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I wondered if you have a controller to accomodate 2 sensors or if I could parallel 2 sensors on 1 input. I doubt that it would work since the other sensor would prevent the controller from seeing the voltage rise from the sensor which is sensing knock. |
forwheeler:
The version for distributor ignition has a "magnetic pickup" output centered around ground, so it will trigger the Bosch CDI. We used to sell to a Porsche tuner in the Daytona Beach area. He used only one sensor with good results. One of his customers describes the mountng location: http://forums.pelicanparts.com/1923608-post13.html Louie Ott is using two sensors wired in parallel on his 928. He measured the output on a scope using a spring loaded center punch on the block to produce a uniform knock signal. He found the second sensor reduces the signal by about 30%, but there is enough range on the sensitivity knob to make up for it. He (Louie928) describes results in this thread on the efi101 forum: EFI University Electronic Fuel Injection Tuning :: View topic - Det hearing system |
sjf911:
I thought of a way to do it with one unit, but you will need two three channel igniters, but only one EDIS module. Use an EDIS to provide three ignition channels to an Interceptor that has been set up as an inverter. The Inverting Interceptor would then drive two three channel igniters, or one six channel igniter. 300zx used a six channel igniter. ******** Parts Catalog |
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sjf911:
Do you mean full sequential six channel ignition, with six dual coils? I would have to study it, but I think you would use six channels of the (inverting) Interceptor instead of three. |
The 2 coil packs run in parallel so 2 coils are always charging and firing at the same time for the same cylinders. I would have to run 12 coils to run sequential such as LS-1/LS-2 CNP or COP. This means the interceptor would have to interrupt/control 2 coils simultaneously for each ignition event as a wasted spark.
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Your drawing shows six dual coils already. Enough to do full sequential and dual plug.
Does the MS have capability for six cylinder full sequential ignition? I'll draw something up and post it. |
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Is the firing order 123456?
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Standard distributor firing is 1-6-2-4-3-5. IIRC, wasted spark is A/A-C/C-B/B-A/A-C/C-B/B firing (1+4/4+1)-(6+3/3+6)-(2+5/5+2)-(1+4/4+1)-(6+3/3+6)-(2+5/5+2).
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Correct, you get around firing order issues by adjusting the connections to the pins of the EDIS or Accel coil packs. I use Accel units from Summit.
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VW Passat six cylinder waste spark coil packs have internal drivers, available from ********.com for about $180. Two required.
Connect J&S Interceptor between coil packs and the EDIS.http://forums.pelicanparts.com/uploa...1256928489.jpghttp://forums.pelicanparts.com/uploa...1256928628.jpg |
The EDIS units directly control dwell and timing of dumb coils, so, you are saying the the interceptor can take a direct coil control output and convert it to a low voltage signal for a smart coil?
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The coil driver signal has to be inverted, so you would need to order an inverting interceptor.
http://forums.pelicanparts.com/uploa...1256947321.jpg |
The Interceptor has an analog output to drive our bargraph display, but the signal can also be data logged.
Link to video showing the interceptor working on the bench. I'm playing an old knock tape into it: Picasa Web Albums - John - J&S Vampire I... Bob Boyer of Random EMS supplied Nize with his equipment. Bob programmed a Vipec ECU to reduce boost when the J&S is retarding from knock. He sent this data log showing the results. The orange trace at the bottom is the bargraph signal, the black trace is boost. I think the time scale is 0.1 seconds per division. http://forums.pelicanparts.com/uploa...1256950868.jpg |
Here's a pic of the pre-production interceptor unit. It can handle up to eight ignition channels.
http://forums.pelicanparts.com/uploa...1256954532.jpg The production units have another knob, for nitrous retard, and the discrete LED's have been replaced with an LED module. Note the headphone jack in case you want to listen for knock. http://forums.pelicanparts.com/uploa...1256954791.jpg |
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1) retards timing, and if knock is still present 2) cuts boost aside from the porsche factory system for the 951, the only other system i know of that has this two-stage timing retard+boost-cut knock protection failsafe is the Wolf EMS. both are available from here; Random Engine Management Systems |
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It runs sequential ignition and injection without the cam sensor by triggering ignition twice when cranking and detectin firing phase with ion current. Very trick. It has CDI ignition, 32 bit CPU, ion-current knock detection (that doesn't go deaf at hi revs), boost control, no cam sensor...and this is from 1994. There is still no ECU that can match it. Doing knock detection by microphones compared to ion current is like navigating with sextant compared to GPS. There is a group that plans to develop ion-current sensing for DIY but it's still in development. http://en.wikipedia.org/wiki/Trionic_T5.5 |
Goran: Saab introduced the APC in 1980. Boost reduction by knock detection, using acoustic knock sensor.
It was an analog system. It worked well, but if we follow your logic, it was junk, and they should have just waited until '94 when they had ion sensing. You can sit around and wait for the DIY group to give you ion sensing, meanwhile you tune by ear or experience, the navigational equivalent of dead reckoning. Without individual cylinder knock control you are in second place, if that. You either leave power on the table or did not finish. You generalize and say knock sensors don't work very well. Obviously, you haven't tried my system. |
Oh, I played with APC a lot. I even have two of them, one partially disassembled. It's a pinnacle of 70's analog technology and quite advanced for it's day.
