which plugs to use

[camas90gsx]

Ok,ive been going through numerous threads and im still not sure if i'm running the right plugs.I have a 90 gsx with evo3 16g,evo3 mani and o2,fic 650's,evo8 maf,wally 255,3inch t.b.e. (no cat),short route f.m.i.c.,m.b.c.,semi built head,b.s.e.,chipped e.c.u. for my setup (with phantom knock removed)and boost gauge to knock gauge conversion,aem uego w.b. and boost,etc..

Now my issue is that i'm getting knock every so often when in boost,and i'm wondering if it might be due to spark blow out.It doesnt really have any pattern,sometimes it will come on before boost kicks in and sometimes only when in boost but alot in 4th gear at 15lbs or more but not in 5th gear at high boost.I obsess on the knock gauge and let off the throttle immediately if i see any knock at all.It could be that i have a crappy knock sensor or it could be legitamate,and that's what worries me.I am at factory 5% base timing and i am currently running bpr7es ngk's.I have my car chipped for my set-up and have great a/f readings,idle is at 850rpm's,vacuum at 21 in/hg and all seems ok other than a little hesitation in lower gears from time to time.

I have read that some people run br7es,which are non-protruding plugs and that is supposed to help with spark blow out.I am wondering if that might possibly be my issue since my knock readings seem so random.Also i dont know if i should be running 7's with my setup either.I havent ran 6's since it was near stock,then went to bpr7es's.And maybe i need to go to 8's possibly?I do have some hesitation in the lower power end from time to time,but seem to have great high end pull all the way to 20lbs.Its just the knock readings that are freaking me out.
If anybody has any ideas on whether you think this could be spark plug related or what plugs you would run in my situation please chime in.Maybe it is just a crappy knock sensor or a spark plug issue,but i cant afford to just go and buy a bunch of parts just to try it out to see if it helps.

 

[bryanwheat]

What do your a/f ratio's look like when the knock is happening? A set of bpr7es plugs should be perfect for what you need.

 

[camas90gsx]

What do your a/f ratio's look like when the knock is happening? A set of bpr7es plugs should be perfect for what you need.

Honestly,my a/f goes up to 10.9-11.2 when the knock comes on in any boost at all.I plan on getting a chip to possibly correct it so that it doesnt go so rich at no or very low boost.I love that it is in that range at med to high boost,but not at minimal to no boost.Thats why this is so confusing,my a/f readings are great and a tiny bit rich even,which should make it even more safe.Im wondering if its maybe a faulty knock sensor or spark blow out.
Thats why i was wondering about getting some br7es plugs instead of my bpr7es's.I heard that the non-protruding plugs might be better for dsm's with higher than normal boost setups,but i dont want to buy and install them if they arent good for my car.I just dont want to replace them if it wont make a difference.I only have about 225 or so miles on my current plugs.I know dsm knock sensor are ultra sensitive,but i'm pretty sure that my chip has some sort of anti-phantom knock option on it.Ill have to check with my chip guy,to verify that though.

 

[92AWDHX40]

Ngk is a what comes from the factory, use those.

 

[camas90gsx]

Ngk is a what comes from the factory, use those.

I am running ngk bpr7es plugs and wondering about running NGK br7es plugs instead.Im not quite sure what your point is,but i'm in full agreement that ngk's are the best plugs for dsm's.

 

[bryanwheat]

Some people seem to have luck with the br opposed to the bpr, but i've experienced spark blowout at lower psi than with the bpr.

 

[92AWDHX40]

I guess you could get the other and see, cheap enough correct.

 

[camas90gsx]

Well,i went and got some br7es plugs but havent put them in yet.I pulled out my bpr7es plugs with about 275 miles on them.All of them were light brown all over the tip and there was some black build up on the first 3 threads from the tip.They usually look more greyish,ive never seen the tan-brown build up on this car before.It seems like they looked too old plugs for the minimal mileage,or like maybe they are running too hot.It says in the chilton that a little light tan on the plug is good,but there was more than a little tan-brown build up on the tips.Im just wondering if thats a sign to go colder to a br8es or warmer to a br6es? Ill want to wait to see what y'all think before i put them in and have to waste another $13.00 on another set of plugs.What do y'all think?

