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Thread: Tuning the 1.4t Cruze - A Mildly Scientific Approach

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    Tuning the 1.4t Cruze - A Mildly Scientific Approach

    **DISCLAIMER - I am not responsible for you blowing up your engine. Take my results and advice with a grain of salt! This is not a definitive guide and is more me learning along the way and documenting my results. This document is updated as I go, please do not be upset that it isn't 100%

    **NOTE - Please read the Help section of VCM Editor to understand how the ECM works. Some of the info is confusing due to flip flopped and incorrectly named stuff, but the basics are there and thanks to the HP Tuners staff for putting that together

    **KUDOS to Chris from HPT, other tuners, and the EFILive folks for helping me understand what I'm doing.

    This is a good link with comments from Chris that are helpful: http://www.hptuners.com/forum/showth...-Tuning/page11


    The 1.4t Chevrolet Cruze is an economy car with an economy turbo, an economy engine, and an economy tune. Out of the box, the car is setup to run as lean as it can and make enough power to make the car mildly enjoyable.

    Preparing The Tune -

    The first thing that should be done is to prepare your tune to take added boost. To do this, I reduced the timing a little and fixed Power Enrichment settings to be richer and faster(disabling delay). I have attached a tune where you can see what I did with timing and Power Enrichment to an otherwise stock tune. It is always ideal to use a wideband too! Unfortunately, I do not have my wideband hooked up yet so I'm playing with fire, don't be dumb like me. On the flip side, people are buying mail order tunes left and right without this being an issue...

    Adding Boost -

    The first thing you can do is go out and do a run on the highway and somewhere safe away from other vehicles to see what your car is doing stock in terms of boost. For my tests, I get on the highway and do a 40 to 70mph WOT run which is perfectly legal.

    With the stock tune, I am hitting and commanding around 12-13lbs of boost. I hit about .65 g/cyl here -



    Now, I want to get more power out of this bad boy. Everything I have read says "Just up the torque limits!". Ok, I'll take this advice and record what happens.

    Engine > Torque Management > General > Peak Torque & Brake Torque Limit

    I added 100 to both of these to start with.


    Next, I went out on the road again and logged. Check this out. Granted, it's not pure apples to apples, but the point is to illustrate how my desired boost and delivered boost have both gone up. Not pictured is how my airmass has now hit the 0 degree knock airmass limit of .70 g/cyl



    That is an extra 3lbs of boost to get me to 16 just from upping the torque management.

    Seeing that I was hitting a .70 g/cyl airmass, I figured maybe the Knock Airmass boost control limiter was limiting me, so I upped these limits for 0 knock, probably higher than I plan to make power-wise.

    Engine > Torque Management > Turbocharger > Knock Airmass


    I then logged with these changes. A little more desired boost, but not much.


    Thinking back to the help file in VCM Editor and what some others have said, I figured now would be a good time to up the Driver Demand table to tell the computer I want to make more power.

    Engine > Torque Management > Engine > Map A - Normal


    Back to logging I go...


    Sweet! More power! I also got some knock when hitting the throttle lightlywhile cruising, so I'll need to do something about that.
    Attached Files Attached Files
    Last edited by Gh0st; 05-08-2013 at 07:45 PM.
    2012 Chevy Cruze A6 1LT RS

    Formerly - 2004 GTO, 2002 Z28, 2007 Colorado, 2008 Silverado

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    Last edited by Gh0st; 05-06-2013 at 02:14 PM.
    2012 Chevy Cruze A6 1LT RS

    Formerly - 2004 GTO, 2002 Z28, 2007 Colorado, 2008 Silverado

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    Senior Tuner cobaltssoverbooster's Avatar
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    those poor injectors lol
    80% doesnt leave you guys much room does it.
    2000 Ford Mustang - Top Sportsman

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    Quote Originally Posted by cobaltssoverbooster View Post
    those poor injectors lol
    80% doesnt leave you guys much room does it.
    Nope. Once I hit ~230kpa these puppies are in the 90's. Stock these things have an aggressive turbo overtemp protection that commands ~10.5 AFR. I've leaned that out to my commanded 11.3 but it's still bad.
    2012 Chevy Cruze A6 1LT RS

