, the trailings will happily push the motor into killing itself.
Ever used a J&S when it's working properly?
You're not supposed to let off when you see the display light up - you're basically using it as an expensive knock monitor if you're staring at the display.
MSD sells one for ~$150.
HKS has one for a little bit more.

I wonder if the 3-channel J&S can handle the assymmetrical ignition spark events from a rotary?


-Ted

GUITARJUNKIE28

lemme try to figure out what you're saying...

one guy blew his motor up, so you blame j&s? i was under the impression i stated to make sure your split was greater than your max retard. and if homeboy was detonating that bad, the motor probably would have gone boom anyway.

it seems to be the general way of things that the people who talk the most **** usually have the least experience. so lemme guess... you've probably never used one yourself, correct?

RETed

DynoJet operator kept telling the FD owner to keep on the gas.
We HEARD the detonation standing 50 feet away.
It wasn't my car.
I wasn't the dyno operator.

If you had any clue on how a J&S works properly, you would know it was not supposed to do this...but wrong application.
I've seen the J&S (single-channel) work flawlessly on turbo'd Hondas.
Single-channel cause the Hondas run a single coil into a distro.
Run the motor...hit detonation (after calibrated)...and the J&S instantly dials back the timing...without lifting off the throttle.
You cannot react faster than the J&S does.


You know they say about "assuming"...
I own one.
It's installed on my FC.
It's just a fancy knock monitor for all I care.

I bet I have more experience with the J&S (single channel) than you do...


-Ted

GUITARJUNKIE28

it wasn't the j&s... i'd say it was the tuner.

John at J&S

RETed: Thanks for the props with respect to our Honda unit, but I don't know why you feel it's your duty to bash the RX7 version every chance you can. Why not state just state it's limitations, and how to make best use of it?

We've been making units for the RX7 since '92. Back then, no one was narrowing the split, so it wasn't an issue. Now that is, take the limitations into account, and use the J&S intelligently. Limit the split to no less than 10°, and set the J&S for 10° max knock retard.

If desired, the units can be reprogrammed to select either 5° or 10° max knock retard, instead of the stock 10° or 20°.

If this is not acceptable, why not try feeding the J&S display voltage into an unused analog port on the Haltech, and use it as an auxilliary retard. Then the Haltech can retard both plugs.

When used this way, no wires need cutting. Leave the J&S White disconnected, and splice the J&S Green trigger wire to the leading coil igniter input signal.

The monitor jack is 3.5mm stereo. The signal is on the terminal defined as "Ring", and varies from 0 to 1.3v. "Tip" and "Sleeve" are 12v and Gnd to power the optional bargraph display.

If the unit is set to retard individual rotor faces (S2 down), the monitor voltage could change with each spark event, reflecting the amount of retard for the face that just fired. Don't know how fast the Haltech can react, so you may want to set S2 up. In this mode, the monitor voltage can change once every three revolutions (one engine cycle).

GUITARJUNKIE28

^ hey, have you got that aux retard to work with a haltech before, or is that hypathetical?

if you haven't yet, i'd gladly roll down there and see if we can make it work. then we can post up and end the debate.

John at J&S

GUITARJUNKIE28: It's hypothetical, though Norwood asked about it last year for use with a Motec, on Kenny Tran's Honda.

When they were running the engine with a distributor and an MSD 10 Plus, they let the unit control timing with knock, as designed, and data logged the monitor voltage. Bob said they could advanced the timing two degrees, and the data log showed knock popping up, and the unit would catch it. Made the same power.

The MSD didn't have enough spark energy to fire reliably when they raised the boost above forty plus psi, even with the plugs gapped to 0.010, so they went coil on plug, and switched to the MoTec 4 channel CDI and expander unit. The J&S is not compatible with that setup.

They were going to use the monitor voltage as a timing control input, but I think they parted company before they could try it.

The last I heard from Bob was that Kenny lost a few engines on the dyno after they switched to the four coil setup.

GUITARJUNKIE28

well i just picked one up from a forum member.

have you any idea of if it'll work with corvette coils? they're the newer c5 style with built-in ignitors. one wire controls both leading. i was thinking about just using that and using a wide split.

*edit*
haltech e8 running the coils in direct-fire mode. i looked through the schematics on the website and it looks like the thing goes before the ignitor... i'd ASSUME i'd just pirate that green wire, and be good to roll.

