J&S Safeguard Explained
12-04-2008, 02:36 PM
#1
J&S Safeguard Explained
ALL INFO TAKEN FROM J&S
http://www.jandssafeguard.com/index.html
Shown is our Marine/Racing version. Features include high energy inductive discharge ignition and adjustable rev limiter. This system is ideal for turbo, supercharged, high compression, or even nitrous applications. An optional display shows the amount of knock retard.
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.
Fits 2 1/16" (52mm) gauge pod Instructions
A built-in light sensor dims the display automatically at night, and increases brightness in direct sunlight.
A ten segment bargraph display shows amount of retard, and thus gives an indication of the engine's tendency to knock at any particular time. The monitor is conected to the J&S SafeGuard with a 3.5 mm stereo cable supplied in the kit. The new SafeGuard units have an onboard LED that glows in proportion to the amount of knock retard. This will assist you in setup of the SafeGuard, but the bargraph gives much more information.
The display shows how much tiiming is being taken out by the SafeGuard. When the SafeGuard is set for 20° control range, each LED is worth 2°. If the SafeGuard is set for "retard all", and it is taking out say 12° of timing, then you would see the 6th LED on. If the SafeGuard is set for "retard separate", then the display becomes more complex. Since the SafeGuard can retard each cylinder by a separate amount, you will see one LED on for each cylinder that is being retarded, and the position of that LED indicates how far. For example, let's say that one cylinder is retarded 4°, another 6°, and another 8°, then you would see the 2nd, 3rd, and 4th LEDs on.
The ten segment LED (GGGYYYYRRR) Air Fuel Display now has a dual resolution feature with a switch that allows accurate tuning for both cruise and full power modes.
The gauge is calibrated for use with a Bosch LSM-11 sensor, operating at 1450°F.
When the switch is in the "Power" mode, the gauge reads between 0.81v and 0.90v, so it may be used with any standard O2 sensor.
Knock/Retard Monitors
All info taken from Jandssafeguard.com
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.
My unit :
http://www.jandssafeguard.com/index.html
Shown is our Marine/Racing version. Features include high energy inductive discharge ignition and adjustable rev limiter. This system is ideal for turbo, supercharged, high compression, or even nitrous applications. An optional display shows the amount of knock retard.
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.
Fits 2 1/16" (52mm) gauge pod Instructions
A built-in light sensor dims the display automatically at night, and increases brightness in direct sunlight.
A ten segment bargraph display shows amount of retard, and thus gives an indication of the engine's tendency to knock at any particular time. The monitor is conected to the J&S SafeGuard with a 3.5 mm stereo cable supplied in the kit. The new SafeGuard units have an onboard LED that glows in proportion to the amount of knock retard. This will assist you in setup of the SafeGuard, but the bargraph gives much more information.
The display shows how much tiiming is being taken out by the SafeGuard. When the SafeGuard is set for 20° control range, each LED is worth 2°. If the SafeGuard is set for "retard all", and it is taking out say 12° of timing, then you would see the 6th LED on. If the SafeGuard is set for "retard separate", then the display becomes more complex. Since the SafeGuard can retard each cylinder by a separate amount, you will see one LED on for each cylinder that is being retarded, and the position of that LED indicates how far. For example, let's say that one cylinder is retarded 4°, another 6°, and another 8°, then you would see the 2nd, 3rd, and 4th LEDs on.
The ten segment LED (GGGYYYYRRR) Air Fuel Display now has a dual resolution feature with a switch that allows accurate tuning for both cruise and full power modes.
The gauge is calibrated for use with a Bosch LSM-11 sensor, operating at 1450°F.
When the switch is in the "Power" mode, the gauge reads between 0.81v and 0.90v, so it may be used with any standard O2 sensor.
Knock/Retard Monitors
All info taken from Jandssafeguard.com
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.
My unit :
Last edited by nwell2k3; 12-04-2008 at 02:52 PM.
12-04-2008, 02:39 PM
#2
Background
INFO TAKEN FROM JANDSSAFEGUARD.COM
Engine Knock-that annoying rattling sound that sometimes comes from under the hood of your pride and joy, is a killer. We have all heard the stories of blown head gaskets and broken pistons. Maybe it has already happened to you, too. But just what is knock, sometimes also referred to as detonation?
