I just buy an rx8 2005 90000km what s the best oïl mineral or synthetic.what s about iridium spark plug ngk are they good or not.thanks

Welcome. Bienvenue:)
This is a thread for making modifications to an 8 btw.
Oil type is a controversial subject. I use Mobil1 0w40 synthetic.
The NGK laser iridium plugs are recommended OEM and should be used for replacement, although some here use the Denso plugs.

love the write up. used to drift 240sx but always loved mazdas more. just got and rx8 so will definitly be refferring to this page alot for when i do my mods. not reall gonna worry about engine mods though. seems too complcated for someone like me whos new to the game. later when i have done way more research for sure though.

So much to read here... But I pretty much am seeing this

very very slight increase from stock while paying a lot of money. This shortens the lifespan of your vehicle.

Is that the gist of the power modifications section? That's what I understood.

N/A power mods won't really have any impact on the lifespan of the engine (because they don't really have an impact on how much power you are pushing). If you go for forced induction, yes, the lifespan is reduced accordingly.

I have seen instances in which NA mods will throw out the tune to such a degree that lifespan will be reduced significantly .
Particularly with intakes but also when the engine makes more power than stock .... it makes the ecu hit 'max. calc. load' and causes the afrs to go uncontrollably lean.

Any engine with modifications which actually increase power output should also be tuned to correct these anomalies .

All true. An untuned engine is never recommended. :)

https://www.rx8club.com/series-ii-en...8/#post4584371

Check out the grey line on this log ...................

Very useful.

those make sense. My brother has a turbocharged, unfortunately automatic, Toyota Matrix XRS and he has to watch his fuel ratio. Sometimes it gets real moody and gets to lean.

I think I'm gonna plan on just air intake and exhaust kit. Probably switch out my wheels (2 are slightly bent from previous owner)

I don't know that I'll ever do a forced induction mod. Seems like too much work and time I don't have

Thanks for all your work gathering this valuable info. Learned quite a bit today.

Hey all. I've had my 8 for a year now, so I'm getting more comfortable (or more antsy) about doing a few small things for upgrades. First and foremost, I want to swap the cat-back exhaust system for something completely custom. Long story short, it's basically going to be straight piped from the cat to the end. I was wondering what kind of problems arose when ppl did that sort of thing. I have to keep my cat due to SCCA class regs, but just don't like the sound (or lack there of) of my car or any other aftermarket exhaust kit. Could someone be so kind as to either direct me to a thread that deals with such issues (I've spent hours searching and reading already), or tell me what happens to the engine when the giant muffler isn't there to provide sufficient backpressure?

Backpressure = bullshit.
It's all about speed, and resonances at times.

"Backpressure" is often used to describe the resonance needed in piston engines where exhaust scavenging is needed to assist with pulling exhaust from the cylinder, which in turn helps power and torque.

A rotary doesn't need, or use, any scavenging effect, so "backpressure" is not something to be concerned about. There is still resonance, but only from merging the pulses as smoothly as possible, regardless of what pressure the merge is done at. So no, there is no problem with the engine if you were to put in straight pipes. There won't be any power gain though, because you are retaining the highest restriction point in the system, the cat.

Keep in mind that if you were to ever blow out the cat, gut it, or put in a catless midpipe, you would have an exhaust that couldn't possible pass SCCA regs. In fact it will be physically painful to drive from the volume, tone, rasp, etc... You will get people pissed off all the time, including people that you would probably prefer didn't, like friends, family, neighbors, cops, etc...

what you wrote only applies to the renesis. Scavenging may be useful once you introduce overlap.

Yes, I should make an exception for all the other engines that newbies have swapped into their RX-8s.

Simply stating what only applies to the renesis and what does not would be enough!

By the definition of the thread, I did. :)

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I'm only posting this here because I'm not sure where I should post this... or if i should make a new thread somewhere.

my clutch knob is scratched out the wazoo by the previous owner (like a ring or something probably) and I'm trying to find a cool shift knob that isn't entirely metal so it doesn't burn my hands off. This is the coolest one I've found so far

http://ts2.mm.bing.net/th?&id=HN.608...d=1.9&rs=0&p=0

Just stumbled on this thread. Thank you Godfather for taking the time to help everyone out. A must read for all owners.
http://i1059.photobucket.com/albums/...WellesClap.gif

Just an update to the thread which can be added if desired, the Racing Beat dual resonated uses stainless steel wool for packaging per their website.

Added.

I really need to overhaul the whole first page, some of the information there has become obsolete. I need time and energy for that though.

much appreciated, great resource of knowledge for all RX8 fans.

great stuff!!

One of the better threads I have been reading. Really in depth and very informative.