TL;DR - pics below of plugs and coils from a normally (no problems) running 2006 MT GT after 42k miles.
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Today I replaced the coils, spark plugs, and wires in my car. I have not been having any issues; just felt it time to do some maintenance. I felt like posting a new thread with pics of the plugs and coils for reference at this mileage in a 2006 car. As far as I can tell, there is nothing out of the ordinary with the wear on everything here. Let me know what you think if I might be mistaken!

The car is a Feb. 2006 build, I believe. I was surprised that I had the original revision coils in the car as opposed to the 2nd revision (N3H1 18 100 vs. 100A... no idea when the 100A came out). Regardless, the old coils appear to be fine. (~1500 ohms A->B, ~8-9M ohms B->C, and open circuit C->A)

This was my first time doing this much work in the engine bay of the car, and I must say; that intake is a PITA! The wire in front of the coil bolts was frustrating as well; I thought I had to remove the fastener entirely at first before just shoving it aside. Overall, this took me just over two hours to get done, having been a slow start at taking things apart.

Replacement coils and plugs are stock, and the new wires are the Moroso wires that Fluid Motorsports has a special on. After wrapping everything up and starting the car, a couple minutes later the idle seemed to settle down quite nicely (even better than before, maybe). Speeding off to work, it seems like the car is mildly more responsive if anything; other than that no real change or improvements were observed (new stuff could be a placebo effect after all, anyway).

 

Underside of the old coils:


All four spark plugs:


Corrosion on the front leading plug! :


Leading and trailing plugs, then over exposed to show the cores:

 

Dam! and I thought mine where bad wowza lol
See now you can save your self a buch of money by not going to the stealer ship lol

 

WOW..what's with where you live? Hellish corrosion on the outside of the plugs

 

Indeed, less than $300 total for parts, whereas I hear stealerships charge upwards around $700+ parts and labor!


I am under the impression that the brown stuff is normal, granted there is quite a bit of it on there.

The corrosion fortunately was only on the front leading plug. All the connections looked solid before I started pulling everything off, so I have no idea about that. In Missouri, we get the whole range of weather; 100+ in the summer at times, and plenty of snow during the winter at times. I say "at times" twice over because the weather is also extremely unpredictable.

 

Put some dialectric grease on the boots...will stop a lot of that...or get some silicone boots that seal better..or both

 

+1 0n the dialectric grease on the boots. You must be enjoying a quicker response. What is your history, gas do you use, what type of driving, do you pre-mix, ever flooded, ever run any cleaners?

 

I'll pick up some dielectric grease as soon as I can; thanks!

History:
I got the car brand new early November 2006 with about 100 miles on the odometer.

Driving habits:
I have been running autocross for the past two seasons so far, and did one PDX event last October. I typically redline at least once a day, and like to do a fair bit of spirited driving.

Gas used:
I always use Shell V-Power (93 octane), and rarely let the gas level go far beyond the low level light before filling back up.

I do not pre-mix.

The car has never been flooded under my watch (who knows how badly the dealership might treat it! ).

Cleaners:
In the first year I had the car I used fuel injector cleaner additives twice about 6 months apart. Another year or so later I learned about Seafoam and used it twice thus far; both times only putting half in the gas tank, other half in the oil. I didn't want to bother at the time with doing a proper engine cleaning by direct injection.

Oh, and to pre-emptively answer a likely question: I have been using 5w20 Valvoline conventional up until my last three or so oil changes (every 3k miles) after which I changed to 5w30. My last oil change, they put 5w20 back in for some stupid reason. I should have said something about it at the time; oh well. More of a reason to just do it myself, I guess.

 

wow, that corrosion on the ouside sucks but the plugs don't look all THAT bad considering they were in there for 42k. Brown is okay, black is bad.

how's the car runnin' now?

 

any improvement you feel is from the plugs.. 42k is way to far to go without cleaning.. i think at 20k they are doneish..

my stock coils made it to 72k miles before i replaced them.. think they were fine.

the green on the top of the one plug is the front lower one. it happens. you likely had a loose plug wire for a while.

bet you mpg goes up!!

beers

 

Swoope: I sure hope so! Originally, I was happy at 18-19mpg all around. Loosely keeping track of my mpg, I noticed it go down to 16 when I made the switch to 5w30, but on this bit of 5w20 again, it went down as low as about 15.

Jedi: I'll post again in the next day or two about driving impressions because really, I only had the one drive to work (where I currently am) on the new stuffs so far.

 

next fill up pull your room fuse to reset the fuel trims.. makes the process faster. and you might think about some b and g 44k.

beers

beers

 

Hrm, room fuse, eh? I guess I'll go digging for that. One of these days I'm going to do a proper engine cleaning; whether it be BG44K or Seafoam... I'm gonna **** off some neighbors with some smoke!

As far as driving impressions now, I'd say pretty much the same; maybe the slightest hint of more immediate response when I stab the accelerator is all. Other than that; all is pretty much the same!

 

pull the room fuse.. you will be shocked..

btw, seafoam is really great stuff. that is the shock treatment.

44k is the kinder gentler cleaner.. aimed at different targets..

at 42k i doubt you need the seafoam. as your stuff seems to be doing very well.

beers

 

I am planning on doing this as well. Do you mind sharing where you got your parts? Already got my plugs, looking for wires and coils. Thanks!

 

Plugs and wires from www.fluidmotorsports.com :

referenced from thread:
https://www.rx8club.com/showthread.php?t=164611

direct link to product:
http://www.fluidmotorsports.com/p-95...ccesories.aspx


Coils from Rosenthal Mazda @ www.finishlineperformance.com :

direct link to product:
http://www.finishlineperformance.com...cat=273&page=1

 

This may be a silly question, but does disconnecting the negative terminal essentially have the same effect?

 

yep,

as long as you step on the brake a discharge everything..

beers

 

I just recently had a dyno run on the car after about 4k miles on the new plugs and coils. Unfortunately, this was a different dyno from a prior run right before the plug/coil swap. The people that run this dyno claim their numbers are typically lower than a dynojet (Dynocom DC1800x) which is what I ran on before @ ~172hp/125tq. The new numbers are 182hp / 135tq. Assuming what they say is true, I would estimate the new coils and wires are giving me a difference in power of close to 15hp. I will take the plugs out in a week or so and post pics of what they look like after 5k miles.

 

It would be wise to perform a compression test so that you can have an idea of the engine condition.

 

If he is running spot on 182hp, shouldn't be necessary.

 

Yea; I am satisfied with these numbers. Out of pure curiosity I *would* like a compression test done, but in this situation I am not willing to shell out that kind of money.