The knocking sounds you hear are the cylinder walls set into oscillation by intense pressure waves, caused by abnormal combustion. Normal combustion is a controlled burn that starts from the spark plug and spreads outward, causing a pressure rise in the combustion chamber. This pressure is then converted into torque on the crankshaft. Ideally, the peak pressures will occur about ten to fifteen degrees after top dead center (TDC), as the piston is on its way down.
Detonation is a form of abnormal combustion that starts off right, but at the last millisecond, something goes wrong. The remaining air-fuel mixture, called the "end gas", explodes all at once, instead of burning in a controlled way. Resultant engine damage is caused by an instantaneous pressure rise that can excede 1500 psi. This is more than double the normal peak combustion pressure, and will blow head gaskets, break piston ring lands and hammer the rod bearings. Another form of damage seen is that the tops of the pistons will be eroded and can even melt.
High octane fuels are resistant to detonation because they contain compounds that slow down the chemical chain reaction we call combustion. If left unchecked, these chain reactions would quickly escalate, resulting in increasing damage to the piston and other engine components. All fuels, regardless of octane, have a knock limit. This is reached when the temperature of the "end gas" reaches an autoignition point. Combustion chamber designers use high swirl inlets and large "quench areas" to fight this "autoignition" problem. There are other factors beyond these mechanical design features which influence "end gas" temperatures. Some of these are: (1) Intake charge temperature, (2) Coolant temperature, (3) Compression Ratio, (4) Boost pressure, (5) Spark timing, (6) Air-fuel ratio, and (6) Humidity.
An increase in compression ratio, boost pressure, or spark timing will increase peak cylinder pressure, which in turn raises the "end gas" temperature. Higher inlet and coolant temperatures also increase the "end gas" temperature. Richer mixtures can be used to cool the charge. At some point beyond about 10:1, however, will again increase the tendency to detonate. A decrease in humidity will also tend to increase detonation.
Solutions
Some things you can change, and some you are stuck with. Obvious things to do are get cold, fresh air to your air cleaner, use the best form of charge cooling (intercoolers) you can afford, and work on your cooling system to bring the temperatures down. Get an Air-fuel meter (O2 meter), and if necessary, install a fuel enrichment device. For turbo/supercharged engines water-alcohol injection can be very effective, but the volumes required mean constant refilling and maintenance, so in the long term it is a specialized solution that has a lot of drawbacks.
Spark retard, within limits is the most powerful means of controlling detonation. Traditionally, this has been a manual affair by simply cranking the distributor back "x" degrees, Some electronic devices can retard timing in relation to manifold or boost pressure and other devices offer simple manual ***** you can alter the timing with if an audible "ping" is heard. Many newer cars are quipped with knock sensors that retard the timing when detonation occurs. This form of closed loop spark control where the vehicle's ecu automatically retards all cylinders when detonation occurs, a situation we call "retard all". On a select few modern engine controllers (Porsche, Corvette) the microprocessor is programmed to retard individual cylinders as knock or detonation occurs. The problem with either of these approaches is twofold: First, the OEM carefully maps a complex set of spark curves and only allows a small degree of retard to take place, typically 4 degrees; Secondly, these ecus are highly specific and are not readily adaptable or programmable for other applications.
J&S SafeGuard versus the Detonation Dragon
J&S Electronics has developed the SafeGuard which uses a knock sensor to provide feedback to it's microprocessor which, in turn, controls the timing for each cylinder on an individual, optimized basis. Firms like DINAN Enginneering, Kenne Bell, and CarTech have successfully used SafeGuards in their installations. DINAN used SafeGuards in their high dollar integrated BMW turbo kits which set very high standards for performance and sophistication. Kenne Bell has used SafeGuards in Syclone and Typhoon V-6 turbos for years to complete a very successful upgrade program for these General Motors vehicles. CarTech Stage III Mustangs completed hundreds of runs at the dragstrip running 12 pounds of boost with times in the low 12's and high 11's. In the last few years supercharged Mazda Miatas have become the rage, but owners have found out that killing the stock timing was not the way to horsepower heaven. By adding a J&S SafeGuard and returning timing to factory specs the missing low end performance and extra horsepower were rediscovered.
