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Thread: Idle Tips & Tricks

  1. #21
    R.I.P Shawn, 1956-2011 WeathermanShawn's Avatar
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    Does look like several people have reported positive results from using MAF Airflow as their Desired Air.

    Thanks again for the positive feedback!
    2002 Black Camaro Z-28 M6 Hardtop 11.0:1CR 425HP/410TQ SAE (400TQ@3500RPM)
    200cc Heads, 228/232 110+2 Cam, 1 3/4" LT's w/catts, GMMG, Koni Shocks, Hotchkis Springs, 35/21 Sways, 17" ZR1's, 3.90 Gears Roadrunner PCM LM-2 Serial Wideband
    EFILive Closed-Loop MAF/SD Hybrid Tune..


  2. #22
    Lifetime Member 5.7ute's Avatar
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    Quote Originally Posted by WeathermanShawn View Post
    Does look like several people have reported positive results from using MAF Airflow as their Desired Air.

    Thanks again for the positive feedback!
    Yep, get maf,raf & dynamic airflow to match & you shouldnt have too many issues.
    FWIW I think the rafig issue is something to do with the way the pcm uses IAC effective area to calculate airflow. I dont have the necessary skills to read exactly what formula the pcm uses, so I am currently trying to work this out.
    IMO what is happening is the lower pressure delta across the IAC from the cammed cars lower idle map has a few flow on effects. These being that the IAC port may be too small to allow enough air to flow through at idle,(Common with some aftermarket throttle bodies) Or quite a few more steps are needed by the IAC to get the required area. We get around this by either cracking the TB blade or drilling a hole in the TB. When this has been done the IAC effective area needs to be changed.
    If you have only drilled a hole in the TB it is quite easy to get this table back in line. For example a 5mm hole in the TB will increase the effective area by 7.8sq mm.(compared to no hole) So you would shift the IAC effective area values down 4 cells.(there is 2sq mm per cell). If I fit an aftermarket TB I measure the IAC passage & compare this with stock. If it is smaller I will also calculate this difference, & once I have it idling at the right amount of steps use this value with the hole size(If drilling was needed) to calculate effective area.
    Last edited by 5.7ute; October 19th, 2010 at 01:12 PM.
    The Tremor at AIR

  3. #23
    R.I.P Shawn, 1956-2011 WeathermanShawn's Avatar
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    I have added a link (also on Idle Tips & Tricks page 1..) that illustrates various tunes for LS1's. These have the majority of Idle Parameters included! As always, I highly enocurage you to build your own custom tunes..

    Enjoy:http:///forum.efilive.com/showthread.php?14661-LS1-Beginners-Tunes&p=131973&viewfull=1#post131973
    2002 Black Camaro Z-28 M6 Hardtop 11.0:1CR 425HP/410TQ SAE (400TQ@3500RPM)
    200cc Heads, 228/232 110+2 Cam, 1 3/4" LT's w/catts, GMMG, Koni Shocks, Hotchkis Springs, 35/21 Sways, 17" ZR1's, 3.90 Gears Roadrunner PCM LM-2 Serial Wideband
    EFILive Closed-Loop MAF/SD Hybrid Tune..


  4. #24
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    I had a problem in my FI/cammed/M6 car where the RPMs would hunt from 500-1200 whenever I pushed in the clutch after being in gear. Like when rolling up to a traffic light, push in the clutch, then the engine would rev up and down by itself. Once at a complete stop, it would settle down to a steady 850rpm idle.

    I tried B4309-Throttle Cracker Airflow in Gear (TC) and it did absolutely nothing to solve this problem. Then I did a little experiment and got the car moving, pushed the clutch in, put the tranny in neutral and let out the clutch (still moving). Ahhh, the RPMs held at 1200 rpm with no hunting. Pushed the clutch back in and the RPMs started hunting again.

    That experiment made me start looking at the B4310 Throttle Cracker Airflow in P/N table. Mine was originally set to all 0s. For grins I set the entire table to 3 g/s. Took it out for a spin and pushed in the clutch and the engine held a steady 1100 RPM or so. A little tweaking of that table to get the RPM where I wanted and reducing it a bit at the lower speeds got it transitioning real nice as the car rolls to a stop. So B4309 is only active when the clutch pedal is out, and B4310 is active when the clutch pedal is in.

    Might be worth adding to the first post as M6 cars are in P/N much more that auto cars.
    2001 Camaro SS
    Built 370 LQ9, Ported 243s, D-1SC 14 psi. 691 rwhp, 643 rwtq
    Best time: 11.6@124 on nitto drags with a 2.1 60'
    "if you're gonna build a time machine into a car, why not do it with some style." Dr. Emmett Brown

  5. #25
    R.I.P Shawn, 1956-2011 WeathermanShawn's Avatar
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    I'll have to try that out. I guess I was under the impression in a M6 that those Tables are generally not applicable..but your experiment indicates it has more of a role than previously thought.

