Page 34 of 36 FirstFirst ... 243233343536 LastLast
Results 331 to 340 of 357

Thread: E38 idle tuning

  1. #331
    Lifetime Member
    Join Date
    Aug 2013
    Posts
    735

    Default

    Quote Originally Posted by nick123 View Post
    Do you put your B1651 and 1652 back to stock after tuning theB1829 table or...

    do you leave1651 and 1652 slightly above your target idle and let it learn down
    I don't think you fully understand the purpose of hymey's procedure.

    The answer to your question is in step 4 of the procedure...

    Quote Originally Posted by hymey View Post

    Step 4.

    We have established correct desired airflow by using our max idle area to find it. Now we have it right we can slightly increase max idle area. This allows the pcm to learn and trim within a fine limit and allows perfection of idle in all conditions cold and hot start, winter and summer, Also full lock, with a/c on in gear and nice throttle feel with no surging or overshoot.

    I have found over time by tuning a variety of e38 combos from blown to 240s cams on tight lsa to baby cams that an extra 4% add on is sufficient.

    So if we first found max idle area for correct idle was 1.10 , our final figure will be 1.14.

    This allows more more air at cold start, The factory pcm adjustment will increase min idle air at cold ect by a multiplier. But we need to ensure that we have enough min idle air at cold start to get a nice idle cold. Cold start enrichment here is very important but that's another topic.

    Add 0.04 to the figure, If it is not enough add 0.02 more. But generally 0.04 is enough with good enriched afrs cold off 13:1.

    This will get your idle correct. Small changes will be required depending on combo and pcm cal. But overall there all similiar outcomes. Max idle area and min idle area always vary from car to car hence why its so important to do a custom tune on each vehicle.

  2. #332
    Lifetime Member hymey's Avatar
    Join Date
    Jan 2008
    Posts
    313

    Default

    Hi guys, instead of using the max idle area I now use the tables B1703 and B1704, these are hard upper and lower limits. As mentioned , when I first started this procedure these values were not present, eventually they come in, the top value in the earlier versions was 60 then increased to 200, therefore a hole is not required with this higher upper limit and can be experimented with , with the earlier OS which had 60 at the upper limit.

    Generally what I find works well , is I run idle timing around 13-15 degrees , (pending on cam). I set the B1704 from 5 to 50 and B1703 from 200 to 90 and run min idle airflow around 13 g/s to 1200 rpm then sweep upwards. Also setup cranking maps to run a bit less then 13, once hot. You will find this is fairly close.

    If the engine is starving for air cold, raise the 90 value up, the 50 will act as a lower limit and if it needs less air you can drop this, some motors end up around 55 and 85, some 50 /90.

    I also use the B1846 table and at the 800 to 1000 mark I set this to 100/110 and blend it back down either side. (experiment with this)

    I can pretty well drop these values in any E38 for a cammed engine and it will be close, if the timing is a bit low at commanded idle rpm (say 850 rpm and it is 8 degrees timing), drop down min idle airflow a bit at a time, say 0.2 g/s until its close. You will find it may want to dip faster then. You will see the hard lower limit of 50 preventing the throttle close lower again. You can experiment lowering this aswell, the last 3 I tuned all ended up the same.

    Note - if you have your idle already setup or throttle plate drilled , These values will be lower again, simply run them at say 50 and 55 and log the airflow and see where it is tracking ,it prevents the requirement of locking out airflow and is a much faster method. Once you work out where it likes to idle , drop the min value down lower and set the max value 30 higher to start with and creep upwards. It will learn very fast in tight parameters, simply log the dynamic airflow and watch the TP% and adjust the min idle air until it is close and again move up/down slightly pending on what it likes.

    Regards

    Joel
    Last edited by hymey; July 31st, 2020 at 10:35 PM.

  3. #333
    Lifetime Member Tre-Cool's Avatar
    Join Date
    Feb 2006
    Posts
    937

    Default

    Nice update Joel.

    I have the idle pretty well nailed in my own car, so i'll have a play around.

    I had been setting the 1703 & 1704 to match the non dtc codes values for a while.

