Spark plugs (
 

I bought some NGK IX Iridiums (9, for those who cant interpret roman numerals) for my boosted engine. Im going to regap them to .28-.30. Anyways my question is, does anyone know what stage prelude spark plugs are stock (I think they are around 5-6?!?. I have the f22a1) . Not the size. I know its supposed to be a step or two colder than stock for boosted applications, so I heard the NGK IX iridiums were good.? Thanks

Re: Spark plugs (
 

not sure about the preludes in specific, but they are probably the same stage or whatever as d and b series, which i'm pretty sure are 6

Re: Spark plugs (
 

Prelude??

Re: Spark plugs (
 

www.ngk.com has a nifty online applet for determining plug whatnot.

9's are used by 500+ whp RSX guys. You think you need them?

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Well my friend used them in his built b18 w/turbo. ran good. couple steps colder to.

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Iridiums scare me with that tiny point. Looks so hotspot prone. I don't like running them in the built K's, but everyone is doing it ::)

You, young sir, are also several orders of magnitude away from a built B-series, beginning with your stock engine... working your way to the Eclipse manifold attached to said engine... and finishing with the tiny ass puling 14B attached to said manifold.

Try a step colder than stock. ZFR6F-11, NGK stock number 4291.

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Also:

https://www.homemadeturbo.com/forum/...?topic=53966.0

It's not anything you need to worry about, but it is food for thought, and will help develop perspective.

Re: Spark plugs (
 

brought back from the dead, I was using ngk bk7re and I could not get my egt to stay stable, then I switch to ngk-4554 in the 8 range and the car ran way better, my friend tried some 9's and his ran way better than with the 7's also.

Re: Spark plugs (
 

Try some 7173's instead of those 4554. It's almost the exact same plug, but the center electrode isn't as recessed. Only the super high CR guys need R5671's with the recessed electrodes because they stand a chance of smacking piston dome into ground strap, whereas the stock or lower CR turbo guys can run the R5672's... whose electrode doesn't come out as far as a stock plug, anyway.

The Black Car in my basement is running R5672-A10's on pumpgas. :o

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thats the thing I am running pump gas, and I think I have high compression, my head is shaved .040 and block .010 and stock head gasket, 9.0.1 pistons. I did a compression check after I put 500 miles on the motor and it was 190 accross. on my old block and my friend's block its 140. so I am a little scared, because its top end driving here average speeds is 120mph.

Re: Spark plugs (
 

What ignition timing you need, and how much power you can push, before you detonate is one thing. It's based on compression, octane, etc.

What temp your plugs are is completely different. Too hot of a plug can cause detonation by becoing a hotspot (too cold, foulling), but colder plugs will not cure detonation if you have either exceeded design limits or have something wrong with your tune.

Average cruising speed of 120 doesn't make me worry. If you incessantly have to yam on the car from 80-120, and lack the self control to not make every one of them back to back WOT pulls, then I might worry. Do you have a dyno? Or failling that a datalogging cable + laptop and an EGT gauge? You can determine best timing and yank a little bit more timing out for safety.

Re: Spark plugs (
 

just get yourself a set of NGK's. I would not use the iridium plugs. Seen plenty of cars not make power utill they switch to the reg. NGK's instead of the iridium plugs.

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I have the a egt gauge, and the complete zeitronix package and a laptop, on uberdata, my car idles high and I cant seem to fix it, so adjusting my distributor timing is hard as hell, I have to starve the engine of air to get the idle down, I have no vac leaks. and I cant seem to understand the timing adjustment in uberdata what is needed etc.I have the boost timing set at .70 right now
the good thing is after switching to the colder plugs ngk-4554, the egt stays at 1500deg in boost, but when cruising at high speeds, it goes to 1900 plus maxed out the gauge scary. the car runs great and pulls hard as hell sc61 no lag during shifting which make suspected my compression being too high because of the head.

Re: Spark plugs (
 

Iridium has a great following with the entire supra crowd. Many other boosted crowds are following suite. There's nothing wrong with using them at all.... Once you get past the cost.
The good news is they're much more resistant to damage than a copper plug. The bad news is you'll know it quickly when you're melting a $1-2 copper core plug.


One step colder on NGK & Denso plugs. More than that without running insanely large power is just a waste.
Their heat ranges are much wider per step than the "traditional American" plugs the 2 heat range rule is based on.

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Iridium are a non-performance design. They accel at being hotspots. Regular electrode plugs don't melt unless you are doing something stupid.

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exactly, stick to NGK BCPR7ES, low cost and heavy duty

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I been running the zex plugs for a while now and work great for me, they have a colder heat range than stock and you don't have to gap them.

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I buy ngk BK7RE in bulk, but I found out that ngk-4554 runs way better in my car. so I am fasing out the 7 and in with 8's 2 steps colder

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I like BRK7E-11 for low power cars, or serious minded (at or a bit over 200 whp) mild NA cars. Most anything past 200 whp is going to want colder.