Spark plug gap question, SR, high boost

[niSm095]

After searching and asking around I've gotten conflicting answers-
I've got a blacktop SR, 2871r, 740cc injectors, rom + afc tune, intake manifold, etc etc...using NGK copper BKR7Es, running 20psi

I've been told different things, but mostly that I should gap higher (.30 to .32) to 'get a more complete spark'. Conversely, I've been told to gap lower ( .25 to .26) by others.

Can anyone expound on either theory and help me with this

[S14_Kouki]

When you push alot of boost the spark gets blown out with a high gap. When the spark plugs are gapped closer the spark does not get blown as easy. Yes gap them to .25.

[GSXRJJordan]

You guys are off by a factor of 10.

Gaps range between .032 (32 thousanths) and .025 or so. Run them tighter at higher boost, .025 sounds reasonable for 20psi.

[niSm095]

nicely put. I get it. It seems I may not be getting a complete burn then? Possibly why I smell a bit of fuel?

[codyace]

.022 here, forever. Coppers, 20 psi, track days, etce tc. Never any issue of spark blow out, 30 mpg, good power.

To me, slightly tight isn't gonna make a huge issue on our end. I think one of the biggest PITA with our car is the weak coilpacks. I always suggest an ignition amp for big boost setups.

[jdm213]

coppers where out quick you should get irridium ngk ones:fart:

[Sileighty_85]

I run mine at .030 with NGK Iridiums @ 21+ PSI no issues but then again i have the Splitfire ignition system

[codyace]

coppers where out quick you should get irridium ngk ones:fart:

Most certainly, but coppers also melt before you burn a hole in your piston too. Gotta have a weak like somewhere ya know?

[s14unimog]

You guys are off by a factor of 10.

Gaps range between .032 (32 thousanths) and .025 or so. Run them tighter at higher boost, .025 sounds reasonable for 20psi.

^ I agree with Jordan the most. Another thing to consider is the grounding of your coilpacks. I've seen blow out issues on my car due to weak coil pack grounds; it only degrades an already weak (for our purposes) coilpack.

[jdm213]

Most certainly, but coppers also melt before you burn a hole in your piston too. Gotta have a weak like somewhere ya know?

so its sorta like a warning =]:bigok:

[McCoy]

so its sorta like a warning =]:bigok:
Yeah... like my copper plugs below. I was able to throw in a new set of coppers, finish the track day and drive home, I probably would have been getting a tow if these were platinum or iridium plugs.

http://www.sr20forum.com/gallery/data/959/medium/aug_08_track_day_plugs.jpg

[s14unimog]

why is the ground all eroded away like that. WTF is up with your car...

[McCoy]

^^^ It's called detonation. Nothing is wrong with the car, I assume it was from the 95F track day + 91 octane + 9.5:1CR = melted plugs. I had done many track days before this and never had an issue and did 5 track days after this too.

If I wouldn't have had copper plugs I probably would have ended up getting a tow home due to a blown head gasket I'm sure.

[codyace]

If I wouldn't have had copper plugs I probably would have ended up getting a tow home due to a blown head gasket I'm sure.

Ding ding!

[s14unimog]

If I wouldn't have had copper plugs I probably would have ended up getting a tow home due to a blown head gasket I'm sure.

Damn, so educate me as to why the ground wouldn't melt away with an iridium plug... Isn't the thread/ground material the same for both plugs...

[McCoy]

Damn, so educate me as to why the ground wouldn't melt away with an iridium plug... Isn't the thread/ground material the same for both plugs...
why does a platinum or iridium plug last longer than a copper plug? I am pretty sure that the ground electrode is coated in platinum on a platinum plug and would withstand more abuse than a copper plug. I've yet to try this theory on the various types of plugs as each time I've done it I've had to replace/rebuild a motor.

[HYPNOTIK]

Fuck iridiums. $3 vs $20, I'll keep my coppers. Plus you can pull out your copper plugs and clean then off with a wire brush, try that with iridiums. Even manufacturers say iridiums don't last as long on boosted cars...


I change my plugs every other time I change my oil. I change my oil once a month. I spend $72 a year on spark plugs while you iridium fanboys pay $80 for ONE plug change with zero benefit except one more thing you can add to your mod list on your Car Domain.

This is from NGK.
Tuned engines, engines driven hard, poor quality fuel amongst other factors can all dramatically reduce service life.and this is from Denso.
Standard copper plugs usually have an estimated service life of 10,000 to 20,000 miles depending upon design and application, Denso recommends changing their Iridium Power plugs before the maximum 30,000 miles.

[jspaeth]

I am running 0.030" of gap on NGK Bp7res-11 or whatever (hope I remembered that number right haha).

I always thought larger gap could yield more power, since you are exposing more air/fuel directly to spark, but at the risk of the spark being blown out.

I have never really (as far as I can tell) had spark blowing out on me........either that or it has and I don't know it, but I think it seems to be working fine

[codyace]

Damn, so educate me as to why the ground wouldn't melt away with an iridium plug... Isn't the thread/ground material the same for both plugs...

I'm not 100 percent sure, but I'm thinking no just based upon their inherent design and properties.

[codyace]

Fuck iridiums. $3 vs $20, I'll keep my coppers. Plus you can pull out your copper plugs and clean then off with a wire brush, try that with iridiums. Even manufacturers say iridiums don't last as long on boosted cars...


