I did a search and I'm not satisfied with the research.

It's time to replace my plugs and is it worth getting the Iridium plugs? I know HKS makes some, which I'm going to stay away from, because it might have blown my friend's FD. I'll be using plugs with a heat range of 10.

Also, were can I purchase a socket to fit these plugs? I sent a PM to metalliman, but he hasn't been on this board for almost one year.

Moderator: Please don't move this thread, since I'm looking for high hp RX-7s that are running a lot of boost.

 

I bought some NGK Iridium IX plugs. 8's and 9's. They where recommended by a friend who said that a lot of high HP guys like them.

He also noticed better idle and less ignition breakup in his car.

 

save the money and buy NGK b10egv's

 

High HP or high boost cars have to use colder plugs. Stock power or slightly mod'd use hot or regular plugs. HKS plugs are nippindenso and the brand had nothing to do with blowing an engine. Sounds like he should not have used colder plugs. There are the same price as other cold/race plugs, so if you need colder racing plugs then yes get iridiums but you are at 300hp (stick with 7's & 9's). For high HP I would put stock 9's on top and race 11's down low.

 

Absolutely!

Believe it or not but these plugs and other non-expensive NGK's work much better then expensive iridium, platinum, etc..

 

Those are the one's I had in my car, they worked great for me. They're ment for motorcycles right?

 

Actually they were designed for snowmobiles, but adopted by Jap bikes. The reason they work so well is because they do not act like glow plugs. The stock plugs act like glow plugs under higher boost and heat.

The other contributing factor is the distace the spark can travel. The stock plugs are limited in spark travel and are sheilded inside the plug.

The B10egv and egi's are like normal plugs that will not act like glow plugs. The glow plug effect causes stumbling, bad gas mileage, and poor performance - They can also contribute to detonation.

 

I went to sparkplug.com website and they showed the NGK B10egv for $5.37 per plug. I then went to rx7store.net and they have the NGK 10.5 for $35.00 per plug.

Also, don't be fooled by my sig; I don't like to give all my secrets away.

 

My local honda store - bikes - has b10egi's for $4.30

I can feel your pain

 

damn the b10egv's at Advanced Auto Parts are like $3.50, they will have to order them but it only take 1-3 days. I your car runs rich then you can hang them up. Plus you will have to machine about 5/16's from the top of the socket to make the wall thin enough to fit. I fouled mine in 2 days of driving, so went back with the BUR9EQ all the way around. Bur9eq work good for daily.

 

I have been running B10EGV for a while. They cleared up some high-RPM misfires and seemed to be fine (no fouling) for general street driving in my car. I bought the expensive Racing Beat socket from Mazdatrix and it works fine. I didn't want to bother with machining my own thin-walled socket, and I figured it would pay for itself in savings on the plugs themselves.

There are some similar Iridium plugs that I have read about on here. I might try them. I think the number is B10EIX.

-Max

 

$7ea for iridium, that's cheaper then the oem platinums and $25 cheaper then then oem iridiums. Max is right, the socket wrench will pay for itself.

NGK BR10EIX Iridium's

I think 10's are too cold for the poster at 300hp (and the wrench is $10 cheaper direct from Racing Beat).

 

How does the iridium help?

 

I usually run the B9EGV (about 350RWHP), but recently swithced over to the BR9IEX iridiums to try them out.

My ignition amp is a Crane HI-6R.

For some reason the iridiums need a larger spark gap to idle smoothly. I ran the B9EGV gapped at .020" but the BR9IEX missfired at that at idle. I opened them up to .030" and all is fine now.

Even on the stock ignition (without Crane) they fire good at 14-15psi boost.


Are they worth the extra cost? I have to waite and see how long they last.

 

So I guess I'm the dumbass here, but are you guys saying that the BR9IEX plugs have a gap like a normal plug? I didn't know that those kinds of plugs were run in rotaries. Damn, I feel really stupid now. Thanx in advance for the info.

Zach

 

I can't see how a "shrouded" spark plug will give better performance unless something is wrong other than the spark plug itself?

Mazda has done extensive research (see SAE papers) on spark plugs design, and the BUR series is supposed to be the "best" for mildly powered Mazda rotary engines.

Maybe some of you guys are running "additives" or some kinda exotic ignition systems?

I don't really care about the B10EV's, as you introduce spark plug gap as a variable.

Maybe someone can get some dyno runs with the B10EV's versus BUR9's versus the NGK 10.5's?

Or are you unshrouding the B10EV's by cutting the side electrodes?


-Ted

 

I've been running them pretty much just like they come out of the box. I haven't changed the shroud, and the gap is even just about the same as they come with. The shroud is not very "tall" on these plugs, so they don't seem all that different from rotary plugs, or at least not as different as you might at first picture in your head.

I have an HKS ignition box, but I was still getting misfires at high RPM with BUR9EQP. I actually think my problem was really just that the ignition was advanced too far, but the B10EGV plugs did smooth things out up there. The gap on surface-gap plugs gets pretty large once the center electrode starts to wear. You can set the gap on the EGVs, and maybe the shroud also protects (not what you want for performance, I know) the center electrode a bit to keep it from eroding so quickly.

-Max

 

Thanx for the clarification guys. I will have to check out the B10EGV's once my engine is built.

Zach

 

Thanks for all the replies.

Max...I'm also using the HKS ignition system and I'll try the B10EGV, are you using the B10EGV on all 4?

Thanks again.

 

Yes, put them in all 4

Chris

 

Max is at least 350hp and you are at 300hp. I don't think you should use 10's on all 4. Why don't you try 8's and 10's and then check them after a month to see if they are fouling. There is no power gains using cold plugs. It's used to counteract spark plug heat soak (so to speak). Here, read this stuff.

 

Yeah, I used the B10EGV in all four positions. First from the bottom, then from the top, then bent over the fender, and finally from a seated position with a big smile on my face. I said 'position'... uh huh huh. Sorry, I couldn't resist making a joke.

-Max

 

I have been running NGk 11.5 race plugs with premix on the street with partial bridgeport and MSD 6a, fouling is not an issue.. The idle was actually better with the iridiums over the standard burq's...Max

 

Max, that was pretty funny.

GoRacer, I guess you missed my post when I said I don't like to give all my secrets away. Trust me I'm making more than 350hp.

I purchased the B10EGV yesterday and will try them out on my FD. Also, I placed an order for the NGK Iridium spark plugs for my brother's Accord V6 and see how well they work on his car.

Thanks for everyone for all your help, I really appreciate the response.

 

In my Mazda comp parts catalog it states
that the EGV plugs are not as long as the
standard plugs.Not good, can someone tell
me how much shorter they are.I ran some
race plugs at one time that were the R6725
10.5.They were like $25 a piece.They were
the correct lenght though.I would guess that
they are the ones Jason has at the RX7 store.I couldn't find them at sparkplugs.com.I may try the iridium plugs
because I'm guessing that they are the right
length, and you can use a standard socket to
install them.If you can verify this, let
the rest of us know.
Thanks,