Denso is iridium($11.99 each). NGK is copper($2.24 each). Both are one heat colder than stock. Which one do you prefer/better for a lightly modified Evo(approx. 300 whp)? Also, please include the gapping. Thanks in advance.

 

using the Denso i have had logged my timing advanve at less then previous vs stock...just FYI

 

So does this mean that I should go with the copper? Or is going to a colder range alters timing?

 

i would like to knw aswell.....also what gap should i run on the ngk;s

 

The colder range allows more heat to be extracted from the cylinder itself, therefore allowing more advance as the fuel is not as quick to break down quelling detonation. From what I've been told Iridium plugs have a longer life span then your average copper plug. I recently ordered a set of Denso IW24s for my car.

 

I thought advancing the timing is bad for the motor.

 

good post on the iridium vs. copper spark plug subject

cliff's notes: iridium is worth it.

 

for some reason my post got edited and some of it got deleted....dont know why

but anyways...timing isnt bad as long as the engine is NOT detonating. The knock detector in our cars will hear knock and start to pull timing. So the timing advance that I saw made me think that the denso's range colder ran better than the stockers

 

After reading this^ and https://www.evolutionm.net/forums/sh...ad.php?t=51949 I guess it is safe to say that IW24 it is! Thanks!

 

I just made the switch from the stockers to the NGK BPR8ES.. I really needed new plugs. The car feels less laggy, has better response, and feels GREAT! The idle is much smoother once it is warmed up... Since they are 1 range cooler then stock the idle is a little ruff until the car warms up. But once it does it is like Buttah! After these I might try the IW24's but these feel great I don't see any reason to pay $11 a plug... They take 20min to install and so what if they don't last as long for under $2 a pop you can't go wrong! I can buy 5 sets of the copper plugs for the price of 1 set of IR.

 

with around 300hp, I dont really think you need a colder plug, you will just foul your plugs sooner.

 

It seems to keep knock counts down.... I like them.

 

You don't need colder at that point, but if it't tuned it won't foul them. It will be a little rougher on warmup but that's not really a big deal.

Mark

 

Anybody using NGK B8EGP or B9EGP? They are supposed to be really good and it actually says "Racing" on the boxes

 

you can use them if you want but they do not have resisters. jason