rotarymotory

Can someone provide some good solid information re the chip mapping?

I believe my chip flipped around 600 miles (more power & response, better sound).

Can someone explain what actually happened in there and WHY?

WHY does it need to run richer(?) for 600 miles?

HOW did remapping improve emissions?

And since it was done so late, was there proper QC evalution time? And could this explain some of the other gremlins under the hood(odd AC cycling, heat issues, mileage issues, rough idle issues, etc.)?.

By the way, my 8 is great. It has none of the above issues. I'm just geeky and want to really understand these technicalities.

Also, thanks in advance, but I've already "searched", not much real hard data there on this stuff, just loose chatter-speculation and complaining.

RM

jd62

I'd like to know what's going on also. We have over 3000 miles on the car now, and it has a beautiful exaust tone, where before it seemed too quiet Mileage has gone from under 13 to over 20 mpg in town. I haven't noticed any appreciable difference in power.

ShawnC

I have 3200 miles on mine. And I've noticed some changes too. Sounds better. Seems like I have more power, but I havn't dynoed it. Plus I had a CEL problem happening about once a week. It was caused by a misfire. And that hasn't happened in about 3 weeks. Seems like things changed around 2500 miles. I'd like to know about the mapping too.

rotarygod

I know on the 3rd gen RX-7s that they had full power from the start. Mazda also put each engine on the dyno before it went into the car to break it in knowing that many owners will just go floor it right off the dealership lot. I haven't heard anything about Mazda breaking in the Renesis at the factory so maybe a 'smart' ecu programming will help keep people from abusing them for a while. It is more critical at higher rpm's and this fits well with what people have experienced. It makes perfect sense but I wish we knew for sure. Sorry I can't provide you with a true response to the original question.

rotarymotory

I'm encouraged to know so many of us have the same hunger for this info. Maybe someone will step up.

I'm perplexed by the breadth of differing experiences owners are having with this engine/chip. What gives with that? Is it the chip trying to sort out differing climates and fuels? Or is it just bad QC.

I'm at 900 miles and it's getting better and better. If as some are saying, the power keeps coming on even after 2000 miles, I'll have no complaints.

The misses and sputterings reported are also odd. If it were me, I'd go in and demand a new brain for the car. An engine that runs at these tolerances and rpms shouldn't "miss". And I understand that 'detonation' is killer on this motor.

Someone's got some splainin' to do...

BTW, I love the way it idles at 1100 if the car is rolling at all(even just barely rolling, clutch in), but drops to 900 when the car halts. Weird.

RM

nk_Rx8

You guys are starting to sound like the stereo guys I know where you put coins on the edge of the speakers and everything sounds so much better. Or the green marker on the edge of the CDs will make them sound so much better!:D

A lot of it is psychological, or temp or humidity changes.

mikeb

thats not the answer we are looking for

canzoomer

Exactly.

A lot of people are posting on these forums looking for magic solutions.

"Mommy make it stop"

"It only hurts if I laugh"

"Well Jim-Bob, If I turn off the DSC, shift from 2nd to 6th at 25mph, use 87 octane, and NEVER drive it after dark, then it almost gets good gas mileage, and didya hear ONE GUY got over 180HP on a Dyno!"

I would be laughing at this if I was not one of the people who bought one.

I should have known better than to buy a car with no history, but no, I just HAD to have the coolest new toy..

Anybody want to buy a Quadrophenic stero amp?
How about a Beta video deck?

darn.

vipeRX7

ROFL!

Gord96BRG

Yeah, the guy who's car had the highest mileage of any tested so far. The same car that dyno'd 9 or more hp than it did on it's first dyno run with half the mileage (2000 mi for first test, 4000 mi for second test). What was that we were told about rotary engines breaking in slowly, and needing more miles to make the rated power? Ah, what the hell, that makes too much sense - let's ignore reasonable approaches to finding out about this and just ridicule Mazda.

If I cared, I'd put my 8000km RX-8 on the dyno. But I don't really care. Those who do care should test their own cars, put on some miles, then test again, so that there's a reasonable statistical base of results to start drawing some valid conclusions before jumping to invalid conclusions!

Regards,
Gordon

canzoomer

What would the point be Gord?
You are in Calgary. At that altitude it would probably affect the test results..

Bsaides, the smell of cowsh%^ would undoubtedly taint the results!

Wait! Maybe that is the trick! RX-8's like bullsh&@!!

Grin buddy! It's a short life!

Gord96BRG

Sure, but that's what standardized Dynojet correction factors are for. Of course, lots of people call BS on the correction factors themselves!

I'm curious to hear how many km the Halifax tested cars had on them, if they fully disabled the DSC for the runs, etc...