    What I have found strange & makes me wonder how the min airflow values are truly calculated out/from. As different OS cals use different B1602 (Airflow Correction Coolant Multiplier) values along with under/over correction multipliers.

    Example: Logging Dynair ecu says 14g/sec for 800rpm idle

    so enter in 14 into the 800 rpm column, if the multiplier for 92c is .29 is the actual min value still 14 or lower? I think it's a lower value as I've found that if i change the multiplier to 1 the car will idle really high and want to pull timing out to get idle rpm down.

    Put it back to the lower multiplier and it's bang on again for blade position and spark timing.

  4. #334
    Lifetime Member hymey's Avatar
    Join Date
    Jan 2008
    Posts
    313

    Default

    Quote Originally Posted by Tre-Cool View Post
    Nice update Joel.

    I have the idle pretty well nailed in my own car, so i'll have a play around.

    I had been setting the 1703 & 1704 to match the non dtc codes values for a while.

    What I have found strange & makes me wonder how the min airflow values are truly calculated out/from. As different OS cals use different B1602 (Airflow Correction Coolant Multiplier) values along with under/over correction multipliers.

    Example: Logging Dynair ecu says 14g/sec for 800rpm idle

    so enter in 14 into the 800 rpm column, if the multiplier for 92c is .29 is the actual min value still 14 or lower? I think it's a lower value as I've found that if i change the multiplier to 1 the car will idle really high and want to pull timing out to get idle rpm down.

    Put it back to the lower multiplier and it's bang on again for blade position and spark timing.
    Trecool , yes I have found that, GMs weird way of doing things, the low value decimal multiplier has to stay.

    A good give away is cranking idle air and corresponding TB percentage. Change the cranking idle air and watch the percentage change. Then while idle tuning you may have the limits set tight around 55 / 57 for say and notice you would have a certain idle air value. Take note of the idle airflow logging and also the percentages and then while logging cranking you can see what's happening. I find I usually have say about 1 g/s less in cranking idle air then min idle airflow but I like the PID to trim down a touch rather then up as it stops the idle dropping to fast as you pull up.

    I have noticed more the way it works in HP and I can see it all builds from a min value and integrals add to that value.

    A good experiment is logging cranking and playing with that then you know what is exactly what.

    Once you have it close , with those limits , I find dropping min idle air value only 0.2 make A a big difference in the way the idle settles when you pull up or drive off. It helps a lot with drivability .

    I have also seen statements on websites stating it has nothing to do with idle. This is untrue as you found from the multiplier .

    The last 3 / 4 cars actually all had varied combos and all ended up the same values. One had a 227 239 114, 2 had small cams and the other was a high comp engine with a 229 240 109 . All had same values.

    The trick is keeping those limits close. I've been doing it this way for a while too I just have not been online.

    The PID can learn much faster and work better in its correct range.

    Regards

    Joel

  5. #335
    Lifetime Member Tre-Cool's Avatar
    Join Date
    Feb 2006
    Posts
    937

    Default

    So with my combo.

    416ci - 226/242@116
    FDFI2650 with 102mm
    3200 stall
    Target idle rpm = 850 in P/N & In-gear then 875 from 8kph & above.
    Idle Spark set to 14 degree's

    At the moment I'm at 30 for min & 90 for max & it's that good i don't think i'll bother changing it from here. i did initially try a 60-90 mix but it would cruise with no throttle because it wasn't dipping into closed throttle or coast down spark.

    It seem's to have mellowed the idle trimming out big time & corrects for any dip from load (AC & steering) pretty quick. I haven't bothered touching the torque reserve table though & have left it zero'd out.

    I'm going to try a slight trim of the min-idle table as it did move from 18% slowly down to 16% over 10-12 seconds when i pulled up to set of traffic lights in gear & it's trimming spark down ever so slightly. however i also forgot i turned the AC off, so it wasn't cooling my supercharger water down either.

    Click image for larger version. 

Name:	veute-idle.png 
Views:	247 
Size:	209.1 KB 
ID:	23433

    Click image for larger version. 