 

[98_gsx_]

As long as you get some NGK coppers you will be fine

 

[1995 brian]

Try cleaning your bpr and see how it turns out if still the same try out your br plugs

 

[camas90gsx]

I put in the br's and no difference in knock readings.Im thinking it has nothing at all to do with plugs, unless i need to be running a colder or warmer plug.I wouldnt think that 6's would be cold enough for my setup,maybe ill throw in some 8's just to see if that helps.Otherwise it could be a goofy knock sensor or something much worse.I hope it's nothing major since i have only 5k miles since a full rebuild.
The thing that confuses me is that sometimes i get high counts of knock with hardly any throttle at zero boost,and then it wont kick in at all sometimes unless i get over 17 lbs.Then other times i get no knock at all up to 20lbs.If anything i would think i could add more timing,since my chip is for a mild timing setup.I just had my timing checked 2 weeks ago and had it set to factory 5%,so i know its not the timing being too advanced.I'm fu####g lost man!

 

[DSM1G90]

You need the "P" (NGK BPR7ES) projected plugs so the spark can be in the middle of the compression area for complete and strong combustion.....and this is factory recommendation.

You use the plain ones and you're not getting the full hit of the explosion.

Plain ones puts the spark at the top of the combustion and the mixture will not explode all at once...and guess what ....... "you might just get some nasty carbon buildup (which is increasing compression levels) of the less effective combustion....." Get that spark in the middle of the combustion, blow out that carbon buildup....things might run better - worth a shot.

The plain ones were designed for Honda lawnmower motors, motors with low compression and flathead motors. - DSM

 

[snowborder714]

I've been using non-projected plugs in my car for a couple years now, as have a few of my friends. No issues that I've heard of, and even a bit of speculation that the non-projected plugs run better.

 

[clipto]

You will be fine stick with bpr7es gapped .26-.28 the black is running rich so at boost u have like 11.1 a/f witch is fine so little Rick so the black on the plug is fine.How many counts of knock are u getting?Can u put up a log?What are you using to moniter knock?

 

[camas90gsx]

You will be fine stick with bpr7es gapped .26-.28 the black is running rich so at boost u have like 11.1 a/f witch is fine so little Rick so the black on the plug is fine.How many counts of knock are u getting?Can u put up a log?What are you using to moniter knock?

I have my factory boost gauge converted to a knock gauge through my eprom chip.The amount of knock varies from pull to pull and has no rhyme or reason.I drove my car to work this morning,which is 38 miles and the br7es plugs seemed to give me less knock.Infact i didnt have any knock all the way to 20lbs,so i dont know.My car seemed to pull smoother and harder too.Maybe it has nothing to do with the different plugs at all,could just be because they are brand new plugs.Im thinking about throwing in some bpr8es plugs just to see what happens,i guess it couldnt hurt.Like i said though sometimes i get knock when i am at 2k rpms with no boost at all as well,so maybe i just have a ultra sensitive or jacked up knock sensor?The thing that sucks is that i can feel it retard the timing with the stupid phantom knock in low rpm's,when i know it isnt real knock.I'll put a log on here later to show y'all what im talking about.

Well i went ahead and put in some bpr8es plugs gapped to 28 just for the hell of it.The only knock i had was in 2nd gear at low rpm when it was still a little cold,which im sure was phantom knock or lifters or something.I took it up to 20lbs of boost with no knock what so ever.
It had really hard crisp acceleration in the lower end,which i was lacking before and good in the upper end as well.Im not sure how it will play out with plugs that cold,but for now it seems wayyy better.Ill have to keep pulling them out ever so often to check for ill effects.It just doesnt seem like i should need plugs this cold at all with my setup.My buddy runs 7's with a significantly bigger hp setup than mine so idk? I guess it just depends on the car.And maybe if i ran a different gap than 28-30 on the 7's it would make a difference.8's are just supposed to be for bigger hp setups than mine so im a little leary.

I have the day off tomorrow and ill be putting in a new turbo-manifold gasket, 02 gasket and 8mm msd wires,so maybe ill throw the bpr7es plugs in as well with less gap and see what happens.Im going to e85 setup soon, so atleast i'll have a few of extra sets of plugs laying around incase i need to run a different plug with e85.

 

[strokin4dr]

I am currently trying the none projected tip NGKs on my car due to the hype on EVOm. They seem to work just as good as the BPR7es so far. I'm gonna leave them in for a while to see how they hold up in the long run.

 

[camas90gsx]

I am currently trying the none projected tip NGKs on my car due to the hype on EVOm. They seem to work just as good as the BPR7es so far. I'm gonna leave them in for a while to see how they hold up in the long run.

Yeah,i ran the bpr8es for a day,and then pulled them out.Then put the br7es back in this morning,gapped them to 26 and they are working great so far.I like the response i get with them.I think my issue is a sensitive knock sensor picking up random crap that wasnt knock.Im going to maybe go with a saturn knock sensor or a guy i know says you can moify the mitsu knock sensor to be less sensitive.Cant remember exactly how but i'll hit him up today so he can refresh my memory.

