Results 1 to 7 of 7

Thread: Need help with understanding where to go from here on this tune/scan.

  1. #1
    Tuner in Training
    Join Date
    Aug 2015
    Posts
    35

    Need help with understanding where to go from here on this tune/scan.

    I have a 2007 Saturn Sky with the LE5 (2.4 NA) stock. I have added the K04 turbo off the LNF to the car with a mechanical boost controller, stock LNF cat downpipe, 60# injectors and a 2-bar MAP. Shooting for between 8-10 psi on the build peek boost pressure.

    I have tuned the fuel to the best of my ability and the trims are pretty close to where I want them after the car runs for a bit. I just flashed a new tune tonight into the car to try and start adding timing and when I did, I had KR across the board. (previously the car was pretty KR free).

    I am very new to tuning and have tried to figure this stuff out on my own by reading a ton and trying to wrap my head around the process. I just feel like I may be missing something here and would like you guys to check it out to see if there is something I'm just not getting.

    The tune here is meant to be for adding timing. The Good and Bad Fuel spark tables are identical. I took the previous good fuel spark table, added 2 degrees across the board, and copied it to the bad fuel spark table. Everything else in this tune is as before. AFR is set to around 11.2 in PE. KR seems to be coming in around 4,500 or so to about 3-4 degrees.

    Something doesn't look right in the MAP reading during the 1st gear pull but, being fairly new to the world of turbo chargers, I don't know what I'm seeing. It almost looks like belt slip on a supercharger setup. (Use to own a GTP and far more familiar with that car's PCM.) Any help, insight, suggestions would be appreciated. Just feel very lost right now.
    Attached Files Attached Files

  2. #2
    Advanced Tuner Dr. Nopps's Avatar
    Join Date
    Jan 2011
    Location
    I'm proudly a successfull stalker of an honor roll student!
    Posts
    368
    Just to cover some basics that you may have already thought about or might actually help.. If you're based off of the N/A factory tune you would obviously not be able to get away with as much timing now your turbo is on. I don't know what you saw in your scan you did'nt like but keep in mind a turbo may show lag that you wouldn't see on a belt/chain/gear driven supercharger. And lastly your exact AFR will greatly influence the threshold at which you begin to knock/detonate. You can safely pull out a little fuel by half or even a whole number at a time. Scan after every time to see if you're even making a difference. Consider getting a 180 thermostat, (heat will always be a contributing factor to that KR threshold as well) you may have to change over the housing to run one if they're not already offered in your style. Sounds like you're 99% finished so cool! And good luck.

  3. #3
    Tuner in Training
    Join Date
    Aug 2015
    Posts
    35
    Interesting. I've compared by tune to others in the repository and they seem to be running more timing than mine so I figured I should be able to up it some and they're running bigger turbos.

    I could set my timing back to what it was at then go with a little leaner mixture and see what happens there. At WOT I'm at 11.2 so that is pretty rich.

    For the 180 t-stat, in the old Grand Prix we use to go with lower t-stats...I ran a 160 in mine...but was told with the Ecotec engines that the lower thermostat may not be a good idea. Since I have seen no one use one, I figured they knew something I didn't. I wish I had heard this before the build. It is a PAIN to get to our t-stats. Requires removal of the cat and maybe the turbo. Not very user friendly.

    I figure the turbo may show lag but not this much. The K04 is used on the 2.0 and spools pretty fast so I figured it would spool faster on the 2.4 since you have a bigger air charge.

    The other thing I was wondering is if there is a change to the VVT settings since a NA engine's cam profile is usually a bit different from a Turbo engine.

    Thank you though for the help! I really appreciate it Doc.

