Has anyone tried these? They're shown as a sponsor of RX7 City, but you go to the website and they don't have any for RX7s. It seems that anything that would assist combustion would be especially good in a rotary engine. I'm willing to pay the extra money, I'm just not sure which ones I could use.

The rotary engine uses a special design of plug so that they can operate at the high temperatures of the engine while getting combustion to begin in the most advantageous positions in the working chamber. If they don't show special plugs for RX-7s, then there's nothing you can use. As far as I know they only sell conventional plugs, which have a side electrode that is curved over the centre electrode. RXs use a surface gap design with multiple side electrodes around the centre electrode. This gives a flat top to the plugs and thus keeps them from being hit by apex seals passing over them, which is clearly a big deal.



Since Mazda and a few OEM suppliers (like NGK) are the few companies making rotary parts, stock is often best.

Racing Beat, among others, sell non-Oem spark plugs. There must be some way to calculate which plug would be usable.

i believe you are misunderstanding the post. last time i check RB sold NGK plugs in different TEMPeratures then stock but they are the same design of course. There is an entirely DIFFERENT design between a rotary plug and conventional plug. Go to sparkplugs.com and compare by scrolling over various plugs and compare those to the rx7 plug. You absolutely Cannot use a non - re plug in an re engine. There is nothing to figure out. It wont work.

There have been a few gimmicky "NEW" plug designs to hit the market. Tests consistently show that they have nothing to offer. A new set of stock NGK's is going to give you the best possible performance.

No. I understood. I looked at the pictures and Racing Beat sells the plugs you describe, but it also sells conventional plugs. There's a long dissertation about choosing temperature etc. How does one apply that to the Pulstar plug?

Clearly you didn't understand. Racing Beat only sells conventional plugs for cars that use conventional engines. They deal with Mazdas, so if someone needs plugs for a Miata, they carry them. Temperature has nothing to do with pulstar plugs though because pulstar doesn't make rotary spark plugs. Everything comes in one flavour: piston engine, single-side electrode plugs. No pistons, no pulstar.

Ignore the "clearly you didn't understand" part. Apparently I was just in a damned shitty mood at 1:56pm today :P

Wrong. Many people use standard plugs in a rotary instead of the surface gap plugs that come stock. Its especially common with drag racers and other high boost engines. The Bx-EGV plugs are a common fitment for rotaries. x is the heat range, I ran B11-EGV in my 10k rpm streetport engine.

This is absolutely wrong. See above ^

First time I've ever heard of this. What's the advantages then? It seems like Mazda and NGK wouldn't have bothered using surface gap plugs unless there was a damn good reason.

Its probably because the plugs are recessed in the chamber, and it may light off leaner mixtures a little easier. I never did back to back comparisons after I went with a standalone. And the difference I noticed before was likely due to my heat range requirements being drastically different than stock. It was basically a race engine, and I was melting the electrodes off stock plugs. I went with 11's all around, and they worked perfectly, and I never had an issue with fouling.



I seriously doubt you could measure a difference on any dyno, and Id be suprised if any real world test would show any meaningful difference. I think any differences are purely theoretical, or at most only significant in laboratory conditions.

I lifted this from the Racing Beat catalogue:



Racing - Street-ported Engine



Racing Beat recommends NGK Spark Plugs for stock or high performance rotary engine applications. The BR10EIX spark plug is recommended for street-ported, racing rotary engine applications. Price shown is for one (1) plug.



Specifications: NGK BR10EIX



B= 14mm Thread Diameter

R= Resistor Type Plug

10= Heat Rating *

E= 19mm Thread reach

IX= Iridium - Offer simproved ignitability and durability than platinum.





This is not a spark plug recommended for the RX7 by NGK. I assume because it is a single electrode type. I conclude that one may run a spark plug such as this in my car.



So the question still remains, how do I figure out which of these Pulstars will work in my car. After I try it, I'll let you know if it's a gimmick, if it blew up my engine or if it truly works.

I'd say just call pulstar and ask if they have a plug with the same heat range, thread diameter and thread reach as the RB recommended ones. It says on their site that they do have multiple heat ratings for certain plugs, so it may just be a matter of asking someone. They don't seem to have much in the way of a code system so you can just ask for a certain plug model, but I'm sure they have access to plugs of the same dimensions.

I dont understand why you are so worried about it stick with the stock plugs if you have a stock engine, you have to change them so often you dont want to buy anything to dang expensive.

I'm curious. Maybe they're better. Besides, I'm a lawyer.

okay so just because you are a lawyer means what? IF you have money to blow spend it on other stuff.... not on plugs that wont do ****..

whats the worse that could happen- you could always sue them.





for real though- if I was a lawyer the last thing I would be dicking with is spark plugs in a 1989 car

Didn't say he was a good lawyer...

