This thread contains all of the discussion posts from my https://www.rx8club.com/rx-8-discuss...t-here-202454/ thread. The primary thread is now closed to keep it concise and not daunting to any new owners that are reading it. Well, not more daunting than the content already may seem. They no longer will have a mistaken impression that they need to read the entire thread.




Questions can be asked here safely, without fear of reprisal or flaming. Another viable thread, if you think the question deserves it, is here: https://www.rx8club.com/rx-8-discuss...llowed-208221/ . Between these two threads, you should be able to get the answers to your questions without getting harassed.




But PLEASE PLEASE PLEASE, do not ask your question until you read the https://www.rx8club.com/rx-8-discuss...t-here-202454/ We will indeed just point you over to that one first if you are asking a question that is answered there.

 

So I have a concern regarding fuel economy. Everyone says that intakes, exhausts, pulleys and whatnot, hardly do anything for horsepower, but every parts supplier claims improved efficiency for all of these mods. Does that mean any of them will provide noticeable fuel economy gains?

Traditional piston engines benefit from cold air intakes, colder plugs and other such shenanigans, but from what I read, rotary engines do not.

My other question is in regards to the slush box's paddle shift times. Is there really nothing out there to help it? I had a friend with a 2000 Audi S4, and it had the torque converter based tiptronic tranny. It sucked until he ordered this tuner from AWE that drastically cut the time down by flashing something into the car's computer. I guess the real question lies in whether the delay in the RX8 is mechanical or computer.

 

Efficiency:
The only MPG improvements that I have seen people get from mods is with forced induction with a gearing change (Series 2 transmission with a Series 1 rear gear). Basically the torque improvements make the load% needed to move the car low enough that when coupled with a gearing change to longer gears, the mileage improves. The only other mod that could be said to make a difference is the BHR ignition upgrade, but that doesn't really add to your mileage, just fixes any mileage drop you might have from a weak spark, and keeps it from degrading like OEM does.

A/T shift speed:
Honestly have no idea about this. I would suspect that the ECU is the primary driver of the shift speed, but it's just a guess.

There are only a few people that have seen deep enough into the ECU to even have a chance at seeing this somewhere in there. I don't want to just toss out names though, since one probably won't tell you, and I know of at least 3 others that hacked the ECU on their own, but don't really care to have it known because they don't like the drama that results when they discuss it.

 

I Hope your calculating from the automatic's specs because i know for sure my 6spd gets atleast 200+whp with no mods, i bought my 05 used in 07 and its paid off in dec 2010, i plan on replacing most of the common parts you listed here with upgraded ones, (nice posts btw) i already have experienced the engine fail and now i have a reman, got the act prolite flywheel along with the act hd clutch kit, had to replace my clutch pedal bracket assembly with the upgraded one, so i know most the things you speak of are true, my only question is the numbers your posting on whp which seems to be slightly off, i thought we'd be seeing and i have seen tons of posts from various people stating the major increase of over 300+whp with forced induction which gets them from around 14.5 1/4 mile to about 13.5 1/4 mile, i'm not trollin here lol just debating on the numbers, everything else seems pretty accurate, i love my 8 and i've been up and down on selling it due to the high cost to maintain, i've got it for sale going for 12.5k with 71k miles at the moment but still rethinking my decision if someone actually wants to buy it, if i do keep it i will upgrade those said parts you described and hopefully it changes my overall opinion on the 8, i know i recently overheated, temp gauge didnt detect anything and no lights came on, i was low on coolant and it wouldnt go over 20 or 30 mph without skipping and hopping, lucky i was a block from my house after traveling all day long in 100+ degree weather which most likely caused it, the 8 is fun to drive and can hang with most of the sports cars in its class, closely to the nissan z and thats pushin over 300hp at the crank, like he said you either love it or hate it, but dont question yourself if you hate it one min then love it the next cause ive been doin that ever since i bought it lol, i do seriously doubt 200whp is accurate sorry ive driven alot of cars in my life all with different power ratings and it doesnt even feel below 200whp, if anyone wants to debate this and correct me go right ahead im open to it

 

this needs to be giant, bright red, and stickied. in every single forum section and sub-section. set to display to anyone with less that 50 posts

 

So without forced induction, running a S1 rear is just a dumb idea? If I were to put one on my N/A, would it just kill acceleration?

