New-ish NGK Spark plug question

[QtrFlsh]

Have a 20k mile '04 with 4lb lower, cat-back, CAI, and have been running the Denso Iridium's for several years, but it seems after a short time, they tend to foul. It is likely due to the truck sitting around more then it likes, and then starting and moving it to clean garage, etc... Likely too much cold starts and not enough boosted driving. Nonetheless, I was wondering if anyone has tried the newer NGK Iridium IX's? I like the NGK's and have used them in all kinds of vehicles since I can remember-plus I get a discount on NGK at my local parts store.

Just wondering-any feedback is appreciated!

 

[DSG2003Mach1]

i just always ran the copper plugs since they're cheap to replace and I would do it once a year just on GP

 

[FireGuy]

I have an 18k 02, been running densos for most of the time I have owned it, never fouled a plug. What heat range are you running? I used IT 16 for a six pound pulley and ported blower. When I added more mods and boost went to IT 20. If you prefer the NGK brand and feel more comfortable with them, you should use them for peace of mind and save a little cash. The important part of the equation is to get the correct heat range and with your setup, it should be very close the the stock heat range. If you change to new plugs and the fouling returns, I would consider replacing your coil packs with new stock ones because they could be weak, even though they haven't had much use. One other fouling issue to consider with rarely driven vehicles, bad fuel and if you use fuel stabilizers they would tend to foul plugs too. In fact, last year I had to change plugs because the fuel stabilizer I used killed one of my fuel pumps, so new pumps, new filter, spark plugs and all new fuel were required. I am not so likely to use stabilizer anymore, just use up or drain the fuel annually.
Sorry so verbose but causes of fouling can be many things even more than I have covered here.

 

[Dusten]

Have a 20k mile '04 with 4lb lower, cat-back, CAI, and have been running the Denso Iridium's for several years, but it seems after a short time, they tend to foul. It is likely due to the truck sitting around more then it likes, and then starting and moving it to clean garage, etc... Likely too much cold starts and not enough boosted driving. Nonetheless, I was wondering if anyone has tried the newer NGK Iridium IX's? I like the NGK's and have used them in all kinds of vehicles since I can remember-plus I get a discount on NGK at my local parts store.

Just wondering-any feedback is appreciated!

My guess is to cold of a plug. At your boost level a heat range 6 plugs is all you need. The iridium plugs are fine. I run copper, but I change them a lot too.

 

[QtrFlsh]

Thanks for the replys. It does appear that I am running a number colder than stock, even though they are denso iridium. Fuel stabilizers and a few longer-than-normal intervals between drives certainly doesn't help the cause. I guess the big deal to prevent pre-deonation when I got that pulley back in 04 was to also go to a colder plug. I did dyno tune it, and even currently run an wideband A/F guage as well as fuel press. and both are where they need to be (except now that a plug or two has fouled!). I'l go back to the 6 range this weekend and report back...I'll ohm the coil packs as I pull em out as well.

Does anyone know the actual Denso part number right off hand? Any suggestions on a good gap setting? I used to use PSP back in the day, but I know he has moved on....

Thanks again!

 

[Dusten]

Thanks for the replys. It does appear that I am running a number colder than stock, even though they are denso iridium. Fuel stabilizers and a few longer-than-normal intervals between drives certainly doesn't help the cause. I guess the big deal to prevent pre-deonation when I got that pulley back in 04 was to also go to a colder plug. I did dyno tune it, and even currently run an wideband A/F guage as well as fuel press. and both are where they need to be (except now that a plug or two has fouled!). I'l go back to the 6 range this weekend and report back...I'll ohm the coil packs as I pull em out as well.

Does anyone know the actual Denso part number right off hand? Any suggestions on a good gap setting? I used to use PSP back in the day, but I know he has moved on....

Thanks again!

One step colder is acceptable for a 4lb

If you're running the correct plugs then id just blame the lack of drive time

 

[ZEN357]

Have you looked at E3 Diamond Fire Plugs?

 

[QtrFlsh]

I was thinking about staying with stock heat range- and paying attention to AFR and detonation conditions. I have a pretty safe tune and have to controller to change spark timing tables- which I have already had to do when 93 octane disappeared from Oklahoma.

E3 plugs are intriguing- has anyone had any luck with them? Nice to not have to set gaps!!

 

[FireGuy]

The Denso stock heat range is IT 16. I would stick with what most folks have used with success, unless you like changing plugs a lot.

 

[QtrFlsh]

Was also looking at Denso web site and after putting in year/make/model, it’s telling me IT20? I have ngk TR7’s... not sure which way to go regarding Denso...is the IT16 showing up in a cross reference from the motorcraft numbers?

 

[Dusten]

Was also looking at Denso web site and after putting in year/make/model, it’s telling me IT20? I have ngk TR7’s... not sure which way to go regarding Denso...is the IT16 showing up in a cross reference from the motorcraft numbers?

The tr7 is two heat ranges colder than stock. I run the br7ef on my built kb truck.

You should be heat range 6

 

[FireGuy]

You may be correct, my cross reference was done using the stock Motorcraft as the base and it showed the IT16 and the IT20 replaced the stock heat range, the 16 being a bit hotter. You may want a bit hotter plug, regardless of manufacture because of your original stated problem.

 

[QtrFlsh]

Update;
I got the plugs changed out-actually had IT-20’s in it. Went with it16 this time-ohm’d the coil packs and they all tested the same and were good. Truck smoothed out so went and got some fresh fuel in it. Back to her old self again! It does still do this strange ‘gurgle’ sound at idle after it warms up-which is likely magnified through the CAI. But it’s always done that with the 4#lower for some reason. I appreciate all the good input from those who have responded here.

 

[Dusten]

Update;
I got the plugs changed out-actually had IT-20’s in it. Went with it16 this time-ohm’d the coil packs and they all tested the same and were good. Truck smoothed out so went and got some fresh fuel in it. Back to her old self again! It does still do this strange ‘gurgle’ sound at idle after it warms up-which is likely magnified through the CAI. But it’s always done that with the 4#lower for some reason. I appreciate all the good input from those who have responded here.

That's pretty normal. Make sure your boost actuator is opening