 

[4yoto24]

Ngk bpr6es

 

[PerfectStorm]

Seems like with your setup you should be running the NGK BP7ES plugs. All things "upgrade" seem to point to these plugs. I went to RRE over here in CA for a similar problem and they fixed it using my DSM link on the GS-T in all of about 15 minutes. I didn't even ask what they did because I was in a hurry, I'll call in the morning and see if he can recall what he did about a year and a half ago. I did get a new knock sensor installed simultaneously so that could've also alleviated the pain.

 

[DSM1G90]

Thus, if both plugs - projected and non-projected plugs- are giving the same results, what's the advantage with each over the other?

Stock manuals mentions projected, thus who wins and who's right, or is it a stalemate with the decision of simple choice what works with what application?

-DSM

 

[Calan]

Thus, if both plugs - projected and non-projected plugs- are giving the same results, what's the advantage with each over the other?

In most cases, non-projected plugs are a little less prone to spark blow-out at higher boost pressures than plugs with projected tips at the same gap.

My guess is that most people won't see a difference until airflow gets up into 45-50 lb/min range, although the gap sometimes needs to be lowered a little regardless of the plug tip configuration.

Like everything else DSM-related, every car and setup is different and likes different things. Use what works best.

 

[MY1GDSM]

IF you want to make it a little less sensitive than use some Teflon tape on the threads.

Don't do this^

Your Chip already has a PK code... .

If anything i would think i could add more timing,since my chip is for a mild timing setup.I just had my timing checked 2 weeks ago and had it set to factory 5%,so i know its not the timing being too advanced.I'm fu####g lost man!

Just set your gap to around .24 and Retard your base timing a 1* or so Untill you have the time to make it up here so I can toss the Ostrich in there... .

I told you before when your base timing was way retarded that I was pretty aggressive with the tune timing wise on that chip... .

 

[camas90gsx]

Don't do this^

Your Chip already has a PK code... .



Just set your gap to around .24 and Retard your base timing a 1* or so Untill you have the time to make it up here so I can toss the Ostrich in there... .

I told you before when your base timing was way retarded that I was pretty aggressive with the tune timing wise on that chip... .

Ya i thought it had a pk removal code but i was gonna ask you for sure.

Anyways i am running the br7es gapped at 27 along with some new 8mm plug wires and it seems great with no knock for the last two days.That is with my m.b.c. set at 15with spike to 17lbs though,if i set it a little higher who knows? My car feels like ive got the boost set to a nice strong setting though.I was having issues with my m.b.c. not wanting to boost any less than 26lbs at full boost so i brought it in to the Perrin office and they replaced the spring.It turns out that Speed Concept in aloha sold me a used or returned m.b.c as a new one,and the spring had been cut and stretched???Anywho,i think i had my boost set a little to high for my setup,or for my own piece of mind for that matter.It was either run off of my internal wastegate 8lbs of boost or 26-30lbs.So i yanked off the m.b.c. so that i didnt blow my s##t up,until i got the m.b.c. fixed.

I think that spark could have been a major factor in my situation since the 8mm wires and different plugs most definately made a difference.Im pretty sure that my plug wires were the ones from the factory,.

Stacy,i would still like to get my ride up your way and run it on ostrich so we can get an even tighter tune.My a/f's have gotten a little more in line since i've put on some miles after resetting the ecu,good call on that man.

 

[camas90gsx]

Well,i went ahead and did egr delete, because i had the kit and had been meaning to do it anyway.Then i put on my old factory lower heat shield,and cleaned up my battery connections while i had the battery out for the egr delete.

For whatever reason i no longer have a knock issue.I had very low counts at high boost once but it was only like 1-3 counts while going up a steep hill.I guess it could have been that my engine bay temps are lower because of the heat shield,or the battery crappy connection could have been a culprit idk?My engine temps are noticably lower on my gauge and you can tell just by popping the hood and feeling it,which could in turn give lower intake temps.It no longer feels like an oven when you pop the hood.
Normally when im trying to figure out a problem i will fix one issue at a time so that it is easier to pinpoint,but it was a really nice day out and i felt like working on my car.I even polished and waxed everything for the first time since last year.
For the time being i am still running the br7es non protruding plugs gapped to 26 along with 8mm wires.I have my boost set to 17 lbs,and it feels strong.I have only put 50-70 miles on it since i put on the heat shield and did the egr delete,so hopefully it isnt just dumb luck and the knock stays gone.