olddragger

iTrader: (3)

Ok--I have been pondering how I can upgrade my ignition. I do not have any problems with the oem thus far (yes i am above 300g/sec). Upgraded wires and connectoers, denso plugs set at 30 gap. Pettit flash tune. redline now at 7.5-8K
SInce I am not having any blowout problems, only rare misfire(who doesnt?) I ask myself why mess with it? My answer is "Hell, I dont know" I just do."

Now my question is in referrence to upgrading to the "Yukons/LS2's"
Its is " would it be better to increase the supplied voltage to the coil (16 V rather than 12V) instead of increasing the dwell time ?"
I am thinking it may be adventasious to increase the voltage. But, I am an almost noob when it comes to this stuff.
Now if it was a single coil system with points I would say Hell Yea, but with this cnp /ecu set up I am not sure.
olddragger

tubingchamp

iTrader: (3)

I'm a newb aswell, but wouldn't you need a 16V battery?

Thought ours is 12V? Hm.

Haven't had to screw around with it yet, so dunno.

Mawnee

hmmm...Kenne bell boost-a-coil ?

MazdaManiac

iTrader: (3)

No additional coil output + lots of added heat = bad idea.

Flashwing

I have a simple solution for you.


As MazdaManiac pointed out, any voltage increases are not going to yield anything but increases in heat generated by the coil. Setting the dwell to 4.5 - 5 ms is going to yield all the spark you need.

paulmasoner

iTrader: (1)

I can answer that a bit better OD. Because you know that although you've had good success(or luck) thus far with OEM coils, it is more likely than not that at some point they will be a point of avoidable failure. And that failure could easily be catastrophic. Although I'm sure you'd love the excuse to tear down the motor and rebuild, you are smart enough to not be asking to do so needlessly

Brettus

iTrader: (2)

I have experimented with increasing the dwell time a little on the stock coils and found that it definately did stop the misfire i had at around 280lb/ft of torque .
How long will they coils last is the question . I'm reasonably comfortable that they will be ok for street use for a while . Not confident they will last at the track however ....

olddragger

iTrader: (3)

good info guys --thanks. now if i could only afford to buy a cobb unit. Must look for coupons.
OD

PhillipM

+1, I've settled on 3.2ms base for our car on stock coils, it's done perhaps 1000 miles all at race-pace and been flawless so far.

cliffkemp

you still running stock coils with 330+whp? If so, that is awesome. No kidding that you have a good wire set with good connections. As long as the connections are very good, they should continue to last fairly well. If the connections deteriorate very much, it will start to show. Just a guess, if you keep the wires and plugs changed out regularly (when signs of power loss are evident and you catch this fairly quickly) you can just change them out and made sure the new set has good connections and should be good to go. Let me know if you ever get your car over that 340whp 'hill' and still keep coils stock. Believe we have discussed this before if i remember correctly. Best of luck to you and hope your car runs/lasts for a very long time.

MazdaManiac

iTrader: (3)

The dwell of the OE coils is internally limited. All you are doing is holding the transistor input high, burning it up.
The spark duration and current remains the same, regardless of the dwell duration after 3ms or so.

cliffkemp

If your coils start to fail, it is not going to be catastrophic as it will just lose power on top end until they quit firing and the car no longer works. Guess that is catastrophic in a way but, change the coils, wires, and plugs and you will be good to go. Stock coils are fine and with good connections, they will last a long time.

MazdaManiac

iTrader: (3)

Unless the leading stop firing under load, which can be catastrophic.

cliffkemp

True. Hopefully the problem would be identified before it got to that point but could happen.

paulmasoner

iTrader: (1)

EDIT: just noticed this was pointed out right above me. FWIW though, that isnt just theory - its actually happened to people here

unless as the coils die you get a leading misfire, and trailing fires as normal... say goodbye to a seal or an endplate

cliffkemp

Of course it is not theory. I am sure it has happened and was diagnosed as such. I do hope people stay on top of their ignitions system well enough to not have to worry about that. When the car is idling and, you notice the idle is not smooth or if you are redlining the car and you see the needle hesitate in the higher rpms, it could be a sign of ignition failure. I am not sure what others do but, I take my car to the dyno after mods and from time to time, I just take it to see if it is putting down the numbers it has been in the past to see if there may be a problem. Staying on top of the car with good maintenance is a good way to keep the ABOVE from happening. It could still happen even if you keep the car up good but, much less likely. In the 58k miles I have put on my car with stock coils and wires, I noticed a few weeks ago the idle change and changed the plugs, wires, and coils and it runs very smooth now. I hope I never have the above problem.

MazdaManiac

iTrader: (3)

There is really only one good way for the hobbyist to diagnose a failing coil (the test in the FSM and observing spots on the bottom are useless as a diagnostic).
That is to tape a good-quality inductive timing light to the windshield and take a drive.

cliffkemp

correct. spots on the bottom only mean that the coil has run hot but, doesnt meant that it is not working properly or at all. Checking with a good quality timing light is the best way to diagnose this problem.

olddragger

iTrader: (3)

Flash --did you mean the Twin Power?
OD

TeamRX8

iTrader: (25)

MazdaManiac

iTrader: (3)

^ Seriously.

Do people here (still) just not understand how a coil with an internal ignitor works?