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Thread: The LNF Tuning Guide

  1. #21
    Pretty sweet... Think about doing a guide for Short Term and Long Term Fuel Trims and everyone should be pretty well set.

  2. #22
    Advanced Tuner 383_Stroker's Avatar
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    Nice write up!

    I'd kind of wandered my way down the same path as many of the changes you recommend.. glad to see that..LOL

  3. #23
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    Wow you are really helping people understand how the lnf works. Not only are you telling people how it works but you are sharing everything you have and asking nothing in return. Your basic tune is about the same thing i have been running, My timing is just a little bit different, I think it has alot to do with the fact i have a hhr not a cobalt.

  4. #24
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    So to put down this power, are you running the pill or not? If so, what kinda boost are you getting and are you using these dals and whatnot. Also what mods do you have, obviously you have the stock ic lol.

  5. #25
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    Well, one major factor would be the time between runs. It doesn't sound like he had a ton of time between runs, and he said the stock intercooler held him back pretty bad. So, I am going to chalk up the power loss to heat soak, tbh.

  6. #26
    Senior Tuner BackyardTurbo_FTW's Avatar
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    So I ran the Stock timing 2nd....You would think I wouldnt have gained a peak of 10whp using your logic there. And I ran them on another car with stock first and exh table 2nd, lost whp on that car too. If you feel you are gaining power, then run it. But the dyno doesn't lie.

    I made 321/392 running the pill. Obviously I didnt post my exact tables, so no.

  7. #27
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    So even on the car without the pill it was the same result cam timing wise then? Thats great to know abot cam timing, just because you flow more air through the engine doesnt mean its holding it all in lol.

  8. #28
    Senior Tuner BackyardTurbo_FTW's Avatar
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    You can see the MAF goes up but the VE goes down.

    And I tried it on 3 diff cars actually, the almost stock car showed lil change over the modded ones. I will have all the graphs up shortly

  9. #29
    Senior Tuner BackyardTurbo_FTW's Avatar
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    Pill Mod, Stock Exhaust Cam vs Modded Exhaust Cam


    This is a Stock Parts + Tune car:


    This one is Catless DP + CP + 22psi Tune:



    Even with the stock Exhaust Table you can see that lil dip at 6K. In the Term one that seems more exaggerated so Im going to try going the OPPOSITE way at just 6K and try and remove that lil dip.
    Last edited by BackyardTurbo_FTW; 10-12-2009 at 11:48 AM.

  10. #30
    Senior Tuner BackyardTurbo_FTW's Avatar
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    Here's one I thought was interesting, helps the thread here with the Section 2 mods


    That is the Pill mod vs a straight tune. Same exact mods on either car. Look at the gain in mid range whp!!!! Almost 50whp gain in the midrange While Im nervous about running this much boost, it def is making gains!!! Cant say that 22psi and 25+ will make the same power anymore

  11. #31
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    Why does your dyno chart look like a 2 year old got a hold of some crayons?

  12. #32
    Senior Tuner BackyardTurbo_FTW's Avatar
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    LOL! Thats the clutch slipping unfortunately

    We call it the MSPaint dyno

  13. #33
    Advanced Tuner Gimpster's Avatar
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    Hmrph, very interesting... that thing just heads south like no other and the whole curve in general got owned.

    I'd been tuning mostly ignoring VE Airflow, and you're absolutly right... MAF goes higher but VE falls on its ass a bit when retarding the exhaust cam. I'd been ignoring VE Airflow because of what a few people said to me on here (and what I'd read), and also because that PID isn't able to be calculated by the PCM when the MAP's are pegged. Like on most of my runs with the pill mod VE Airflow is at 67.725 lb/min heh. I just assumed because of that the whole PID was useless. Maybe it has a bit more meaning than I was giving it credit for.

    I went back and really carefully examined my logs. Sure enough, even though MAF airflow is up load % is down by about 4-5% on average with the exhaust cam retarded.

    I think I'm going to start tuning off that more and ignore the airflows, because if the car doesnt think the load is high.... y'know?

    The loop-d-loop graphs are pretty awesome the FWD LNF cars are a stimulus to the clutch industry.

    EDIT: I don't know what to attribute my trap speeds to except better driving I guess. Fuckit.
    Last edited by Gimpster; 10-12-2009 at 10:11 PM.

  14. #34
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    Cooler air seems to be getting me quite a bit more trap. But, I was also adjusting the timing for the cold weather too.

  15. #35
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    VE airflow is actually a very useful PID. BTF previously correlated it very closely with whp/10 on his dyno. When someone who owns a dyno and has made as many significant modifications and reflashes as him can say that, i'd say its significant.

