Thread: what plug gap / boost psi are you running?

Everyone should post what compression, ECU and Ignition system they are using or this is all useless. A stock mechanical DE distributor is going to need a lot less gap than a AEM with independent coils.

Example:
99' DE totally stock (ecu/dist/comp) 9.5:1 20psi BKR7EIX .018 gap - At it's limit gets blow out at certain RPM's
99' DE AEM EMS4 with 4x LQ9 coils 9.5:1 24psi BKR7EIX .25 gap - No blowout yet going to gap higher

With my last ignition setup I was running for the last couple years, I never got a hint of blowout. AEM Twinfire CDI with GSXR1000 coils, AEM standalone. 700+whp and no issues even at .030" gap, My 2.2L VE-T with 12.5:1 compression on a 6262 didn't have any blowout either with a .030" gap on the bosch copper 8 heat range plugs. I don't think it was possible for the ignition system I had to misfire due to being unable to produce a spark. LOL! Very solid and reliable ignition setup. Cheap and simple as long as you have a standalone to run it

My 9:5.1 de+t motor was breaking at higher rpm up gapped at .030 on 15psi. Re-gapped to .025 and no more blowing spark issues.

If I very slowly/gently increase my RPM I notice towards the end of the RPM band (6k+) the car starts to back-fire a little and sounds like it's breaking up. Would you notice this without boost as well? Does that mean I need to close my gap or is this normal behavior? I don't really notice this under boost. Gap is at .028

Misfire at high rpm is not always blow out. I had to increase the gap on mine from .028 to .032 to prevent misfires.

Heat range 8 spark plug part # 4554. NGK non resistor. I've used them with MSD ignition boxes without any issues with EMI. They have the same case as the BK series plugs but a non-projected tip. Best part, they are easily found at Autozone and are pretty cheap.

Old threads FTMFW. I think i always found the best balance at .028 on high boost (GTI-R setup on my 9.5:1 stock lowport DE with S4 cams).

If you guys haven't already, you should check out the thread that @Vadim did on "half gapping" or whatever it's called. I did it recently and really liked the results on my stock DE in the NX at .044" gap.

I use either BKR7E's or BKR7IEX (iridiums), sidegapped. On OBD1 ECU with NEMU, using Roller Rocker (and 99 SE-L) distributor. I'm able to run .045 gap at 10 psi with no breakup. Granted it is much more difficult to measure a gap of a sidegaped plug, thus it could be .040.

I use either BKR7E's or BKR7EIX (iridiums) have the IX plugs in right now.
Gap is currently ~ 0.030 and at this gap I'll run anywhere from 8 - 17psi...
Even though when boost is turned down, I should open the gap...

I run S15 coil on plug

Once I switched to the S15 coils I was able to open the gap up back to normal N/A gaps. 1.1mm or 0.035" again at 11 psi.


Super late reply...

I push about the same amount of air into the cylinders at 11 psi that most do at 15 psi.