Misfires Fixed - Avoid Denso Iridium (IK20) Spark Plugs (pic)
#1
Misfires Fixed - Avoid Denso Iridium (IK20) Spark Plugs (pic)
So my car was hopping a little at high boost after the EPL tune. I thought maybe clutch or wheel spin, but then I got a CEL for misfire.
Had the codes read and misfire on cyl 4. I had just changed plugs to the IK20's about 2000 miles ago, so I didn't think plugs. I had the original coils, so I put the new 997 coils in.
No change. I did pull a plug while I was doing coils and I thought they looked weird, but I thought, nah, they are practically new...
So had the codes read again and now misfire was in 1 & 2. So I thought maybe plugs. Got some Bosch FR6 LDC copper plugs in and no more issues...
Here is a picture of the Denso plug. Top is mine and bottom is a new one. You can't see it extremely well, but the little tip has basically been burned down... Guess the IK20's are no good for high boost. I am running 1.1bar on K16's.
Thanks to Tony at Stuttgart here in town for helping me SOOOOO much!!!
Had the codes read and misfire on cyl 4. I had just changed plugs to the IK20's about 2000 miles ago, so I didn't think plugs. I had the original coils, so I put the new 997 coils in.
No change. I did pull a plug while I was doing coils and I thought they looked weird, but I thought, nah, they are practically new...
So had the codes read again and now misfire was in 1 & 2. So I thought maybe plugs. Got some Bosch FR6 LDC copper plugs in and no more issues...
Here is a picture of the Denso plug. Top is mine and bottom is a new one. You can't see it extremely well, but the little tip has basically been burned down... Guess the IK20's are no good for high boost. I am running 1.1bar on K16's.
Thanks to Tony at Stuttgart here in town for helping me SOOOOO much!!!
#2
What gap were you running on the plugs?
What heat range were those plugs relative to factory?
I don't see why the Iridium plugs would cause a misfire where the copper plugs do not if you have the correct plug and gap for your application.
What heat range were those plugs relative to factory?
I don't see why the Iridium plugs would cause a misfire where the copper plugs do not if you have the correct plug and gap for your application.
#5
IMO, typically with a lot of boost you need to run a lot smaller gap. You could be blowing out your spark with a large gap combined with a lot of boost. A colder heat range plug is also a good idea with significant boost.
This is a pretty good read on spark plug performance from NGK:
http://www.ngksparkplugs.ca/tech-info-spark-plugs.cfm
Last edited by BlownVette; 08-22-2009 at 02:36 PM. Reason: Added link to NGK spark plug performance
#6
Good read there! I am pretty new to blown engines so I am learning... Would the gap being too wide cause the plug to basically melt on the tip like mine? Maybe they got too hot cause of the compression and gap?
#7
no harm intended purely educational intent
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#8
Blowers blow, turbos blow, you... well....
#10
Well, you would think that if they list the IK20 for the 996TT, they would gap it right or at least tell you what to gap it at... I have never had to gap a plug differently... It is just a learning thing, but I spent a lot of time "learning" that I should have gapped the plugs... And this car is not a good one to learn on! Although, I can do my plugs in 2.5 hours now!
#11
I'm surprised. I used Iridium plugs in my Supra as they were the ONLY thing that wouldn't melt down quickly - I could go a YEAR on them running meth, race gas, the works without misfire. I did gap them but you have to be REAL careful doing that with these since the pin is so brittle. Iridium is a VERY hard material, if it melted down I'd be surprised if another plug held up much better if it's got the same heat range and gap...
#12
I have put 8000 miles on iridium plugs making between 700 and 800hp on the Turbo with no ill effects thus far.... Mine would have been the equivalent of IK24 though. I gapped them down to .030 as well
Justin
Justin
#14
Back in the US - arrived last night!
Here's the page from the 996TT manual. Plug gap 1.6 +/- 0.2 mm
Best wishes for the holidays!
Jon
#15
Well, you would think that if they list the IK20 for the 996TT, they would gap it right or at least tell you what to gap it at... I have never had to gap a plug differently... It is just a learning thing, but I spent a lot of time "learning" that I should have gapped the plugs... And this car is not a good one to learn on! Although, I can do my plugs in 2.5 hours now!
First, why would you not call or PM Tony and ask him what to run, it's his tune? As far as I know, he only recommends one plug. I have never had misfire issues since I changed.
Second, ALWAYS double check your plugs out of the box. You never know if someone drop a box a pinched one down a little.