Plugs for boosted Apex

[om600]

What are the best plugs to run in a boosted Apex

 

[mbarryracing]

Stock plugs, gapped at 0.018"

 

[FLYBYU]

Stock plugs, gapped at 0.018"

I would agree with that.

 

[kinger]

^^^^^^^^^^^^^Plus 3 that is what I have always ran. 10 psi 91 gas.

 

[FLYBYU]

The gap is crucial!!!!!!!!!!!!!!!! To big and you'll blow the spark out.

 

[rxrider]

X2 on what mbarryracing says

 

[mulot30th]

the more boost, the less the gap... with the stock coils, I found out... there is about no way I can avoid missfires above 25 psi of boost, even with the motec ecu, and that regardless of what motec guy told me.. I tried... and can't get it to properly ignite at 27 psi even with the gap set to a ridiculous .013"...

 

[mbarryracing]

At those boost levels, you need more amperage at the spark plug that the stock coils can't provide.
AKA: large MSD coils, of which a MOTEC can drive

 

[desperado]

The dwell needs to be optimized for running higher boost on the oem ignition system with the MoTeC and IGN4 setup. Gap @ 0.018" and increase dwell 0,5ms in the dwell table for drag racing and the engine will be happy to 34psi+ boost. This should not be done on a trail application as the coils will have a tendency to overheat, but it is perfectly ok for drag racing. Another method is to increase dwell 0.5ms using the 3D dwell table with battery volt on one axis and boost on the other.... leaving dwell stock at lower absolute boost value than 200kpa and ramping up the dwell when boost level exceeds 200kpa.

The reality of the stock induction ignition system is that it uses too much energy to ionize the plug arc, leaving too little actual arc time on high boost. optimizing dwell takes care of that just as well as reducing gap which makes ionization faster and leaves more time for the actual arc between the electrodes.

We have been running 32psi countless times on the dyno with the oem system on C16 without any issue. If missfiring happen at only 25psi, then something is out to lunch big time somewhere on the sled or in the tune, no question about that.

I hope this helps.

 

[mulot30th]

my coils on my apex with the motec really have hard time sparking past 25 psi. I reduced the gap from 0.018 to 0.015... made it better... then upped the boost to 27... and missfiring started to show again. can't see what else would do it.

bad coils?? maybe... don't know.


But what is the IGN4 setup you are talking about?

 

[FLYBYU]

Aem makes plug on coil replacements that are better than stock.

 

[desperado]

my coils on my apex with the motec really have hard time sparking past 25 psi. I reduced the gap from 0.018 to 0.015... made it better... then upped the boost to 27... and missfiring started to show again. can't see what else would do it.

bad coils?? maybe... don't know.


But what is the IGN4 setup you are talking about?

IGN4 is the external ignition driver used to control the inductive coils. Make sure your overboost cut is not what is causing your issue: ADJUST -- FUNCTIONS -- BOOST CONTROL -- SETUP -- OVERBOOST CUT. It should be set at least 50kpa above the maximum boost you inted to run to avoid fuel cut on boost spikes.

 

[FLYBYU]

I know it says that multiple in training videos.

 

[Srxspec]

CR9E plugs @ 7300 rpm & 96 lbs of boost gapped to .012", of course, a little better ignition than the stock Yamaha! Have run as high as 137 lbs of boost (on accident)!

 

[mbarryracing]

Are you using a fresh set of plugs and fresh known good fuel? Either can result in the symptom like what you described. As well, I encountered issues with battery voltage dipping down and causing fits when the boost went up too. Theory is that the fuel pump loaded more when the rising rate fuel pressure raised accordingly.