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Thread: RX8 LS1, Tuning Advice & Data Logs

  1. #1
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    RX8 LS1, Tuning Advice & Data Logs

    Came here looking for some advice and to make sure my tune isn't going to blow up the car. Recently swapped an LS1 (LM7) into an RX8 and I'm going through the rigors of tuning.

    I've scoured the forms did things like Russk's idle config to make sure everything is good for Idle, also went into the repo and pulled a few similar vehicles to grab bits out of that make sense and finally I've watched LowbuckLS and High Performance Academy's videos but I didn't want to overwrite the base config with a bunch of cobbled together junk.

    I have my initial stating point, but here is what is in this thing.
    2000 Chevy Silverado, LM7 5.3 v8
    - Jegs, 228/230 112 (.585 / .585)
    - 862 Heads, LS6 'Blue' Springs, Trunnion Upgrade
    - 92mm DBC Throttle Body, no holes.
    - LS6 Intake
    - EV6 30lb
    - LS3 Camaro Shorty Headers
    - Full dual 3" Exhaust, no Cats
    - Full Fbody Camaro Accessory drive
    - 4L60E with the Corvette Servo swap
    - Yank 3600 Stall

    Now to put it nicely, this is my first time working with an engine with a Cam so I'm a little new in that aspect, as well as Auto transmissions in general, I've always driven manuals. Anyways, the tune I have in it seems to drive quite well, but it's very rich at idle just by smell. One thing I do not have is a Wideband, I'm working on getting one shipped now (If anyone knows a good place to get the Wideband bung welded up in houston hit me up!)

    Some things I'm noticing:
    - Smells rich at idle
    - Slight 'Cam surging' at low rpm
    - Shift points seem to be ok, but it kicks going from 1 -> 2 /// 2 -> 3 & 3 -> 4 is almost not noticeable.

    Here is the tune file and a log file. Just want to make sure I'm on the right track or if someone sees something glaring I'd appreciate a heads up! Not sure if I'm missing anything, but I'll get it to you if you need something extra.
    Attached Files Attached Files
    Last edited by [email protected]; 09-25-2020 at 04:01 AM.

  2. #2
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    That commanded PE is very lean for a starting calibration, try 1.22 or higher until you get a WB to look at then you can start going leaner, when you know where it is at. Under base spark corrections>fuel, remove the spark that is going to be added with this richer commanded PE, there's a lot in there. Can you log TPS and cylinder airmass, those help follow along in the spark tables?

  3. #3
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    Murfie,

    I've modified the PE tables a little bit and was hoping to run them by you, I pulled these from another tune that was close to mine, I think it's still a bit low but if you could take a look and let me know if this lines up more with what you were thinking. I was looking at the Spark Corrections > Fuel table and not sure how much I should pull out. The way I got these numbers was using the Scanner Command module to add spark to populate the table properly, RinkRat456 goes over this in the Idle Tuning guide so I thought that was good, could you take a closer look and see if I should pull those out more?

    I've added TPS and Cylinder Airmass into my Scanner and will go and give this a little run later this afternoon to get those values back to you, but for now I am attaching the updated tune and I'll attach logs when I can get them.
    Attached Files Attached Files

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    You wont know whats happening with the Power enrichment until you look at a wideband, its better to err on the rich side like I suggested, and a flat value across the table is fine until you get a wideband. The base correction fuel table shouldn't have anything to do with idle, cold start it might command a little rich, but once warm and in closed loop it is stoich and that table shouldn't be a factor, until it goes into power enrichment or some other open loop transient.

    This is the table I'm referring too. If you are not sure how to set it up to get a benefit from it, just zero it out for now, and simplify the spark to the HO/LO tables and the idle tables /w adaptive adjustments.
    Base spark correction fuel.PNG

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    I've dropped the PE Table to "0" Across the board when I saw this, I do have a log with the previous tune with those specifics that were asked for. I'll flash the new tune with PE zero'd out through the whole table and grab a new log after a drive tonight. Thanks for the quick drop with the table you were talking about. I'm really new to this but I did look up the specifics around PE and noticed that a Wideband is required for tuning this -- and pulling from another tune really isn't the best outcome.

    "Simplify the spark to the HO/LO and idle tables", you're saying to just modify the tables with one value instead? It seems to be running great, with those values, albeit they might be a little low with the removal of the PE table. Any guidance around this?

