Long Term Spark Plug Thoughts

[jimlloyd40]

I'm about to tune the car with EQT Stage 1 and I already purchased a set of NGK 91006 Rs7 spark plugs. I know EQT is no longer recommending these but do you guys think it'll be okay to just put these plugs in without gapping to 0.024" and replace every 10k miles? (Eliminate incorrectly gapping plugs variable) Of course I'll check the plugs to make sure they come pregapped correctly at 0.026" (I think) but I'm not going to gap the plugs/touch the top at all.

The NGK racing plugs that EQT is now recommending come out to be $180 and this isn't even a track car..

You can get almost 6 sets of Ruthenium spark plugs which work great and lots of guys in the forum are using without any problems.

 

[jimlloyd40]

It seems easy to hand wave this stuff away as user error, but I get why EQT did what they did. We don't know why that grounding strap is breaking off, but if it takes your whole engine with it and there's enough cases of it happening, better to just recommend the nuclear option and ensure it doesn't happen.

I'm EQT Stg 1 and was going to get the RS7 plugs, but I'll probably try the Ruths gapped to .024". People are really finding you don't need a one step colder plug?

Yep no need for a colder plug on a street driven car.

 

[jimlloyd40]

Ruths okay for 10k miles on an is38 GTI?

I change mine every 15, 000 miles and they're fine.

 

[jimlloyd40]

Even though they are a stock heat range plug? They’re still ok to use with an is38?

Yes

 

[aaronc7]

The denso race plugs are still crazy expensive for a spark plug, but end up being a good middle ground (price wise) between Ruth/RS7/Denso IKH and the NGK race plugs. I ordered a set and gonna see how it goes. I'm not as worried about super fast fouling or cold start issues since it really doesn't get cold here. Anyways they come out to around $100 a set.

 

[ZuMBLe]

The denso race plugs are still crazy expensive for a spark plug, but end up being a good middle ground (price wise) between Ruth/RS7/Denso IKH and the NGK race plugs. I ordered a set and gonna see how it goes. I'm not as worried about super fast fouling or cold start issues since it really doesn't get cold here. Anyways they come out to around $100 a set.

Are you going to run them with the EQT wire kit? I hear that really smooths things out and gets rid of knock and crank walk. The trick is to swap the #2 and #3 cylinder wires to cause a "cross fire" which will improve HP and smoothness.

Link to demonstration which shows the spark intensity with crossfire.

 

[Nineeightyone]

Well this got big quickly. Meanwhile I have a set of OEM NGK plugs to go in, currently at 27k miles on what I assume are OEM plugs. Now it just needs to not feel like 12°F outside so I can get the new plugs in, and I guess start checking them at oil changes/changing every other.

 

[tigeo]

Now if FCP Euro would only stock Ruths.....

 

[ZuMBLe]

Now if FCP Euro would only stock Ruths.....

I'd be doing 3k intervals. Haha.

 

[Acadia18]

Are you going to run them with the EQT wire kit? I hear that really smooths things out and gets rid of knock and crank walk. The trick is to swap the #2 and #3 cylinder wires to cause a "cross fire" which will improve HP and smoothness.

Link to demonstration which shows the spark intensity with crossfire.

YOU'LL GET CAUGHT UP IN THE.... CROSSSSS FIRRRRRE!!!

 

[victorofhavoc]

I think everyone is making this too complicated...

You need a colder plug if your cylinder temps are too high and you're getting preignition. Once upon a time, before ecu were as smart as they are today, it was common to go colder for every 100hp jump. Today's plugs and ecu are far superior and if you're running cylinder temps so hot as to warrant a colder plug, it's a good idea to ask "why". Does your cooling system just need more capacity to keep temps down? Are you starving the engine of oil or are you using low quality oil so that there's excessive rubbing and wear creating the extra heat? Is your intercooler undersized and are iat just getting so high that you're not cooling the air enough before it enters the cylinder?