I was actually curious to whether running a turbo or S/C would hurt fuel economy. I hear rotaries are supposedly most efficient at like 3000 RPM, which shocked me, cause piston engines suck more fuel proportional to RPMs. So it makes me think forced induction wouldn't hurt it too much, and might even improve it over stock. I mean, the most efficient engines out now tend to be factory turbo.

It's a shame no one has looked to improve on the 6 speed auto. It's a good tranny from my experiences so far, and it has 6 speeds! That's still industry leading, when a lot of cars still only pull 5 speed manuals. And the paddles could be really useful, though their layout is questionable.

Lastly, and sorry if my rambling is bothersome, why does the auto motor make less power than the manual? I know the older autos only had 4 port engines as opposed to 6, but the new auto engines seem to be the same as the manual engines. It can't just be the higher redline, can it? And what's keeping the auto from 9000 rpm? Just tranny limitations, or can the 6 spd auto handle that kind of RPM?

 

Ouch. Please don't go with custom fonts and colors unless it's needed. That is nearly impossible to read. Line separations and such help too. I cleaned it up so I could read and response clearly.



Unless you have a dyno that you can post, I am going to stick by my statement. The highest NA stock dyno ever posted was 200whp I think. ONE. Commonly, they dyno's post NA healthy engines in the 180whp to 190whp range. I have no problems accepting if yours posted 200whp as well, or even higher, since exceptions are always the rule


If you are just basing your number on 'feel', then you are experiencing what most do when they come from other cars to the 8 and aren't expecting the power delivery.

200whp or not, that is a single number, representing the PEAK power on a dyno chart, and is only referring to the power from the engine (minus drivetrain losses). You then have gearing that could make that 200whp anything from a stump puller to too-quick-to-shift. But the real reason it feels faster than that to you is how much "area under the curve" it has. With it's long gearing and flat torque curve, it holds most of it's available torque for a longer section of the RPM range than most piston cars can, and thus have a much wider effective and usable power band. Most piston engines have bands of 2,000 to 3,000 tops. The 8 makes ~90% of it's torque across a 6,000 rpm range. More area under the curve.

The numbers I posted aren't guesses, but known fact.

 

In theory, yes. I don't know of anyone that has done so however. The theory is that your engine load % will climb as you have to inject more fuel and air to make the more power needed to maintain highway speed, and it roughly offsets the gearing change.

Someone has to be the first to try it though

Again, in theory, FI can make an engine more efficient. More power makes it easier to move the same weight, lower load %. You really have to add the gearing changes to take advantage of it though. The turbos can get better economy with stock gearing than the superchargers.

In practice though, most guys that go FI have no interest at all in fuel economy, only speed and acceleration, and do everything they can to improve THAT, generally at the expense of economy. For example, using the right foot as much as possible, which is the biggest detractor from economy. When you get more power for fun, you usually tend to use it alot, and power = fuel

Also, rotaries move more air to produce the same amount of power that piston engines can, roughly 30% more air.

I'll refer you to my Auto vs Manual section of the post above. Remember, making "less power" refers to horsepower, which is a function of torque. They make basically the same torque up to 7,200rpm, where the rev limiter kicks in on the AT and they have to shift, ending the horsepower curve climb. The manual keeps going, so the curve keeps climbing, until 9k and the manual's rev limiter.

It's just a numbers game...it will "feel" just as fast 0rpm to 7,200rpm. The 4port AT made a bit more torque than the 6port MT/AT, but still less power due to stopping the horsepower curve climb early.


If you see a car with a torque about the same as horsepower, it means their peak is about 5,252RPM (the point at which all graphs cross TQ/HP lines due to math), and probably their redline too. See one with high torque and low HP, they have a really low rev limit. A high HP to low torque, a high rev limit. (Each example meaning "in relation to the other")

 

when you say full brake job i think you should break it down
does that include pads and new rotors, or just machining them

 

If I ever boosted my engine, I would run a fairly conservative setting. I don't need ridiculous power, though a bit would be nice and more bottom end torque would be greatly appreciated. I can't even break my tires loose and burn rubber.