Name:	veute-B1829.PNG 
Views:	264 
Size:	166.8 KB 
ID:	23434

    Something i've been playing with big time on this car is the pedal demand table, i've dulled the absolute shit out of it down low to keep it driving in a straight line and work as a built in traction/torque limiter. otherwise it'll blow the tyres off all the time if your not careful. it'll make 18psi from 2400rpm if i let it have 100% etctp.

    Click image for larger version. 

Name:	veute-pedal.PNG 
Views:	254 
Size:	149.8 KB 
ID:	23435
    Last edited by Tre-Cool; August 2nd, 2020 at 09:58 PM.

  6. #336
    Lifetime Member hymey's Avatar
    Join Date
    Jan 2008
    Posts
    313

    Default

    Quote Originally Posted by Tre-Cool View Post
    So with my combo.

    416ci - 226/242@116
    FDFI2650 with 102mm
    3200 stall
    Target idle rpm = 850 in P/N & In-gear then 875 from 8kph & above.
    Idle Spark set to 14 degree's

    At the moment I'm at 30 for min & 90 for max & it's that good i don't think i'll bother changing it from here. i did initially try a 60-90 mix but it would cruise with no throttle because it wasn't dipping into closed throttle or coast down spark.

    It seem's to have mellowed the idle trimming out big time & corrects for any dip from load (AC & steering) pretty quick. I haven't bothered touching the torque reserve table though & have left it zero'd out.

    I'm going to try a slight trim of the min-idle table as it did move from 18% slowly down to 16% over 10-12 seconds when i pulled up to set of traffic lights in gear & it's trimming spark down ever so slightly. however i also forgot i turned the AC off, so it wasn't cooling my supercharger water down either.

    Click image for larger version. 

Name:	veute-idle.png 
Views:	247 
Size:	209.1 KB 
ID:	23433

    Click image for larger version. 

Name:	veute-B1829.PNG 
Views:	264 
Size:	166.8 KB 
ID:	23434

    Something i've been playing with big time on this car is the pedal demand table, i've dulled the absolute shit out of it down low to keep it driving in a straight line and work as a built in traction/torque limiter. otherwise it'll blow the tyres off all the time if your not careful. it'll make 18psi from 2400rpm if i let it have 100% etctp.

    Click image for larger version. 

Name:	veute-pedal.PNG 
Views:	254 
Size:	149.8 KB 
ID:	23435

    Nice mate

    I generally find the same 60 is a bit to high. All different but generally 50 is pretty close to the bottom but less will work fine too.

    Sounds like min idle air is about 0.5 sec to high. However I don't mind it when they settle like that.

    Cheers

  7. #337
    Lifetime Member Tre-Cool's Avatar
    Join Date
    Feb 2006
    Posts
    937

    Default

    i ended up pulling out .2 across the board and that seems to be good enough.

  8. #338
    Member
    Join Date
    Jan 2009
    Posts
    70

    Default

    A friend had RPM in Delaware install their Stage 3 cam/head/etc. package in a 2008 Z06. They won’t share the cam specs with me. It has a very choppy idle. Average MAP is 75 kPa at 870 RPM with only a few kPa variation. He is happy with the car except when he shuts the engine off, it does not quit immediately, but pops and crackles for perhaps another 1 to 2 seconds. So I have a few questions: When you shut the engine off, does the ECM just kill the injectors; or, both injectors and coils? And, if only the injectors are turned off, could the run-on be caused by fuel clinging to port walls being ingested then ignited by the spark plugs? If that is the case, can the run-on be improved by making the numbers in the Evaporation Factor table smaller?

  9. #339
    Member
    Join Date
    Aug 2015
    Posts
    67

    Default

    It's my opinion that, since "Race Proven Motorsports" in Delaware won't give out the cam specs, that's a good sign that people shouldn't deal with them. Heck even Katech and Lingenfelter publishes their cam specs.

