NGK plugs.....platinum vs resistor
 

Are platinum plugs worth getting over the standard resistor plugs?

No, unless you want to pay 4x the standard price, the only difference is that they last longer.

And the nopistons single turbo section sucks!

lol. The platinum plugs are only $1 more at the local parts store. When I saw the price, I started thinking they migh tbe worth it... Standard plugs dont last longer than 10K miles on the leading side, and at $5 a plug, its killing me.

Consider some NGK B10EGV or other gappable plugs (B9s might be a good choice if you have fouling problems). Sparkplugs.com has them for like $5 each. They aren't much cheaper than the stock surface gap plugs, and you'll need to buy or make a thin-walled spark plug socket to install them, but they are said to make the car less prone to ignition break-up at high RPM/boost. Gap to 0.022" or so. I just installed some tonight and found that they were already gapped properly as delivered.

-Max

what are the best type of plugs anyways? Iridium, platinum...which one is best??

Hmmm. I would have said yes, the plats are worth it. I have always felt they helped the car start more easily and for me there was only a dollar price difference also. I recently had to put 'regular" plugs in since I couldntt find the plats and immediately noticed a difference in starting.

Thats it, im getting platinum. Ive been having some hot start problems, and hopefully platinum plugs will help it.

That was the origional reason I got them. I am a believer for .... 4 years now on my modded FC.

iridium is the best, especially the one made by hks because it is a cold plug. It is good for high hp application. I know NGK and denso make iridium also but im not sure they are cold plugs or not.
The stock and platinum plugs tend to foul faster with high hp engines (more fuel to burn).

But for the price.. at around 20-25 a piece how much longer does irridum last....

Just ask the guys who really know what works the best. There is a thread in the performance section about sparkplugs or search under sparkplugs and RICERACING. Or just take Max's word for it. B9EGV or B10EGV.
Nick

i just ordered 4 B10egv form sparkplugs.com.. Do i have to mention to them anything else. I know when i buy stock plugs at mazda they still give me two trailing ad two leading but I have a friend and he says it really doesn't matter. thanks

Hung

I dont believe it matters when you use colder than stock plugs.

Cool thanks

-Hung

I got the tip from RICE RACING, who I think is a trustworthy source of of info. :)

You will definitely need a special spark plug socket to install the B10EGV and similar plugs because the hex portion ends up below a ridge on the rotor housing that will prevent a regular socket from going on far enough. I have heard of some people using thin-wall motorcycle sockets, grinding down thier own socket, buying a suitable socket from someone on this forum (search), or buying the socket from Racing Beat or Mazdatrix. I bought mine from Mazdatrix.

Also, for a nearly-stock car, I would think that the B10EGV would be too cold. NGK makes warmer versions of the same plug that might be a better match for the needs of a stock or mildly modified car. B8EGV seems to be the warmest and would probably work well for leading plugs. B9EGV is a little colder and should be good for the trailing position or both if you've got moderate mods.

The stock BUR-7EQP (leading) and BUR-9EQP (trailing) plugs are probably fine for many cars as well. You don't a special socket to install them, which makes them easier to install. If you get ignition break up (and many cars do), the B*EGV style plugs may be an improvement.

It is a good idea to read what has been posted in the forum and try some plugs to see how they work for you. It is ultimately your responsibility to find out what works for your setup and decide what plugs to run, perhaps with some trial and error along the way. Different cars and setups have different needs, so no single plug will be best for all of them.

-Max

As usual, Max is correct, different cars have different needs and ultimately it is up to you to analyze and determine the needs of your car.

I can say that, for my car in its present condition, I have always used NGK platinum 9's all the way around and I have never had any spark related problems either in high rpm breakup or fouling (note from my sig that I do have a high power ignition).

Now I may just be lucky or there may be some truth to the fact that if you really stomp the hell out of the throttle a few times a week (or more) fouling plugs don't get a chance to develop.

I think most people would agree that my engine and turbo qualify as "heavily modded". My current set of plats have been in for just over 10K miles without any sign of deterioration. BTW my gas mileage with these OLD plugs on a long road trip this last weekend was over 21 mpg. . . not indicative of plug problems.

