J&S individual cylinder knock control.

[jdmawd]

Using a single knock sensor, the system detects the onset of detonation and retards the timing on a per cylinder basis. A mode switch lets you select a maximum of either ten degrees or twenty degrees of knock retard. In the ten degree range, the unit retards one, two, or three degrees per ping. Double that for the twenty degree range. The system is always trying to re-advance to stock timing. In the ten degree mode, it re-advances at the rate of one degree every twenty revolutions.

The system does not need a cam or crankshaft reference to determine which cylinder to retard. The unit is programmed to "know" that the knocking cylinder is the one that just fired, and that it won't fire again for two more revolutions. When the knocking cylinder comes around to fire again, software dials in the retard amount for that cylinder. It does this as each cylinder goes by, building up a different retard amount for each cylinder.

The unit has a high energy ignition with constant energy dwell controller. The system monitors the coil current, and adjusts the dwell time to achieve seven amps of coil current. Compared to a GM HEI, this is a 62% increase in energy stored in the coil. The system can also be used to trigger an MSD.

The Marine/Racing version features an adjustable Velvet Touch rev limiter. At the selected limit, the system fires two cylinders, then skips one, and repeats this sequence. For six cylinder engines, the sequence is fire three, then skip two. If the engine goes 100 RPM above the selected limit, the system will skip as many cylinders as needed. A test point is provided to adjust the limit, scaled at one volt per 1000 RPM. For example, if you want to set the limit at 6250 RPM, adjust the knob so that the RevTestPoint reads 6.25 volts.

Standard automotive units are also available for single coil foreign and domestic vehicles as well as multiple coil applications, including Honda, Miata, Subaru, Eclipse, Toyota.

For engine builders and dyno operators, check out our Knock Finder Dyno Timing Controller.

this product was brought to my attention by a friend. anyone using this product?

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

 

[rdrkt]

A lot of the Haltech guys run this on their setups. I know that Smithey is using the basic JS knock sensor setup on his 600hp car. Although I dont know why anyone would want it unless they were running a system that did have knock detection.

 

[jdmawd]

This may be totally wrong. But if this allows you to retard timing in only the cylinder that is knocking wouldn't that function alone be worth the cost. rather then the ECU pulling timing across the board and killing power? doesn't that ultimately solve the fighting the ECU tuning problem.

 

[nine5raptor]

I would definately help with the "tune to be safe on the hottest cylinder" problem, and your egt would be more useful as the egt's across the board should much closer together, giving you a close to actual reading as opposed to having the average of 1 cylinder at 1700, 2 at 1550, and 1 at 1450.

 

[rdrkt]

Well knock is one of those issue that EVERYONE has an opinion on. IMHO I think the ECU sees a lot of knock that isn’t true knock thus killing your power. I also don’t think that one cylinder is going to knock THAT much more than the other ones. The DSM fuel rail and intake manifold seems to be designed well enough that we don’t have to worry about that like some of the MR2 guys.

However if you found a way to intercept the signal that the stock knock sensor would sent the ECU you would still run into the issue of the stock ECU wanting to feed too much timing. Back when I was running my hacked up 1g MAS with my setup I would see 23 degrees or more timing on pump gas. That is WAY too much. That much timing will actually cause more knock.

Historically these units are used in setups that don’t have knock sensors like Rx-7s, Haltech standalones etc. Even if you went to all the trouble of making it work I don’t know if it is really necessary. In the near future you should see me making well over 400 to the wheels on pump gas and I wont have a knock sensor. As long as you are not tuning your car right on the edge you shouldn’t need it. Guys like GrocMax use it on his customer’s Haltech cars as a nice safety measure for street cars on pump gas but on a stock ECU I would give it the thumbs down.

 

[rdrkt]

Originally posted by nine5raptor
I would definately help with the "tune to be safe on the hottest cylinder" problem.

Since when has this been a problem in DSMs

 

[G-Ell]

Doesn't the AEM EMS have a similar program like this?

 

[rdrkt]

Originally posted by G-Ell
Doesn't the AEM EMS have a similar program like this?

No. In a DSM application the AEM uses the 2g knock sensor but it only pulls timing across the board not for individual cylinders.

 

[DSM mechanix]

i thought (not sure) that the EMS did not pull timing, it displayed it for you and asumed you would make the appropreite changes?

 

[rdrkt]

Originally posted by DSM mechanix
i thought (not sure) that the EMS did not pull timing, it displayed it for you and asumed you would make the appropreite changes?

You can program the AEM what to do during a knock event. Whether that be pull timing, add fuel or ignore it.

 

[ttawd3s]

In a 4G63 motor I doubt that this would be useful at all, unless you had a custom intake manifold or a wacky fuel injection system. If #4 knocks, guess what.. # 1 is right behind it, then #2, then #3... If you have a air distrubusoin problem then this would "help" tune it out, but the 4G63 doesn't have that problem... Now a 6G72 3/S motor almost always runs lean in #6 b/c the POS fuel rail design, but change the fuel rail design, and its all fixed.. The Buick grand national Turbo V6 Has a bad problem of getting more air into the rear two ports, killing the 2 rear cylinders b/c a bad intake design, but its fixable by buying a aftermarket intake or a "power plate" that evens the air distrubusion out. The point is, if you have a one cylinders that is weaker, tuning on a cylinder to cylinder basis isn't the right solution, fixing the design flaw is. But the DSM doesn't suffer from any air distrubution problems, so the cylinder to cylinder knock monitor isn't needed..

