Open Source Naturally Aspirated Performance Tune File
 

There seems to be two different approaches to tuning RX-8s. The first is to find a tuner you trust and pay them to put a file on your car. The second is to buy the tools and do all the work for yourself. If you are like me, you just can not help but want to muck with your own stuff. The problem is that there is so much you can do and, in most cases, not enough time to do the project justice.

As an alternative to doing it all by yourself, how about we all work together to make it happen. I can pitch in editing help in addition to getting some free dyno time. Anyone out there have an NA car they would like to modify? Anyone have time to act as a secretary to document each tune release and maintain a depository so others can make use of the work?

I would like to help develop an open source (free to all) tune (reflash for stock PCM) for naturally aspirated (and nitrous, and turbo, and supercharger but that is probably left for a different thread) RX-8s as a collaborative effort. I propose that all the maps and logged data be added to the thread (or a related repository) so that others that want to play with RX-8 tuning can take various files at different points in the development, edit them and make them their own. Perhaps several different types of maps can come from the project, daily driver, track, high octane, and more.

Anyone interested?

Is anyone out there thinking about going to a professional tuner for a NA reflash? If so, maybe we could get the tuner to participate in this project and let us post the results.

It is a long shot, but maybe there are some tuners out there that would share.

It just seems that a tune of that cailber on a likely modded(minor performance- intake, exhaust, pulley, flywheels etc) NA car would be fairly unique to that car..

somebody call 911 and report a stupid-epidemic ...

https://www.rx8club.com/showpost.php...2&postcount=16

I can see my favorite Publix employee has joined us. That is ok because he is polite, always has something nice to say and always contributes something meaningful to the topic of the thread.

As for your contribution this time, I put some thought into picking this section for this topic. For your benefit, let's start with a reading lesson. This area is titled “Aftermarket Performance Modifications” and ment to contain “Discussion of power adding modifications”.

Now for a lesson on comprehension-
Please read the first posting in this thread and you will see that it is targeted at creating a family of free NA tunes. These tunes would be an aftermarket (not provided by Mazda on new equipment) performance (there should be a horsepower gain) modification (it would not have come on the RX-8 and thus must be a modification). The end result is a file or files that comprise a physical thing for making people's cars run better. What this thread is NOT about is using an Interceptor-X or any other one device or technique, to do the performance modification and thus it does not belong in another section.

If you would be so kind, please actually contribute to generating something of value for others here or take your input elsewhere.

The nice thing about mass air flow based systems is that they allow for more air to get into the engine and will properly fuel for it. In this case, I know the RX-8 allows for up to 350 grms/sec of mass air flow while most stock cars are probably around 200 grms/sec. There is a lot of head room in the fuel system (I think Mazda planned for FI from the start). Most of the mods that are out there allow for more air into the engine and thus a one tune fits all approach might work.

That being said, I think we should find the situations where people require different versions and test then post files for those versions as well. If we post and examine the datalogs then make decisions on changes to make on the forum, then others can read, follow the logic and, if they agree, give the files a try for themselves.

You may be right and this may not be possible but I would sure like to give it a try.

some of us know how to bring out the best in people...dont we..

:lol2:

Why don't you go first?

I just ordered an EMU :) Gonna take a while to set it up properly for NA/nitrous but once that's done I'm game..

I think thats already been done..

Are you up for using the factory PCM even after you get your EMU?

I'll be using the EMU with 0'ed out maps for a while to get some baseline data logs.. Also to see just how high I can push the progressive shot

OK, where?
I don't see any calibrations posted.

I'm a little confused by this...are you, or aren't you affiliated with EFI Dude? My impression is that you are, and you guys have already been working on NA plots...to this extent, to have open source tunes wouldn't we all need the same reflash tool? But there are three - Hymee, Cobb, EFI that are imminent to market and many aftermarket reflash tools appear to have the capability to swap tunes amongst their respective ownership group.

Yes and Yes.
The guys at EFIDude are friends but I do not work for them (see https://www.rx8club.com/series-i-engine-tuning-forum-63/reflashed-today-using-efidudes-138881/page2/ in the EMS forum for a more complete explanation). I have used the tools for almost a year and happen to know that they work. I’ve also asked Hymee to send me his and would like to get the AP as well. I just plain like to play with this stuff and learn along the way.

Unencrypted tune files can be flashed by any tool (I think) so, if we develop some, they should be usable by all.

OK. I think the idea of one thread that has a table of available tunes for download is great.

Not being a computer guru, I just question the ability to take a file and transfer it freely between flash tools...but if it works, all the better for end users.

No matter the flash tool they are all trying to modify the factory PCM, so they need to give it a file that the PCM can understand.. A common tune format is not too far fetched, as long as the tooll developers decide to cooperate on this point.

This is great idea!!!

It looks like we are going to need two things before we can start testing tunes. The first thing is a target air/fuel ratio that everyone is comfortable with. I’ve started a separate thread on the subject to get feedback from others. I’ve also asked around a bit and the consensus seems to be 13:1 for good normally aspirated horsepower while still being somewhat safe. The only caveat to that is that you need to watch your cat temps as they will climb if you run the car hard for long periods of time. I would suspect the extra heat might affect cat life as well but that is just a guess.

The second issue is Long Term Fuel Trim and how it affects mixture under high loads. I have attached two screen shots of rips with the same car with an initial 5.5% positive LTFT and then after the LTFT was cleared (by pulling the magic fuse). There is a significant difference. I’ve also included a screen shot of the car building LTFT after the trims had been cleared. Lastly, the data file is attached as well for your viewing pleasure. Just go to www.efidude.com and download the ProLogger application (for free). Do not bother to install the drivers as you only need them when you want to download data from the logger. Once installed, go to file import car data and import the attached file (after you have unzipped it).

I will start a separate thread to see if we can collect some data on stock and modified intake LTFT building. I’ve also put a call into Mazda North America to ask them what they expect LTFT to do as an engine ages.

I don't think there's really any way to predict what LFTF will do over time.. However it's definitely good to keep an eye on it to check for any sensor / fuel injector problems

:icon_no2:

That's like saying you found a significant difference in your putting accuracy after the lobotomy.
You change a few more variables when you perform a hard PCM reset than just the trims.

You really are coming to this party a bit late. So much of what you are trying to learn about the PCM has already been dissected in depth over the last 4 years. More reading, lest posting.

what's LTFT. I'm new to this, sorry

LTFT = Long Term Fuel Trim
STFT = Short Term Fuel Trim

What RG said. It's a correction factor that the PCM develops while in closed loop mode. Basically, based on the amount of air coming into the engine and the amount of fuel the PCM thinks its injecting, the AFR should be X. If the observed AFR is different from X, the PCM injects less or more fuel to compensate. That's STFT. If the condition persists, over time STFT gets copied into LTFT.

In the RX-8 PCM, its even more complicated than that.
There isn't a regular open/closed loop switch - there are ranges where the system alternates between the two and some parts of the open-loop range are still trimmed while others are not. There are operating conditions where the fuel calculation is completely unaffected by fuel trim.

Plus, LTFT is a weighted average of a range of STFT values.