    Personally, i look to VE airflow when i make a hardware or tune change

    Quick edit after re-reading somethings: Making the numbers more negative is cam ADVANCE. Making them more positive is cam RETARD. Hence the tables shared here are advancing both cams. Food for thought - doesn't overal cam advance move the powerband to lower RPM?
    Last edited by oldskool; 10-13-2009 at 06:22 AM.
    2013 Cruze Eco - CAI, Catless DP, Catless MP, ZZP FMIC, Ported Intake Manifold, Mild tune (17psi), best 43.5mpg, 175ftlbs (pid)

    2008 Solstice GXP - ZFR 6758, catless, AEM stage 1 water/methanol injection, Hahn Racecraft Intercooler, solo street race cat back, LE5 throttle body - 307whp on a dyno dynamics (stock turbo numbers), 100 octane EFR6758 numbers - 463whp/454wtq

  16. #36
    Senior Tuner BackyardTurbo_FTW's Avatar
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    I dont know if this is accurate but it seemed to work on the dyno. I think of the MAF as air being pulled in and the VE as air able to be used by the engine. So if I see a rise in MAF and a dip in VE, I think to myself Im pulling more in but not actually consuming that air.

    I just use that logic in my head, Im sure its not in any way scientific, just made sense after watching a bunch of dyno pulls and logs

  17. #37
    Advanced Tuner Gimpster's Avatar
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    The issue is when you're using the pill that PID is floored for a good portion of the RPM band when you're at the upper limit of the MAP's. At least it is on my car, to 67.xxx lb/min. The only thing I had to go off at that point was MAF airflow. I mean maybe if we ever get a 3bar option on the table that won't be an issue. It just seemed weird to me to base my tuning off an incalculable PID. Are none of you other guys seeing the PID peg to its upper limit like me during pulls?

    On the exhaust cam tuning... I'm 99.99% sure that - means retard and + means advance on the exhaust cam, but who knows I'm starting to feel stupid anymore. If you log it after subtracting from that table the logged * is less, and if you config a custom overlap PID that also moves in the right direction. Both line up perfectly with what my RPD show me on the cam phase screen too.

  18. #38
    Senior Tuner BackyardTurbo_FTW's Avatar
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    I read 31-33 VE thru the band even with the 25+ psi. I did do another car with the pill that read 60's at some point, he had a faulty map sensor tho!!

  19. #39
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    http://www.hptuners.com/forum/showthread.php?t=22247

    Please see that thread - the best i could conclude is that + is retard and - is advance (see page 1). If anyone has proof otherwise i'm open to it for sure, but a custom overlap PID only works if you know what the sign on the values mean. The thread above has some nifty formulae for calculating change in overlap and cam advance/retard. Its too bad we can't get clarity from Chris or Bill on what the signs correspond to.
    2013 Cruze Eco - CAI, Catless DP, Catless MP, ZZP FMIC, Ported Intake Manifold, Mild tune (17psi), best 43.5mpg, 175ftlbs (pid)

    2008 Solstice GXP - ZFR 6758, catless, AEM stage 1 water/methanol injection, Hahn Racecraft Intercooler, solo street race cat back, LE5 throttle body - 307whp on a dyno dynamics (stock turbo numbers), 100 octane EFR6758 numbers - 463whp/454wtq

  20. #40
    Advanced Tuner Gimpster's Avatar
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    First off.... I tend to be a very visual learner. I'm not stupid, but sometimes things come to be a bit slow until I can visualize in my head how it works.

    On the cam timing issue:

    oldskool, I've read that thread before, and thought I had understood what it all meant but obviously I didn't comprehend. However, after doing some other reading on my own I'm starting to realize what it means. I looked at an old cam card I had for MR2 and it says: Overlap is calculated by adding the intake valve opening timing (before TDC) to the exhaust valve closing timing (after TDC). Draw that out on a paper and it all makes sense.

    AHA, and with the PID I made below the overlap DOES decrease. That should've been my first clue all along.

    Okay, several things. Here is the PID I made for cam overlap, its really simple and stupid:

    [PID.2172] + [PID.2178]

    This custom PID agree's 100% with what the RPD is showing me for overlap on the cam phase screen, but maybe I'm dumber than I thought and its bunk. I mean we've already proved the RPD to be incorrect/questionable in other areas. It would mean the *'s logged have to correspond to the statment on the cam card I bolded above to be correct.

    SO okay, I understand now and agree that + is retard and - is advance. It would be nice to get clarification from HPT, but not holding my breath. It also shows that this motor does enjoy overlap.

    ---

    On the VE airflow issue:

    Here's my car logging VE airflow on a typical run with the pill installed:



    Without the pill everythings hunkydory and I also have no DTC's set even with it in. I just assumed the MAP's were maxxed out until the upper RPM range and so VE airflow then fell back into range.

    Idears? Doesnt seem to hurt anything except my ability to log VE airflow.
    Last edited by Gimpster; 10-13-2009 at 10:18 AM.