COP , Coil on plug issue backfiring...

[GST98BIG16G]

Hi guys ill begin my story from the start so there would be no confusion.
I got all the parts needed to biuld my own COP setup , ordered a thick aluminum plate from Jayracing. I soldered every connection possible and wired everything as it supposed to be. I had the car run fine , but it wasnt tuned. I went to AMS and Chris tuned it for me with DSMLink. I got 320hp 310tq to the wheels. I was pretty happy, so then that day i beat on the car(i had to ) it was fine . Then maybe a day or two later i drove the car and at WOT full boost 20-21psi it backfired BAD. I was lost , then i looked into the wiring and found that power transistor wires were a little overheated and melted, so i got a new plug for it and soldered everything nicely(i tried switching to a different power transistor). That did not work. I looked into COP wiring and couple days ago redid the whole wiring from the inside of connectors to the plug with 14 gauge wire. I redrilled bigger holes where the wire passes from the bottom spark plug cover to the connectors on top, and i did put rubber wire grommets so it would not touch the aluminum. It thought i was all good but no its a DSM!!! it backfired again after a day of beating on it..... The coils have aluminum pieces with small springs that touch spark plug and coil ,so its a pretty tight and good connection there. Im just lost.... Guys Please help ASAP

 

[ebanks89]

I had a problem with my cop setup when I first bought it, back fireing, and felt like I was loosing power. I got in touch with the person I got the cop from and told him what was wrong he advised me to gap my spark plugs to about 24-25 and that solved the back fireing and the feeling of lost power. What kind of plugs are you using? and what do you have them gapped to? stock plugs ngk brp6es=up to 15lbs. of boost, ngk brp7es=15 to25lbs. of boost ngk brp8es=25 to 30+ lbs. of boost.

 

[GST98BIG16G]

I had a problem with my cop setup when I first bought it, back fireing, and felt like I was loosing power. I got in touch with the person I got the cop from and told him what was wrong he advised me to gap my spark plugs to about 24-25 and that solved the back fireing and the feeling of lost power. What kind of plugs are you using? and what do you have them gapped to? stock plugs ngk brp6es=up to 15lbs. of boost, ngk brp7es=15 to25lbs. of boost ngk brp8es=25 to 30+ lbs. of boost.

they are brp7 and they are gapped properly , we did that while on the dyno(way back).

 

[TOONAH]

I have been studying COP for a while and am currently designing a new way to do it. I have a degree in Electronics and don't want to bore you with too much theory. Here is what is important. The 4G63 uses the 'Wasted Spark' ignition method. There are two transistors in the Ignition Module. One for the coil that fires cylinder 1 and 4 simultaneously and one for the coil that fires cylinder 2 and 3 simultaneously. Most DSMers wire the COP so that coils 1 and 4 are in series as are 2 and 3. They do this because the 300M coils contain more inductance and inductances in parallel produce a sum of less inductance. This means that the currrent through the primary side of the coil increases. Since the transistor is in series with the primary coil, the current through each transistor nearly doubles. Of course this current is drawn throught the 12V supply wire and a 16 gauge wire cannot handle 10-14 amps for long. So if you wired your COP setup in parallel, that is why your wires are melting. Also the transistor pack will not last long. My design is using IGBT drivers, one for each of the four 300M coils. The IGBT's for Cyl's 1 and 4 will be driven by the transistor pack Ch A and IGBT's for Cyl's 2 and 3 by transistor Ch B. You would probably understand if you saw a schematic. I have all the parts but have yet to wire and test it. The 'dwell' of the primary ignition signal has a very important relationship to the current through the IGBT which is also related to the amount of inductance in the coil. There is a formula to describe it. I will examine my test circuit's operation with an ocilloscope before I try it on my motor.
A lot of experienced DSMer's will tell you that COP is of no advantage unless you use it along with a CDI ignition controller such as the ARC-2. I have my own theories which are too complex for this forum and besides which I have yet to test them out. Basically, I can say that if the 300M coils are wired in series the spark will only produce about 50 milli joules of energy. Somewhat less than the OEM setup. When COP is done right using IGBT's
the energy in a 3 milli second dwell time can exceed over 200 milli joules. Now that is good for a more energetic and efficient burn! Equals more power and better gas mileage!
However, if you follow me down this path, you should use spark plugs two heat ranges colder or you could burn a hole clean through your nice new forged piston's dome.. Did it done it been there. On a motorcycle I souped up. It hurts. My advice is put your OEM ignition back on and wait for me to test out my circuit. Probably have some results by Christmas. Bench tests that is. Motor is finished but won't go in 'til next spring.