    If you see anything in this log that's concerning, please let me know, as well as anything else that's in the tune linked above.
    Attached Files Attached Files

  6. #6
    Tuning Addict 5FDP's Avatar
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    Never set the power enrichment EQ Ratio to zero, if you ask for no enrichment under full throttle it's going to command no fuel and possibly hurt the engine.

    Just set it to a 12.0 commanded AFR while you work things out and get a wideband.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  7. #7
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    These were the fuel changes I was suggesting until you could get a WB on it. Also avoid areas where it gets out of closed loop until you get the WB hooked up.

    quinchu changes.PNG

    These are the table you should be concerned with for idle spark.

    Idle spark.PNG

    Using the VCM scanner vehicle controls at idle, you want to see a few things.
    Once you found base running airflows that the car idles with(you have), you should take a log like I did posted below. One the car was warm, I started at a high commanded spark like 50, this closed the throttle(yours will be IAC) you maintain the desired RPM. I slower worked my way down to the low teens with spark. This showed me the idle spark the STIT wanted to be at, you kind of see the plateau around 0 STIT and 21/22* of spark. This is what I used in my idle advance tables. At 37* the throttle was closed as much as it could be, and MAP did not get any lower with more spark. This is what I used in my HO/LO tables. I then blend the values coming/ going on/off the idle table so there isn't a violent jump with airmass anywhere in the spark tables, no more than 3* per .04 cylinder airmass. less is smoother.

    From here you can use it as a base to set the base running airflow and idle spark to what ever you want as you will have the relationship between airflow and spark for your desired idle speed. whether it be you like 10* or 35* of spark advance at idle. The over/underspeed tables will also not work as hard and almost not even matter. The goal is to give the ECU the airflow and timing that match you desired idle speed, that allows it to predict events well and give a strong idle. fuel, air, and spark all good and your car will idle good. You want it to have control to open and close the IAC or raise/ lower the spark, so the middle ground is probably the best spot to put them.

    Your idle spark is too high, but I cant tell you how much too high untill you take a log like below and control the spark 1* at a time for 15 seconds, it should take a few minutes to go through all the different sparks and find where your Idle adapt wants to actually be.

    My idle spark capture.jpg
    Last edited by murfie; 09-29-2020 at 04:18 AM.

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    I setup my VCM like you had yours in the picture and I commanded spark from 50 down in 10-15 second intervals as you suggested. This is with the modified Tune with the changes you proposed. Trying to understand the plateau you were talking about I'm looking for the specific point at which it peaks, it seemed like it was idling very very well at around 35-40* and when I went lower than that it was a significant amount of hesitation and it would have to fight to keep the idle up.

    Here is the Log from that Scanning session and the new Tune with your recommended changes, hope it can help out with seeing where I'm going wrong.
    Let me know what you see in the logs, having a hard time making heads or tails of them.
    Last edited by [email protected]; 09-30-2020 at 04:23 PM.

  9. #9
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    Quote Originally Posted by 5FDP View Post
    Never set the power enrichment EQ Ratio to zero, if you ask for no enrichment under full throttle it's going to command no fuel and possibly hurt the engine.

    Just set it to a 12.0 commanded AFR while you work things out and get a wideband.
    I've set the PE to 1.2200 across the board for the time being, I saw your post before I flashed the 0 PE table and that was a very good thing. I haven't taken it out yet with the new changes, but at this point I'm a little terrified to drive it because things don't seem right with this tune at all. Strange thing is that I grabbed this tune from a vehicle that is modified almost like mine, same cam, heads, same injectors, same motor and trans, newer ECU though (had more options) so that might make a huge difference.

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    Lower your base running airflow Idle airflow to 8.5 g/s. I choose this value as its what airflow you see with your IAC closed, the "base", A lower RPM will make this lower, but I don't think you will want to go lower than what you have and Ideally the RPMs shouldn't ever go lower than idle. This is lining up airflow with RPM. Repeat the log and lets see if the IAC will open up a bit and allow for more spark control, you still had some idle adapt STIT even at 9* and never reached the plateau I referred too. It looks like 41-42* gave you the most vaccum, so thats a good low cylinder airmass value for your HO spark table. We are just finding values and populating tables in the calibration to get the ECU a better understanding of whats going on, what its controlling windows for RPM/ airflow should be. We will find a good spark here shortly. It will figure out the fine details with the spark when we are done with idle.

