This is actually why I use the NGKBR8ES series of plugs.

The BPR series of plugs hang a bit lower in the combustion chamber and are closer to the piston. The BR series plugs are further away from the piston which not only gives you more room between the piston and plug but it is also a cooler plug.

The idea is you always want to run the hottest plug you can that won't cause denotation. You can run to cold of a plug and it will foul out more quickly than it's hotter counterpart. You should technically run a few different heat ranges to see which works the best for your application.


I actually change my plugs just as often if not more often than I change my oil, especially if I know I am going to go race, I'll toss in a new set of plugs. Cheap insurance. To replace the 4 NGK plugs its like $12, why not?

Also, FWIW, the stock heat range would be BR7ES.


Good luck with the rebuild!


-Bink

 

Bink - i too tend to go through plugs failry frequently the only issue for me with the 9 head is running the expensive iridiums

I know joey was bummed to also have to shell out $50 for a set and even more for the special "race" versions but since he's on the 8 head now i'm sure he's a bit happier

The plugs i had in there were actually LFR7AIX's

 

Ahh, didn't realize this was an Evo IX we were speaking about. In that case, I see what your saying - not as cheap as $2 per plug!



-Bink

 

Yeah the plug will show signs of eating itself very quickly if the heat range is wrong.

The electrode is better insulated and has a large surface area to distribute the heat into the waterjacket... without that you have a glow plug. 2 stages in the wrong direction with the amount of power Pat is making would make the ground strap have a "thermal" event. I bet he melted the ground strap.

that really sucks Pat.

Here's how I designed my engine...
What's the highest RPM you can consistantly and quickly change gears on your 1-2 shift? 9500? 10k?

Set your piston speed (and therefore stroke) based on that value and run the best R/S ratio possible (reduces side loading, friction, and bearing load). that may mean that you need a 92mm stroke or a 94mm stroke. Both commercially available cranks.

4G64 block is a no brainer IMO. 6mm taller deck... and relatively inexpensive to purchase.

I would suggest a 92mm crank 4g64 block and alum 162ish mm rods... you can still rev it to 9500-10k, but you'll improve your powerband. Idea is to make the MOST horsepower by shifting your powerband as faaaar to the right as possible, while still being able to shift the gear box. If you can shift at higher RPMS... keep the piston speed down and move the VE to the right. Horsepower is directly proportional to acceleration. Doo eet.

 

just for $h!ts and giggles i checked out NGK's website, i didnt realize they made so many different plugs. has anyone run either the Laser Iridium plug, Laser Platinum, or Iridium IX ? see which ones wear better n deal with the high cylinder/boost levels or heat..obviously any plug is going to fail if subjected to detonation but im sure here has to be one out there that is more resistant.

I also noticed they have a racing plug listed on their website. im actually thinking of contacting them and finding out more information n let them know the issues some people are having.

 

I am much more happier now i switched to the 8 head and dont have to spend all that money on plugs lol. I ran the iridium 9 plugs, the 2 step colder ones and for a set it was $150 bucks I still have 2 boxes just sitting in the garage lol. Glad im on the 8 head now

 

damn

 

i called and talked to NGK today n the plug they recommended for your car Pat was a R7438-9 Stock number 4656

 

ive got a plug they recommended for me on the way also that i guess doesnt have an electrode strap at all... im curious to see these..

 

You guys are quoting the Racing plug part numbers.

I have a set of the Denso 5346 (IKH24's) and a set of the Denso 5347 (IKH27's) and they're like 45 a set.

 

correct Ernie the part numbers i posted are for the Racing plugs but from what the NGK tech was telling for the levels of boost alot of us are pushing and the metals the other plugs are made out of he wasnt surprised to hear them melting. pretty much said they wernt designed fot that type of use.

 

http://www.jegs.com/i/NGK+Spark+Plug...438-9/10002/-1

 

am I the only one who finds it funny you were at the track the SAME day your son was born!

man, I like racing and all, but my wife would have cut me off for life if I wasn't there in the hospital with her when she was pushing out kids out.

 

truf!

 

can you get any information as to what is different about their material choice between the two plugs?