J&S Electronics has more than a decade of experience in wrestling with the thorny issues that surround knock-sensing and detonation. It is not a simple matter of hanging a microphone on the engine and listening for the tell-tale "knock". If you have discussions with OEM powertrain engineers they can tell you of the difficulties they face in the areas of signal discrimination or "noise" as well as the issues related to how the actual control over the timing should be done. J&S's SafeGuard has sophisticated mathematical controls or algorithms than discriminate between noise and actual "knock", and has user adjustable controls that allow for sensitivity as well as amount and speed of retard. Whereas OE retard schemes are limited to say 4 degrees, the J&S SafeGurad can be set for up to 20 degrees of ignition retard. This prevents catastrophic failure than can occur should you loose engine coolant or some other unforseen event. The J&S SafeGuard will control the timing of each cylinder in proportion to the degree of detonation occuring, thus maximizing performance and preventing engine damage.
Detonation is the precursor to preignition and only J&S Electronics can provide you a real-time solution to your ignition timing that both maximizes performance and protects your investment.
Preignition and detonation are two separate and distinct events. It was first pointed out as far back as 1906 that the two phenomena were not only quite distinct but were in fact not related to each other. In the first place, preignition in itself does not produce an audible "knock" and if it is audible at all it could be described as a "dull thud". Because preignition is frequently brought about as a result of persistent detonation, the distinct "knock or ping" of the latter came quite erroneously to be associated with it.
It is by no means uncommon for preignition, or in this case it would be more correct to describe it as autoignition, to occur at the same phase as the timed spark. In this case the ignition can be switched off, and the engine could continue to run perfectly steadily without the slightest observable change in performance, sound, or any other characteristic. The danger, however, lies in the fact that all control of timing can be lost and ignition may creep in earlier in the cycle.
The danger of preignition lies not so much in the development of high pressures but rather in the very great increase in heat flow to the piston and cylinder walls when the ignition occurs too early in the cycle. This increase in heat flow, in turn, raises still further the temperature of the hot spot or surface which is causing the preignition resulting in even earlier ignition. At some point the temperatures are elevated to the point where the incoming charge is ignited, causing backfiring in the inlet tract. The belief, still widely held, that preignition can give rise to dangerously high cylinder pressures is totally false. Under no circumstances is the peak pressure resulting from preignition appreciably higher than from a spark-initiated ignition and, in both cases, the peak is reached when the maximum pressure is attained at or just after top dead center, that is to say, about 10 degrees earlier than the normal optimum. As the time of ignition is further advanced by either advancing the time of the spark or by earlier preignition, the maximum cylinder pressure falls again due to the excessive heat loss, for the piston is then compressing gas at or about its maximum temperature, and the intensity of heat flow is increased many times. The danger lies not in the production of excessive pressures but of excessive heat fow. The intense heat flow in the affected cylinder can result in piston seizure followed by the breaking-up of the piston with catastrophic results to the whole engine.
In nine cases out of ten, preignition is initiated by overheating of the sparkplug electrodes or some sharp point or edge that has gone "critical". We are accustomed these days to focus all our attention on the subject of detonation for it is the limiting factor controlling the performance of a spark-ignition engine. We are apt to forget that the real danger is that it leads on to preignition. In itself, detonation is not dangerous... It is the preignition it gives rise to that can so easily wreck an engine. J&S Electronics SafeGuard is your best defense against detonation and the harmful effects it can lead to.
new 8 channel unit coming soon
INFO TAKEN FROM JANDSSAFEGUARD.COM
Engine Knock-that annoying rattling sound that sometimes comes from under the hood of your pride and joy, is a killer. We have all heard the stories of blown head gaskets and broken pistons. Maybe it has already happened to you, too. But just what is knock, sometimes also referred to as detonation?
The knocking sounds you hear are the cylinder walls set into oscillation by intense pressure waves, caused by abnormal combustion. Normal combustion is a controlled burn that starts from the spark plug and spreads outward, causing a pressure rise in the combustion chamber. This pressure is then converted into torque on the crankshaft. Ideally, the peak pressures will occur about ten to fifteen degrees after top dead center (TDC), as the piston is on its way down.