    Make both in gear and P/N like this. (adding 2.5g/s to each cell of a stock 5.3 table to get to that 8.5 value when hot, you were at +7 on the hot side and -3 on the low end from stock.)

    21 19.5 17.7 13 11 9 8.5 8.5 8.5 8.5


    Your IAC does seem a little out of control. Is it old or dirty? It might just be the effect of it trying to maintain idle with airflow not spark, although it seems like its only after the IAC open past a certain point, and starts to calm down the further open it was going. Then 189* IAT is kinda high, if you could open your hood to allow some cooler intake airflow while doing this that would be OK. Doing it with hot air like this can skew results a little.

    Heres a picture zoomed in on just the spark and Idle adapt from my previous pic, I marked where the plateau(spark window) is at 0 adaptive STIT. looking for a pattern in the noise, but it will be the spark at STIT 0.

    Idle adapt.PNG
    Last edited by murfie; 10-01-2020 at 05:23 AM.

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    So here is another tune and log, I did your recommend airflow and it seemed to be hesitating alot while trying to idle, of course that's normal for this thing so far. I did another 50 to 1 step down commanding spark, 50-35 it kept dipping really badly and catching itself to stay on, the lower the spark got between 15-1 it was idling really well, but there was a ton of knock on the graph -- if research has taught me anything, knock is BAD for the engine.

    Around the IAC question, it's a stock DBC Throttle body from an LM7 so it is very old. I have pulled it apart and cleaned it previously when I was doing the idle air tuning. Turned out to be not gummed up at all so I just did a light cleaning on it to make sure there weren't any problems, sprayed out the connectors to make sure those were good to and they were. New connector on the harness side so I don't think that has any bearing. Little more context from this run, hood is open this time so IAT is down substantially from what it was previously.

    Still not seeing that plateau you were talking about still seems to be pretty all over the place. IAC would jump up when the engine would almost die, but that's expected as well.

    Attached are:
    Current Tune
    Startup from Idle -> Operating Temp
    Commanding Idle -> 50 to 1

    Hope this helps out a little more. Really hoping to get this thing situated soon, but from what I've seen, tuning is an ongoing thing!

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    At idle there's not a lot of energy in the amount of air/fuel exploding in the cylinder so even if it is knocking its very unlikely to cause any damage. WOT knock is what damages engines. Also the likely hood of it being real knock and not just noise picked up by the sensors for something rattling, is extremely low, the main evidence for this is its occurring at lower spark values not the higher ones. Im going to say your IAC just doesnt like being relied on to control the RPM, thats ok I think you got all the info you need.

    I see the plateau between 24-26*, I made a math and smoothed the Idle adapt STIT so maybe you can see it easier. I also made the shape of the plateau I'm looking for. Your tune is calling for 24-26* at idle spark tables, so I think thats good. Base airflow was just a little high and tilted.

    Idle smooth adapt 24-26.PNG

    From the cold start log, everything is looking good. RPM flare is short and minimal. IAC valve is open and once warm is still open and in control of the idle air. Not ever open way too much. MAP at cold start is low and as it warms up it gets higher. This should make decel and throttle on tipin very good.

    Set your over and under tables to have less control and that should help smooth the spark out.

    over-under.PNG

    Make this change to your MAF curve and lets see if your fuel trims come back closer to 0. Multiply by .93 the MAF values seen at idle, removing 7%. Add MAF frequency to your channel list, and take another log. This one will be with the engine warm hood up, idle for 60 seconds, use pedal to raise RPMs to 1500 RPM for 10 seconds, then 2000, then 2500, then 3000. Doesn't have to be exactly perfect, just try to keep the throttle steady and build a stair case in the log. This will confirm more of the MAF is good and fueling is good.

    MAf fuel.PNG

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    I see exactly what you're pointing out now, that makes more sense to me, it was just so chaotic that I wasn't looking in the right place for that Plateau.

    Ok, so I took your advice from above, setting the over and under values to what you had in your screenshots, as well as setting those MAF frequencies. I'm going to attach the start up log again because it's kind of interesting, after those changes, I'm getting a ton of surging and you'll be able to clearly see that in those logs. It was causing the car to almost shut off and then pick right back up, then continue that for the entire duration it was idling.