    Formerly - 2004 GTO, 2002 Z28, 2007 Colorado, 2008 Silverado

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    Ill be watching this, Ive got my eye on a 1.4L Sonic as an eventual DD. Love my V8, but the 15-16mpg hwy is hard to swallow as a DD.
    ~Erik~
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    Tuner snowvette's Avatar
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    Quote Originally Posted by Gh0st View Post
    Nope. Once I hit ~230kpa these puppies are in the 90's. Stock these things have an aggressive turbo overtemp protection that commands ~10.5 AFR. I've leaned that out to my commanded 11.3 but it's still bad.
    So injectors could be a power adder.
    2007 Chevy Trailblazer SS AWD with boltons GP tuned
    2012 Chevy Cruze A6 LTZ RS Vermount Stade 0 tuned

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    Quote Originally Posted by snowvette View Post
    So injectors could be a power adder.
    Don't get me started on that!!!
    2012 Chevy Cruze A6 1LT RS

    Formerly - 2004 GTO, 2002 Z28, 2007 Colorado, 2008 Silverado

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    Senior Tuner cobaltssoverbooster's Avatar
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    Lol those bad boys are like why he going wot I got nothin left!!
    Definitely a good read so far though. Hope you keep em coming.
    2000 Ford Mustang - Top Sportsman

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    Quote Originally Posted by Gh0st View Post
    Don't get me started on that!!!
    LOL, saw that.

    Great job Gh0st, looking forward to updates! Same test with drivers demand tables maybe? Wish I had more time to experiment.

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    Quote Originally Posted by Regalgse View Post
    LOL, saw that.

    Great job Gh0st, looking forward to updates! Same test with drivers demand tables maybe? Wish I had more time to experiment.
    Done! My next step is to up the driver demand tables even more to see what will happen as something is still limiting me from the full 230kpa that I set for my max limit. Between work, kid, and the crappy weather lately, it is really hard for me to find time to experiment and especially do so with as much detail as I need to. I haven't even commented yet on what I'm logging and I'm not 100% sure I understand how all the limiters work yet to completely determine what is holding me back.
    2012 Chevy Cruze A6 1LT RS

    Formerly - 2004 GTO, 2002 Z28, 2007 Colorado, 2008 Silverado

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    One thing I've noticed that is slightly scary to a relative boost noob is when letting off the gas, the measured boost kpa spikes to 240-250kpa. Would this indicate the BPV?
    2012 Chevy Cruze A6 1LT RS

    Formerly - 2004 GTO, 2002 Z28, 2007 Colorado, 2008 Silverado

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    Will update my first post probably tomorrow. But I wanted to give an update.

    I have found I am still being limited my torque management. When logging peak torque, I am finding a direct correlation between my peak torque number and how much boost the ECM will command. I decided to make my peak, brake, and overboost limits all exactly the same and that has brought me from 224kpa to 229kpa desired in some spots.

    I figured it was torque management because I would line up my peak torque reading with the RPM axis and saw that my peak torque was going up and down almost perfectly in line with what my tune states for limits.

    Tomorrow morning I'm going to set my Engine TM tables to 300 across the board to see if the desired KPA holds beyond 260ft lbs of peak torque.

    I'm also having a really bizarre issue with *light" throttle. I'm talking about just tapping the gas pedal -



    I've also attached my latest log if anyone wants to observe.

    ***EDIT: I could be wrong about the torque management, but maybe not. With the change to 300 for the TM tables, I have started commanding 229kpa in some areas, but not completely.

    There are two tables I haven't touched yet that, according to the E78 guide, are also related to modifying my desired boost -

    Pressure Delta Factor - The E78 help guide says this controls how much the boost increases per cycle.
    Overspeed Limit Min - I don't understand this one at all. VCM Editor says "overspeed limiter airmass cannot go below this value. Set this high to remove turbo overspeed limiting."