Now another question arises. What is considered conservative in regards to boosting a rotary, and what kind of power can be expected on such settings? 5-8psi is conservative for a piston engine, but rotaries are new to me. Also, can the stock internals safely handle moderate boost, or will it drastically kill my engine's longevity?

So, in theory, if I removed the RPM cap in my auto, I would be matching the M/T's peak HP. So, can the new auto handle that kind of RPM, since the old one couldn't? Also, how difficult would it be to reprogram an auto's ECU to accept the increased redline? I don't want it still shifting at 7500 in "M" mode.

 

I'll edit.

Full.

I never advocate machining rotors. If they are hot spotted or deposits, get new ones. If they are warped, get new ones, if they are perfectly fine but you are getting new pads, leave them alone.

 

Most low boost set-ups are 6psi. Superchargers, this will put you to ~240whp (assuming 9k RPM), turbo's this will put you to ~260whp. Assuming you have a stable and good tune, and keep everything properly cooled and properly lubricated, then you won't drop much life off your engine.

Keep in mind though, that Mazda is already cranking alot of power through a tiny engine. This is not the way to make something last. Power works directly against lifespan. Forcing more power into any engine will not improve it's lifespan, only subtract from it. I say "forcing", because there are things like removing that cat, which has other health benefits that probably offset the slightly increased wear.

If you get a rebuild from a known and good rebuilder, then your seal tolerances can be closed up a bunch, which also boosts lifespan, as well as power.

Yes, in theory. However the lower RPM limit for auto's is because of the transmission. Remove at your own risk. Also, since drivetrain loss % goes up as the RPM goes up, and an auto loses more from the viscous nature of the transmission coupling, you probably won't quite get there.

The AccessPORT can change the redline, including increasing it (a few have gone to 10k, but it isn't recommended) and decreasing it (handy valet mode). BUT, you have a 2009 right? They stopped development of the AccessPORT for series2. The ECU made too many changes for COBB to find it worthwhile, so there is no AccessPORT that works with the 2009. It's pretty much no-option until someone with a 2009+ takes it upon themselves to hack the ECU, and shares it.

 

So then, in your opinion, what are the most worthwhile mods when can do for efficiency and/or power? You said rebuilding the engine and a solid aftermarket ignition will improve life, efficiency and potentially power. Removing the cat will make more power, but will that help economy?

 

The AccessPort is useless to me anyways, as it was M/T only, if I remember.

 

I think that yes, removing the cat could help economy. But when I get my BHR midpipe in a week or two, I will probably be using my right foot even more than before, so my mileage might actually suffer.

The mileage swing range on this car is so drastic that it's pretty much "drive for the mileage you want" if you care about it. Most health engines can easily get 22-24mpg, but you have to be soft on the throttle, stay low load, etc... all in the drive style. It doesn't take more than a couple blasts down the on ramp to drop the total tank mileage to ~20. Non stop high load full throttle, a healthy stock engine will make 9mpg (lots of feedback and numbers from guys tracking their 8s). It's a big range that is most easily affected by your right foot.

Cat failure can drop mileage to 9mpg or so in a hearth beat. Ignition weakening will drop it slowly, but can make it drop all the way down to 9mpg or so.

9mpg is where everything seems to bottom out. Likely due to a physical cap on the amount of fuel that can possibly enter the engine. Stuff failing just puts your engine's load % more and more into race conditions, until it's full load full throttle to maintain highways speed (been there, done that )

Incorrect. The AccessPORT is 2004 - 2008 only. Transmission didn't change the ECU structure/compatibility any.

 

sorry bout the custom fonts << is new to posting on the forums here, thanks for the reply, i've never had dyno before since i'm fairly new to the rotary world, but i'll check it out and see what numbers i get and i'll definately post for you, btw sorry if i seemed cocky i was mearly debating on posts i've read in the past, like i said i'm open to info and suggestions due to the fact i love my 8 and wanna know everything about it, i seriously could care less if i have less than 200whp all i care about is passing up other cars in my class that have twice the hp lol and not to mention leaving them far behind me on the twisties & curves, if you are true about the numbers this car sure presents itself to "feel" like it has more and i think the quickest car i had before the 8 was my 03 toyote celica gts action package 6spd, i think it had like 197hp at the crank not sure bout the whp i wasn't into the whole mechanical aspect back then, thanks for the info though, hopefully if i keep it and replace those parts you were mentioning above i'll get better performance or atleast more reliability, lol im not holding you or anyone responsible if im not satisfied though after install, thanks again

 

The manual had a slightly different engine mapping, because of the redline changes and the different gear between the transmissions, or so I was led to believe. Apart from that, the older auto's had different engines from manuals all together. I know the newer auto's have the same engine, just tuned down, but I would think it makes a difference.