Regards,
Gordon

canzoomer

Of course, we all want to know the details.
I believe that they are supposed to be posting the rest on the info soon.
I do know the one that made the least power had the lowest mileage:
" the red, which had significantly less km on it (I think it was around 2500) was a bit lower at 158.3 HP and 123.5 torque."

While one can "correct" for altitude, temperature, etc., it strikes me that those "corrections" can only lead to making the figures look suspicious.
Ultimately the correction factors are estimations.
It is not much different than when we pick an arbitrary factor for power loss through the drivetrain.
When people say a 15% loss is normal, for example.
If we take a 100HP engine, get 75HP at the wheels, we see a 25% loss.
However if a 300HP engine is attached to that same drivetrain, I doubt that the driveline loss triples to 75HP..
It should be roughly a fixed amount.
The amount of friction and mass of the driveline components should not rise very much with the torque ouput, at least not in a linear fashion.
If people say a Miata loses 25HP in it's driveline, and the Miata engine is 150HP at the crank, then that is a 16.7% loss
The same driveline on a 220HP engine is a 11.3% loss.
Applying that figure to a 238HP engine means we should see around 213HP at the wheels. Even if the driveline loss increases by 50% on the 238HP engine, we should still see 200HP at the wheels.. And that is a 15.7% loss.

At best we are still seeing something like 15 to 30HP missing.
That's the "X Factor" in all of these estimations.

When I bought my car I expected to see something like 213HP at the wheels.
Anything below 200 is unacceptable.

rotarymotory

Wow, is this thread off track! Maybe we can start over...
I'm not looking for a "magic solution" to anything. My 8 is running beautifully. It's got the power I expected. It's delivering the mileage I expected. It's a great car. A fantastic driver. Even an all-around marvel. But, alas, that is not the point.

Here are the points:

-I am curious about the chip mapping. Not just WHAT and WHEN it happens(I'm kinda getting a feel for that), but WHY it was engineered that way.

-I'd like to understand the logic behind the "break-in" chip flip sequence. (My car HAS changed over the miles. It sounds different. It has more HP. Ex: under 600m it did not have the power to be parrallel parked without feathering the gas. Over 600m maneuvering in parking at idle by just feathering the clutch is no problem.)

-I'd like to understand the sequence and logic behind the intake tract valve openings and closings(I saw that charts, very helpful). The one around 5500 seems oddly placed for my brand of urban geurilla driving. And its actuation program seems very unaware of conditions. If these sequences are purely mechanical, that's oddly yester-tech for such a sophisticated motor. Quaint even. (Don't get me wrong, I'm a huge yester-tech fan. If it is running outside any ECU oversight, that's pretty awesome. Hard to believe, but awesome.)

Someone have at it.

RM

canzoomer

OK, a simple explanation, I hope:
Engines are a compromise between power output , fuel economy, emissions and driveability/smoothness.

To make the most power an engine needs to flow lots of air, add fuel in the correct proportions, and turn the explosion into mechanical energy at the crank.

If you want peak power you design all elements for peak power.

That means you sacrifice low rpm torque, smoothness and economy. Emmissions will also be pretty high.

Modern engines incorporate different parallel hardware design elements that try to accomodate various goals.
For example a common practice is to have long intake tracts that support low rpm torue, smoothness and low fule consumption.
They also have short tracts to support high power at higher rpm.
They mechanically switch between these at different rpm and throttle levels.

The computer senses what the rpm and throttle opening is and switches between the intake models at different times, as requested by your gas pedal, the speed, and the rpm.

They also have to adjust richness and ignition timing and duration to allow the engine to stay within emissions regulations and to avoid pre-ignition detonation (knock).

Complicated business, so a computer reads sensors and makes adjustments in real time to reach the optimal compromise.

These adjustments are based on a "map" of information of when and how much to adjust fuel input, ignition timing, opening and closing of the intake tract elements, and so on.

No matter how much you model the engine on a computer, the sets of variables are huge.
Air temperature, gasoline, altitude, humidity and air pressure, component manufacturing variance, assembly variance, and changes due to age and wear.

If the ECU tells the fuel injection system to add more fuel, and then the sensors see higher emmissions levels, then the ECU has to tell the ignition timing and other systems to compensate, or if they can not, then the fuel has to be diminished.
A lot of the systems have to be balanced so that they do not create a conflict.
Some of the settings variables are "locked". For example the opening of the intake tract sets happens at a fixed RPM.
Some of the variables are floating, such as the ignition timing. Still they have constraints. Too little fuel richness will result in pre-ignition, or "knock" where the fuel ignites too soon, before the spark plugs fire. Leaner mixtures will ignite sooner.. This knock will break engine parts.