All that being said, I am replacing my 10K old plugs this week (with new plat 9s) because I have a dyno tune session on the 16th and a road race school date on the 22nd.

Unless I notice a problem on the track, I will keep the 9s as my universal plugs. If I notice any spark related problems, I will be replacing them on track day with a set of the wire electrode 10s that seem to be the choice of the roadracing contingent.

Good Luck

Jeff, how long do the platinum plugs usually last on your setup? I cant seem to get more than 10K miles form the leading plugs before the electrode has deteriorated anough to affect how my car runs. Thats with the regular resistor plugs.

It is easier (smoother graph) to dyno tune a car with cold plugs rather than the platinums

Or, you could use what I've been running in mine. A friend found the R5671A-10 pt.no. NGK5820 at NAPA. They're a V-Power electrode tip with a "10" heat range. The beauty is they have a 5/8 hex instead of the 13/16 so you can use an unmodded socket. Even with my ground socket I had trouble getting the EGV's tight with my AC and Pwr steering in the way.

I think they have a pt.no 5238 that is a "9" heat range too. I've used these for 6 months with no problems.

The factory BUR's misfired at high boost/rpms on me, most likely because the gap was too wide and they're un-gappable. I gap the new ones at .022.

Best of all these plugs are only $1.69 ea and they last a long time. Longer than my EGV's did.

Scott

I have had the current set of plat 9s in there for over 10K with no discernable degradation in power or performance. Gas mileage, AFRs, engine temps and every other measure I can record seems to be consistent with the original installation day data. There is little to no physical evidence of fouling nor is there any visable accumulation of deposits (of course that could be because I regularly tromp the hell out of the accelerator).

In my TII, I had a set of plat 9s last 25K with no problem and only replaced them cause I thought I should.

How long will they last?----I once again defer to Max's assessment----different vehicles have different results. Of course it really can't hurt to try a set and see how you like them.

Thanks for all the info everyone.

Back from the dead(thanks to me), but at least Im posting info...

I just installed B8EGV's(L) and B9EGV's(T) in my car. First off, my last set of BUR's lasted me 6K miles. Second, my power was very unpredictable. Sometimes, the car would make awesome power, sometimes it would make barely adequate power. So I tried some colder plugs thinking that very minor detonation was occuring from the plugs being too hot. I got the new plugs installed last weekend, and I can already tell a huge difference. The car always has more power, especially in the low end and midrange, and the power doesnt fall off at high rpm's(that wasnt much of a problem, but was present nontheless). I definately think my stock plugs were causing detonation from being too hot now. In a few more days, Ill pull the plugs and check for fouling or anything else. All in all though, Im very happy with the swap so far. One downside I did notice though is that my engine is a little rougher through the powerband, but that may not be related to the plugs directly, but possibly just masked somewhat by the stockers.

I just ordered plugs from and spoke with sparkplugs.com for my CRX. You can do a search for colder plugs (since their not listed). I gor NGK iridiums for $7ea. They also Had Denso for $12ea, which is why I called. Take this for what it's worth: Was told NGK & Denso are sister companies and whenever one comes out with a new design, the other follows with a cheaper copy. The Denso is supposed to be about 10% better and the first with iridium. So is it worth almost twice the price? Maybe "only" if you're racing for money.

Since HKS, Greddy, Blitz etc do not manufacture spark plugs, you can assume they all come from the same place. Unfortunately there doesn't seem to be a cheaper sister company version for the RX7.

My stock coil system uses a Crane HI-6R to fire the leading plugs.

Never had problems with BUR9EQs. I went to the B9EGVs and the car runs better at idle and full load.

BUT: when I installed BR9EIXs, my idle started really misfiring. Tried them on multispark and back on stock ignitor. Still bad idle.

Soon as I replaced the B9EGVs, the smooth idle came back.

They are trash in my opinion and not worth the extra cost. Unless maybe my 4 were all bad which I doubt.
I even played around with the idle fuel ratio to see if I could get them to fire correctly. No luck. I gave my $30 plugs away with less than 50 miles on them. Worst plugs I ever had.