Coil Dwell Settings with ProTuner & AccessPort
07-24-2012, 08:16 PM
#201
yessir --i grew up around cars in the 50's and 60's--the am radio would sing at times
Get a 58 oldsmobile and a spray bottle and watch the fireworks around the ignition system too.
very good points.
Very true about what you said concerning the actual coil output. You did leave out one option though in which the dwell time can remain oem yet an increase from the coil can be realized. Increase the voltage going to the coils.
1 to 2 volts increase to the coils primary supply wire can have very good results without increasing dwell. A host of factors have to be considered before you do this--including coils rise times, wiring, etc etc. It is an option. Admittedly it is easier and cheaper just to increase the dwell!
Get a 58 oldsmobile and a spray bottle and watch the fireworks around the ignition system too.
very good points.
Very true about what you said concerning the actual coil output. You did leave out one option though in which the dwell time can remain oem yet an increase from the coil can be realized. Increase the voltage going to the coils.
1 to 2 volts increase to the coils primary supply wire can have very good results without increasing dwell. A host of factors have to be considered before you do this--including coils rise times, wiring, etc etc. It is an option. Admittedly it is easier and cheaper just to increase the dwell!
07-25-2012, 12:20 PM
#203
lol--with all the electrical stuff coming out in the new cars they are going to end up needing a 24 V system!
I went with the msd 8247 coils ( need dwell of 3.3) and a kenne bell "boost a spark" with a 5psi boost hobbs switch. On the oem dwell table the dwell is fine until the upper rpms. The coils do well with the oem table and my plugs gapped at 28, but i wanted a little more. So I push a little more voltage to them after 5psi of boost--which is really not that often. But when I do, the ignition is there. My plugs are now gapped at 35
I also changed the wires etc as has been mention. I went with an 18 ga for grounds and primary power.
Its just another more expensive way of doing it. My system can be adjusted with a simple switch.
I went with the msd 8247 coils ( need dwell of 3.3) and a kenne bell "boost a spark" with a 5psi boost hobbs switch. On the oem dwell table the dwell is fine until the upper rpms. The coils do well with the oem table and my plugs gapped at 28, but i wanted a little more. So I push a little more voltage to them after 5psi of boost--which is really not that often. But when I do, the ignition is there. My plugs are now gapped at 35
I also changed the wires etc as has been mention. I went with an 18 ga for grounds and primary power.
Its just another more expensive way of doing it. My system can be adjusted with a simple switch.
07-26-2012, 07:19 AM
#206
A proper dwell table compensates for the actual voltage to provide the optimum dwell regardless. Simply using a multiplier on the OE dwell table for the GM coils was an epic fail. Adding a volt or two in that situation is just as dumb because you have no real idea what you are doing. Which in your case is dead nuts on. If the dwell was optimum and you could override the table just add a volt or two it would oversaturate the coil, which bad things start to happen like detonation. Adding a volt or two is just a wild *** guess pulled out of your butt rather than understanding what is going on and doing it right.
Adding a volt or two in this case does nothing because the dwell table automatically compensates for it, which is the whole ball of wax in a nutshell
Adding a volt or two in this case does nothing because the dwell table automatically compensates for it, which is the whole ball of wax in a nutshell
Last edited by TeamRX8; 07-26-2012 at 07:29 AM.
07-26-2012, 10:15 AM
#207
This part is, IMO, both useful and correct: "A proper dwell table compensates for the actual voltage to provide the optimum dwell regardless. Adding a volt or two in this case does nothing because the dwell table automatically compensates for it, which is the whole ball of wax in a nutshell."
Using a multiplier based on the ratio of the new dwell vs the stock dwell, while incorrect, may be "okay". Similarly, pushing the coil to very high duty cycles without knowing the spec for operation of that coil in the as-installed environment, may be "okay" or may lead to misfires resulting in engine destruction. Some may may even call it "a wild guess".
Using a multiplier based on the ratio of the new dwell vs the stock dwell, while incorrect, may be "okay". Similarly, pushing the coil to very high duty cycles without knowing the spec for operation of that coil in the as-installed environment, may be "okay" or may lead to misfires resulting in engine destruction. Some may may even call it "a wild guess".
07-26-2012, 04:39 PM
#208
you --again --are jumping to conculsions and have it wrong. Oh yea the computer will adjust the dwell according to the voltage if the computer is AWARE of the increased voltage. Such insight--golly gee you are smart.
But if the computer is NOT aware then it doesnt. So go do a little more research before you say "I babble nonsense". Matter of fact you need to educate yourself a little before you post any more misleading, unidirected, ranting. Obviously, you have no idea what system I am using, my settings or my results, yet you post how bad it is. Keep on thinking that parking lot boy. One day you may understand.
But if the computer is NOT aware then it doesnt. So go do a little more research before you say "I babble nonsense". Matter of fact you need to educate yourself a little before you post any more misleading, unidirected, ranting. Obviously, you have no idea what system I am using, my settings or my results, yet you post how bad it is. Keep on thinking that parking lot boy. One day you may understand.
