RX7 plugs in RX8??

[Herblenny]

Can someone post some information about this??

[Herblenny]

OK.. I guess NO ONE.. LOL!
I'll post some comparison pics this weekend!

[Herblenny]

after a bit of research, only the RX7 plugs for the trailing will affect the housing.

I'm curious since leading is the main fire, Can I use the leading from RX7 and trailing from OE RX8 plug?? Lets have a short debate

[Herblenny]

From the other forum

Originally Posted by MazdaManiac

If you are talking about RX-7 plugs (BUR9EQP [NGK-5255], IRE01-31 [NGK-5720]), DO NOT run those in your trailing position. They will bottom out and distort your housings.
If you are talking about OEM RX-8 plugs (RE7CL, RE9BT), do not run trailing plugs in your leading position. They are too short and the electrode design will induce shrapnel.

Either run correct OEM plugs in their proper positions or run RX-7 trailing plugs (BUR9EQP [NGK-5255])in the leading position for turbo applications if so desired.

The trailing plug on the FD is 21mm. The trailing on the RX-8 is 19.
When you tighten an FD trailing plug into the Renesis trailing plug hole, it bottoms out before the gasket hits the mating surface.
This means the base of the electrode is pushing against the housing.
I've seen the damage. Don't do it.

[Phoenix7]

I heard you CAN use 8 plugs on the 7 but they must be gapped properly, don't know much other than that though.

[WE3RX7]

I dont mess w/ the plugs on the 8 unless serious boost is introduced. I ran the last 8 on 8.5 psi on stock plugs all day with no issues... OE should be fine for most if not all NA applications on a renesis...

[Herblenny]

I put some new FD leading plugs (7s) on the 8. Measurements are the same and after installation, car started right up! It actually idled perfect. But didn't have a chance to drive it around. But I think its ok? I guess I'll find out tomorrow....

[Herblenny]

Plugs..

Comparison between FD plug vs. Renesis..

As you could see, trailing plugs have different thread length..



But the leading length is VERY similar..






And here is the reason why I wanted to use FD plugs... because I have like 70-80 new plugs

[Herblenny]

My impression on the FD leading plugs....

When first cranked, it started it right up and felt smooth.

I was on the interstate and engine felt really smooth... but lacked slight pull that I had previous. After about 120 miles today, I noticed it really lacked power. I also noticed that when rev'd up, it had slight break up.

I just put my old plugs (less than 5k miles) back in after removing some carb build up. Immediately I noticed noticeable power and when rev'd up, no hesitation or break up.

Thats my impression with FD plugs.

[Nexcis]

I know this is in the wrong forum but... it's relaited to the conversation...

Okay, given your recent findings Phil, what is your impression on using the 8 plugs on the 7?

[Herblenny]

Well, I know a lot of FD owners running 300+ HP prefers to use all 9s instead of 9s and 7s.

That being said, Trailing 9s from 8 will not work on FDs. So, that only leaves with 7s for the leading.

Now I think its not much to do with FD 7s but could be something majorly wrong with my 8. Last night, I did all the resets and crank the car up and let it idle for 10 mins. This morning, I got it started and the car idled quite badly. RPM will hike up to 2k and then drop backed to 750 and idled like ass. I'm going to swap both leading and trailing with my older plugs this afternoon and see if its any better... I8U stated that it could be the PCM... I'm taking the car into the dealership in the morning and see what they could tell me.. I'm quite fed up the the 8!!! I know a lot of you think its a great car, but I'm starting to think differ.. I've literally tried everything I could do but now I'm hitting the wall on this damn car!! And its worth less than my FD The headache isn't worth it!! We'll see what the dealership says... If its going to cost me more than a grand, I'm NEVER buying another fucking Mazda Rotary for daily!

[Nexcis]

You know how some FDs were / are cursed? I think you got one of those 8s that are. I've yet to have any problems with my 8.

[Herblenny]

Maybe so... I'm taking the car into the dealership tomorrow at 9. I've been collecting ton of extra parts just in case they tell me its the PCM, Engine, TB, coils, sparks, wires, wiring harness, UIM, LIM, injectors, etc... Only think I haven't bought is the fuel pump

[rx8man]

My rx8 had, RE6C plugs in it, which no company where I live can find anyhing on these plugs, but I did get giving on the RE8CL plugs--$85 EACH.
I'm running BUR7EQ's (costs $14) in the leading at the moment, could be a little down in power? No problems yet-- but these haven't been in there very long.

[rx8man]

Originally Posted by RotaryResurrection

btw, the re6 plugs are the early plugs that came stock in the cars, and the re7 plugs are the updated versions, supposedly to combat flooding. You can get the re7 and 9 plugs on sparkplugs.com.

Cheers, No one here knew what I was talking about, when I rang around for Re6 plugs.

One Qustion, that someone may be able to help with?? Coils, when I did the 20b transplant, I used Bosch Coils with the LTX (mircotech) -- has bosch done a set for the rx8 -- yet??? Coz the Mazda Dealer here want $115 plus tax per coil.