When do you need to upgrade plugs from 9s to race plugs?
 

I have an RX6 single turbo, a mild street port, and all the bolt-on stuff. I have been running NGK BUR-9EQP plugs for quite a while, and I am wondering if it is time to switch to NGK race plugs like 10.5 or 11 (and which ones?).

The reason I ask is that my car would start to ping during tuning if we leaned it out to what one would normally run. I am not saying I want to run it lean, but the tuner seemed to indicate that my car was more prone to start pinging as the mixture got lean than other cars that he has tuned. He cited high intake temps as one reason (peaked at about 50C with my IC fan on -- I've got a stock-mount IC), but I am looking for what else might have been a contributing factor and the idea of needing to run colder plugs has crossed my mind.

So, what plugs do you think I should be running? Are 9s okay, or should I run something colder? What do you recommend for leading and trailing?

Read a complete list of my mods here.

Thanks,
-Max

The best mod you can make is to scrap the style of plug you are using ! regardless of heat range they are shit !

I recommend using single electrode B10EG or B10EGV or RA series (race plugs) as a minimum in a high HP aplication like yours for both L & T plugs, all are NGK's.

Only go for the 11.5 if you are endurance racing, they will misfire even with a good ignition system when the engine is "cold" and are pretty easy to "wet" is you fuel metering is out.

10's are a good compromise for thermal resistance and give less cold misfires than 11.5's.

Just my tips.

Thanks! That was a very informative response. Now to find some strange plugs... ;)

-Max

I've seen a lot of good results with the HKS twin power .... but if I remember correctly you run that box!! Interesting .....

Looking for these on the net, I found them at http://www.motodepot.com/street/engi...k_special.html . Are those the right ones?

Rice-

Why is that style better?

I found a pic of a B10EGV on page 2 of this PDF file.

I am surprised at the recommendation to run something other than a surface gap plug, but I am certainly interested in any comments you have on that subject, RICE RACING. I know that you know what you are doing. Do I have to modify the plug at all before installing (remove/add gasket washer, re-bend electrode, etc)?

Also, these do not appear to be resistor plugs. Will that work with the stock FD coils and an HKS TwinPower?

Does anyone know the NGK part numbers for their "rotary" racing plugs? The 11.5s seem to be the NGK R6725-11.5 as I discovered on the Racing Beat site.

I am also interested in feedback on whether my plugs may have been a contributor to the pinging the tuner noticed when setting my fuel maps.

Sorry for all the questions, but I am just trying to understand so I can make a good choice.

Thanks,
-Max

My 11.5 race plugs are single post plugs.

I'm listening carefully to this post. I run rich intentionally and need to change plugs often and I prefer something cheaper than $9 a plug.

Cheuk

Ok, there is no modification needed to those plugs, simply gap to .02" or around 0.9mm...the reason for using these is that they do not misfire like the SD style plugs through precise gap control.

Your plugs can be a contributor for sure, I have another tunner blow up a customers engine that I built simply due to too hot a heat range plug (B8EGV) and It occured after a dyno run, put simply detonation can occur with a rich mixture when the spark plug gets hot enough to act like a glow plug in a diesle...you need to select the right heat range for your application.

Now there is no problem using non resistor plugs with your coils and it will not effect your ecu or radio as some people may warn you.

In regards to the R series plugs, the ONLY difference between these and other "platinum or paladium (EGV)" plugs is that the body is made from a better heat resistant alloy for all out endurance racing. If you are going to use high octane leaded gas then you do not even need the EGV plugs, the EG range will do as their ground and tip electrodes are less prone to lead fouling.

If you need them I sell them for $40 Aus for a set of 4 (B10EG) I think freight would be about $25?

Thanks for answering my questions, RICE RACING. I really appreciate your help.

I am going to try to source the plugs locally to save shipping. It seems like the US web sites had boxes of four for US$20, but I've got a bunch of motorcycle racing shops nearby that I will try first.

Thanks,
-Max

Just a bit of warning... on those short bodied spark plugs, if you have a block that is 1980 or newer, you need to either order a special socket from racingbeat or mazdatrix, or take a spark plug socket and shave it thin with a grinding wheel or something. A standard spark plug socket won't fit into the block with that damn lip that they started putting on it. Next time you have the engine out (you may even be able to do it with it in the car, but I wouldn't recommend it), have that fucking lip machined off, that thing is a pain in the ass...

I have found two perfect plug sockets, the one from my old man's chainsaw and also a plumber's tap socket.

maxcooper> before looking at plugs as a problem, I would get rid of the stock intercooler. THat would help more than any plugs on the face of the planet.

Rice> Have to disagree on your call to use the B10EGVs.