I definitely don't consider APC junk. It's good for it's day but it had inherent drawbacks that were recognized by factory and subsequently removed by Trionic: 1. It was "programmed" to taper boost above 4000 RPM as knock sensors went deaf from chain noise in engine. 2. It couldn't control ignition. Only lower the boost. Winding back boost is very slow and engine risks damage under period turbo is spinning due to inertia if pinging. You would prefer to keep motor on edge of detonation on each cylinder instead of collectively (and slowly) lowering boost. 3. It was tuned for looking for knock overtones in iron B202 block (which many didn't quite understand and retrofitted it to another engines, most notably Volvo iron engines). It didn't always work. Back to present day: Delphi is about to release their own mass-production ion-sensing ignition cartridges in 2012. 15 years late but I sincerely hope that mass production of ion-sensing ignition will give DIY:ers power to adopt it to MegaSquirt just like they adopted EDIS. This will be nirvana of DIY EFI. It will be Linux in IBM and Windows world of aftermarket EFI. A DIY MSIII + Delphi ion current coils will be a terrific package. Delphi Ionization Current Sensing Ignition Subsystems Right now, I'm aware of only handful of manufacturers besides SAAB that utilize it: Harley Davidson Bugatti Veyron BMW (in their new cars). Regarding my comments on microphone knock detection: It works (and has been working since early 90's) but is still something that needs to be tuned per engine type to be really effective. Ion-current implementations don't care about block resonant frequency...it will detect knock after each combustion in any engine, thus very fitting for universal ECU. |
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I wonder how much each of those ion sensing pencil coils will cost? |
gorean et al.;
all that sounds good for when it's available in the future and i hope it's available soon. while we're waiting for a better mousetrap, the vipec, wolf, and j&s safeguards all work extremely well. proven on the dyno and on the track. plug-and-play. on porsches. today. |
now that i think of it, given how active j&s john is in the industry, i would not be surprised if he came out with a new j&s system that uses ion sensors. in the end, it's enthusiasts like us who win. :)
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Ah, technology. The R&D depts are already experimenting with integrated ignition/DFI/ion sensing cartridges that will fit the center plug hole location of most engines. I am just waiting for the day that I can drop two of these into my early 911s twin plug holes. :)
Since we are still living in today, looks like Wolf and J&S are my solution. |
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Bob Boyer at Random EMS gave me the skinny yesterday - he has a great wealth of knowledge to share. It doesn't hurt that he lives 3 miles down the road. :)
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he also has one of the fastest race-dominating 951's in the world, running wolf EMS with J&S safeguard;
http://gallery.silentmedia.com/main....serialNumber=2 http://gallery.silentmedia.com/main....serialNumber=2 http://gallery.silentmedia.com/main....serialNumber=2 the wolf+j&s has also been running on several race-winning 930's for several years. |
I wonder what kind of downforce he is getting from that rear wing? It sure looks like a steep angle of attack!
Mark |
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J&S Ion Sensing
Yes, I have been working on an Ion Sensing system, starting in 2011. I made a couple false starts, then began again in 2015.
It's been on and off the back burner, since my wife died from cancer, then again after I was hit by a car while walking, broke both my legs, two years ago. I'm doing well now, but my right knee is messed up. It will take knee replacement surgery to fix it, but I can walk and play pool as is. The initial version is for distributor ignition. I have a pre-production version installed on a 1990 Chevy Suburban. The ion sensing electronics are mounted and encapsulated on top of the distributor cap, with connectors feeding the ion signals to the processor unit, and supplying power to the ion sensors. I have another version in the works for direct ignition, but I'm not ready to publish anything on it. This version requires an MSD or other CDI system. I designed the processor unit in 2016, but I don't know what the final version will look like. It has a small oscilloscope mounted on the front panel, so you can monitor the ion signals, but that scope went out of production as I was finishing the first prototype. The designer sold me the parts to build and install another one in the second unit. The processor has a bunch of knobs, switches, and LED's, and is designed as a research tool, not really for the retail customer, as I don't know what features will end up in the production version. It has output jacks to feed signals to an external lab scope, with a knob to select what signals are being looked at, and one to select which cylinder is being displayed. It also has an input for an acoustic knock sensor, using the same detection and control system as used in my SafeGuard system. One of the switches on the front panel let you select knock control by ion sensor or by knock sensor. The acoustic sensor will probably go away in the production version. I included it in the prototype as a way to "prove" the ion system is actually detecting knock signals. An LED array shows misfire with yellow LED's, knock with orange LED's, and, preignition with red LED's, for each cylinder, and there is the familiar LED bargraph I use in my SafeGuard gauge, showing the amount of retard from either the ion sensors or the acoustic knock sensor. I also included an off the shelf eight channel data collection system with USB output. The user interface is straight out of the '80's, and needs to be updated, but I ran out of knowledge. http://forums.pelicanparts.com/uploa...1741377829.jpg http://forums.pelicanparts.com/uploa...1741377829.jpg http://forums.pelicanparts.com/uploa...1741377829.jpg http://forums.pelicanparts.com/uploa...1741377829.jpghttp://forums.pelicanparts.com/uploa...1741379445.jpg |
930 engine makes too much noise as well to use a knock sensor.
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No, the 930 engine is not too noisy to use with knock sensors. Where did you get that idea?
Several members on here are using the SafeGuard system. Do a search on here to see who is using it, then ask them if it works. |
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