CB Street Eliminator Spark Plugs?

[Alexander_Monday]

Anyone here running Street Eliminator heads?
What spark plugs are you using?
As I get higher into boost I believe I am experiencing spark blowout.
I have 4 EGT thermocouples and I can see EGT drop under boost on #3 or #2 then immediately recover off boost.
They are sensitive enough to see the recovery start during shift between gears then go down more.
I have put a set of AC Delco D585's, a set of off brand, and now a set of used GM from a Denali in.
I am getting IGN1a's, but perhaps the NGK DCPR8EA projected tip plugs are part of the problem?
Here was a really bad drop out of #3:

EGT3_Under_Boost.png

[64 sunroof]

What gap are you using on your plugs? on other engines i have used projected and non projected plugs both types have needed to be gapped fairly tight ~0.018 -0.022 ish to run high boost even on IGN1A coils

[Alexander_Monday]

I am using 0.028" gap.
Looking back at older logs I did notice that the after changing the plugs the problem moved cylinders and got worse.
Duh, that could be an indexing issue as well as gap.
I haven't had to index plugs since the late 70's / 80's on the bracket car I had when I was a young'un.
I'll mark on the socket and pull them and see which way they are pointed in relation to the intake and exhaust.

[panel]

I know a lot of air cooled guys run an NGK plug. Maybe not your p/n but possibly guys on the Samba might chime in.

[Steve Arndt]

Check for streaks on your insulators. use dialectric grease. Spark and blow out easily under high cylinder pressure at the boots themselves and never make it across the plug gap.

[Alexander_Monday]

No streaks on the insulators.
Take it with all the grains of salt needed, but #3 plug center electrode was pointing almost exactly away from the intake valve.
#2 was really close to the same.
#1 & #4 weren't pointed directly at, but about 45 degrees side facing to the intake valve.
Marked on my plug gapper where electrode needs to point for each plug.
When to the close Oreillys with my gapper and went through plugs to find appropriate ones.
Had to lathe down an 18mm plug socket for the DR8EA plugs because in front of #3 is busy.
That took a long time taking off .15mm at a time since it is hardened.
Gapped them to 0.21" and installed them and new HEI style wires.
Hopefully I will get the IGN1A coils mounted and wired tomorrow.

[Alexander_Monday]

Got the AEM IGN1A coils mounted and wired.
Set a new dwell table and battery correction %'s.
Put it in test mode and tested the spark with a spare wire and plug on all 4.
Wow, those coils are strong compared to the D585's.
Fired it up and let it warm up.
Though it was my imagination, but the exhaust tone sounded deeper.
Had time to take it for one spin up the highway.
Ran like a champ at WOT on the on ramp.
Got home just as my wife was getting out of her vehicle.
She mentioned how much better it sounded so it wasn't my imagination.

Don't know which it was, or if a combination of 0.21 gap, stronger coils, non projected plugs, or plug indexing.
Oh, also used dielectric grease as mentioned.
Now I can concentrate on tuning the finer things.

[Steve Arndt]

Nice. I've ran the IGN1 coils for along time. They are solid. Just don't overdwell them.

[Alexander_Monday]

I derived these settings with excel based on the voltage vs current chart I found here: https://linkecu.com/documentation/IGN1A ... 20Coil.pdf

PAGES FROM IGN1A SMART COIL.PDF.jpg

I did have to extrapolate for 6V since 6V is not included.
These settings do not appear to be pushing the coils hard.

Ign1A Dwell Settings.jpg

IGN1A 14V Dwell Table & Duty Cycle.jpg

IGN1A Amps @ 14V.jpg

[Steve Arndt]

Looks good.

[Piledriver]

GTG, much better choice for high boost, the GM truck coils are bangers but very limited dwell range..

Having said that, iridium plugs fire hotter/easier/last ~forever.

Bosch/NGK triple electrode (copper core) plugs have very extended core nose and ~eliminate plug clocking issues.
(The Bosch versions were OE on the ur-Quattros)