Lots of testing has to be done on engine and chassis dynos to ensure that these settings and switch points are correct.
Change one variable a bit, and it all may change. Read a bit about chaos theory if you want a better understanding just how unpredictable complex systems can be!
One small change in environment or parts can make a significant difference.

In the case of the RX-8 engine and the ECU, we see that Mazda put in an ECU "map" that makes less power and uses more fuel than they had set as a goal. It is not an easy business for them to do a map that satisifies all the requirements flawlessly.

However, if stuck in a situation where they have to choose betwen power, fuel consumpition and emmissions, they have to choose the decision that satisfies the emmissions goals, as that is the law.
Fuel consumption and power output are marketing goals only. Success is defined as meeting emmissions specs first, power specs second, and fuel consumption specs third.
Reliability is also a goal that has to be met, or in the long run their costs go up too much.

Finally there is cost.
Mazda made a conscious decision to sell the RX-8 at about 20% or more below it's direct competition. They have a goal to sell a certain number of units per year. If they do not acccomplish that, the RX-8 and rotary engine development is over.

So, they have failed in meeting some of their design criteria, and have ben forced to downgrade their power claims, and soon probably their fuel consumption claims.
They are trying to stop these failures from snowballing into a total failure, by still claiming power figures that are higher than actual, because if they market the RX-8 as a 200HP car, they go directly into competition with a lot of cars that sell for less money.

Most consumer will choose a conventional piston engine in a GM product over a rotary in a Mazda. They have to sell something "better" with more features and options at a lower price to grab market share.

However, if they fail in any of their design goals than they are sunk.

It is easier to sell a small number of Porsches at a higher markup. People will pay more money to own a Porsche.
They will NOT pay more money to buy an RX-xxx.
The third Gen RX-7 proved that point. A good fast car, with lots of sports car performance. At a price point that was too high to sell many units.

I am sure that there is a lot of furious activity within Mazda as we speak, trying to figure out a way to wring more power and fuel economy out of the Renesis, while not necessitating any costly recalls for hardware upgrades. At the selling price of the RX-8 they can not afford to do that.
The engineering time and costs involved in doing htis work is pretty high. Software development is never cheap. And when it involves expensive hardware, with lots of dyno and chassis testing, it is slow business.

However, if they can not accomplish that, their hopes of the RX-8 being a large volume seller are fading fast.
Once the first year glow of the styling wears off, the desirability will fade quickly..

By a year from now, if it is not fixed it will be seen as "Nice looking car, but no go, and they had a lot of problems. Guess this is the last we will see of the rotary"

And then the value will plummet.
So that is why I chose the buy-back. I HOPED they would succeed. They came close.

They still may succeed. It is possible that they will issue a new ECU map, wich at least partially solves the power and fuel consumption issues.
I am not willing to wait and gamble on that.
I talked to Mazda PR and suggested that I, and perhaps many owners would be willing to pass on the payback, if they would commit in writing to providing such a fix, within a reasonable time frame, perhaps a year.

They declined.

Draw your own conclusions.

rotarymotory

Excellent info. Thank you. Thank you.

If I may, why is a richer mixture helpful early in break-in? Or is this effect just an artifact the electronics "learning" their conditions, starting from a conservative setting?

And, what do you think DID happen at 600m, when it changed? Is there just an arbitrary point where the chip evaluates conditions and performance and "settles in"?

BTW, I'm keeping the car. Maybe curiousity will kill this cat, but I just can't wait to see what happens... from behind the wheel. I'm betting Mazda will fix the "problems", even though my car doesn't have any.

I believe... if it weren't for the vocal de-criers, Mazda could have kept it quiet and done a "stealth" recall fix to the ECU. Then they could have revved up the PR machine and made it all into lemonade. But, it ain't goin' that way.

This isn't over yet.

Again, great informative post. Thanks.

RM

klegg

As I recall, you were selling you car back and getting a TT. May I suggest giving it a rest? I really do not think this is healthy for you, and I mean that. Go enjoy your very nice new car and your family!

canzoomer

Sorry to have bothered you.
I stand by what I said, however.
As I have said on this forum on one than more occasion, I like the RX-8 a lot.
I do not like the way Mazda have handled the situation.
Before I took them up on the offer of the buyback I pursued the various options I could think of to end up owning the car they sold me, as advertised.
I would much prefer they would provide that car.
I am not interested in their $500 or the "free service"

So, I politely requested that they fix it.

I was also told that I am not the only one who had made that request.

It is my belief that as they firmly have declined our request that they do not feel that they are in a position to remedy the problems.

On this thread we are discussing ECU maps, and how it relates to the RX-8 problems with power and mileage.