On BP Ultimate, using 7EQs and 9EQs (As per factory settings and config) and 14psi my car made 272rwkw.

C16 and 23psi and 9EQs lead/trail, car made 327rwkw. My car ran its 11.1 with 9s all round.

B10EGVs foul very quickly in my experience, especially when running pre-mix and you get the mixtures out slightly.

Thoughts?

Cheuk> WHen Matt gets over there next week I am getting him to grab me a set of the HKS plugs. Should be interesting! :)

B#EGV plugs were reccomended to me by Matt, he seemed to swear by them, and after using them so do I, they even cough an engine into life when ya have poured some ATF down its throat.

My engine ran crisper and smoother with B8EGV leadings and B9EGV trailings than it ever did with BUR7EQ and BUR9EQ plugs in it.

Matt reccomended the B#EGV type of plug for any engine running premix.

I think Max ment stock mount intercooler. If I recall correctly he has the M2 medium.

I have to agree with Rice Racing here. I've been running B10EGVs for a while, and as long as the tune is right they are a great plug. I also re-gap them the same as Rice (20 thou). these are great if you are making plenty of power and somewhere near 20psi. If you're tune is out you will foul them pretty rapidly though! :)

(I'm making 500+hp at the flywheel and running 130mph down the quarter if you need a reference point)


Rice, I heard a rumour your yellow car was for sale? is it?

have a look in the aussie section of the forum, it's not just a rumour

A777, good to hear a responce from another member who has high HP car doing good times :)

Yeah my car is for sale, had it in the Sydney trading post this week.

PS: You're car is real nice !

I've been using EGV's in everything I've built and have never had a problem with them. The only other plug that you'll probably find a little smoother and will make a little more power with would be the 11.5's but being a colder a plug they are prone to fouling.
The coldest plug that NGK makes for the rotary are the 13's and are of the surface gap type. Those work very well in motors ran at continous high 9000+ rpm conditions. They also make the most power especially when used with the thin sealing washers but are very prone to fouling.

crispeed

Hey Crispeed,
Where can i get a set of these plugs, ive always run NGK and never had problems, but i think i need something else for the new motor.

Ohh yeah, did you get my email, i will be using the 3rd gen intake manifold, let me know on the price please so i can send the housings/manifold down, i need to get this motor back together soon. I can ship it out monday if that is okay with you. Let me know, thanks.

Thanks for the additional info everyone.

I now have four B10EGV plugs and a suitable socket to install them (thanks Kurgan, I hadn't thought of that). I'll be putting them in tomorrow. I'll also be able to inspect the plugs that are in there to see what story they tell.

The car is tuned (a few hours with a wideband on a dyno) but intentionally a bit rich to avoid detonation. Hopefully they won't foul and maybe I'll be able to go a little leaner before it pings if the plugs really were a contributing factor. I am not running pre-mix, so that might help avoid fouling.

I do have an upgraded IC (M2 Medium), but it is mounted in the stock location (as opposed to front-mounted) so it gets hot on the dyno because of the lack of air flow.

-Max

I installed the plugs today and the car seems to work fine after a light drive, but I haven't really gotten into it much yet. Hmm... maybe I should go do that now.

My old plugs had a fair amount of crap built up on them and some erosion of the center electrode, but no signs of meltdown. The car was running really rich before I got it tuned, so perhaps some of the build-up was from the pre-tuned days. They had the light brown/white stuff built up on top of the carbon, and it was in little bumps which is something I hadn't seen before. I could describe this all day, but it probably isn't that useful, so I'll stop. I should have taken a picture, but I already discarded the old plugs.

-Max

how much gap?
 

How much do you gap the plugs? Rice Racing says 0.9mm or 0.02" but 0.9mm does not equal to 0.02" (0.5 mm). Which one is it? How about just take an average of it and make it 0.7mm?

Chuck

I checked the gaps out of the box and they were all about 0.027, so I left them as-is.

My J&S has been going nuts since I installed the plugs. I am not quite sure why, but I think I might switch back to 9s or try the 10.5 race plugs as replacements. I've got a track even Friday that I will try the EGVs at, but if they are still freaking out the J&S I'll probably put some 9s in.

-Max

What your J&S is picking up is a misfire, You will need to gap the plugs down to 0.02".

If the misfire persits (sometimes felt and not always audible), you can run an ignition amp if you do not already have one instaled.

However the stock ignition system should handle this heatrange no problem as long as your fuel delivery is spot on, If it is too rich the plug will get overcooled (at part throttle) and the first few times you give it some love you will get a misfire. After the plug gets to operating temperature there will be no misfire at all.

You will not have this problem with hotter running spark plugs like 9's, however once the plugs gets too hot (from extended use) it can be the cause of detonation.

Hope this helps you.