 

[larryd]

Does this get a reading from the knock sensor itself?

If it does not but still reads knock someway then I could see it being useful in the light that you could disconect your knock sensor and then decide what you want to do by controlling issues with this unit?

 

[John J&S]

Hi: My name is John Pizzuto. I'm the designer of the SafeGuard, and will try to answer any questions you have.

larryd: All our DSM kits have shipped with a separate knock sensor. If we have the characteristics for the stock sensor on file, we will calibrate the unit to use the stock sensor. Note to self: Visit Mike Welch and measure stock sensor.

ttawd3s: In general, you are correct. It's always better to fix the real problem. Some problems are harder to fix than others. The best example would be hotspots caused by poor design of coolant passages.

rdrkt: If the factory system retards all cylinders equally, then the SafeGuard could be of some benefit. The unit has a sensitivity control, so it can be set to activate before the stock system kicks in.

 

[rdrkt]

Originally posted by John J&S
rdrkt: If the factory system retards all cylinders equally, then the SafeGuard could be of some benefit. The unit has a sensitivity control, so it can be set to activate before the stock system kicks in.

To the best of my knowledge the factory setup and the AEM both retard across the board. But as I said previously bang for the buck definitely wouldn’t be there. The 1g sensor isn’t AS sensitive as a 2g one but it is still pretty damn sensitive. Enough so that it wouldn’t be worth it to have something MORE sensitive in a factory type setup.

In the case of the AEM it uses a 2g sensor and you can calibrate what it does at X voltage as far as knock goes.

In both cases I don’t know if the J&S would be worth it $ wise. That doesn’t mean it isn’t awesome just not practical price wise in our apps.

 

[Groomz]

The Smithoid Eclipse put down 501whp on 24psi, so I would assume that some major fuel and timing tuning was involved, because I don't see that much power being made at that psi every day. In my opinion if you tune for power with fuel and timing advances, then the J&S would be great because of the extra safety it offers. The DSMlink allows for knock threshold to be defined, but it is still using the factory sensor. The J&S is using its own sensor which may be able to "hear" things that the stock unit cannot. Stock to lightly modded, the J&S is probably overkill. People like JDMawd might benefit from it or anyone else who has a fairly advanced setup.

I think that the LS1 Corvette's use an individual knock retard control, but I am going from memory.

The worst thing that could happen by putting this device on your DSM is that it pulls timing before the ECU does. I know for a fact my 2G pulls timing whenever it feels like it. I think the best setup would be this:

Get a DSMlink and set the knock threshold way high, so that only during sever knock it would retard all the cylinders ( knock retard for all cylinders is obviously a little overkill, especially when its phantom knock ). Then use the J&S unit to catch low to mid level knock and have it retard the timing on an individual cylinder basis. Obviously this is a 2G only option, but maybe you could just convince Hal to put a 2G ECU in your 1G?

 

[rdrkt]

Originally posted by Groomz
The J&S is using its own sensor which may be able to "hear" things that the stock unit cannot.

I dont think that an signifigant knock event would be missed by a DSM knock sensor.

 

[dsmturboawd]

Originally posted by rdrkt
To the best of my knowledge the factory setup and the AEM both retard across the board.

100% correct. think about it: there is ONE knock sensor, how can it tell which cylinder to retard, even if that was logical.

correct me if im mistaken, but you can't adjust ignition timing for individual cylinders unless you have coils for each plug. so for us guys with stock ignition and 2 coils, this product is not an option.

 

[John J&S]

dsmturboawd: Put on your thinking cap.

Only one cylinder can knock at a given time. Which one is it? It's the one that just fired.

When will THAT cylinder fire again? In two more revolutions.

When the knocking cylinder comes around to fire again, software dials in the calculated retard for THAT cylinder.

Set up some counters in software, and bingo, each cylinder can be retarded a different amount. You don't even need a cam or crank sensor, and we have versions that work with a distributor, waste spark, or individual coils.

I wrote the software for this in '90. We got a few calls from people back then, saying what we were claiming is impossible. I got the idea for it in the late '80's, from a "Road and Track Magazine" write up on the Porsche 944 Turbo. It had individual cylinder knock control.

Here's a link to a thread from a Subaru guy in the UK. He's claiming he can safely run five degrees more timing, for a 23hp gain. Some of the terms he uses are a little weird. "Det cans" are earphones connected to a microphone on the block. "Delta Dash" is a data logger/ECU tuner from EcuTek.

http://www.scoobynet.co.uk/bbs/thread.asp?ThreadID=179486&Page=17

 

[Groomz]

Originally posted by rdrkt
I dont think that an signifigant knock event would be missed by a DSM knock sensor.

The 2G knock sensor is sensitive enough to pick up wire taps from the old Soviet Union, thats not the point. The J&S is specifically designed for knock, while the 2G unit will retard timing for just about anything it picks up. I don't think you could fool the J&S into thinking ticking lifters or other noises were knock, while the 2G sensor could pick up knock on the moon if you put it there.