As a lawyer, I'm interested in finding out the answers to questions that other people are afraid to address in a practical way. Issues that haven't been dealt with before are the most interesting, regardless of the cost.

And just how many of those "issues" do you think have been previously addressed and deemed to not be a problem, or even an issue? Sometimes the reason noone asks the question is because the it has been asked and answered before by the very people you think are afraid to ask it.



Spark plugs have been around a very long time, and generally follow the same design. Gimmicks come quickly, and fade just as quickly when people realize that its not a technological advancement, its just a profit oriented gimmick. They come and go so quick its easy to miss them. Do you seriously think spark plugs with a built in capacitor are a new invention? Try this one. Modern ignitions are capacitive discharge. The capacitors that store energy until it peaks and discharges are stored in the ecu, and fire the coils directly.



Second, did you ever stop to think about just how many engineers OEM's employ to design their engines? Do you seriously think that spark plugs dont get their fair share of attention? How about the proprietary spark plugs in the current f150 engines(and possibly fords whole modular v8 line)? Or the surface gap plugs mazda uses on the rotary?

Seppuku, pass the popcorn man.

Seriously if there were a specific type of plug for the RX7 than every generation wouldnt use the next "gimmicky" plug out there. I believe RX-8s use iridium...so what if the next RX7 uses a pulstar like plug??? It's all about ignitibility and theres no denying RX7's gain HP with a better ignition system.

Are you the guy that didn't ask because you asked and answered it before? Have ever used these things? If not, you don't know. I'm just asking if anyone had any experience, not whether you approved.



Pursuing your logic (and ignoring the obvious factual inaccuracies) the Wright Brothers should ntot have bothered because Leonardo had tried flight and anything anyone claimed to be new technology would be mere gimmickry and not worth experimenting with. I do believe that the OEM engineers did the best they could with the available technology. But remember, at the time they were designing this car mainframe computers were the rage and the new fangled PC was just a gimmick. Memory took up too much space for them to be practical. Every RX7 forum I've been on is dedicated to what the aftermarket engineers can do from body panels to suspension to engine management. According to your logic, nobody should ever bother with anything other than cosmetic aftermarket items because they are mere gimmicks. Don't you think the OEM guys did their best with the engine management system. Check out the guys discussing that stuff. Theorize in one hand, spit in the other. Let'sput the question to a practical test.



Now with respect to my question, its plain that no-one has any experience, therefore, no-one can give anything more than theoretical speculation to offer. If anyone should have any experience before I get around to it, please let me know. Thanks



Sisyphus

OMFG! Dont mess with the plugs, if they worked for a rotary they would be offered, besides I always want just a normal run of the mill plug, if you use a platinum or whatever they will burn up the engine before the plug burns up!





Can I get some of that popcorn? Who the hell has the cherry coke too?

For those unfamiliar with the Greek myth, Sisyphus was damned by the gods to eternally push a huge stone to the top of a mountain, only to have it roll back to the bottom where he would be forced to do it all over again. Not unlike searching for a better spark plug for the rotary engine.



Problem with the aftermarket is that new products are more driven by marketing types than by engineers. For every worthwhile product that becomes available, there are ten that are utterly useless, IMO.

I personally wouldnt use those plugs in a rotary, and I don't care what Racing beat says, they have been around a long time, but they are not an authority on spark plugs.

One day I was super bored when I couldnt sleep and I ended up reading a bunch of articles on plugs from the NGK main website. Specifically about plug interchange and cross referencing when it comes to numbering, the article said that even though 2 plugs might have the same heat rating, the heat rating is derived from testing in the engine the plugged was originally designed for, and the heat dissipation of a plug is more than what they called the "thermicity" of a plug, but a combination of the plugs construction and the engines construction. So the true heat rating of plug would differ in a iron water cooled, from a aluminium air cooled engine. Meaning a recip motorcycle 10 is not the same as a rotary car 10, its relative to starting point on certain engine. Also the insulator is designed to with stand the standard thermal load of a certain engine. They warn against simply using plugs based on thread, size and number, its asking for trouble.

If you want colder plugs, NGK makes the Racing series which are rotary specific, yes they are 35 bucks a plug, but a rotor and housing is a lot more. I've taken a part a 12a that someone used cross referenced autolites in, and it wasn't a pretty sight after the insulator went through the motor. The racing plugs also last forever even with a CDI, so you would probably go through 5 sets of motorcycle plugs before one set or R series plugs anyway.

i have used B9es fron NGK on all of my rx7s from time to time. so have a few friends. they help when your car has a flooding problem. they'll run in a pool of gas. and they are crazy cheap. i think they are jet ski spark plugs i think...



they are not flat top.



i skimmed over most of this thread, dont know for sure if this was covered...

I'm gonna try these plugs next, no harm no FOUL...harr.