jintei

iTrader: (23)

Just want to clarify which spark plugs are best suited for this engine and the gap as well.
There has been information regarding this on the forum but I can't find an exact answer on which one works the best.

From the parts bible thread:

"Spark Plugs: PK20TR11
Spark Plugs (stock): NGK BKR6E or BKR6E11
Spark Plugs (BPU): NGK BKR7E or BKR7E11"

Can anyone tell me which one to get and what's the difference between BKR6E or BKR6E11 and BKR7E or BKR7E11 (I assume 7 is colder, but what does it mean exactly?).

Also, what would be the best recommended gap? I have seen people mention .028 (inches I assume?).

Thanks,
David

Vrank

iTrader: (4)

If your car is a bolt on car, do the 6. The 6e11 are iridium I believe, and will last longer than a copper plug. Leave them as is gapped out of the box, should be fine. On a bigger turbo or more boost than a ct15 should be pushed, I'd run the 7. Yes 7 is colder.

Anyone runnin an .028 gap better be on a bigger turbo throwing big boost at it. If not and that's what it takes to keep the car from breaking up, then the coils are about done.

jintei

iTrader: (23)

Thanks for the reply.

I am currently having a break up under hard acceleration (not sure if that's the correct term).
Basically, under normal acceleration, the car boosts just fine. But when I stomped it, it would boost and the exhaust would pop (like a silenced thump) a couple times, almost like a fuel cut.
I made sure that it's not a fuel cut since I lowered down the boost to 10psi and it is still doing that.
Mostly happens during the night when the air is thicker. Afr reading is normal (about 11.4 max on Hi throttle).
I also checked my coils and made sure that there are no cracks.

Let's say I get the 6e11, what would be the gap out of the box and what would be the ideal gap for my setup?

Thanks,
David

Vrank

iTrader: (4)

Dude I've run a 58mm on my vvti 1j and had no break up over 25psi on plugs gapped around .032 that came out of my gfs car. matter of fact, those plugs have been in my car over 15k miles prob closer to 20k with at least another 12k from her car. my car made almost 300whp @11psi on stock turbo about 3 months ago. i havent done the plugs this year. And though I can smell that I need them, I can still get wot pulls to 13psi no sweat. Check the gap out of the box wanna say its around .042. You should not need to approach low .030s. If you still have break up you have other problems.

Also, these are the same coils/wires that came on my swap from Japan that I've had running for 3 years on/off at 400whp. The wasted spark coils are pretty good. I'd suspect fueling or your atmospheric bov.

jintei

iTrader: (23)

Yes, I am suspecting my fuel pump as well since it is still the stock sc400 with 12v mod. I am going to replace that next with a walbro 255 or denso (kyosan) 300lph. I am going to do the spark plugs first since it's the cheapest. Thanks for the info!

Ali SC3

iTrader: (10)

the ones that end in IX are iridium. the ones without it are copper.
If it has a -11 on the end (1.1mm) the gap is .043 in, If there is no -11 on the end the gap will be .032 in

So a BKR6eix is a 6 range iridium that will come gapped at .032 and these should just drop in.
If you were stock - bpu not running much boost you can even use the BKR6eIX -11 with the larger gap.

Vrank is correct you have another issue, .028 is what I would run with 1 coil on the distributor at your boost levels, and your coilpacks should be able to do much better than that. my vvti coils are gapped at .032 on an na-t and I hit 18 psi no problem. I have seen a supra tt bpu with the .043 iridiums hit 18 psi as well without any spark blow out, but .032 is more recommended with higher boost on a single turbo.

jintei

iTrader: (23)

Thanks, Ali. So would you recommend when I install my BKR7E (that's what I bought), I should just drop them in without gapping?
I was thinking just install them the way they are out of the box and see how the car is running.
If it's still breaking up, then I would lower the gap to .03

What do you think?

And by "breaking up", is that the case that I'm having (silenced thumps from the exhaust like a fuel cut under hard acceleration)?

Ali SC3

iTrader: (10)

what kind of boost do you plan on running, that will determine the heat range but generally if you are turning the boost up you can use a 7 range.
the breaking up is like a pause in acceleration and when its not bad its for a split second here or there and you can push through it, but if its bad enough it will really slow you down. I would try changing the plugs first if they are copper and old then that can happen. Thats why I usually run the iridiums you wont have to worry about the plugs again for a much longer period of time.

BKR7E are copper .032 and should work, I usually double check the gap with a gauge to see if they are .032 and they usually are and then drop them in.