    Even though that was happening I took another log with your steps from above, I warmed up the car, then I let it sit and idle for 60 seconds, after that I took the car to 1500, 2000, 2500 and finally 3000 (This thing is LOUD just sitting here idling, and it was almost painful with the 3k rpm, really to move away from straight pipes, wanting to get the tune at least on track before I throw any more money at this thing.

    I'll be attaching 3 files like last time:
    Current Mixtune - from the modifications you suggested
    Startup Log from Cold to Operating Temperature
    Step Log from Idle (60), 1500 (10), 2000 (10), 2500 (10) and 3000 (10)

    From just looking at the logs, it looks like it's getting way too much fuel as the STFT and LTFTs are trying to pull fuel from the config, which I have a feel is exactly the case. Again, complete amateur here.

    Any ideas why it's idling really badly now, I had the hood open and the IAT was lower as it's actually a nice night! Really hope this helps -- And thanks for sticking through this with me, I appreciate the support, tuning community seems to be a really great one when it comes to helping out the new guys.

    Some good news though, my AEM 30-0300 is coming in on October 9th, so I won't be without a Wideband from here on out.
    Last edited by [email protected]; 10-02-2020 at 09:53 PM.

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    I think that is too much on the underspeed correction, did you try +/- 8 degrees on both?

    It's going to be a game with the idle timing, it should like upper teens or right around 20 and the base running airflow is something you can play with too. It might want 8.0 or even 9.0g/sec at idle.

    I personally would also get rid of the timing pull at start with the ECT spark correct table, it's removing a lot of spark and if you aren't accounting for that on warm up it might be throwing you off.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

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    Still learning here, so bare with me. Underspeed / Overspeed correction was suggested by Murfie, and honestly I'm flying by the seat of my pants here, what do you mean by did I try +/- 8 degress on both? Like make them match, so in underspeed, make it 8 instead of the 17s I have in there right now? Also the ECT Spark correct table was copied from the Stock tune, my thought for that table is that based on the coolant temps that it would adjust the spark, I left it alone because I'm not sure what it would do if I played around with that too much. Could you give me a little bit of an explanation of the functionality so I can try to understand those modifications?

    Looking at the Base Running airflow table in Idle -> Airflow we actually bumped that up because what was gained from the Airflow config (RussK) was essentially false and didn't represent a good running engine. Murfie is trying to help me understand that spark should be the main indicator of a well running engine instead of just stuffing more air in and I am just trying to learn and understand.

    I have a 5* over cam, 228/230 112LSA, honestly if it wasn't already in I probably would have left the stock one, I didn't imagine that it could throw things off this much.

    A little backstory, I bought the car from a guy who was going to street it, some 'tuner' just threw a gto tune in it and called it good. I started back off with a stock tune and tried to look at other tunes with similar setups. I got it running quite well, but to be honest that was just tinkering and I had no idea if I could potentially hurt the engine. I had thought to take it to a shop and call it a day, but to be honest it's way more fun learning this than I had expected.

    This was the tune I pulled off the car when I first got HPTuners, It's UGLY so be weary.
    Attached Files Attached Files

  16. #16
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    You IAC control is causing that. I think its bad or your MAP sensor is. It should be a lot more stable that it is considering its a stepper motor and MAP is swinging wildly more than I would think possible from just the IAC valve. Ive seen bad alternators put AC ripple into circuits and cause all sorts of weirdness too, so diagnosis from a scanner log can be hard sometimes.

    17 degrees is commanded in the underspeed at -500 or less( 400actual rpm (900 idle target-500)) 25 idle spark+ 17 adaptive to give 42, which in the previous log I told you gets you the most MAP. At 400 RPM the engine is stalling you want to do all you can to bring it back to life. In reality we already know at the Base idle airflow your adaptive wants 24-26, to achieve the idle, after setting your base running airflow to the lowest MAF seen when IAC was fully closed, so 24-26 is the highest you will want to make spark, you can certainly go lower with spark/ higher with base airflow and open the IAC more(it seemed happier more open), just keep the relationship in the table and the ECU adaptive will be happy so you will never be more then +/- 50 RPM(+/-2*). Doing this will effect IAC on decel and throttle cracker, which may cause a cruise control effect instead of engine braking that may or may not be removed with reduced throttle cracker. This was all assuming your IAC would be stable which it is not. Before it started moving uncontrolled, you can see spark was already very stable. You can also see the MAF changes fixed your fuel at idle. I also see you picked up on what my log suggestion did and made the right call about what I was going to suggest next. People say you get a false lean reading tuning with open headers, but this is showing rich with open headers.... for tuning stoich, narrow bands are as good as a wideband. Its cold start open loop, Power enrichment and transients you need the WB for. And there's an argument to be made that you don't need it for cold start. The multiplier table gets rid of that ECT spark at low RPM when cold. It mainly for driving near peak torque RPM/light throttle before the car is warmed up. These tables are multiaxis tables not just a flat 2D table. What I want to know is why its at 30* and not the 24-26 in the idle tables. If you could add all the different types of spark channels to the scanner It might show something.