I understand that while our cars were in port they were under some considerable pressure to release them. I felt that given more time they might be able to accomplish something.

You are being a bit hypersensitive here. This is a discussion. Mos t of us are being polite and discussing ECU maps and speculating on a situation based on this software.
As we have not been apprised of all the details we have to review what has happenend and discuss some of the possible occurences and the motivations for these actions.

I did not do so in a way to slander Mazda. Indeed I sympathise with their situation. Sometimes software projects can be stubborn and incalcitrant. A lot of software products have been released with very blatant bugs. it is a common albeit distasteful practice, driven by marketing pressures.

If you find discussion of these bugs discomforting I suggest you read another thread, that you perceived as less threatening to your feelings.

klegg

You missed my point.
You are selling the car back. You have purchased a new car. Put this whole distasteful event behind you! Go live your life!

I am not attacking you, I am trying to help you! You seem to have become fixated on this whole thing. If I was you, I would be out driving my TT, or spending time with my family! Once you made the decision to give back the car, this whole thing became a moot point, no?

canzoomer

Sigh... pardon me for having a discussion with somebody.

The fellow asked about ECUs and I tried to answer him.
Apparently to some degree of usefulness as he thanked me.

I am hanging here for now for a coupe of good reasons:

1) I still have the car and am driving it. It will be some time until Mazda buys it back. Hopefully soon enough that the fellow who is selling me the TT can wait.

2) Who knows, maybe something positive will happen? It is possible that somebody will come up with a cure? Maybe Mazda?

3) Perhaps somebody here will go over some magic mileage figure and some hidden function in the ECU will flip and Shazam! an extra 20HP and 5mpg will magically appear. Like a genie..

4) Maybe Bern will be allowed to say what happened and we will all see the light.

5) Maybe one person reading this will not make the same mistake I made, and will go buy a car from a car maker with some higher level of integrity.

6) Maybe one of the hardcore types who hate me so will pop a vein and I will witness it.

Like somone mentioned, this is getting to sound a lot like Catholics and Atheists. Pardon me for standing outside the church.

canzoomer

Speaking of ECUs, there is a project to build your own fuel injection computer. It works pretty well. I know one guy using it on his 1982 Chev and he swears by it. And his Chev makes mucho HP. Maybe a littel too simplistic for our use on the RX-8, but still an nteresting project.

http://www.bgsoflex.com/megasquirt.html

Reading about this, and maybe looking at the source code and details will help in understanding how this all works..

bugbear

klegg - give canzoomer a rest he's just trying to provide some information for which rotarymotory seems grateful. the fact he's still around to provide information, even if he is going over to the darkside, should be accepted.

klegg

"Maybe one person reading this will not make the same mistake I made, and will go buy a car from a car maker with some higher level of integrity.

Maybe one of the hardcore types who hate me so will pop a vein and I will witness it."

His info is great, its the above comments that are troubling.

Again, I am not attacking him. I think we have all seen him starting to lose it. I really am ligitimately concerned about the guy!

canzoomer

Don't worry, I am fine.
Thanks for your concern though, I appreciate it.

I am now pretty darned calm about all this, although a week ago I was awestruck at just how inept someone could be to sell a car in Canada with no plan to provide basics like block heaters, or suitable wheels for snow tires.
I got over it. I understand, they are not very good at doing their jobs as Mazda CANADA.

However, I am now calmy certain that they are not a good company to buy a car from.
Yes, Mazda in Japan have built a wonderful car.
However, once it hit our shores they have totally fumbled the ball.
Having done that instead of taking the approach of "Oops, we screwed up, please be patient while we figure out what to do to fix it". they have simply tried to gloss it over with falsehoods.

The Mazda credo seems to be:
If at first you don't succeed, lie and lie again"

In the meantime I am living my life, happy that I can personally get out of the mistake, and trying to help others avoid falling into the same trap.

Still, it IS a nice enough car, that if I find some practical solutions for the power and mileage problems, I am willing to work out the other, smaller issues with or without Mazda's help. I know perfectly well how to install a circulating heater, and other small things are also fixable.

There, is that clear enough, or do the "happy happy *****" need to take another kick at me?
If there is somebody who needs help it is some of them.
I am reminded of schoolyard days. If one kid disagrees with a clique they try to bully and discredit him ruthlessly.

canzoomer

You are welcome. I am trying my best, despite the resistance..

While this is not definitive, i can think of a couple of reasons they may want to run a rich mixture during breakin:

1) A new engine is tight fitting internally, and the friction may cause extra heat to be generated. If we run a richer micture it generally runs cooler.

2) Until the seals fully seat some mixture may escape, so the resulting fuel/air charge is diminished. Running rich would help overcome that tendency.

This is just speculation on my part.