07-27-2012, 09:45 AM
#210
Unless you have the power supply wire connected to an independent electrical source separate from the rest of the vehicle then how is the PCM not aware of the voltage?
You are correct. I have no idea what you are doing. We are discussing controlling dwell with a modified OE dwell table using the Cobb AP.
You are correct. I have no idea what you are doing. We are discussing controlling dwell with a modified OE dwell table using the Cobb AP.
07-31-2012, 05:31 AM
#214
I generally have no clue what you are doing, lol. A set of D585 coils and the posted dwell table is all that is needed. If you want to blast at max capacity then a set of Motronics/Mercury coils with the necessary Ground wires and a dedicated high amp power supply lined wired to an unused fused ignition switched relay in the engine bay fuse box with appropriate dwell table will blow anything else out of the water. As noted earlier by Dan, only two of the OE coil wires are required. Even the so called RX8 ignition experts never recognized this fact. Besides the additional external power and ground wiring, which is easily accomplished with the adapter wiring harness, no other equipment is required/necessary.
Last edited by TeamRX8; 07-31-2012 at 05:37 AM.
08-01-2012, 11:07 AM
#215
Ignition systems need to be tailored to the individual engine, the way it is set up and how it is to be used.
It is insinuated by your posts that there is only one system out there that will work and that is not true.
It should be obvious to you that an ignition system for a forced induction engine has different demands on it than one that is on a NA engine. Once again you have failed to take that into consideration.
The NA renesis engine really doesnt need a higher output ignition coil in its NA form--it DOES need a coil that has a longer lifespan than the oems.
The system I run simply works for forced induction, better imho than the others I have seen. The drawback is that it is more expensive, but for a fi rx8 engine, the ignition system is one area in which you dont want to cheap out.
Will other ignitions system work on fi rx8 engine? Of course. But, the way I went has a few more advantages.
It is insinuated by your posts that there is only one system out there that will work and that is not true.
It should be obvious to you that an ignition system for a forced induction engine has different demands on it than one that is on a NA engine. Once again you have failed to take that into consideration.
The NA renesis engine really doesnt need a higher output ignition coil in its NA form--it DOES need a coil that has a longer lifespan than the oems.
The system I run simply works for forced induction, better imho than the others I have seen. The drawback is that it is more expensive, but for a fi rx8 engine, the ignition system is one area in which you dont want to cheap out.
Will other ignitions system work on fi rx8 engine? Of course. But, the way I went has a few more advantages.
08-01-2012, 08:25 PM
#217
Agreed that these coils did develope a rep for failure. Do you have any idea why that happened? Probably not.
The reason the msd 8247 coils developed a rep for failure is because when they were first released a bunch of uninformed people bought them without paying any attention to their dwell requirements. This was some years ago. They thought the dwell would be the same as for the GM coils. Well, it's not. The dwell for the msd 8247's is only 3.3ms. So unless they backed their dwell times down, the 8247's over a short period of time would fry from being overdriven. Once people started paying attention to coils reduced dwell time requirement they became pretty solid. As solid as coils go anyway.
Failure points? Don't make me laugh. I have an FI renesis engine. I have failure points everywhere.
The device I do use for the ignition coils power supply has been tried and tested for the past 10+ years. It has proven to very very reliable and it has a built in through and through fail safe. It is only activated via the hobbs switch during boost. It is seamless.
Since the oem dwell table is sufficent for the 8247's up until around 5K rpm, I only needed a little bump of increased voltage from that rpm upward to get the coils to perform as designed. And I only needed it during boost as the coils perform ok even at a lower charge level. I did have a slight "flat spot" felt while driving under load at around 6K rpms. That is now gone.
I also have been able to widen my plug gap. From the Pettit recommended 28 with the oem ignition--to now 36 without any problems. My plugs are cleaner and my power is better from 6K forward. I run rich a/f's from my tuner. At times during high loads and rpms it will be below 11. That was my tuners call.
So my ignition system is built to fit my specific engine, its tune and my driving style. It is probably not one for the mass's.
The reason the msd 8247 coils developed a rep for failure is because when they were first released a bunch of uninformed people bought them without paying any attention to their dwell requirements. This was some years ago. They thought the dwell would be the same as for the GM coils. Well, it's not. The dwell for the msd 8247's is only 3.3ms. So unless they backed their dwell times down, the 8247's over a short period of time would fry from being overdriven. Once people started paying attention to coils reduced dwell time requirement they became pretty solid. As solid as coils go anyway.
Failure points? Don't make me laugh. I have an FI renesis engine. I have failure points everywhere.
The device I do use for the ignition coils power supply has been tried and tested for the past 10+ years. It has proven to very very reliable and it has a built in through and through fail safe. It is only activated via the hobbs switch during boost. It is seamless.
Since the oem dwell table is sufficent for the 8247's up until around 5K rpm, I only needed a little bump of increased voltage from that rpm upward to get the coils to perform as designed. And I only needed it during boost as the coils perform ok even at a lower charge level. I did have a slight "flat spot" felt while driving under load at around 6K rpms. That is now gone.
