Spark plug FAQ: NGK V-powers, not Bosch platinums...

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Spark plug FAQ: NGK V-powers, not Bosch platinums...

Post by DerFahrer » Thu Feb 27, 2003 5:39 am

Just so everyone gets a chance to see this, Josh and I have decided to put together this FAQ about the frequent mistake of choosing improper spark plugs.

The correct spark plugs to use in Subaru engines are NGK V-Powers, part no. BKR6E11 for the EJ22, gapped somewhere between .038 and .043 inches.

Several people (including myself) have tried Bosch Platinums in a quest for better performance. What we ended up with was worse performance and $30 down the drain...

I feel this is very important to people new to this forum, who are enthusiastic about their cars and want them to run in excellent condition for a long time, yet who are just that, new. They come with lots of good questions, but this usually isn't one. They fall victim to false advertising claims for these plugs and buy them anyway, and then learn that their hard-earned money, which could have gone to maintenance or performance goodies, is wasted.

Anyone else feel free to add input or ask a question...
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Post by boostjunkie » Thu Feb 27, 2003 2:42 pm

This information was taken from my post in the engine forum. I figured it might be good to put in here. I found this information on gapping WRT boost levels here: http://www.anythingsubaru.com/articles/article001.html

SPARK PLUG GAPS AND BOOST LEVELS

It has been found that if boost levels pass 1.2 bar, then the spark plug gap should be closed down. Look at the chart below.

1.2 bar Ngk pfr 6b9 .9mm or .035"
1.25 bar Ngk pfr 6b9 .8mm or .032"
1.3 bar Ngk pfr 7b9 .7mm or .028"
1.4 bar Ngk pfr 7b9 .65mm or .026"
1.5 bar Ngk pfr 8b9 .55mm or .022"

It has been found that the rapid pressure change in the cylinder can, in high boost applications, shift the spark off the end of the plug and cause a misfire.

The early model pre - 1997 cars are only rated at 1.1 bar of boost. Post 1997 are rated at 1.3 bar.
In some countries, differing weather conditions can denote hotter or colder spark plugs. I use NGK spark plugs and this is only a guideline based on standard models.

Regards,
James Laird
[url=http://www.angelfire.com/md3/91turbolegacy/images/On_the_Lawn.jpg]1991 Legacy Turbo (RIP)[/url]

[url=http://www.angelfire.com/md3/91turbolegacy/images/Summer_Car_Wash3.jpg]2000 Celica GT-S[/url]

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Post by ciper » Thu Feb 27, 2003 7:41 pm

Also realise that you shouldnt end up paying more than 10$ including tax for your plugs.

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Post by boostjunkie » Fri Mar 14, 2003 5:04 pm

Oh, and colder ranges in NGK correspond to a higher number . . .ex:

BKR6E11 (stock range)
BKR7E11 (one range colder)
BKR5E11 (one range hotter)
[url=http://www.angelfire.com/md3/91turbolegacy/images/On_the_Lawn.jpg]1991 Legacy Turbo (RIP)[/url]

[url=http://www.angelfire.com/md3/91turbolegacy/images/Summer_Car_Wash3.jpg]2000 Celica GT-S[/url]

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Post by IggDawg » Fri Mar 14, 2003 5:06 pm

I'll attest to the fact that the Bosch plugs weren't just bad, they were terrible. I was getting frequent and SEVERE misfiring at part throttle. I put in the NGKs, and the problem instantly went away.
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Post by Ogre » Wed Apr 16, 2003 9:20 pm

D'OH!

Two weeks ago I put in Bosch Plats. The old plugs were not in the best of shape... old but no signs of any engine issues. So I did actually get somewhat of an improvement over what I had before. The Plats are causing problems 'eh? Well, I've not seen that... but I am looking for an increase in performance and the Plats didn't give that to me...

Where can I get these NGK's at? (Note: I am out in the middle of freaking no where in Utah, about 3 hours from Salt Lake City so I might have to order it online)
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Post by vrg3 » Wed Apr 16, 2003 9:21 pm

I've gotten them from AutoZone and Advance Auto Parts in various cities... A local place might not carry them, but most chains I'd imagine would. Shouldn't be more than $1.50 each at the most.

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Post by DLC » Wed Apr 16, 2003 11:25 pm

Hey Ogre, finally another poor Utahn :D

Any Checker Auto will have them, but your best bet might be from an online store.

Dave
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Post by Ogre » Fri Apr 18, 2003 3:17 am

Where you at Dave? I just moved from Orem to Vernal.

I think I just went 10 years back in time.
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Post by 91scoobiesubie » Mon Jun 16, 2003 11:55 pm

so every one agrees v powers are best? what about denso

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Post by 91scoobiesubie » Mon Jun 23, 2003 1:57 am

what is the part number of the ngks for my ej22t and what should i gap them i live in eastern pa

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Post by legacy92ej22t » Mon Jun 23, 2003 2:46 am

Hey another pennsylvanian! :D the stock # is 2756 BKR6E-11.v-power the only way to go!Gap is 0.039-0.043 inch.If you have the manual for the car read it.It tells you a lot about tune-up and maintenance stuff.there is a lot of usefull info in it.if you plan on doing much to your car i would pick up a haynes or chilson manual from a local auto parts store too.good luck :)
-Matt

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Post by THAWA » Mon Oct 06, 2003 10:41 pm

What makes the v-powers better than the other plugs from ngk? Like their iridium or platinum ones?
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Post by vrg3 » Tue Oct 07, 2003 1:10 am

Platinum plugs don't perform better; they just last longer. The problem is that Platinum is actually not as conductive as copper (around 100,000 mho/cm versus 600,000 for copper), so some of the spark voltage is dropped inside the electrodes.