The downside to using a colder plug when you're not getting preignition with a stock range is that you'll likely not burn away all of the combustion matter and that will result in a plug that's fouled much sooner. A non-projected plug is even more likely to foul sooner as the electrode isn't as exposed to the combustion.

If you're running crazy high cylinder temps, only running race fuel, or pushing a big shot of nitrous there are certainly advantages to running proper race plugs. At this point though, you likely have a custom ecu that doesn't have the same safeties in place to prevent detonation.

 

[aaronc7]

Once upon a time they weren't making 400, 500+ hp out of a 2 liter 4 banger on a regular basis either. It's neat but makes the motor high strung, it is what it is.

They ECU does have pre ignition detection and safeties though which is nice. Will normally result in a misfire or "cylinder pressure too high" code, and shut off the cylinder to save the motor.

I think it can get a little hard to choose if you're running that 400-500whp hybrid turbo range. Yeah, normal daily commute you really don't need or even want a super cold plug. But what if you happen to get on it a bit for 10+s? You want that colder plug to be 'safe'. An annoying compromise. Just like you you big power GTI guys, you don't need or want drag radials for a daily but otherwise it's just spin city, so what do you do? lol

I don't think E85 is the end all savior either... it doesnt really lower EGT all that much and there are technical papers that discuss how ethanol is more prone to pre ignition than gasoline.

If you fall into that 400-500 hp range dilemma, that I guess one way to go about it would be to try a 2 step colder plug and check up on it every so often... is it fouling up quickly? OK then try 1 step colder etc. At least that's my train of thought as I'm about to try a 2 step colder plug.

My RS7 plugs have always looked really good, is38 and vortex, didnt run them more than 10k but I'm sure I could have easily.

Yes, this is a funny topic that everyone freaks out about. I over think everything so this is normal for me....but not something I"m gonna be losing sleep over.

Sorry, long post. I do that sometimes.

 

[jimlloyd40]

Once upon a time they weren't making 400, 500+ hp out of a 2 liter 4 banger on a regular basis either. It's neat but makes the motor high strung, it is what it is.

They ECU does have pre ignition detection and safeties though which is nice. Will normally result in a misfire or "cylinder pressure too high" code, and shut off the cylinder to save the motor.

I think it can get a little hard to choose if you're running that 400-500whp hybrid turbo range. Yeah, normal daily commute you really don't need or even want a super cold plug. But what if you happen to get on it a bit for 10+s? You want that colder plug to be 'safe'. An annoying compromise. Just like you you big power GTI guys, you don't need or want drag radials for a daily but otherwise it's just spin city, so what do you do? lol

I don't think E85 is the end all savior either... it doesnt really lower EGT all that much and there are technical papers that discuss how ethanol is more prone to pre ignition than gasoline.

If you fall into that 400-500 hp range dilemma, that I guess one way to go about it would be to try a 2 step colder plug and check up on it every so often... is it fouling up quickly? OK then try 1 step colder etc. At least that's my train of thought as I'm about to try a 2 step colder plug.

My RS7 plugs have always looked really good, is38 and vortex, didnt run them more than 10k but I'm sure I could have easily.

Yes, this is a funny topic that everyone freaks out about. I over think everything so this is normal for me....but not something I"m gonna be losing sleep over.

Exactly what I did. Started out with the 2 step colder racing plugs and they fouled out. Then the 1 step colder RS7 plugs with no problems but decided to try the stock heat range Ruthenium and they work fine also. So costs considered the Ruthenium wins.

 

[DrFunkalupicus]

So most of my driving is short trips in town. It is stop and go but never a traffic jam and I never push the car hard with the occasional spirited drive on the weekend. I’m probably not seeing any benefit by running the RS7 plugs am I?

 

[scrllock]

So most of my driving is short trips in town. It is stop and go but never a traffic jam and I never push the car hard with the occasional spirited drive on the weekend. I’m probably not seeing any benefit by running the RS7 plugs am I?

For a stage 1 IS20 I really really really doubt you need more than stock heat range.