Should I change the coils on my RX8??
 

Hi, this is my first post but if anyone is in two minds about whether to change the coils or not I can now say that it is an absolute must! The car has done just over 40,000 miles and I read that the coils can start to fail around this age. I decided to change them as a precaution and the results have been amazing.

My RX8 started everytime before the coil change but it seemed to crank for ages before catching. After the change it starts within a second of turning the key.

This isn't the biggest improvement though... the power delivery (especially in the lower revs) is now much more immediate. The whole car feels much smoother to drive and the power surge at about 6,000 rpm is now really obvious.

I sourced the coils from ebay and had them fitted at my local Mazda garage. The total bill came to £300 but it has been worth every penny. It is like getting a new car again. In summary, if your RX8 is around the 40,000 mile mark I would strongly recommend changing the coils - you will be amazed!

yup, amazing what fresh coils can do for our cars.
The coil replacement is actually VERY easy and we have a step by step guide on this site if next time you want to save yourself a little money.

congrats.

Now get out there and drive that great car. :)

It would be interwesting to test the resistance across the contacts on old stuffed coils vs new ones - may give some insight on what to look for ....

where can i get a good price on coils?:grouphug:

Start by checking with the forum vendors here on the board.

Holler at the BHR guys, they have sweet prices for what they offer. Who knows, with the holidays around the corner maybe they can do a group buy or something.

I just had the same experience, except I have 17k miles. Glad I went to BHR, the oem coils are defective garbage.

I just bought a 2006 RX8 about 4 weeks ago with a little over 51,000 miles on it. I don't know any of the maintenance history on it, other than it had a new battery put in right before I bought it, and I've been thinking about replacing the plugs, coils and wires on it. I was wondering if there is anyway to tell if the coils had been replaced in the past? The car seems to be running fine right now, it starts up quickly and seems to run strong when i get on it, but this is my first 8 and I am still getting familiar with the car and how it runs. I know the ignition system is a weak spot on these cars and I want to make sure that mine is operating at peak performance but I don't want to replace parts if they are still good. Any advice would be greatly appreciated. This board is really outstanding with all the technical knowledge and information on here. I've spent hours reading all sorts of threads and I've already started premixing with Amsoil Saber Pro based on the information i've read here.

Thanks in advance for any advice.

Cheers!

I thought mine were okay, until I replaced them. I don't think there is a way to be certain if yours are going bad, mine started fine and pulled "hard." It also lugged sometimes as high as 3k rpm, and was somewhat easy to stall, however I didn't recognize those issues until they had gone away.

I definitely would. At that mileage i would also clean the MAF sensor, inspect the catalyzer and change the plugs regardless of the coil replacement.
I like the peace of mind that some little extra check-ups give :)

Are the SII coils identical to Series I ??

Grungepup and 9krpmrx8 just got through putting my BHR ignition kit and new fuel pump mod on, and I have data for it.

My 07 6spd auto has 21,600 miles on it, and was running very smooth and quiet, but the fuel pump would quit pumping fuel when cornering hard if it was less than 3/4th's full.

I ran it below 1/2 tank, and the new pump never hesitated or even made any sound.

I have a Scanguage II that read 269 horsepower at full 3rd gear power of about 7krpm (the rev limit for auto) last month. Of course we all know that that HPR is too high, but so is the factory rating of 212 HPR.

So this weekend, after the BHR ign coil install my 8 was reading up to 285 under the same conditions and approximate mild weather and elevation.

If I compare the 269 HPR to the 285HPR it's a 6% increase, so I add add 6% to the decreased HPR of about 200, and I get back up to 212 HPR or a 12 HPR increase from the diminished stock coils.

Also, I didn't install the new plugs I bought so I could do this pretty good test, and my butt dyno said the stock exhaust actually has a rumble now.

Why put any stock coil on, if it immediately starts going downhill.

IMO that BHR has the stuff!

Friend of mine and myself just installed a full MSD ignition system, and yes, the stock stuff smells Ford's style low cost hardware... Can't handle high RPMs, lots of heatness, increasing the famous "lack of power"... That's ridiculous.

My full ignition system wasn't older that 3000 miles, we have a simple way of watching engine's level of performance ( 50-150 km/h ) always on the same road, with that whole new stock ignition system i was performing approximatively 11,5/12 seconds, with the MSD system as only change ( mounted on a new stand, support i mean, with heatness shield ), it gives 10,5/10,7 seconds, the stock ignition is soooooo pathetic on that car, couldn't believe it... :crying:

dealer question..
 

If I take her to the dealer for new coils and plugs, how much should I expect to pay? I'm in Houston Texas if anyone has any local input...

Keep an eye on the MSD ignition. We've already done testing with their LS2 style coils and they didn't last long. A well known local tuner shop here in Phoenix also refuses to dyno any car running those coils as well.

Thanks for the replies and advice. I think I will definitely change the coils. I see on the BHR website that you can also get plugs with the coils. Are those the stock NGK plugs or something else? Are there any other components I should consider changing besides the coils, plugs and wires?

I would love to see a resistance test on a new set, and an old set. Maybe I will donate mine to the cause whenever I decide to replace them, but Im at 65K on my coils and running fine so oh well.

autozone duralast 33each?????

Isn't it better to solve the problem once and for all?
Keep in mind that improperly firing coils reduce the spark plug's life and are a concern because of the extra carbon buildup that a weak spark generates.

Next time attempt replacing them yourself. You will save yourself some cash. Its a really simple diy.

Well...

Ok, if we took those, that's because we know lots of people in Europa ( including most of the heavier greek FI'ed renesis ) using those, for a long long time. Best ignition specs of all existing kits ( even than Okada's ), great reliability for all we know, lower Temps, increased power.... Heavy, fastest, big n' cold, i'll handle the rest, don't worry, it's easy to check 'em, and we got 'em for a good time now, track days and daily red zones, and yeah, you can tell your "well known local tuner shop" they can survive that, even a dyno day, we did it, and nobody died ( wonderfull power curve, we've found back all the missing poneys ) . ;) :rofl:

Sorry, this made me laugh, i'm not sure you were serious though. :p: But yeah, seriously, by the way, the stock system must be changed, i had a coil failure with an all new oem system, that was epic...

bring lots of lubricant and remember to take deep breaths.

I'll start taking bets on how many days until he calls Ray to ask about his coils and how he keeps them from burning up. Ray could post up when he calls you? :yelrotflm