Tune and Log Review Request - twa track session in an e85 LFX swapped mazda rx8

[Rx8-LFX]

Hello,

I am hoping some of the more knowledgeable users could review my Tune file and two log files from a track session in my LFX-swapped Mazda RX8. Do I understand the logs correctly, and does it show that my throttle body never opens 100%? This is a Camaro 2014 LFX with flex fuel and around 78% E85. I would appreciate any feedback a lot.

Thank you.

2007_LFX_RX8_Flex Fuel Enabled 5-3-25.hptLog-0006-2G1FF1E37C9164334.hplLog-0007-2G1FF1E37C9164334.hpl

[KillboyPowerhead]

Looks like an E39 ECU and a 2012 LFX? Not sure how different it is from the 2014 E39A, however. Found in Edit > Calibration Details.

What polling rate are you using for the channels? Log looks very choppy. Could do at least 50ms polling rate with no issues.

There are many throttle (and accelerator pedal) position channels to choose from for some reason - just add all of them and see which one shows 100% and then remove the rest. Otherwise looks like the throttle is behaving as it should (following the pedal position).

Curious what intake and exhaust you're running. Any engine mods? Tune looks fairly stock or close to it in a lot of areas such as VVE, MAF, SOI, VVT, spark.

[Rx8-LFX]

@KillboyPowerhead,

Thank you for your feedback. This was the first time I used the log function and pretty much used the default channels as I was setting the standalone loging the night before the track day. I have to learn about the VCM and the logging config so I appreciate the pointers about the rate and channels. I will play with those.

This is running on e39 ECM, and the swap kit provider sets up all those as a 2012 LFX. I have a JacFab IM spacer, the exhaust has racing cats in the dowpipes and then is open all the way to the muffler with a flow through 3" HKS. I do have a solar performance 76mm TB but have not installed it yet. The air filter is in a tight location and is not a Cold Air Intake for sure LOL. This swap kit is shipped with basically a stock tune with only the changes necessary to make it work in another chassis. I would not mind a bit more power to be honest but will stay with the stock engine (internally) for sure. Just want to be able to take advantage of the e85

I added the e85 sensor and enabled it in the ECM. I did see that the timing adder table for the e85 added had quite a bit of timing added so I was happy about that.

I also have quite a bit of rev hang which is a bit annoying. I am trying to learn what changes I would need to make to take advantage of the e85 flex system and how to eliminate the rev hang.

Thank you.

[KillboyPowerhead]

Just by looking at your MAF I'm thinking you could get more out of what you have; based on your log I see upwards of ~190 g/s which is ~8850 Hz on the MAF, whereas I'm at ~240 g/s at 8850 Hz - I do have MACE cams but I estimate that they account for about 10% extra airflow, so I suspect you could still see another 10% from where you are now.

I also noticed in my testing/logging that intake air temps make a pretty significant difference so hopefully you can direct the outside air toward the filter. On my 2015 Camaro I removed the driver's side fog light to get more air into the filter area (not sure how much of a difference that made, but the surrounding area/bottom of the hood are dirtier than before so there's definitely some extra air flowing toward the filter. Also thought of adding a duct pointed at the filter but was worried that the filter would get soaked when it rains).

For spark, I'm using 91 and for the most part I'm 5 or 6 degrees more advance vs stock (tuned for 87 from factory); with 93 I think you can get another degree or two; not sure how much farther you could go with E85, or if there even is a need to go farther (wherever MBT is).

Not sure how much there is to gain by adjusting the variable valve timing with stock cams; guess you could just do a bunch of WOT pulls and see what your max airflow (MAF Hz) is, then advance/retard the intake a couple of degrees from 4000 RPM toward redline and see if the MAF (Hz) reads any higher, at least that's what I did when playing with the MACE cams. Likewise I don't know if there's anything to gain by adjusting SOI unless you adjust the VVT; you just want to make sure you're not injecting before the exhaust valve closes.

[Rx8-LFX]

KillboyPowerhead, Thank you for the additional feedback and for pointers on how to go about tuning the MAF and VVT. I will definitely try to figure something for the cold air intake.

How much timing do you see at WOT, I can tell that the e85 adder table adds as much as 25 degrees of timing to the base tune and I have seen around 15 degrees at WOT on the original tune and now I am seeing as much as 38 degrees at WOT with the E80 in the tank.

[KillboyPowerhead]

I'm at 28, 29 degrees at the higher RPMs, higher airmass. My spark tables were adjusted by my previous tuner (Overkill), and considering he made a business out of tuning I imagine he spent some time on a dyno to prove his work. I don't know much about E85 but I'm guessing you'd inherently need more advance compared to gas simply because the air/fuel mixture burns slower? But who knows how much more advance to compensate for this (I guess whatever the E85 adder tables says? However that was determined), but I guess it makes sense that you should have at least more advance than 28 or 29.

[Rx8-LFX]

Thank you again for your feedback. It helps a lot to have a baseline. I will continue adjusting the tune and will report on my progress here ;-)