I change my plugs every other time I change my oil. I change my oil once a month. I spend $72 a year on spark plugs while you iridium fanboys pay $80 for ONE plug change with zero benefit except one more thing you can add to your mod list on your Car Domain.

This is from NGK.
and this is from Denso.

Wire brushing? These aren't 2 stroke dirtbikes here lol. Yes I see your point, but I don't even waste my time with that haha.

In regard to spark plugs, copper plugs are known to be a 'dirty' plug...that is, they absorb most of the dirty particulates from cobustion, when compared to iridium or platinum. Sure on paper copper may be the 'better conductor' but in a combustion process it is not ideal

PS: A proper set of Platinum or Irdium plugs will last you 2 or 3 years on a tuned turbo car. Tuned being 11.5ish wot, not 10afr. At that rate you save money with them. But, in the even you do melt one, now you're out more money.

PS: I don't even change my coppers than often. Probably twice a year. Again if your tune is on, you should be set.


I always thought larger gap could yield more power, since you are exposing more air/fuel directly to spark, but at the risk of the spark being blown out.

You are correct. You want to run the highest gap with least amount of blow out (sorta like gas...you want to run the lowest octane while not detonating)...But also like gas, you often fall on the side of safety when doing it (like me running a very tight gap, or when we get gas getting 93, even if tuned for 91).



I have never really (as far as I can tell) had spark blowing out on me........either that or it has and I don't know it, but I think it seems to be working fine

You can notice it...almost liek sligth misfire. Usually found in higher boost situations, or with weaker coilpacks. You can also see it on a dynosheet.

[s14unimog]

I am pretty sure that the ground electrode is coated in platinum on a platinum plug and would withstand more abuse than a copper plug. Incorrect, the iridium, copper, platinum refers to the electrode material only. I was being sarcastic when I asked you to educate me. The ground material is identical among all three plugs. I've yet to try this theory on the various types of plugs as each time I've done it I've had to replace/rebuild a motor.

I think you have another problem...

Fuck iridiums. $3 vs $20, I'll keep my coppers. Plus you can pull out your copper plugs and clean then off with a wire brush, try that with iridiums. Even manufacturers say iridiums don't last as long on boosted cars...

^ I would love to see an actual quote that supports this. Where the hell are you buying your plugs. I buy a BKR7EIX-11 for $6.95 from Advanced


I change my plugs every other time I change my oil. I change my oil once a month. I spend $72 a year on spark plugs while you iridium fanboys pay $80 for ONE plug change with zero benefit except one more thing you can add to your mod list on your Car Domain.

Why does your car require so much frequent maintenance...




PS: A proper set of Platinum or Irdium plugs will last you 2 or 3 years on a tuned turbo car. Tuned being 11.5ish wot, not 10afr. At that rate you save money with them. But, in the even you do melt one, now you're out more money.



^true statment

I'm not 100 percent sure, but I'm thinking no just based upon their inherent design and properties.

I was just bringing this to light b/c he has almost zero electrode or insulator failure. so this weak point, that cause his plug failure would be the same for all three listed plugs.

[McCoy]

I think you have another problem...


I assumed you were being sarcastic. care to enlighten me what other problem I have... besides having detonation on a hot track day?

Here is what my pistons looked like, surprisingly enough the motor did make it through an additional 5 track days like this.

http://www.prmsg.org/albums/album107/S13_SR20DE_detonation_piston2_side.sized.jpg

[HYPNOTIK]

I haven't been in the real world for awhile but over here iridiums are $20. The stock plugs are BKR6E on a SR20DET and BKR5E on a DE, I don't know where you're getting that they are iridiums?

[fliprayzin240sx]

I haven't been in the real world for awhile but over here iridiums are $20. The stock plugs are BKR6E on a SR20DET and BKR5E on a DE, I don't know where you're getting that they are iridiums?

Fuck you Casey...if you can find me some 9 heat ranged plugs that doesnt cost an arm and a leg, I'll buy them. I used to run BCPR7ES-11 in the states, fuckers were only $1.25 a pop.

[Sileighty_85]

I haven't been in the real world for awhile but over here iridiums are $20. The stock plugs are BKR6E on a SR20DET and BKR5E on a DE, I don't know where you're getting that they are iridiums?

dude you need to shop on base, and not buy this stuff from Sanzyou and other part shops. Dont get me wrong i love Sanzyou's, but stuff like this are a little expensive at tuner shops.

But i bought Iridium's for my Hachi at the gas station right across from the main gym for like $8 a pop IIRC.
the only time i saw iridium's for almost $20 was at Makmon, or Do it yourself but they came is a pack of 2.
Have you tried Touguchi's? over by gate 3 (i think) Parts he doesnt have to special order from main land are pretty cheap.

There is the internet also you dont have to buy stuff there on the island.

Like Phase 2 you can get (4) iridium's for like $38, even with shipping you will still save money.

[s14unimog]

I assumed you were being sarcastic. care to enlighten me what other problem I have... besides having detonation on a hot track day?

I would assume you are leaning out somewhere; do you have a wideband on the car?

[McCoy]

I would assume you are leaning out somewhere; do you have a wideband on the car?
I do now... mainly because of this. I was on a JWT rom tune, actually the same ECU I've been using for 6 years now and about 50 track days +/-. I've since switched over to a calum basic ecu and will spend alittle more time making sure the tune is safe with the new 50trim T3 setup.

[HPKMotorsports3]

sorry to thread hack but i have a stock redtop and being a ka man the whole sr thing is new to me... i was wondering what do you guys recommend for spark plugs and gap??