The big selling point with platinum plugs is that they only need to be changed every 100,000 miles or so. To me that's not so great, because the idea of having to remove a plug from an engine after it's been there for 100,000 miles scares me. You also really should be reading your plugs more often than that just to check up on the state of your engine.

It is true, though, that because the platinum electrode won't wear away as easily, you can make then smaller, exposing more of the spark to the air/fuel mixture. But the V-groove does a pretty good job of exposing the spark with copper.

Another issue some tuners may have with platinum electrodes is that you can't adjust their gap. That means you can't experiment with different gaps with platinum plugs unless you buy lots of different platinum plugs, which is expensive. It's not necessarily the case that the optimal gap with a platinum plug will be the same as the optimal gap with a copper plug.

I don't know as much about iridium plugs, but I think that they're basically a step up from platinum. Iridium is even more sturdy and resistant to wear so they last long and have smaller electrodes. Iridium is actually more conductive than platinum, though still nowhere near copper (around 200,000 mho/cm). I think you can gap Iridium plugs too.

Copper with the V-groove is just a good proven cost-effective design... It's been common experience that platinum doesn't perform as well though it does deliver on longevity. I don't know, but it's possible that iridium would perform better due to the smaller electrode. I'll just stick to my $1.30 coppers though.
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Post by THAWA » Tue Oct 07, 2003 4:58 am

Excelent info, big thumbs up
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Post by vrg3 » Tue Oct 07, 2003 6:10 am

Thanks, THAWA.

Oh, and I also wanted to point out another thing as I read my post again -- whenever possible, you really shouldn't take a plug out of the engine and then put it right back in. The washer at the base of the plug is a crush washer, meant to act as a sealing gasket (just like the one around the oil drain plug). It really only should be used once and then discarded. I don't know where you can get a good replacement washer; that's why I just put new plugs in whenever I take mine out.
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Post by FreddexTurbo2Go » Wed Oct 08, 2003 2:22 pm

I put the Platinum NGK's in my car a couple of months ago. I bought the one's listed for my car and didn't adjust the gap on them. I was told that all spark plugs come pre-gaped so as long as it is the correct plug for my car it would be fine. Is this true?

Fred
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Post by vrg3 » Wed Oct 08, 2003 3:21 pm

All spark plugs come pre-gapped, yes... the "11" at the end of the recommended part numbers earlier in this thread means "1.1 mm gap."

But, it's a good idea to at least check the gap before installing them.

Manufacturing tolerances or just jostling during shipping can make the gaps different. I've gotten a set of NGK coppers with gaps varying by up to a tenth or two of a millimeter. That's not widely different, but at the least it causes asymmetry in spark strength.

With platinum plugs, you cannot adjust the gap. The electrode's not meant to be bendable. They're supposed to be a little better packed when shipping, so they should hold their gap.
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Post by DerFahrer » Wed Oct 08, 2003 3:37 pm

By the way, the set of NGK V-Powers I have in my car right now, I gapped them to .040" just out of experimentation, as the recommended gap for a stock N/A setup is .038"-.043". I think the .040" gap, pretty much in the middle, is the best gap for a stock N/A setup like mine. I'm most happy with this particular set of plugs...
2000 Subaru Legacy B4 RSK

"Der Wahnsinn ist nur eine schmale Brücke/die Ufer sind Vernunft und Trieb"

*Formerly subyluvr2212*

Please email me at fahrer4184@gmail.com if you want to contact me.

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Post by DOA » Fri Oct 10, 2003 7:24 pm

On the crush washer point, your right in saying that you shouldnt really do it, but it really wont affect either the engine compression or the plug itself. I would tend to think that they are only used so that its easier to get the plug out instead off it sticking in thru corrosion (dissimilar metals just really aint a good idea). Also I dont really think that the very low torques that your supposed to set them to would completely compress the washer.
Only my own thoughts on the matter like and you are still correct in what you say :) .
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Post by vrg3 » Sat Oct 11, 2003 4:48 am

Perhaps you're right that it's not meant to seal.

But as for preventing corrosion, don't you still have interfaces between dissimilar metals? The washer isn't the same material as the head and as the plug, right?

It should compress fully; it doesn't take much to crush this type of washer.

Another reason for the crush washer (related to what you're guessing) could be just to serve as an indication that proper torque has been reached. If you don't have a torque wrench, you can install a spark plug by threading by feel it until the washer seats, and then tightening until you feel the washer crush.
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Post by Rallitek.com » Wed Oct 15, 2003 6:31 pm

At Rallitek we have been really impressed with the Denso Iridium plugs
We have seen better fuel economy ,better throttle response and improved power. They are a little pricey at close to 20 bucks a plug but they are the lates in spark plug technology. We also recomend going colder as you raise the boost.

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Post by free5ty1e » Tue May 18, 2004 3:10 am

Anti-seize on the threads make the spark plugs a bit easier to remove, too - and di-electric grease on between the boot and the plug couldn't hurt. As long as we're giving advice on plugs.

At what point should we (turbo Legacys) switch to BKR7E-11s? I'm still running stock boost for now but when increasing said boost I'm sure the colder plugs would help reduce the risk of detonation. Any comments on the subject?
-Chris
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Post by nzKAOSnz » Mon Dec 06, 2004 3:05 am

vrg3 wrote:I think you can gap Iridium plugs too.
No. Cant gap them.
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New Plugs HALO PLUGS might be the answer $$$$ back guarantee

Post by GT8 » Sun Feb 05, 2006 8:44 am

http://www.haloplugs.com

I will be experimenting with these plugs in my vehicles I have. What I will do is keep this forum atune of my results. I too have tried Bosch Platinums 1-2 and 4 and hated them.

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