Nevertheless, would one of those work with an '09?

Also, my local dealer said no matter what I do, don't mess with the cat, as Mazda will void every bit of warranty possible. Even if your clock stops workin or your front bumper randomly disintegrates, and you have a non-OEM cat, they won't fix it. The mechanic said he can fudge everything else, for the most part, as long as you can produce the original parts if they need to send something away.

 

Yes, the 2004 and 2005 autos had 4 intake ports vs the manual's 6 ports. 2006-2008 all engines were physically the same 6 port, 2009+ again, same engine between transmissions (but different from 2004-2008).

You are correct that there is different gearing, and thus different engine mapping values between auto and manual, however the maps themselves isn't what makes the AP able to talk to the ECU. In order to talk to the ECU, any device needs to read the correct PIDs, essentially data point, but think of them more as telephone numbers. If you don't know the phone number to someone, you have to guess, trial and error. It's a bit easier with the ECU, since a subset of those PIDs are always "calling" the ODB2 port, so it's just a matter of listening to what is coming in and recording those PIDs for later immediate grab. But that doesn't really get into the ECU by itself. Usually, software has to be used that will essentially "copy" the entire ECU to a laptop or other computer, where the entire set can be hacked apart and it's massive hex file(s) figured out. Once it is figured out, you can write a program to specifically replace sections of it safely. This is where the AP shines, as they pinpointed everything, and reflashing is basically generating the section of the hex files that relate to the engine maps, then copying those maps into the right points of the hex files in the ECU. Even 1 character off, and you can "brick" the ECU, and need a new one. The ECU for the manuals vs automatics is physically the same structure, coding, etc..., just they have different values in the engine maps sections, and they use the automatic transmission gearing code that manuals ignore.

The problem with 2009+, is that Mazda changed the ECU structure and how everything is layed out....dramatically. Enough so that COBB determined that it would essentially be like starting from scratch to re-hack the ECU and build a product for it. And the number of 2009+ RX-8s being sold wasn't high enough to support development, even if every single RX-8 owner bought an AccessPORT. So they canceled development on it.


Your dealer lied to you, either intentionally or through ignorance.

BY LAW, a dealer has to prove that a modification from stock directly caused the failure you need repair. The burden of proof is on them. I have a whole warranty section above if you want to read the details on it. I went through a long warranty legal fight with Toyota and learned alot about it.

The only thing that can be harmed by removing the cat is the ozone, someone's nostrils behind you, and/or someone's ears. And Mazda isn't offering a warranty on any of those.

They are either trying to frighten you, or are idiots.

Read the bottom section of the warranty section though. If MNAO asks "is this car stock", and the dealer says "no" without explanation, then they could deny it off the top without digging deeper, and you might get a "no" without knowing that it was simply that no one bothered clarifying anything.

 

I hope Mazda continues sales of the '09+ RX8 without major mechanical changes, so that, perhaps, someone believes the total sales warrant a hand held tuner. Sure would be nice if someone hacked the tranny controlling part of the ECU and told it to shift faster when I pull the paddle! Also, so hold a damn gear. I wanted to accelerate in sixth today, going 80mph, and it down shifted to fourth. I didn't need it to go like stink, I just needed to casually pass someone.

I think my dealer was just misinformed, cause he seemed like a cool guy, telling me to autocross the hell out of my car and they'll fix it. Haha. He told me to beat it to **** on the street if I can, cause the car loves it and warranty will cover it. Nevertheless, I wouldn't want to have to argue with my dealer and sue them just to fix something.