    I'm going to raise the Pressure Delta Factor to 1.5 across the board and see what effect it has. The challenge with this for me is that I have another tune that seems to have no boost/torque limit and gives me max boost, but I didn't understand how I got to that point other than plugging in numbers in tables.
    Attached Files Attached Files
    Last edited by Gh0st; 05-08-2013 at 12:55 PM.
    2012 Chevy Cruze A6 1LT RS

    Formerly - 2004 GTO, 2002 Z28, 2007 Colorado, 2008 Silverado

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    Continue the good work. I think many people are watching.

    According to the histogram from the log you posted calculated peak torque was 177, maybe I fell behind but where are you getting the 260 lb-ft from?

    Also what is the issue your having. Is that a max timing histogram?

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    Quote Originally Posted by Regalgse View Post
    Continue the good work. I think many people are watching.

    According to the histogram from the log you posted calculated peak torque was 177, maybe I fell behind but where are you getting the 260 lb-ft from?

    Also what is the issue your having. Is that a max timing histogram?
    I was logging Peak Engine Torque which I have now stopped logging as I'm not sure it matters and that is what I was basing my info off of.

    Maximum Engine Torque is also what I am logging(I think that is the 177 figure) and according to the E78 Help Guide, if my Predicted Engine Torque Cmd is *higher* than my Maximum Engine Torque, then I am still being limited by torque management. In this case my Predicted is indeed higher than the Maximum reported.

    That timing screenshot is knocking. Doing 70 on the highway, lightly tap the gas pedal and I start picking up 1-2 degrees of retard in that range, it's pretty weird.
    2012 Chevy Cruze A6 1LT RS

    Formerly - 2004 GTO, 2002 Z28, 2007 Colorado, 2008 Silverado

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    Have you seen a 2013 Cruze file? Way less timing almost everywhere. I can see why. Every time I take mine out and scan it, I'm pulling timing.
    2007 Chevy Trailblazer SS AWD with boltons GP tuned
    2012 Chevy Cruze A6 LTZ RS Vermount Stade 0 tuned

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    Quote Originally Posted by snowvette View Post
    Have you seen a 2013 Cruze file? Way less timing almost everywhere. I can see why. Every time I take mine out and scan it, I'm pulling timing.
    Can you upload one? These engines are designed for 91octane and Id be interested to see what else is different.
    2012 Chevy Cruze A6 1LT RS

    Formerly - 2004 GTO, 2002 Z28, 2007 Colorado, 2008 Silverado

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    Setting the Pressure Delta Factor to 1.5 across the board is helping. I'm now hitting a max desired of 240kpa(my Boost Max Limit) but the desired starts to slowly trail off around 4800rpm. I'm pretty happy with this as it seems these things don't do much past ~5200rpms anyways. However, I wonder if there is a way to get the actual boost I get to ramp us faster...

    2012 Chevy Cruze A6 1LT RS

    Formerly - 2004 GTO, 2002 Z28, 2007 Colorado, 2008 Silverado

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    You da man
    2012 Chevy Cruze A6 1LT RS

    Formerly - 2004 GTO, 2002 Z28, 2007 Colorado, 2008 Silverado

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    Quote Originally Posted by snowvette View Post
    Have you seen a 2013 Cruze file? Way less timing almost everywhere. I can see why. Every time I take mine out and scan it, I'm pulling timing.
    Stoich is 14.13 for E10?

    The tune has more timing than mine does in the cruising area but WOT is less. There's more static retard.

    Overboost Limit is zeroed out. The Knock Airmass boost control table seems better.

    Fan profiles are more aggressive.

    I don't know. I guess I need someone else to also pull a 2013 tune to verify. I could be wrong and it is 100% legit stock.

    I attached the differences file
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    Last edited by Gh0st; 05-09-2013 at 07:20 AM.
    2012 Chevy Cruze A6 1LT RS

    Formerly - 2004 GTO, 2002 Z28, 2007 Colorado, 2008 Silverado