Which spark plug should I use ?

[Dangerouspower]

I have a wiseco high compression piston, wiseco valves, wiseco timing chain, and a yoshi slip on.
I like NGK but will try other ones if there better.
Right now Im running a NGK CR8EIX which is an iridium plug. Which is hotter.
I have read some things that if you raise the compression that you should run a colder plug. So what should I run ?

[ltz4-rum]

Raising the compression above 12-1 doesn't necessarily require you to run a colder plug. (It will require you to run race gas!) I race with a 13-1+ wiseco piston with a stock heat range E3 sparkplug with no problems. The key is to get the jetting correct...Remember, it's better to be a little on the rich side.

As the saying goes:"lean means green!."

[Dangerouspower]

I am running the 13-1 piston same as you. But this winter Im putting a 3 layer base gasket so I dont have to worry about detonation. My jetting is good. What is the # on your E3 plug ?

[Joshz400_03]

CR7E is the stock z plug. You are running a step COLDER right now. Iridium is good but not as good as a standard copper plug. Iridium lasts much longer because of the material but it doesn't have as intense of a spark as a standard plug. I ran a CR8E in my 434 and it worked great. As for the E3's all those dual tip blah blah just seem dumb. I would stick with the NGK over anything. A spark is a spark.

[Dangerouspower]

So would you go with CR7E or CR8E Josh?

[zookie400]

rpm, jetting, and compression will change plug heat range requirements. i run a 9 with 13.5 on a mx engine that is held to redline always.

im with josh, sounds like 8 range would be fine. if your jetting is good, check the plug color before and after you change heat ranges. if the jetting stays the same but now the plug is black, you need to go to a hotter plug (ngk hotter is lower number, colder is higher)

[Dangerouspower]

Ok thanks. I will try out a 8. Is there a special tool or some trick to removing and putting the plugs back in besides taking the plastic/gas tank off ?

[ltz4-rum]

Hey Josh,
it's nice to know we have a expert in the forum when it comes to spark plugs. The mere fact that you say the NGK is better than the E3 because the E3 is "dumb" makes me wonder how much you really know. I appreciate the fact you are loyal to NGK but does that really mean all other spark plugs are junk?

[atv4life95]

NGK's are the most commonly used plugs out there. The reason being that they perform very well, last a long time, and are inexpensive.. They've also showed their reliability over the years, while other plug companies who haven't been around as long, like E3, haven't had the chance to show their full potential. There's obviously a reason that Suzuki put an NGK plug in their engine. Why not just use it? You aren't getting anything positive out of running an E3 plug. Not saying that they're bad, but why change it? If the thing was designed for an NGK, leave the NGK in there...

[CFM-Z440]

Most fancy spark plug designs are purely gimmicks. Iridium plugs are about the only thing I know of that can make a difference, and that's only really if you have a weak ignition system, and its a very slight difference. All multi spark designs are a joke. Electricity always takes the path of least resistance, and often times, the extra crap involved actually shields the combustion that much more...

As far as heat range goes, more combustion heat (higher compression) needs a cooler spark plug to avoid pre-ignition. In a Z, I would run a cr7e up to around 12:1, if you're over that, I would go to a cr8e (one step colder). You are better off with a plug that is a step too cold than one that is a step too hot. The heat range has nothing to do with power output, its a rating of how quickly the plug transfers heat to the head. Too hot will allow the ground strap to glow and cause pre-ignition / detonation, and too cold will allow deposits to build up, or even fouling if you're way off.

[ltz4-rum]

I agree that NGK's are an inexpensive plug...and this is why the manufactures use them. This is also why the manufactures use certain shocks, air filters, handlebars, etc. is to keep the prices down. This doesn't means it's the best product out there, just adequate.

I think the NGK plugs are adequate, but I switched because I personally had a NGK plug fail. When I began looking for an alternate source for plugs I made the decision to switch to E3's. The whole point is that anyone who is going to make a statement or claim against something should really back it with facts and not just because they haven't used it.

[CFM-Z440]

Originally Posted by ltz4-rum

The whole point is that anyone who is going to make a statement or claim against something should really back it with facts and not just because they haven't used it.

Originally Posted by CFM-Z440

Electricity always takes the path of least resistance, and often times, the extra crap involved actually shields the combustion that much more...

Maybe you missed that part


I have more than adequate experience.

Look at the massive ground strap on the E3 spark plug. Tell me how that is not going to shield more of the fuel/air mixture from the ignition point. If the E3 makes ANY more power than a normal spark plug, it is not from more complete combustion, it is from the extra compression you get from the extra material taking up space in the combustion chamber. My biggest concern would be how easily you could bring on pre-ignition with that ground strap if you had too hot of a plug in it. Either way, I see no advantage to this type of plug and you're not going to beat anyone by running it, that you wouldn't have already beat with a stock style plug.

This is much like the "split fire" plug gimmick that was all the rage 15 years ago.

That said, I have always used NGK plugs in 90% of everything I work on, in the automotive, powersports, and marine industry. I have yet to see one fail that was the fault of the plug itself. I would rate the NGK's quality higher than Champion or Ac Delco, which are the other common options in my line of work.

[Dangerouspower]

Thanks guys !

[Joshz400_03]

CFM basically said what I was referring to as dumb as taking the path of least resistance. I'm sorry I didn't feel like typing up a huge response like he did to explain something that anyone can figure out on their own. Yes I like NGK more than others because they make a great plug. There are not any cheaper than any other autolite or bosch.

[SedaliaPowerSports]

I have been running the NGK CR8EK and been very pleased 1 plug has been in all season. Dont know what advantages it has if any, just thought I would share.