    Its not a game with it, I have a method behind all this, not just a feeling or a set of numbers I always use that has always worked.

    MAF fuel trims.PNG

    MAF fuel trims smooth adjustment.PNG
    Last edited by murfie; 10-03-2020 at 01:53 AM.

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    ** I haven't cleaned the MAF before, so I'll go grab some cleaner and spray it out tomorrow, it could be something like that as I have no idea what kind of life this had before. The alternator is brand new though, cables are routed away from anything sensitive (below / side of the block) and the other things are routed to the opposite side of the block.

    ** You're exactly right with the whole cruise control thing previously, this was happening on every drive with the old configuration. I'm not running open headers, it's a dual 3" into two resonators and then into some generic mufflers for the time being. I'm working on sourcing a ship to go 2 -> 1 into a borla rx8 exhaust I just picked up. Wideband also came in which is a big push to get the new exhaust since I need someone to weld in the Bung.

    Any specific spark channels you want to see added? I can add those channels and then do another run to see where that 30* is coming from.

    Since I've already pulled apart the IAC, do you think it would be a good investment to just go grab another one from a parts store and install it instead of trying to figure this one out? It seemed to work really well before we made those previous mods always sitting quite steady even at idle. I could do the same with the MAF but I think it just needs a good cleaning probably.

    ** I've made the modifications that you suggested in those two tables and I'll do another test tomorrow with the idle - 1500 - 2000 - 2500 - 3000 and I'll also include the startup log as well. If you get back to me in the morning then I'll make sure to add those channels and get those to you.

    Little side note, I'm going to do an IAC relearn that I saw in some other guides and see if that has any affect on the idle. I'll post a log when I do that in the AM.

  18. #18
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    See if you have these channels.

    Spark advance.PNG

    I know throwing money away at parts isn't something most like to do. It doesnt seem to like being extended far and closing the air channel. What you can do is unplug the IAC when you have the RPM surging and see if it stabilizes. If that happens and a relearn doesn't fix it, IAC valve is what I would replace. If it continues surging with IAC unplugged, then IAC is just trying to fix the surge caused by something else thats causing a vacuum leak. EVAP would be my next guess if you even have one, as it has a electronic controlled open/close. Then PCV system, if you are running one, as its open/ close is mechanical.
    Last edited by murfie; 10-04-2020 at 03:52 AM.

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    I'm really not shy about throwing a few extra bucks at something I can throw on and test to see if that's the problem. Can always return the parts if need be. I've done an extensive search for vacuum leaks and I've come up with nothing. Everything on the intake manifold and throttle body are on there, if you can suggest some place I might have over looked than I'm all for checking.

    EVAP and PCV systems have been removed due to this being more of an 'offroad' vehicle, didn't have them when I purchased the motor either.

    I'll go ahead and try the IAC unplug method to see if that works and will report back, also I'm going to add those spark channels and rerun the log from start up. Already made the modifications to the MAF table you proposed above, fingers crossed.

    Anything else you can think of, I don't mind trying, just let me know what it is!

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    I made those Modifications to the MAF and here are the results. It's still surging really badly. I did try to remove the plug from the IAC and that didn't help at all, I did the IAC reset to have it relearn the settings and it's topped out, if I add more screw depth then it just makes the TPS go up and stay there even after a relearn. Took the MAF out and cleaned it with MAF cleaner let it dry and put it back in. I also did another once over for vacuum leaks and came up with none.

    Here are the files from tonight, I made sure to add in those channels, but only 2 of them had data associated with them.

    Latest tune file
    Start up to Operating temp
    Idle - 1500 - 2000 - 2500 - 3000

    I hope those two extra channels can help out. It drops to about 300 - 400 rpm and then surges back up to 1000 - 1200 rpm, but that's all in the logs as well!