I was becoming real curious as to what spark plugs I should buy for my application and my mods. The car is basically all street driven with a fair amount of mods. (fmic, dp, hiflow cat, catback, PFC, intakes...) What I don't understand is the point to running different rated plugs (is it to make start-up easier?). If it was my choice, I think i would choose 10.5's all around. Would anybody else agree to this?

BTW - I'll see if I can post some pictures later of why I need new plugs. The plugs seemed to be so old that when I replaced the wires today, the core of one of the spark plugs came out with the wire (leaving the casing to the spark plug still in the socket).

 

I run NGK 10.5 Racing plugs all the way around. Performance difference is noticeable. It is rather expensive though.

 

10.5s will foul out pretty quick on the street. Most people go with all 9s. As for type of plug check out my site. I have every type of plug I have heard of being used in a rotary with reviews on most.

As for the plug coming apart like that I can't believe you have so many mods but have neglected your plugs. Old plugs can cost you well over 30hp.

 

I think you have to understand why to use colder plugs. The more boost the colder the plugs, not mods. Running 10.5's will not help and more likely waste your money and run like crap. You also have to look at your current plugs and see how they are burning, that will determine if you need to go colder, warmer, stay the same, mix heat ranges, etc.

http://www.ngksparkplugs.com/techinf...31000&country=

 

My mistake... I did realize that is cooralated more to boost than mods. So you wouldn't recommend running 10.5's all around? It seemed to have helped wReX up there... What would you recommend upon not seeing my plugs and guessing. I'm just not in the position to pull them right now (the car is too far away).

Here are the pics:

The core of the plug

Another one

The old stockers

 

I am running all 9's

 

We just discussed this 3 days ago:

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/spark-plugs-500rwhp-347332/

 

^ I searched... didn't think i would need to look in that thread for 500hp considering I'm not even close.

 

I'm definately leaning towards 9's all around, maybe 9's and 10's. Now can somebody explain NGK's lettering or atleast tell me which one would be the best to use?

 

http://www.ngksparkplugs.com/techinf...31000&country=

Did you read that link? There are five pages of very good information, with photos. The difference between 'hotter' plugs and colder plugs is the amount of heat that they dissipate. Dissipating more heat will keep cooler combustion temperatures, resulting in lessened chance of detonation, assuming all other variables remain the same. If you've turned up the boost, you've added more heat, so you should definitely be using plugs that dissipate more heat.

Colder plugs will foul more easily, they will develop carbon deposits on them, which can lead to misfiring, poor mileage, and in extreme cases the carbon deposits can either become super-heated (and cause detonation) or flake off and damage your apex seals.

Take one step at a time. Try NGK 9's all around, that will avoid installation issues that come with the non-rotary plugs. The part # to look for is BUR9EQ or BUR8EQP if you want the platinum plugs. I just bought some of them today at Kragen Auto Parts. The local Autozone and Star Auto Parts don't stock RX-7 plugs.

-s-

PS, your photos show absolutely nothing useful. Take photos of the electrode side of the plug, the part that goes inside the engine and makes spark. Here are photos of my old ones, they were in there way too long:

 

I only put the photos up to show how old the wires looked and especially to show how the core came out of the spark plug (which I didn't even think was possible). I also haven't taken the plugs out because it got too dark outside for it. I'll try and do that tomorrow for pictures and analyzing purposes.

 

Thanks, that was exactly what i was looking for. Are the non-platinum ones iridium?

 

No, the non-platinum BUR9EQ's will be plain old copper electrode. They should cost around $5 each. Platinum ( BUR9EQP ) will be more expensive and most shops don't keep it in stock, and iridium will cost even more, and as far as I know is not made in the flat-face design that is used for our cars. The iridium plugs from the RX-8 should fit, but they're pretty pricey. There are motorcycle plugs that fit, but you'll need a special socket to install them so I wouldn't recommend that just yet.

-s-

 

nice website...ty.

 

Hey dis1 , I've read your website in the past, it was very helpful. Do you have any updated information? Have you tried the new iridium RX-8 plugs yet? How about the NGK iridium ( BR7EIX ) motorcycle plugs?

Any particular recommendations concerning wires (jacobs, MSD, NGK, Magnacor, ultra...)?

Thanks,
-scott-

 

Thanks,

No, I have not had a chance to test the Rx-8 or NGK iridium plugs yet. I just don't drive my car enough anymore so the testing takes a long time. Right now I'm still testing the BRISK plugs, which are looking really good. There was a post in the 1st gen forum a few months ago with some interesting links regarding the BRISK plugs.

As for wires I have a little info in the main upgrades section of my site but basically:

Jacobs: Bad boots that can pop off
MSD: Nice wires but very very poor fit. Modifications are required
NGK: can't go wrong
Magnacor: Some users report problems particularly with the 10mm ones. maybe the boots, maybe EMI
Accel: Great
Taylor: Great

dis1

 

hey taylor, just run NGK BUR9EQPs all around. advance auto usually has them in stock.

 

is that the platinum?

 

stock

or if single hks iridium plugs (like me)

 

i cant edit my previous post....ignore it....i have the answer

 

yeah man, i called around to all the stores and they only have the non Platinum's in stock (BUR9EQ's). I think I'm just gonna run these for a while to see how they do.

 

Well here's 2 of my plugs from the front housing (towards the front of the car). What can you guys tell me from this?

 

They don't look as bad as I expected but they are a bit hard to see.
dis1

 

It noticeably cleared up the idle and evenness of thr rpms though
When I first cranked the car, I put the rpms up to see if they were firing fine and there was a lot of hesitation about 5k (like one of the plugs wasn't firing) so i got under the car and pushed all of the wires on the plugs and coils again and everything is perfect now... couldn't have asked for any more.

 

Doesn't that white on those plugs mean your running a lil lean