 

[GST98BIG16G]

I have been studying COP for a while and am currently designing a new way to do it. I have a degree in Electronics and don't want to bore you with too much theory. Here is what is important. The 4G63 uses the 'Wasted Spark' ignition method. There are two transistors in the Ignition Module. One for the coil that fires cylinder 1 and 4 simultaneously and one for the coil that fires cylinder 2 and 3 simultaneously. Most DSMers wire the COP so that coils 1 and 4 are in series as are 2 and 3. They do this because the 300M coils contain more inductance and inductances in parallel produce a sum of less inductance. This means that the currrent through the primary side of the coil increases. Since the transistor is in series with the primary coil, the current through each transistor nearly doubles. Of course this current is drawn throught the 12V supply wire and a 16 gauge wire cannot handle 10-14 amps for long. So if you wired your COP setup in parallel, that is why your wires are melting. Also the transistor pack will not last long. My design is using IGBT drivers, one for each of the four 300M coils. The IGBT's for Cyl's 1 and 4 will be driven by the transistor pack Ch A and IGBT's for Cyl's 2 and 3 by transistor Ch B. You would probably understand if you saw a schematic. I have all the parts but have yet to wire and test it. The 'dwell' of the primary ignition signal has a very important relationship to the current through the IGBT which is also related to the amount of inductance in the coil. There is a formula to describe it. I will examine my test circuit's operation with an ocilloscope before I try it on my motor.
A lot of experienced DSMer's will tell you that COP is of no advantage unless you use it along with a CDI ignition controller such as the ARC-2. I have my own theories which are too complex for this forum and besides which I have yet to test them out. Basically, I can say that if the 300M coils are wired in series the spark will only produce about 50 milli joules of energy. Somewhat less than the OEM setup. When COP is done right using IGBT's
the energy in a 3 milli second dwell time can exceed over 200 milli joules. Now that is good for a more energetic and efficient burn! Equals more power and better gas mileage!
However, if you follow me down this path, you should use spark plugs two heat ranges colder or you could burn a hole clean through your nice new forged piston's dome.. Did it done it been there. On a motorcycle I souped up. It hurts. My advice is put your OEM ignition back on and wait for me to test out my circuit. Probably have some results by Christmas. Bench tests that is. Motor is finished but won't go in 'til next spring.

very interersting issue. The wires are not melting anymore. Now i noticed when i warm up the car and get out n the street and WOT it does not backfire , but when i get to my gym about 15-20 minutes if i floor it backfires again , so i dont think its wires , it may be coils?!?!? If it was wires it would backfire all the time, but now its just when i drive them for a while...

 

[cbrfrenzie]

I have been studying COP for a while and am currently designing a new way to do it. I have a degree in Electronics and don't want to bore you with too much theory. Here is what is important. The 4G63 uses the 'Wasted Spark' ignition method. There are two transistors in the Ignition Module. One for the coil that fires cylinder 1 and 4 simultaneously and one for the coil that fires cylinder 2 and 3 simultaneously. Most DSMers wire the COP so that coils 1 and 4 are in series as are 2 and 3. They do this because the 300M coils contain more inductance and inductances in parallel produce a sum of less inductance. This means that the currrent through the primary side of the coil increases. Since the transistor is in series with the primary coil, the current through each transistor nearly doubles. Of course this current is drawn throught the 12V supply wire and a 16 gauge wire cannot handle 10-14 amps for long. So if you wired your COP setup in parallel, that is why your wires are melting. Also the transistor pack will not last long. My design is using IGBT drivers, one for each of the four 300M coils. The IGBT's for Cyl's 1 and 4 will be driven by the transistor pack Ch A and IGBT's for Cyl's 2 and 3 by transistor Ch B. You would probably understand if you saw a schematic. I have all the parts but have yet to wire and test it. The 'dwell' of the primary ignition signal has a very important relationship to the current through the IGBT which is also related to the amount of inductance in the coil. There is a formula to describe it. I will examine my test circuit's operation with an ocilloscope before I try it on my motor.
A lot of experienced DSMer's will tell you that COP is of no advantage unless you use it along with a CDI ignition controller such as the ARC-2. I have my own theories which are too complex for this forum and besides which I have yet to test them out. Basically, I can say that if the 300M coils are wired in series the spark will only produce about 50 milli joules of energy. Somewhat less than the OEM setup. When COP is done right using IGBT's
the energy in a 3 milli second dwell time can exceed over 200 milli joules. Now that is good for a more energetic and efficient burn! Equals more power and better gas mileage!
However, if you follow me down this path, you should use spark plugs two heat ranges colder or you could burn a hole clean through your nice new forged piston's dome.. Did it done it been there. On a motorcycle I souped up. It hurts. My advice is put your OEM ignition back on and wait for me to test out my circuit. Probably have some results by Christmas. Bench tests that is. Motor is finished but won't go in 'til next spring.

