Erik@MIL.SPEC

iTrader: (94)

What was the gap?

I know a guy running iridium 9's on the street, and he isn't having problems.

apevo8

iTrader: (9)

probabley gapped too big since i did it

C6C6CH3vo

iTrader: (9)

Besides SES code 0300, how can I determine if misfiring?

I heard of lean spikes on WB but how can I know without running a 4 gas analyser?


I run the BPR7IEX like you - best plugs out there for evo for under $10ea. I'm at about 330 - 350 whp (mustang dyno range) at 24psi with water/methanol. So should I open gap to about 0.028 and go from there?

Plugs are only 2 months old, can I regap and reuse them - Dont want ground falling off.

Thanks (for possibly 5 -10 more whp )

iTune

iTrader: (3)

a misfire will register a lean spike if your WB has a high sample rate(innovate LC-1/LM-1) but it may not be enough for you to see unless it was a serious/consecutive misfire.

A misfire can also be picked up by the knock sensor and registerd as knock, or the most common way to tell if you are missing is a loss in power(shaky torque curve) and a actual "mis" which can be felt and heard along with backfiring..ect.

If your gap is too large, you will most likely get a misfire across all cylinders, in which this case you will deffinatly pick this up using a high sample rate WBo2(fast high spiking lean conditions) and it would be felt and would deffinatly show up on the dynograph.

For you power(not boost), i would open back up to about .028 and start from there. You may not be able to run .028 but you won't know until you try.

For gapping these plugs, use a feeler type gauge(can be bought at pep-boy, advanced autoparts..ect) and be careful not to hit the small electrode on anything(including the feeler gauge). On a feeler gauge type gapper, be carefull on to shove the feelin inbetween the ground strap and the electrode, if the gap is too small for the feeler used, don't shove it in there. To open up gap, use the end of the feeler gauge to stick on the side of the ground strap(in the curve of the ground strap) and slowly and very lightly pull the ground strap out. Check the gap again and repeat. If you have gone too far(take your time!), take a block of solid wood, lay it on a desk or ground and tap the ground strap of the plug on the block of wood very very lightly and then check the gap. If it's still too large for the gap you want, do it again until it's perfect. This take practice to find the right force used to move the ground strap little by little. The key is to go slow and light. If you went too far(gap too small) use the feeler gauge gapper to open it back up. Repeat process until it's where you want it(in your case start at .028). Do this for all 4 plugs. Making sure your measurements are perfect for each plug. Don't allow there to be different gaps on different plug, like saying.....thats close enough. Take your time and make them all perfect.

With practice and learning how to know what a misfire is, you will get it right.

Good luck!


CJ

C6C6CH3vo

iTrader: (9)

Adjusted (pulled) gap from the 0.024 to within 0.002 of the 0.028, then I lightly sanded with 600 grit to get exactly 0.028. Of course measured with brass feeler shim

I will do a log tomarrow to see where I stand - I graph my rpm vs time on excel scatter chart and it shows power changes. I dont get a # like on a dyno but it will show smallest of changes compared to prior pulls and will be more accurate if cond same

iTune

iTrader: (3)

I just realized your actual power level, next time around....you will benifit from running a colder plug. The general rule of thumb is to go one step colder per every 100hp made over stock. So, stock heat range is 7....next time go with a NGK BPR8EIX. This can also allow you to run slightly more gap, as the firing end temps and cylinder pressures will decrease because more heat is able to escape the combustion chamber and make it's way into the head and ultimatly into the coolant journals. In identical spark plug types, the difference from one heat range to the next is the ability to remove approximately 70°C to 100°C from the combustion chamber!

Also, make sure you properly torque down your plugs!! this is also very very important for proper heatsink to the head...as this is one of the plugs main jobs and without a proper seat, half of what the plug is supposed to do is not happening. Use a torque wrench if you have one and torque them down to 18.0~21.6ft/lbs.

CJ

iTune

iTrader: (3)

also, for you people with access to a dyno, the rule of thumb on plug gaps in race applications is to open them up in .002" increments at a time. When the motor begins to lose power or slow down then go back .001-.002" and this in most cases is the optimum gap. This is actually reverse of the way i recommended above if you are doing this on the street. It is easier to measure power changes from gap and of course misfires(loss of power and/or shakey torque curves, fast jumpy lean spikes from WB02S).

CJ

C6C6CH3vo

iTrader: (9)

0.028 causes a spike in A:F at 4500rpm. Normally 11.7 but now 12.2. Since this is a spike, I take it as misfire. I will close them down to 0.026.


I like the BPR7EIX even at my power over the 8 heat range. remember I dont need the added colder plug due to W/M, and without the W/M I just have any other 7 heat range eng - if I'm making any sense

iTune

iTrader: (3)

I was unaware that you were running water/meth. even then, when you are running it, you will benefit from the colder plug. keep in mind that its the power your making, not the boost pressures being run that determins what heat range plug you should run. the heat range of 8 won't hurt you at all when not using the w/m.... it is not a big enough jump and can only help raise the detonation threshold even when running low boost on pump gas. I would not run a 9 heat range on low boost....but a 8 will be fine.

C6C6CH3vo

iTrader: (9)

Too late, I allready ordered some BPR7EIX's to go in at 0.026 gap when they arrive tomarrow. Seems to be no missfire at 0.026 - that lean spot I noticed at 0.028 definately disappeared.

Maybe someday I'll try the BPR8EIX at 0.028 but for now the 7's work fine