    Probably most of us want Airflow to decrease during shifts..no one wants Rpm's to increase during the shift, but I will definitely try it out on the RoadRunner this week.

    I appreciate the tip. I may have to think it out a bit, but again many thanks for sharing your experiment..
    2002 Black Camaro Z-28 M6 Hardtop 11.0:1CR 425HP/410TQ SAE (400TQ@3500RPM)
    200cc Heads, 228/232 110+2 Cam, 1 3/4" LT's w/catts, GMMG, Koni Shocks, Hotchkis Springs, 35/21 Sways, 17" ZR1's, 3.90 Gears Roadrunner PCM LM-2 Serial Wideband
    EFILive Closed-Loop MAF/SD Hybrid Tune..


  6. #26
    Senior Member Sid447's Avatar
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    Just to add hopefully,

    I used to get frustrated when manoeuvering a car at slow speed; such as in and out of a garage, or over speed bumps. As a habit had fprmed, over 14 years of BMW manual cars, of not touching the throttle and just working the clutch pedal. The Bee-Ems had a great set-up with instant response to changes in engine load at or near idle that didn't need you to keep adjustinging the accelerator to keep the engine from stalling.

    Have worked at trying to achieve the same with the GM PCM's for a manual car. One of the changes tried was to adjust (raise) the timing in BSIG {B5932} right at the low-speed area where the engine would be when letting out the clutch at 0% TP.


    Though still way short of the responsive nature I had from the 1980's Bosch Motronic system, five years of fiddling (sometimes going backwards, sometimes in a circle) there is a decent improvement!
    Last edited by Sid447; April 28th, 2011 at 05:10 PM.

  7. #27
    R.I.P Shawn, 1956-2011 WeathermanShawn's Avatar
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    Sid, I have done the same thing at times with timing in BSIG in the same manner you are describing. I agree raising the timing in those areas allows the car to 'crawl' around better at little to no throttle.

    The trick is to remember that is also the area of BSIG where general start-up and Idle also is referenced. So the timing that gives you that nice crawl is also your Idle Spark.

    So, a lot is preference. On my mildly aggressive cam (10 degrees of overlap) I settle on ~26 degrees of Spark in that same BSIG you are referencing. I then tweak the TC in Gear and add a 'dash' of air at a 1000-1600 RPMS and 0-6 mph to insure it crawls in the manner you are describing.

    I guess its the little things like that to help add to the comfort of your ride...
    2002 Black Camaro Z-28 M6 Hardtop 11.0:1CR 425HP/410TQ SAE (400TQ@3500RPM)
    200cc Heads, 228/232 110+2 Cam, 1 3/4" LT's w/catts, GMMG, Koni Shocks, Hotchkis Springs, 35/21 Sways, 17" ZR1's, 3.90 Gears Roadrunner PCM LM-2 Serial Wideband
    EFILive Closed-Loop MAF/SD Hybrid Tune..


  8. #28
    Senior Member Sid447's Avatar
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    Yes,

    though @ zero TPS in 1st gear and when crawling (1-6 kph) the scan shows in the .24/.28g/cyl window, especially after a cold start.

    Good idea on the {B4309} TC In Gear tweak (with B4311/12 at stock M6 values of 3.2 & 1.6)
    Tried with this same 1.6 figure into {B0107} and 1.2 (from table B5916) entered into {B0108} but unsure if it made any difference.

    Steve
    Last edited by Sid447; April 28th, 2011 at 05:19 PM.

  9. #29
    R.I.P Shawn, 1956-2011 WeathermanShawn's Avatar
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    I have published a LS1 Idle Tuning Tutorial in PDF Form..http://forum.efilive.com/showthread....l=1#post129525

    ..WeathermanShawn..


    Last edited by WeathermanShawn; March 2nd, 2011 at 01:20 AM.
    2002 Black Camaro Z-28 M6 Hardtop 11.0:1CR 425HP/410TQ SAE (400TQ@3500RPM)
    200cc Heads, 228/232 110+2 Cam, 1 3/4" LT's w/catts, GMMG, Koni Shocks, Hotchkis Springs, 35/21 Sways, 17" ZR1's, 3.90 Gears Roadrunner PCM LM-2 Serial Wideband
    EFILive Closed-Loop MAF/SD Hybrid Tune..


  10. #30
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    Hey Shawn - In the initial post you suggest not tweaking any of these:

    1. IAC Effective Area (unless different TB size).
    2. Start-Up Airflow Corrections
    3. Airflow Parameter(s) that affect Idle.

    Is it possible to get a list of specific parameters for #3? I'd like to check them against my tune to see if they have been adjusted before I go thru your tutorial.

    Thanks.

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