With the mods in my sig, what brand, type, and gap of plugs should I get?

 

I would recommend Denzo Iridiums IK22. If you are using the stock coil pack you can gap them at .032. I have a higher output coil pack so I gap mine at .038. After 20,000 miles they still work great but I will replace them at 27,000 miles.

These plugs have a habit of becoming loose so after a couple of hundred miles re-torque them to 22 ft/lbs.

 

I've heard some issues from ECU tuners with the Denzos. I'm running the NGKs... a bit cheaper and they aren't known for unscrewing themselves (but it's still a good idea to check).

http://www.detroittuned.com/products...20070124153222

 

Sounds good. I've used the Denzo's in the past on other cars, but also the NGK's.

I think you can get the Denzo's at Checker/AutoZone, etc...

 

I prefer the NGK over the Denso. I've had the Densos loosen up on me. Not so with the NGK's.

Lot's of info here:
https://www.northamericanmotoring.co...&highlight=ngk
Jim

 

What are the general thoughts on the Beru Ultra X Plugs

 

I've used and installed all the brands of plugs. But my personal fav. are the NGK's. We've had the best luck with them and lasted the longest.

 

I went with the NGK's, $24 at Napa... Thanks again for all the help!

 

I've had Denso IK 22s for a couple of years/20,000 miles. I've checked them at 10K and checked them today at 20K. At my 10K check there was side electrode wear on all plugs. Today I noticed that there was side electrode wear on #1 and #2 and centre electrode wear on #3 and #4. I gapped them at .035 thou new and have regapped them at .035 both times. I suppose I could try a greater gap. I may try the NGK plugs next.




Jeremy

 

We had another club member blow a Denso out of the hole, stripping the threads as it went. If you have these plugs, be sure to retorque (22 ft-lbs) frequently.

 

NGK Iridium IX

 

The reason for the side wear on 1 and 2 is because these two fire from the side to the center electrode(backwards) the other two fire from the center to the side. This behavior is by design due to the DIS system (one coil fires two companion cylinders at the same time). Be advised that the plugs that fire from the side to center require, about 20% more energy to accomplish this task due to higher resistance when compared to the other two plugs. When viewed on an secondary ignition analysis waveform the cylinder under compression should have a peak firing voltage of 5-7Kv, while the cylinder on the waste spark should have a range of 3-5kv. Without making a comparason between the original spark (which has 4 side electrodes based on the aforementioned concern) and the single side electrode there may be no advantage (maybe even some loss).

 

Has anyone found the BKR7EQUP (JCW) plugs locally, or is online the only source outside of the dealer?

 

Ok thanks for the info frenchie. I've never measured my peak firing voltage before. Moreover, I think it'd be neat to hook up an oscilloscope to see how each plug is operating!

I've never had a problem with Denso's backing off from tourque setting before. I've checked the tourque every few thousand miles and they've all been @ spec. Just remember not to over tourque them as they're going into aluminum!

Jeremy

 

Here ya go:

http://www.ngk.com/results_cross.asp...R7EQUP&x=0&y=0

I have bought these plugs from this site and actually got the correct part. I have an 05 MCS/JCW, and I have changed my plugs myself every 20K miles. From the stealership, these plugs are $35-40 each. That $8.07 is mighty cheap in comparison!

Rawhyde

 

There is a cycle shop in the Dallas area that can get them for us locally, but sparkplug.com carries them for like 8 bucks a pop. Discounted shipping for larger amounts so it's not killer to get 3-4 boxes at a time.

 

Ok what shall I order ladies/gentlemen. NGK BKR7EIX with Pre-set .030 gap or NGK BKR7EIX-11 with pre-set .044 gap or NGK BKR7EQUP with preset 4 pronged/electrode gap? Again I've been running Denso IK-22 with adjusted .035 gaps.

Jeremy

 

[quote=frenchie;2008715]The reason for the side wear on 1 and 2 is because these two fire from the side to the center electrode(backwards) the other two fire from the center to the side. This behavior is by design due to the DIS system (one coil fires two companion cylinders at the same time).quote]

Soooo...why not swap these plugs around so they wear more evenly, say at 10k miles?

 

[quote=ridingfar;2010348]Super idea Ridingfar!

Jeremy

 

Excellent idea….consider this though, worn electrodes equates to a wider gap beyond specification. Wider gap requires more energy from the coil, which the coil can handle up to a point…..I would be more concerned about the pressure in the combustion chamber extinguishing the spark prematurely resulting in self induced misfire, resulting in high oxygen readings at the O2 sensor (false lean)….The ECU responds by commanding more fuel….resulting in non homogenous mixture which will poison the catalytic converter. In the end there is no such thing as a free lunch.

 

Good info, and that's why I thought more uniform wear resulting form swaping them at 10k would be better than continued electrode wear on just the two plugs from 10k to 20k (assuming a 20k change interval).

Or are you indicating you believe a 10k change interval should be adopted?

 

Appears to have happened to me as well last night. I just started another thread on this. What are the chances the threads aren't stripped ???

 

I would go with a set of NGK's. I've used the NGK Iridiums in all my cars and haven't had a single problem yet.

 

just be sure to torque correctly and check every so often
(I check mine every 5000 miles at my oil change.)
and use a small dab of anti seeze.

I have run the NGK and the denso ... maybe just because of the way the planets are lined up ... but I can tell the difference ... and the denso plugs make the car (OK ...MY car) idle more smoothly and never a miss.

 

It may seem like common sense, but just to add to COR BLMY's list, be sure to torque down the plugs when the engine is cold.