Detonation is a form of abnormal combustion that starts off right, but at the last millisecond, something goes wrong. The remaining air-fuel mixture, called the "end gas", explodes all at once, instead of burning in a controlled way. Resultant engine damage is caused by an instantaneous pressure rise that can excede 1500 psi. This is more than double the normal peak combustion pressure, and will blow head gaskets, break piston ring lands and hammer the rod bearings. Another form of damage seen is that the tops of the pistons will be eroded and can even melt.
High octane fuels are resistant to detonation because they contain compounds that slow down the chemical chain reaction we call combustion. If left unchecked, these chain reactions would quickly escalate, resulting in increasing damage to the piston and other engine components. All fuels, regardless of octane, have a knock limit. This is reached when the temperature of the "end gas" reaches an autoignition point. Combustion chamber designers use high swirl inlets and large "quench areas" to fight this "autoignition" problem. There are other factors beyond these mechanical design features which influence "end gas" temperatures. Some of these are: (1) Intake charge temperature, (2) Coolant temperature, (3) Compression Ratio, (4) Boost pressure, (5) Spark timing, (6) Air-fuel ratio, and (6) Humidity.
An increase in compression ratio, boost pressure, or spark timing will increase peak cylinder pressure, which in turn raises the "end gas" temperature. Higher inlet and coolant temperatures also increase the "end gas" temperature. Richer mixtures can be used to cool the charge. At some point beyond about 10:1, however, will again increase the tendency to detonate. A decrease in humidity will also tend to increase detonation.
Solutions
Some things you can change, and some you are stuck with. Obvious things to do are get cold, fresh air to your air cleaner, use the best form of charge cooling (intercoolers) you can afford, and work on your cooling system to bring the temperatures down. Get an Air-fuel meter (O2 meter), and if necessary, install a fuel enrichment device. For turbo/supercharged engines water-alcohol injection can be very effective, but the volumes required mean constant refilling and maintenance, so in the long term it is a specialized solution that has a lot of drawbacks.
Spark retard, within limits is the most powerful means of controlling detonation. Traditionally, this has been a manual affair by simply cranking the distributor back "x" degrees, Some electronic devices can retard timing in relation to manifold or boost pressure and other devices offer simple manual ***** you can alter the timing with if an audible "ping" is heard. Many newer cars are quipped with knock sensors that retard the timing when detonation occurs. This form of closed loop spark control where the vehicle's ecu automatically retards all cylinders when detonation occurs, a situation we call "retard all". On a select few modern engine controllers (Porsche, Corvette) the microprocessor is programmed to retard individual cylinders as knock or detonation occurs. The problem with either of these approaches is twofold: First, the OEM carefully maps a complex set of spark curves and only allows a small degree of retard to take place, typically 4 degrees; Secondly, these ecus are highly specific and are not readily adaptable or programmable for other applications.
J&S SafeGuard versus the Detonation Dragon
J&S Electronics has developed the SafeGuard which uses a knock sensor to provide feedback to it's microprocessor which, in turn, controls the timing for each cylinder on an individual, optimized basis. Firms like DINAN Enginneering, Kenne Bell, and CarTech have successfully used SafeGuards in their installations. DINAN used SafeGuards in their high dollar integrated BMW turbo kits which set very high standards for performance and sophistication. Kenne Bell has used SafeGuards in Syclone and Typhoon V-6 turbos for years to complete a very successful upgrade program for these General Motors vehicles. CarTech Stage III Mustangs completed hundreds of runs at the dragstrip running 12 pounds of boost with times in the low 12's and high 11's. In the last few years supercharged Mazda Miatas have become the rage, but owners have found out that killing the stock timing was not the way to horsepower heaven. By adding a J&S SafeGuard and returning timing to factory specs the missing low end performance and extra horsepower were rediscovered.
