Some of you may not know that Mazda modified the Ignition Coil BASE PLATE by incorporating a hollowed out ridge down the middle (approx) of the 4 ignition coils.
Previously this was a flat area on S1's.

The concaved groove sits under the location where we have seen a Burning or arcing of the Ignition Coils in Series I RX-8's...white marks on back of Coils.

The Ignition Coils used are the same as late S1..

4 x N3H1-18-100B (-9U)

The S2 Base Plate # N3R1-18-105 cost of about $28.

Has or will this solve the "early retirement" of the ignition coils seen in S1's??.., well I am looking on the positive side, why would Mazda do the base plate mod if it was not the answer?..I guess time will tell.

Will the S2 base plate fit the S1??

While there are slight changes to the fixing locations, until someone actually gives it a try on a Series I RX-8..I can't be 100% positive, at the moment I am thinking 95%..
The Ignition COILS will definitely Fit onto the S2 Base Plate, it is the fixing lugs to the engine area that "could" be an issue.









Below is a side image of an S1 Base Plate (poor pic)

 

Why Mazda made the recess is a mystery to me. I wonder if the area will allow more cooling to the coil. And not cause premature failure. ?
So far the coil mounting is the same as the S1 version. As in our kit mounts on the S2 the same as the S1.
But I might run down an order one tomorrow and check out the "to the engine mounting" points.

 

Flat metal components like the S1 plate in the picture are weak and prone to bending/warping. My bet is that the change is for added rigidity, nothing more.

 

I don't think rigidity was an issue. It also looks like the material is a bit thicker than it used to be.

 

Certainly Not for rigidity, the metal is very strong...I cant even bend the extending metal add ons and mounting brackets..

The purpose of this groove is obvious, it prevents 100% contact with the base of the coils where arcing has been an issue and will allow some air movement....

Check out this pic of a member who wanted firing order info....ignore his Red markings, see the white arcing/heat marks on the FLAT S1 Base Plate, right where the new groove is on the S2 plate.

Mazda modify parts for a reason, usually to rectify "In the Field" or Warranty issues, like Coil Failures, I have never heard of the S1 coil plate being weak or prone to bending or warping, IMO your 'bet' is wrong.

You also notice there are two separation pins for two of the coils, where the S1 has 4 cut slots, this new bracket has two and the two un-threaded pins.

Remember that these plates get VERY Hot from engine which dissipates into the Coils themselves, now with an air space or gap under the coil where the arc normally occurs must help.

 

To me it looks like the TOP fixing part of the bracket (Coil Plate) is a little different, it has two holes, one round and the other square, the square one is for an electrical fixing point (from what I can see in my car).

The OCV is around this area, very hard to see without pulling apart...

 

Wow this is really good info.... As always you rock Ash.

 

Sounds like I lost my bet. I was just guessing and knew someone would correct me. It is true. I am really a motorcycle guy and used to very lightweight aluminum components that are often stamped to increased strength. To be honest, I have never had my hands (yet) on a coil mount plate. I have a strong feeling that there is a BHR coil assembly in my future, though. But right now I'm waiting for a Cobb S2 AccessPort and maps, which I'm told is in the works.

 

I have my S1 plate out and will snap up some better pictures for your comparison. I will try to duplicate your shots tonight.

 

Thanks mate..

 

Do the coils really get that hot, or is the heat coming from the engine? If they heat up that much, maybe a standoff would be good for airflow and to keep them out of direct contact with the mount plate? It would only have to be a couple of mm thick.

 

My camera gave up it's ghost, so here are cell phone pics instead

 

Nice find Ash. You are relentless at getting the info for the people . We appreciate it mate.

Paul.

 

It will be interesting to see if the S2 will fit an S1, there are many changed to the mounting brackets....it will more than likely fit, may need to re-drill or mod part of those brackets..

BTW: MANY, Particularly Pettit modders have cut Holes in their plates "thinking" they are cooling their Coils, when all they are doing is exposing them to more Rising Engine HEAT...don't do it.

Pettit even recommend 4 Hole Cutting!

 

Yeah well as I have said before, I was a parts guy that actually LOOKED/Opened the 'millions' of Mazda parts I have sold to people, observing, asking questions.

So I could give my customers answers and service, not just a Blonk behind a counter with no interest in what he does.

Time for another RE-medy maybe..Paul

 

whats the bracket part number? I snapped two of the bolts and I dont know if there is enough threading for a good connection.

 

N3R1-18-105 Series 2
N3H1-18-105 Series 1

 

has it been answered if the series 2 baseplate can replace the series 1 baseplate in a series 1 rx-8?

 

Yes, but it's not needed.

 

well im gonna need a new one soon, so ill probably end up getting the series 2. plus the bhr ignition coils. last time i changed the coils one of the bolts on the base plate snapped, so i have it tied down with a wire tie-down. it seems to do an ok job, but would like to not keep it there for a while

 

I'm not sure how much they cost new but I'm sure if you start a WTB or check out the part out threads, someone will have one.

 

Interestingly Mazda are saying (from Warranty Claim Returns) that old Ignition Coils were 'working properly'.. see TSB.

https://www.rx8club.com/showpost.php...8&postcount=18

 

Looks like the proper way to test the oem coil is the one I have been advocating. With a timing light.

 

If the broken bolt was one of the ones for a coil, it shouldn't matter. The BHR coil kit comes with a new base plate that mounts onto the original base plate. Three bolts holding it on is good enough. Many people have dropped one of the nuts and are running around with one missing.

 

Do the coils need to be mounted to the base plate prior to testing the engine? I left off position 3 (R/L) and 4 (R/T) 10 mm bolts to ensure my swap works? I know the coil has a ground (pin A or rightmost pin with the coil pointing up and the pins facing you).