  4. #4
    Advanced Tuner Dr. Nopps's Avatar
    Join Date
    Jan 2011
    Location
    I'm proudly a successfull stalker of an honor roll student!
    Posts
    368
    I'm mainly refering to the difference in timing on a N/A tune vs. forced induction tune in general, (supercharged Buick Regal 3800 compared to normal Regal for example) not so much the difference in your tune vs. repository tunes. You can try adjusting either timing or AFR or both to remedy the KR, just try them seperately at first to narrow down which one seems to have the biggest effect on your KR. In fact if backing off on one of those looks like the magic cure, you can usually tweak the other a little harder than you had been. The T-stat isn't really a must, and some will say it's not even worth it. But I've never seen anything other than great results, and wouldn't expect otherwise when the general operating temperature is lowered on a properly running fully warmed up engine. And running cooler should allow you to tweak it even more, generally speaking. I would'nt think one of those would really lag too bad. I was just thinking that with you paying so much carefull and close attention to your scans, you may have picked up on one of the very subtle differences in the parameters you're scanning between the turbo vs. the supercharged readings you've seen in the past. Just the way you described it made me think along those lines anyway, also being optimistic and all hoping everything is normal/healthy for that setup honestly. SIDENOTE: I think the incomming aircharge is what lags out a turbo & the exhaust gasses drive it but I can't find my textbook from auto class at the moment, I could be wrong. You may be able to reduce some of the EGR effect produced by the VVT but that's beyond just basics, so use discretion there if you even decide to mess with it at all. I think you can increase some valve duration a little on a turbo motor to gain some power, but not as much as on your old supercharged setup. If you use too much valve overlap alot of your boost can just go whistling completely through the engine preventing power production past a certain point. I also remember forced induction motors seem to enjoy a different heat range of spark plus as well. However I forget if it was just with supercharged motors or whether to go with colder plugs or what, just research that through reliable sources if it peaks your interest as well. Thats really about all I can think of. I hope it helps or at least clarifies what I was thinking earlier. That new 2.4 block is definately my first candidate so far for the lower end if I ever get back to building a turbo four banger of my own, so I really hope it keeps working out for you as well as it's been doing so far.
    Last edited by Dr. Nopps; 06-07-2016 at 12:20 PM.

  5. #5
    Tuner in Training
    Join Date
    Aug 2015
    Posts
    35
    Thanks Dr. Nopps.

    Well, the mid to high end of the tune seems to be FUNCTIONING well but the trims look horrible and the idle is demonic.

    I found my car is fine running a leaner AF. I'm at 11.8 and ran as lean as 12.6. At 12.6 there was some KR and at 11.8 there is none while the engine runs great. However, once I did my VE Tuning and got the table to get my trims around +/- 2% then did my MAF tuning and got the trims around the same I put the two together, set the switch over from VE to MAF to occur at 2,000 rpms and turned things like the coast down and COT settings back on, the trims are all over the map and horrible.

    Some are -20 LTFT + STFT...some are <1...some are +7. If I put the transition to MAF from VE at 3,000 rpm and go to accelerate between 2 and 3K rpm, the fuel goes wicked lean (+18:1), the engine stumbles then comes back. Reducing that to 2,000 rpm got rid of that.

    However, when I'm slowing down and come to a stop, the actual AFR goes wicked lean again (17:1+) stays there for a bit, then settles down. I don't know why it only does this once I kind of "finalize" the tune and turn the coast down and COT back on but it's frustrating the piss out of me.

  6. #6
    Advanced Tuner Dr. Nopps's Avatar
    Join Date
    Jan 2011
    Location
    I'm proudly a successfull stalker of an honor roll student!
    Posts
    368
    When tuning this way, (much newer car than I'm used to) did or do you even have to exclude all of the data from below 2000RPM while MAF tuning/scaning process with a filter or something?

  7. #7
    Im not an expert with those pcms but you will probably wanna tune the VE and MAF in separate open loop files by failing the MAF for VE only and setting dynamic to 400rpm for MAF only, if youre not doing that already. That way both tables are accurate in case of sensor failure. Then blending shouldn't be an issue.

    As for knock I would try starting at some pretty low timing on 93 octane and then try bringing it up. Even LNF cobalts usually run about 16deg i believe at WOT on 93, and those engines have lower compression ratios. Try running just like 10deg just to be safe and get the KR out then work your way up