J&S Electronics has more than a decade of experience in wrestling with the thorny issues that surround knock-sensing and detonation. It is not a simple matter of hanging a microphone on the engine and listening for the tell-tale "knock". If you have discussions with OEM powertrain engineers they can tell you of the difficulties they face in the areas of signal discrimination or "noise" as well as the issues related to how the actual control over the timing should be done. J&S's SafeGuard has sophisticated mathematical controls or algorithms than discriminate between noise and actual "knock", and has user adjustable controls that allow for sensitivity as well as amount and speed of retard. Whereas OE retard schemes are limited to say 4 degrees, the J&S SafeGurad can be set for up to 20 degrees of ignition retard. This prevents catastrophic failure than can occur should you loose engine coolant or some other unforseen event. The J&S SafeGuard will control the timing of each cylinder in proportion to the degree of detonation occuring, thus maximizing performance and preventing engine damage.
Detonation is the precursor to preignition and only J&S Electronics can provide you a real-time solution to your ignition timing that both maximizes performance and protects your investment.
Preignition and detonation are two separate and distinct events. It was first pointed out as far back as 1906 that the two phenomena were not only quite distinct but were in fact not related to each other. In the first place, preignition in itself does not produce an audible "knock" and if it is audible at all it could be described as a "dull thud". Because preignition is frequently brought about as a result of persistent detonation, the distinct "knock or ping" of the latter came quite erroneously to be associated with it.
It is by no means uncommon for preignition, or in this case it would be more correct to describe it as autoignition, to occur at the same phase as the timed spark. In this case the ignition can be switched off, and the engine could continue to run perfectly steadily without the slightest observable change in performance, sound, or any other characteristic. The danger, however, lies in the fact that all control of timing can be lost and ignition may creep in earlier in the cycle.
The danger of preignition lies not so much in the development of high pressures but rather in the very great increase in heat flow to the piston and cylinder walls when the ignition occurs too early in the cycle. This increase in heat flow, in turn, raises still further the temperature of the hot spot or surface which is causing the preignition resulting in even earlier ignition. At some point the temperatures are elevated to the point where the incoming charge is ignited, causing backfiring in the inlet tract. The belief, still widely held, that preignition can give rise to dangerously high cylinder pressures is totally false. Under no circumstances is the peak pressure resulting from preignition appreciably higher than from a spark-initiated ignition and, in both cases, the peak is reached when the maximum pressure is attained at or just after top dead center, that is to say, about 10 degrees earlier than the normal optimum. As the time of ignition is further advanced by either advancing the time of the spark or by earlier preignition, the maximum cylinder pressure falls again due to the excessive heat loss, for the piston is then compressing gas at or about its maximum temperature, and the intensity of heat flow is increased many times. The danger lies not in the production of excessive pressures but of excessive heat fow. The intense heat flow in the affected cylinder can result in piston seizure followed by the breaking-up of the piston with catastrophic results to the whole engine.
In nine cases out of ten, preignition is initiated by overheating of the sparkplug electrodes or some sharp point or edge that has gone "critical". We are accustomed these days to focus all our attention on the subject of detonation for it is the limiting factor controlling the performance of a spark-ignition engine. We are apt to forget that the real danger is that it leads on to preignition. In itself, detonation is not dangerous... It is the preignition it gives rise to that can so easily wreck an engine. J&S Electronics SafeGuard is your best defense against detonation and the harmful effects it can lead to.
new 8 channel unit coming soon
Last edited by nwell2k3; 12-04-2008 at 02:52 PM.
12-04-2008, 03:20 PM
#3
video
Video of the J&S being tested:
from John:
I installed one on an F150 Lightning earlier this year.
> They came supercharged from the factory, set to 6 psi, but
> the truck in the video is running 19 psi. The owner had it
> tuned to run on 91 octane, but we ran it on 89 for a month
> to test the J&S. In the clip, the owner said he was
> alternating between 91 and 89.
http://video.google.com/videoplay?do...45722815533155
from John:
I installed one on an F150 Lightning earlier this year.
> They came supercharged from the factory, set to 6 psi, but
> the truck in the video is running 19 psi. The owner had it
> tuned to run on 91 octane, but we ran it on 89 for a month
> to test the J&S. In the clip, the owner said he was
> alternating between 91 and 89.
http://video.google.com/videoplay?do...45722815533155
Last edited by nwell2k3; 12-04-2008 at 04:15 PM.
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