I also have been able to widen my plug gap. From the Pettit recommended 28 with the oem ignition--to now 36 without any problems. My plugs are cleaner and my power is better from 6K forward. I run rich a/f's from my tuner. At times during high loads and rpms it will be below 11. That was my tuners call.
So my ignition system is built to fit my specific engine, its tune and my driving style. It is probably not one for the mass's.
08-01-2012, 11:25 PM
#218
I'm not sure where you came up with that idea because the std D514A LS2 coils are only run at around 3 mS dwell by GM. The higher dwell table was used on the D585 truck coils, which handle 5.5 mS.
With new plugs gapped at 0.060" my RX8 starts on the first cranking rollover every time now and spins solidly to 10k.
Otherwise you are missing the point. You are doing it the old way, which is fine if that's what you want. It's not necessary though. Not at all.
Maybe you need a Holley on there and a distributor with points :-P
.
With new plugs gapped at 0.060" my RX8 starts on the first cranking rollover every time now and spins solidly to 10k.
Otherwise you are missing the point. You are doing it the old way, which is fine if that's what you want. It's not necessary though. Not at all.
Maybe you need a Holley on there and a distributor with points :-P
.
Last edited by TeamRX8; 08-01-2012 at 11:28 PM.
08-02-2012, 09:45 AM
#219
you have a wide spark plug gap and no where near the cylinder pressure I do or the rich a/f's. So why mention it?
Sometimes the old fashion way is better than the latest and the greatest. Have you ever considered that? By the way, this type of system is being used by a LOT of people. It is not old fashioned. Lol. Obviously you dont see the advantages in my application.
In many cases a carburetor ( holley is old school) and a distributor ( not with points) will make more power. It just depends. Once again you need to think about what you are posting.
Sometimes the old fashion way is better than the latest and the greatest. Have you ever considered that? By the way, this type of system is being used by a LOT of people. It is not old fashioned. Lol. Obviously you dont see the advantages in my application.
In many cases a carburetor ( holley is old school) and a distributor ( not with points) will make more power. It just depends. Once again you need to think about what you are posting.
08-03-2012, 01:04 PM
#220
Registered
you have a wide spark plug gap and no where near the cylinder pressure I do or the rich a/f's. So why mention it?
Sometimes the old fashion way is better than the latest and the greatest. Have you ever considered that? By the way, this type of system is being used by a LOT of people. It is not old fashioned. Lol. Obviously you dont see the advantages in my application.
In many cases a carburetor ( holley is old school) and a distributor ( not with points) will make more power. It just depends. Once again you need to think about what you are posting.
Sometimes the old fashion way is better than the latest and the greatest. Have you ever considered that? By the way, this type of system is being used by a LOT of people. It is not old fashioned. Lol. Obviously you dont see the advantages in my application.
In many cases a carburetor ( holley is old school) and a distributor ( not with points) will make more power. It just depends. Once again you need to think about what you are posting.
With the Boost-A-spark, you may be able to run a .060 gap.
08-03-2012, 03:15 PM
#221
Hey Rote--yep I moved it up from the Pettit recommendations of 28-30 to 36 without a problem what-so-ever. I run the denso plugs. But, remember the bas is not activated unless i am in boost which is not that often. So I didnt want to open it up to much at once. I am good at 36 for now.
Steve Kan is supposed to be back in Atlanta soon and we will look at this plus a couple other things then.
Steve Kan is supposed to be back in Atlanta soon and we will look at this plus a couple other things then.
08-05-2012, 09:17 AM
#223
i could take the hobbs switch off and run the bas all the time, but why use it when it is not needed?
I need more ignition while in boost, i dont need more ignition when i am not in boost.
I understand what you are saying team, that i could just set the dwell map for the specific dwell my coils need and call it a day, but I can't do that. My tune is locked and my tuner would not be back in town for a while. So by phone i spoke with him and he was ok with this approach. When he returns and we can get on the dyno, then we will see what happens.
From what I understand, with the bas i can even safely overdrive the coils for the short period of time that I am in boost. You can't do that with just a change in the dwell table.
Heres the kicker--if we decide that tuning the dwell table will be the best thing to do then I can use the bas as a boost a pump unit with an off and on switch. That would certainly help in keeping the tanks balanced while on the track.
I need more ignition while in boost, i dont need more ignition when i am not in boost.
I understand what you are saying team, that i could just set the dwell map for the specific dwell my coils need and call it a day, but I can't do that. My tune is locked and my tuner would not be back in town for a while. So by phone i spoke with him and he was ok with this approach. When he returns and we can get on the dyno, then we will see what happens.
From what I understand, with the bas i can even safely overdrive the coils for the short period of time that I am in boost. You can't do that with just a change in the dwell table.
Heres the kicker--if we decide that tuning the dwell table will be the best thing to do then I can use the bas as a boost a pump unit with an off and on switch. That would certainly help in keeping the tanks balanced while on the track.