John at J&S

Are you going to run waste spark for the leading coils, and use the J&S monitor port as an input to the Haltech?

Note that the Green wire needs to see an ignition trigger every 180°, so you will need to run waste spark for the leading coils.

GUITARJUNKIE28

yea...

green wire from haltech = both leading coils in wastespark... haltech just calls it direct fire in the setup.

but just to clarify everything--one wire controls both coils.

and what if....IF we got 3 boxes? one for leading, two for trailing. as long as it's dialed in correctly, shouldn't that work?

sillbeer

I'm using a motec M8 and can't run split on my 20b. It ran fine when I was in Japan at 578rwhp but just recently it started making me wonder. Would the J & S unit be worth investing in?


-Destin

RETed

I was only stating my experience with the unit as a data point.
Nothing more, nothing less.
People seem to think it's some wonder box that would miraculously work with the stock RX-7 ignition system - the below info was not available back then (this was like 5+ years ago!).

I didn't even know there was an "RX7 version" - or are we talking about the single-channel version?



That particular FD3S that blew up was using the stock ECU - we had no control over the stock split.


I think the 5 / 10 degree option is a lot safer than the 10 / 20 option.
Is this something that can be done on earlier manufactured units?


Now this is some great information - is this only applicable to your latest version, or can the earlier boxes do the same thing?
I love your products (have one myself), but after seeing one bad experience, it leaves a bad taste in my mouth.
I've since disconnected the ignition function and run it purely as a knock monitor.
For the $500 I paid for it, it's a very expensive knock monitor!


-Ted

RETed

Dude, that was uncalled for.
You really want me to start bashing your ****?


-Ted

John at J&S

CLR (Carlos Lopez Racing) used to run a J&S with zero split on his distributor car. In fact, he's the one who asked me to design a unit for the Rotary.

He called here one time after running the unit for a while, and said "this thing is worth $800 to $1000." He said the performance was night and day, compared to the MSD BTM's he had been using.

Haven't talked to him since '94, when we had a dispute over another product.

crispeed

I remember that dispute way back then!

Anyhow I've been using John's products since the beginning on both piston and rotaries and have always got good results. Every rx-7 I build and tune must have one. The idea of using the output of the J&S to a stand alone have been done before. Some people even got little boxes made to trigger relays,circuits etc. based on knock. I've seen one that cut power to the boost controller in the event of knock.
Most people still believe that ignition retard on a rotary is going to stop knock. It's not!
Here's a little clue to what helps a lot. The first thing the human mind does after hearing knock is to lift the right foot. Why not use the power and speed of the ECU to do the same. It's much faster than the brain most of the times
With that said figure out which program or programs in your stand alone ECU best suit the need. I have!

crispeed

Hey John.
What's the output level of the unit when the 1st Led on the monitor lights up?

John at J&S

RETed: I guess this is where the misunderstanding started.

The difference between the Honda unit and the RX7 unit is primarily in software, relating to the engine cycle.

The RX7 version was always single channel, retarding only the leading plug, unless you ran zero split with a distributor. I have a three channel version in the works, but can't say when it will be finished. I'm in the process of switching all my designs to a newer Motorola processor, so it will be a while.

The cycle for a piston engine is two revolutions, compared to three revolutions for a rotary. To keep track of the knock in each rotor face, I programmed the knock detector as a six "cylinder", that fires every 180°.

I don't know why the engine blew on the dyno. It may have gone lean, and went into pre-ignition. Pre-ignition means the mixture went off before the spark, so retarding the timing further won't help.

Normal detonation happens at about 45° ATDC on a Rotary, so we have a knock "window" set up in software to listen at that crank angle. Pre-ignition happens at a different crank angle, before the spark event. Since spark retard cannot stop pre-ignition, we don't listen for it.

Bob Norwood called me a couple of years ago. He said, (paraphrasing) "I don't know you and have never bought anything from you, but I've had some high horsepower RX7's come through my shop, and we're talking 600hp, and the ones that live on the dyno have one of your units installed." Then he went on to tell me that he was tuning a Motec for a Honda race team, and thought it might be a good idea to get one and play with it.

crispeed

''Pre-ignition means the mixture went off before the spark, so retarding the timing further won't help.''
Pre-ignition I believe is what is responsible for most of the blown up rotaries. Even the ones with the perfect tune can't compensate for any type of pre-ignition.

''Spark retard cannot stop pre-ignition.''
I'm in total agreement and have said this time and time again.