Is it ok to mix and match ignition coils?
 

I pulled my ignition coils because I plan to swap the front and rear ones to troubleshoot a misfire. When I pulled them out, I tested their resistance, as shown in the Whitney Automotive video on YouTube. All 4 of my coils show a higher resistance than in the video. But it seems like testing for resistance wouldn't be the most accurate way to see if they're bad, unless you're getting practically no resistance when you should be getting some, or vice versa.

Anyway, the resistance on one of my rear coils is quite a bit lower than the other three. So I went to look at the receipts for the coils, because the previous owner said he had put in new coils and that they had a lifetime warranty. Now that I'm looking at the receipts more closely, I see that one coil was bought from one store, and it's a $60 coil. 2 were bought from another store, and they're both $30 coils. And one there's no receipt for a 4th coil, so I have to assume it's old.

With coils being sourced from potentially 3 different places, could that cause me any problems? I think I'm going to just replace all 4 to be safe. Just curious if having different resistance on the different coils (or other subtle differences) because they're from separate manufacturers would cause any problems.

In theory it's fine, but if they're all different ages, better wipe the slate by changing all 4.

It's good that you're replacing all 4.

I'd imagine that having 4 different manufacturers coils would each have a slightly different firing response, so there might be some unnoticed regarded/advanced ignition in one combustion chamber or the other, which might put a tiny bit more stress on the eccentric shaft. I highly doubt that that would hurt anything though.

The difference in health and performance of the coils could indeed cause engine and/or cat problems in the long run. Best to replace all four with new coils of the same manufacture.

You have a number of options for coils:
- The Cheapest option: BWD/Intermotor coils from auto parts stores like Advance Auto. 4 coils, 4 plugs, and 4 wires can be had for around $190-220 total based on whatever promotion is running at the time, shipped to your door for free. They are considered to be the first coil revision and you should expect to need to replace them around 20,000 miles, 30,000 miles max. They often come with a "lifetime warranty" by the auto parts store, which could potentially be leveraged for perpetually new coils.

- The Best Upgrade: The BHR ignition coil upgrade can be had for around $500, which eliminates the need to continue replacing coils periodically, as well as deliverying a significantly stronger spark for minor mileage and power gains. It is a proven kit with top notch customer service supporting it. It includes the wires, you still need to add plugs ($80)

- The For-Sure OEM: Mazmart sells all 4 coils of the latest OEM coil revision (C) for around $250, (just the coils, you still need to add plugs and wires) Supported by top notch customer service. They will likely last longer than 30,000 miles, but we don't have much solid data on how long the latest coil revision will last.

- The Most Expensive option: Buying from a dealer will run you around $300+ for the coils, $500+ for coils, wires and plugs, and if you have them do the install, expect to get a bill for anywhere from $700 to $1,800. You may not get the latest coil revision. Yes, you are getting shafted if you take this option, so bring lube.

- The Highest Risk option: Ebay coils continue to pop up as counterfeit, mislabeled, dead on arrival, and have zero post-purchase support largely. They are the "cheapest" listed price, but when you add that $92 or whatever to the price of anything in the list above from having to do it over again, you can see that they are no longer the cheapest option. Do it right the first time. "Motor King" coils are popping up at an attractive price on Ebay, but are being proven as ineffective, to the point of being unable to get the engine fired. "Mazda" branded coils on ebay are almost always counterfeit. Check the seller's name though, since some of our vendors sell legitimate coils there. The price will be $200+ though. Anything sold as "Mazda OEM" under ~$26 per coil should really be considered as suspect and probably counterfeit.

Be wary of "LSx D585 coil upgrades", as not all D585 coils are created the same, and the standard generic D585 coil is not properly designed internally for the RX-8's ignition needs. They generally "work", but there are anomalies and performance issues that have to be solved, if they can be solved. Definitely NOT a plug and play option, even if it is advertised as "plug and play"

GB: SakeBomb Garage IGN-1A Ignition Coil Kit
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Thanks to all 3 of you!

Thanks again for all the great info. Just an update on this... I think my problem may extend beyond coils to a coolant seal :-/
https://www.rx8club.com/series-i-tro...-photo-263739/

So anyone see different coils than any of the models or part numbers? The coils I got on my Rx8 are slightly different, but they look close to the stock coils. The only numbers/markings are P51. I included a picture if anyone has seen these type of coils?
https://cimg5.ibsrv.net/gimg/www.rx8...801d69eb88.jpg

Its not OEM. It might work for a while but at what cost?
It could kill your cat then engine. Not really worth using IMHO.
I posted a pic ages ago of a badly melted and cracked coil that was identical to look at as a Mazda coil, but just a nasty knockoff.
This was just an experiment on my very old an tired original engine. The coil lasted only 200km before it failed.
As it had a 2 year warranty I knew i could cash out, although of course they were not keen to refund the cash. Sent me a new set I that I never used. I now have 7 spares if you want them. BTW I also got a full refund. Just dont do it. Its your $$ though.
The BHR new style of coils are simple swaps with OEM wires and are fantastic. Highly reccomend them. The latest C type coils from Mazda are supposed to be great but I have not used them. In AUS it works out to be the same cost for BHR as Mazda. Cheers.

FYI Advanced Auto has lifetime warranty coils.
Been a while, but I think about $35@.
If you save your receipt you'll never have to buy another coil.

Just get the BHR ones and forget it, they work the best and last the longest. NEVER, EVER mix coils, a sure way to help kill your engine.

Once you go ign1a you never look back.

Yeah got these really strange ends only even questioned it because I got new wires and they don't match :) anyone seen ends like these before on RX8? The part number on the wire doesn't search accept the ZE81, which is the stack RX8 NGK part number.
https://cimg8.ibsrv.net/gimg/www.rx8...ce09895f46.jpg

I've owned my Brilliant Black 04 since 2015 and it had the BHR coil set on the car when I bought it. The receipt shows it was purchased in 2013. I have never had an issue with the coils in that car!

I have had BHR coils in my 2008 40th Anniversary Edition RX8 since 2009 and they have been flawless. I upgraded to the updated BHR version in 2018 just because I could, and again they have been flawless and stellar in performance.
In fact the BHR coils are the most widely purchased aftermarket product bought by RX8Club members, by far.
Cheers