 

RIWWP, you forgot about me and Shinkateen (He has teen in his name so he has to be young) .
Not all teens though, there is always an exception, and I happen to be one of those. My first car was a hand-me-down 05' Base model AT, then I sold it and got my 05' WB 6MT... I happen to spend alot of my time reading about the rotaries and RX-8s... Im 17 almost 18 which means ive been driving my RX8(s) for almost 2 years now (leagally ). I have yet to have a crash (Knock on wood ), but I have lost control before. Practice is the best way to avoid a crash. Learn the pedals and brakes, shifting, etc.

I recommend to anyone who is young to practice driving in a empty parking lot so you can feel how your car handles and get used to it. SCCA would also be a good way to get used to the chasis on the RX8.

RIWWP forgot to mention that for all the younger rotor-heads ( Dont worry, you will know if you are one) need to look into a rotary book called:

Street Rotary- Mark Warner


Its a really good read about the history of the Rotary and gives you a complete tear-down of how a rotary engine works etc. and teaches you.

oh and Mods sticky this thead

 

100% agree. I used no universals or statements of what will happen. Simply what is statistically proven to happen, regardless of what your first car is, and the statement "How prepared are you to lose a car that you will probably form an emotional attachment to?"

I know we have several of valuable teenage members on here. But we have also lost quite a few 8s to teenagers...


That post was a near direct quote from my discussion with Grog about his desire to own an 8, and it has been quite pleasing to see that he is another one outside the norm.


...and shinkateen only acts like a teenager, he is past that age though.

 

I am currently looking at a few different cars.

1. One of the 8's I am looking at has been in a prior accident where the airbags had not deployed(carfaxed) . The owner told me that the accident was not bad. He replaced all of the panels, and upon inspection I couldn't find anything wrong with the front end of the car. (He replaced front bumper, and hood). Does anyone have any experience with how this car does in a typical fender bender? What should buyers look out for?

Other then the accident report, the carfax shows that the seller was very good with maintenance and whatnot. He took the car in all the time to the dealer for updates and maintenance almost every 4000 miles.

Also on this car, the brakes need to be replaced. How much should I ask him to lower the price so I can do this?

2. When I get the car, (most will have over 40k miles) should I immediately replace coils,plugs, etc just to be safe?

3. One car I am going to be looking at (owned by VmanX on these forums) has busted power steering, due to control unit. What should I do? Get the car and buy a new unit? Take to dealer to fix. etc etc.

 

If it was indeed just a fender bender, you shouldn't have any issues. The front bumper + hood damage only tells me that it was probably sliding under an SUV slightly, and as long as the electronics under the front part of the hood all look fine and original wiring, and the radiator plumbing there looks original, then you can accept his word that it was very minor. If any of that stuff was replaced, then it was likely more severe than he is saying.

This is a definite bonus. Makes the 8yr 100k warranty on the engine core that much more valuable, since you will have the documentation that Mazda will ask for.

Depends on if he is already including that in his price? If he priced the 8 with the pending brake replacement in mind, then no need to drop it further.

Certainly can't hurt. Might not be needed if the ignition is working correctly right now. If it is the same car as above, if you have the records, you should be able to figure out when they will be needed.

Hard to offer you advice there. Assuming it is priced with that fix in mind, it depends on how much mechanical ability you have. If you aren't confident, take it to a dealer.

 

I recently looked at a 2004 RX8 with only 41k miles. Fully loaded, sunroof, leather etc etc. The owner installed a beautiful sound system with gps and satellite. New tires, and very clean engine compartment and all around. He said that him and his professional tech buddy fully rewired all the car when doing the sound system, and it seemed like a very good job.

The owner said he did all of the maintenance himself and constantly keeps oil and fluids topped off. The car accelerated beautifully, and handled very well if not a little stiff in the suspension.

What concerned me was that while driving on the highway, the radiator light (I think that was the one, kinda looked like a miniature Jefferson memorial) came on. The guy said that it probably just needed to be topped off, and that the light would go off after a little more driving, which it did.

Thoughts?

 

The coolant reservoir sensor is known to crap out and cause the Coolant light to come on, normally when taking tight turns or up in the higher RPMS... its just the sensor, your not low on coolant (Make sure before obviously) its just the sensor. Its a pretty common bug/problem...