Very nice! I also have a degree in EE and designed a similar setup, except mine replaces the stock power transistor. I tested it on the bench, and on the car with no issues what so ever. I have 10 gauge wires running to my 300m coils.

Here is how I did it:
I pulled the CAM signal in off of the CAS and actually turned the two channel into a 4 channel system. With the 2 ECU inputs and a CAM sync signal I now control each coil indipendantly and no longer have a wasted spark setup. I am unsing some Magneti Marelli coil drives used on the Haltech ECU, with built in current limiting and thermal shut down features. Drop me a PM if you are interested in chatting, I'm sure I could learn something from your design as well.

 

[peypey's ride]

Where are your plug gaps set at? Are you runnin a MSD box or anything like that? I have found in my experience that with a COP setup, if you dont have an upgraded ignition box. You should gap your plugs alil smaller. Stock gao is .028, try goin to .025. How much boost are you on?

 

[GST98BIG16G]

Where are your plug gaps set at? Are you runnin a MSD box or anything like that? I have found in my experience that with a COP setup, if you dont have an upgraded ignition box. You should gap your plugs alil smaller. Stock gao is .028, try goin to .025. How much boost are you on?

it does not misfire all the time , please read my responses. .025 at 21lbs

 

[1gDSM4g63]

Not to sideline this forum, but GST98BIG16G is the a certain intent for going to a coil-on-plug setup? I mean in your case there is no need to spend $600-$1000 for that and if your car continues the backfire you really should go back to the normal until it's proper solved.

 

[polarmoment]

Very nice! I also have a degree in EE and designed a similar setup, except mine replaces the stock power transistor. I tested it on the bench, and on the car with no issues what so ever. I have 10 gauge wires running to my 300m coils.

Here is how I did it:
I pulled the CAM signal in off of the CAS and actually turned the two channel into a 4 channel system. With the 2 ECU inputs and a CAM sync signal I now control each coil indipendantly and no longer have a wasted spark setup. I am unsing some Magneti Marelli coil drives used on the Haltech ECU, with built in current limiting and thermal shut down features. Drop me a PM if you are interested in chatting, I'm sure I could learn something from your design as well.

a 4-channel system would be easy enough using a pair of d-flip flops and the cam sync to set/reset them. i've got a similar setup on the bench for my MR2, using a honda ECU and splitting the ignition signal into 2 channels to fire waste spark coilpacks. depending on how any particular CDI charges the capacitor too, it could be used to turn a single channel MSD into a 4 channel.

Of course this current is drawn throught the 12V supply wire and a 16 gauge wire cannot handle 10-14 amps for long. So if you wired your COP setup in parallel, that is why your wires are melting. Also the transistor pack will not last long. My design is using IGBT drivers, one for each of the four 300M coils

another part of the issue with running them in parallel is that i believe there is a current clamp in the PTM that limits current to the neighborhood of ~6A. that means each coil would only be charging to 3A, resulting in a pitiful spark.

a while ago i proposed the idea of using individual drivers for each coil. i thought honda igniters would work very well, since they're very efficient, have low RDSon, and already have a tach output that can be OR'd together to drive the tach.

the issue i take with IGBTs for performance ignition is the RDSon. they can sap as much as 2v out of the ignition circuit, and less voltage means longer dwell times necessary to achieve the same primary current (and stored energy is a function of primary current). they work great in CDI applications because that 2V is such a small percentage of the ~500v charge dumped through the capacitor. when we're talking about a standard 12v ignition system, it's a whole different story. high voltage MOSFETS in parallel would likely work very efficiently with minimal on-resistance. the R/C car makers used to use this technique to minimize power losses through the speed control, since they had such limited power to work with from the start.

 

[Burnett03]

Another dissapointed COP owner.. Who would have though..

500hp here on the stock coils. COP only yielded me about 446hp.

 

[hisandherturbo]

SORRY to bring the dead back to life........ but if I didn't, I would have been told to search..........., anyone have any kind update? I realized the COP limits to, and just thought I had a bad COP, or my brown (used to be white) wires needed replaced. I see now, the standard COP's are more of a gimic it seems like.