looks like the only change is the bottom how its recessed

 

is that not how the B revs were? It has been a while since I looked at one but I thought that the B rev was similar.

 

We have these in stock by the way. 2 sets now but I'm bringing more .

MAZMART - Serving The Mazda Community Since 1980. RX8 Ignition

Paul.

 

Damn, my coils (ordered elsewhere) arrived yesterday and they are the B version.

 

So when I opened the box I found that the coils inside has the 'C' part number stamped onto them, while the box was labelled 'B'. I guess I lucked out. Aside from that, the coils looked physically identical to the 'B' coils I removed from the car.

 

Here you go, Version 'C' (N3H1-18-100C available at Mazmart):

MAZMART - Serving The Mazda Community Since 1980. RX8 Ignition

Paul.

 

Does anyone know the order these coils go? My mechanic tells me ignition coil A is causing engine light to come on. Is this the one nearest the front of the car or the bulkhead?
Driving a 2003 RX8 imported from Japan.
Appreciate any help/guidance out there
Tom

 

Your mechanic should be able to show you which one he's talking about, if he knows what he's talking about. Generally, it's wise to replace all 4 if one is found to be faulty anyhow.

Paul.

 

As always sound advice from Paul @ Mazmart....

Tom, I would be buying all 4 new OEM 'C' iteration Coils from Paul..

 

Thanks lads.
I bought a set of coils (100C), leads and plugs (NGK) online recently and my mechanic fitted them but engine light remained on and diagnostic said fault with all four ignition coils! They came in Mazda original parts boxes and supplied by UK dealer on eBay...

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=251258753335
Re-fitted old ones and issue reverted to one faulty coil...this time coil A (prev ign coil B - unlikely to have replaced coils exactly suggesting just one acting up)
Appreciate it is worth replacing all four which is what I have intended to do. Also wondered if system recognises new C coils?
Will revert to seller.
Thanks again for help.

 

I just had the dealer install 4 new coils w/ wires so I wonder what they were after my BHR kit seemily failed. Guess i'll pull one off this weekend and see.

 

if u got it from one of the US dealers, it's B revision for sure. Since Mazda NA still have thousands of B left.

 

Just wanna update this to whoever search and came into this thread

MNAO will NOT change the part number, I think they are just being lazy, now most if not all of the so called 100B-9U coils u get from MNAO are C inside the box, they actually just label the C over with their own 100B-9U label.

I installed at least 30 sets of C coils into people's car, so far so good, some got over 20K out of it already with no signs of failure, well of course even B doesn't fail that fast. but it does seem that it will last longer than B.

 

Great information on this site. Any idea whether the coils purchased from Advanced Auto Parts are the Cs? I just purchased an '04 RX-8 with around 30,000 miles. The car runs great, but it's probably time to replace the coils. The price with discount at AAP is only around $90.

 

I wouldn't worry about it, the updated coils die just as fast as the older ones. And the store bought brands won't be copies of the updated coils.

 

Thanks. I ordered the AAP coils and will just be prepared to change them out every 30,000 miles or so.

 

One of my OEM coils failed at less than 20K miles, so you might want to be prepared to watch them as they approach that interval.

 

I must be one of the lucky ones. My 2009 has almost 50,000 miles on it, and the coils are still fine. I should probably replace them preemptively soon.

 

Can you define what "fine" means to you?

https://www.rx8club.com/series-i-tro...-plugs-234383/

 

Me too, I just did my S2 on it's original B Coils today (first time) at same mileage and although they were fine, I did them as a 'safety' measure too, renewed my Denso racing plugs (had done about 28K) and a little dark but looked good, better than my original install NGK's (for me, the Denso's had none of that milk chocolate caked on crud)...I will keep used ones, just wanted to have a look and I thought new Coils, new Plugs I had in my new parts stocks.

Leads/Wires looked fine (almost brand new externally) and I know that is not the proper way to judge/test them...IMO Leads get changed too often.

Did a full service and a recondition charge of my original almost 7 year old Panasonic Battery as my RX-8 was off the road for almost a year while using my NC.

Anyway she fired up for the first time like it was new, actually faster than my NC.

The 4 old Coils, not a mark on them (not that this is an indicator).

As for owners having one faulty OEM Coil early on in cars life, well I have not heard of very often, in fact I think this is the first time I have and I guess like anything can fail.

All good...now to enjoy my 8 during winter here in OZ.

 

I did not feel or notice anything wrong with my original s2 "B" coils at 30k and a little over 3yrs, but after changing them my dyno plot looked much better. This was not a back to back test, so it could have been something else, but coils were the only thing that physically changed on the car.

The replacements were "c" even though they had "b" on the box. After almost 2yrs and 20k I did not notice anything wrong with them (including in my butt dyno and straight line speed on track). I was planning to dyno them in the next couple of months to see how they had held up, however, now that my engine is out I am replacing them. The replacements that came though a US dealer are "c" coils again even though "c" is not on the box. I'm slso doing plugs and leads at the same time (I did not do leads last time, so they were still original).

One thing I noticed - one of my plugs has a corroded top. There was also one with a corroded top the 1st time I changed them. Seems a little odd to me so hopefully new leads helps. The plugs overall look like I left them a bit long as well (~22k and 2yrs).

After all this, I'm thinking that 1yr/10k on plugs, 2yrs/20k on "C" coils and 3yrs/30k on leads is a pretty safe maintenance schedule.

I've also ordered coils for our Civic Si - it is on the original ones after 7yrs and 94k, but it seems to be knocking more than I remember now so hoping this helps.

 

The one that failed on me was the trailing on the rear rotor. I noticed a slight change in performance, pulled the plugs, and found a wet one. I tested that coil by swapping it to the other rotor. The problem followed the coil, which ruled out the plug and lead. Rather than play Russian Roulette with replacement coils, I just opted for a BHR setup. No problems with that so far.

 

The improving/internal updates of OE Coils from S1 have seen a better life.
There have been 4 iterations from 2004MY.

 

Understood. My car is a 2011 that came with Rev B coils.

 

I have been noticing that my RX-8 doesn't seem quite as fast as it should. Usually that goes away with new plugs (which were done right before garaging it last fall), but this spring it's still feeling slower than it used to. I guess I'll be looking at replacing the coils soon. I also need new tires, and will almost certainly have to replace my brake pads after my first track day this Saturday. Ouch.