Awesome. Thanks!

 

LTFT's are derived from STFT's. If the STFT's are as close to zero as possible, the LTFT's will be zero.

Don't we want to start with 0's across the board for LTFT's before starting into open loop?

 

Care to elaborate on why?

 

Hey, no-coast-punk, just wanted to thank you for all your contributions to this thread, which basically gave me enough information to start on my own tune!

I've been loading a new tune and resetting my fuel trims every time I drive to school in the morning (~80*). So far I've been using STFT's to adjust my closed loop VE, and I've been using Actual Lambda/Commanded Lambda to adjust my OL WOT tuning.

I also started with using a flat >1< across the board for the VE, just because I think it's easier to tune from and blends much better than the stock map. After adjusting, I realized that the cruising values are all above 1.00, and the OL WOT values are below 1.00, meaning any positive LTFT value at all with throw the OL WOT fuel trims in the wrong direction, especially if your AFR's are already set too low - or worse - stock

To reiterate my plan:
1. Keep LTFT's at ZERO for tuning
2. Use STFT's (when you're at/near target afr for a steady load) for cruising VE's.
3. Use Actual Lambda/ Commanded lambda as a % for VE adjustment.

Seems to be working out so far, thanks for pointing me in the right direction!

 

Hi guys.

I have question for you about best Target AFR in closed loop for improve fuel economy.
I already did MAF calibration, and my LTFT are very closed to zero, even my STFT are close to zero before VE fine adjustments.

I would like to know what AFR target are you using in closed loop, I mean, the car run usually in 14,7 - 14,6 at cruising 120 km/h (3500 rpm aprox) over 50% of load, so I increased the target for that RPM/Load ratios to 15,4 AFR because I saw in wikipedia that its he best fuel economy point, attached its the stoichiometry graphic for gasoline, and fuel economy is a little bit better now.



What to you think about that ???

 

The best way to monitor fuel economy is to watch IDC's at a given RPM. Lower IDC's mean you are getting better economy. This eliminates any sensor errors and focuses purely on economy.

Rotaries have weird lambda requirements. Peak power happens somewhere in the 13:1 range, not 12.6.

 

So its been a while since I put the stage 1 tune on. Here is a quick log update.

Small 2nd Gear Pull.



The Idle Log

 

Yeah this is interesting

 

What is so interesting here?

 

After reading through this thread I saw some valid points. The method is one I just can't agree with. Only using VE for correction is a "Band Aid"

 

its interesting because his LTFT is sitting at 13.88

 

I wouldn't use the term "interesting " .

I would go with "fu*ked up"

 

Lmao

 

Back in the original log, LTFT was like 20.12 I think the STFT is better also.

 

what you still don't understand is, if your stock tune had 20.12 LTFT it means something else is MECHANICALLY WRONG with the car, like your jet air hose is broken.

your compensating a mechanical failure with software.

 

No, I understand that. My AP screen broke and I didnt get to do any logs or what not for a month. I got it back and did the logs again, and there was a change. I was just pointing that out.

 

You know you're the third person in the last month that I've heard/know that the Cobb AP screen has failed.

The other two guys are local members.

It's starting to make me nervous about mine.

Going to have to look for a backup just in case.

 

Just make sure everything on the AP is backed up on the computer. And remember the last map you flashed. It cost me 25$ to have COBB replace it, and then another 10$ to have it shipped back to me. was not THAT bad. took about 2 weeks.

 

Could you, you know, say something then? Why is maf scaling superior to Adjusting VE tables? These forums are really the only place that preach that gospel. Unless there is a specific reason in regards to 8's, no professional tuners do it this way on any car I know of. I see you call out a lot of comments like yours when the shoe is on the other foot, so... any proof, or can you pick out the part you disagree with? He's laid his argument on the table, and his is in line with pretty much every thing I have ever read about the subject. So why is the 8 so special and unique specifically?

And he's a loudmouth for helping people? Get a grip, behavior like that is exactly why our car has the most poisonous community I have ever seen for any car. What makes your resume stand out more than his? I'd say working on race cars does qualify him as an expert, if not what does? Post count? sheesh.. Regardless if your going to throw insults, at least back it up with some sort of argument, it isn't a given that you know what you are talking about fyi. So could we actually discuss the theories, instead of throwing insults?

 

Team was one of the original beta testers for the development of the Cobb on the RX-8 and is probably one of the best NA RX-8 tuners here.

It doesn't matter what the expert tuners do on other platforms because 90% of them could not tune an RX-8 effectively if their lives depended on it. Which is why there are very few competent RX-8 tuners.

It is no ones job to spoon feed anyone. Do your homework and educate yourself.

 

Do you think spewing venom like that is going to get him to open up and help you? People are what they are. Your not going to change them.

 

This isn't about me and I am not asking for help. This is pretty basic theory, so all I'm asking is for him to stop insulting people he disagrees with and discuss it like an adult. Is that so hard? His approach=nobody wins, get it?

As far as MAF scaling and VE's go there is no difference between this car or any other as far as I'm aware, if you disagree please explain so we can discuss and learn something. If not, I have no interest in a pissing contest or watching ya'll stroke each others ego and offering zero evidence for your or his assertions.

Guess what happens when you do your homework on this car? Google returns comment threads where the so called experts are rolling their eyes because somebody is trying to help someone. Childish IMO..

 

Quote the insulting part of my post.

 

c'mon guys.. This should be a place of learning.

 

It is, all that is needed to know is already here. You just have to read between the lines.