    We can read its web site description about its "Stage 3", listen/watch some video footage then draw some conclusions. First, they advertise the package includes "custom dyno tune", so you know that while the wide-open throttle may be well-tuned, unless they spent hours on a load-bearing dynamometer, idle and part throttle have likely received little attention. Second, that the car has a "choppy idle" and that "RPM" feels the need to use a set of "660 dual valve springs" tells me the camshaft has got to be pretty radical. That explains your friend's rough and possibly unstable idle and also tells me that, to get the idle and part throttle reasonably drivable, would take a lot of calibration work...far more than a customer is likely to get during a chassis dyno session. If you listen to the videos on RPMs' site, the both cars' idle is really rough and unstable. That tells me the cams are radical and the idle needs plenty of cal work.

    As for what happens when you press the ign. button to shut off the engine, I don't know all aspects of that, but what stops the engine is the ignition system being turned off, ie: voltage to the coils primary side is zero and, thus, there's no spark. The fuel pump is also shut off which means little or no fuel flow after the ign. voltage to the pump is cut. Injectors are normally closed so, once the injectors are no longer pulsed, there's no fuel flowing unless the injectors are leaking, which is very easy to diagnose if you have a fuel pressure gauge.

    If, after the ign. is shut off and the fuel is shut off, the engine popping and crackling afterwards is a real head-scratcher because there is no spark. Now it is possible that the chamber walls, valve heads and plugs are carbon-fouled and, after shutdown, carbon residue glowing on the chamber walls and plug tips is igniting a small amount of fuel leaking from faulty injectors, but if all those problems exist, that engine must be pretty screwed up.

    What do the plugs look like when he pulls them? Are they carbon fouled, ie have soft, black, sooty residue on them?

    I would suggest diagnosing any problems with leaking injectors or with carbon deposits, first, and then changing the cal if necessary, but, again, to get idle and part throttle right in an engine with such a radical camshaft, a lot of work by an experienced calibrator is going to be required....far more than one would typically receive in just a chassis dyno session by the engine builder.

    I have a '12 ZO6 with a Katech-built engine in it which has a far less aggressive camshaft than what I think "RPM" uses in their "Stage 3". The car came from Katech making great WOT power and torque but the idle and part throttle cal. was awful. I have spent dozens of hours over several years attempting to get idle and part throttle drivability to a place I feel is closer to "optimized".

    If I was that customer, I'd have taken the car back to this "RPM" and tell them to fix this f'ing car.

    Lastly, looking at the videos of two C6 ZO6es on their chassis dyno one made 620 at the tire and the other made 635, which, is indeed impressive, but the idle of those cars was really rough and surging. Also, on the second car, the dyno's AFR data says at WOT the engine is running at 13.3:1. OMG, that is pretty damn lean. If the fuel has 8-10% ethanol in it (as do most pump gas and even some unleaded racing gasolines), that AFR would be scary-lean.
    Last edited by Hib Halverson; September 9th, 2021 at 07:26 AM.
    Hib Halverson
    just another f'ing "Tuner In Training"

  10. #340
    Senior Member
    Join Date
    Dec 2016
    Posts
    131

    Default

    Spot on post! I've fixed plenty of idle and part throttle issues from other "tuners" over the years. As mentioned, WOT is the easiest part.

Page 34 of 36 FirstFirst ... 243233343536 LastLast

Similar Threads

  1. Idle/Idle Transition Tuning
    By Rhino79 in forum General (Petrol, Gas, Ethanol)
    Replies: 10
    Last Post: January 11th, 2007, 04:10 AM
  2. Idle Tuning
    By lplott in forum General (Petrol, Gas, Ethanol)
    Replies: 7
    Last Post: November 26th, 2006, 06:03 AM
  3. Stock maf = perfect idle. Big maf = unstable idle. Any tuning suggestions?
    By onfire in forum General (Petrol, Gas, Ethanol)
    Replies: 7
    Last Post: July 11th, 2006, 02:58 PM
  4. Idle Tuning
    By 98WhiteDevil in forum General (Petrol, Gas, Ethanol)
    Replies: 1
    Last Post: June 19th, 2006, 03:36 AM
  5. tuning idle
    By BACKinBLACK in forum General (Petrol, Gas, Ethanol)
    Replies: 51
    Last Post: April 12th, 2006, 08:07 AM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •