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Thread: Mustang cam tuning for power and drivability

  1. #1

    Mustang cam tuning for power and drivability

    Hi,

    Due there is completly lack of information how to tune cams, i do share my knowledge with You.

    I have similar cams to hot rods, but little more overlap, duration and lift, they are custom, so there is no remote possibility to tune them, I'm sure, except of parameters, You need to here it and feel it.

    228/238 (268/276) @.050” (0.006) duration, 473/473 lift, 110 LSA, intake 106 centerline (13 deg overlap (52 at 0.006))

    Main thing from cam parameters what You need to know is when exhaust valve closes. This I had on card, but You can calculate it here:

    http://www.wallaceracing.com/cam-deg-calc.php

    In the parenthasis there is timing at 0.006, so this same as Ford use in tune.
    IVO BTDC: (28 - 15 is stock cam) 8
    IVC ABDC: (60) 40

    EVO BBDC: (72) 53
    EVC ATDC: (24) 5

    At first how many people say about loosing fuel and how to avoid with 2 methods of calculation. On the end how it looks with my testing, You choose what is best for You.

    So at very first You need to change value in Fuel/intake valve open, which is factory set at 345 (360-15 stock cam intake opening).
    Stock cam has overlap only at lift 0.006, so they end spray at 345 latest.
    What is interesting us is overlap at 0.05, due at this point our vaporized fuel will get out of the exhaust valve due overlap. If new cam has no overlap at 0.05 lift, then in this value You should type 360-opening time at 0.006, so at this example 360-28, so 332.
    But we have cam with overlap of 13 deg, so our potential goal is to not loose fuel at idle and light load and not to have over rich idle condition.
    In this case we need to start spray later. There are different opinions how to do that, one way is to test for the richest condition of fuel trims or wideband. So changing values from 345 to 348...350...etc for test (again see my final conclusion later, in this case I haven't seen any changes on fuel trims).
    Of course many people says, that this cause spraying at open valve so washing oil from the walls and so on. But at high load it sprays anyway on open valve, it's just with about 60% injector pulse. Look also, there are many cars that makes batch or semi batch fire and it's normal for them.

    Second method I used was calculate (but still look at my final conclusion).
    Before cams Mustang has idle inj pulse about 3,2 ms, after cams about 5, it's nearly twice! (what I seen, that will be so with cams what ever You calculate) and and light load cruise if varies from 3 to 5, so I don't want to have potential wasted fuel in this conditions. So let's say we don't want this bellow 5ms.
    At idle I have 730rpm, so I need to know how much time injector sprays per degree, so 120000/730=164.38ms so this is total time that crank rotate twice at this rpm, so now 164.38/720deg=0.228ms, so at 730 rpm 5ms spray takes 5/0.228=21.92deg (for eg for 1500 its 45, so we see at 1500 only part will be sprayed on open valve)
    If we know this value, and we know when exhaust closes (at 5 atdc), then we need to finish spray at 5+22 deg so at 27 deg atdc. Is this case we put in Fuel/intake valve open 360+28=388deg.

    But what I tested finally with external gas analyser and, MPG checking and butt dyno feel, best was to not spray to avoid fuel loss, but spray as stock is designed completly not carrying to spray after exhaust closes, but do thay same way as stock, so check when valve opens at 0.006, so in my example 28 deg btdc, so at 332 deg, so all fuel is sprayed on closed intake valve.
    This gives better idle and better MPG overall. Gas analyser says, that AFR is not changing at idle if it's set at 400 deg or 300 deg, it's always this same and rich about 13.2. If You would like to get it leaner, only way is to force open loop at idle and tune with gas analyser, not even with wideband, due one is not reading correctly when missfire are there and some fuel gets to the exhaust.

    At his point You should redial Your MAF for given AFR.

    Now idle and drivability....
    For sure You need to change idle/idle airflow, this is easy, just log Your maf weight values rising rev and idle and put them there. They will be higher for about 20-30 percent than stock.
    Next You have to change that throttle reacts faster when idle drops, to do this I set Idle/Int Time Underspeed to 0.5 and Overspeed to 4.0. This will make that if idle drops throttle will react fast, but if revs are too high they will not drop very fast, so they will not bounce. You even can start drive nearly without touching gas pedal - I'm still working on to have it like in EU cars.

    If You have also problem with hanging throttle/rpm, You can test to change idle dashpot decay or idle dashpot minimum.
    If You don't want to have bucking while driving with foot of at 700-1000 rpm You have to fight with dashpot minimum.
    Modify values for 0 and 1000 rpm so, that when car is driving with foot off, will not get bellow 1000 rpm. Even when with brake You get less, then engine will open tb and applay load. Once You stop, You can have even 600 rpm, that not affect driving.

    Mine idle air:
    6.000
    6.000
    6.000
    6.000
    7.000
    8.700
    10.000
    16.000
    18.000
    22.680
    22.680

    Mine idle dashpot decay:
    0.000
    0.022
    0.029
    0.044
    0.066
    0.182
    0.218
    0.277
    0.328
    0.350
    2.000
    2.400
    4.186
    4.900
    6.392

    ide dashpot minimum
    500 3.00
    900 1.00
    1000 0.5
    3150 1.0
    5800 5.0

    Idle dashpot:

    0.82
    0.83
    0.83
    0.76
    0.71
    0.48
    0.19
    0.09


    Cams drive better without IMRC deletes.

    Now spark, with such cams You can lower idle spark, modify spark decel that at 1250 rpm they will have little less advance and also modify Your bdl knock and mbt to add max 4 deg an ligh load, this will compensate for lost compression.

    Mine idle:
    8.000
    8.000
    8.000
    8.000
    8.000

    Mine decel 1000, 1150, 1500
    8.000 10.000 11.000
    8.000 10.000 11.000
    8.000 10.000 11.000
    8.000 10.000 11.000
    8.000 10.000 11.000


    Mine are added so, bdl and mbt:
    500 750 1000 1500 2500
    0.1 0.000 0.000 0.000 0.000 0.000
    0.2 0.000 0.000 0.000 4.000 3.000
    0.3 4.000 4.000 4.000 4.000 3.000
    0.4 2.000 2.000 2.000 2.000 2.000
    0.5 2.000 2.000 2.000 2.000 2.000
    0.6 2.000 2.000 2.000 2.000 2.000


    You can also add some on driver demand engine table,
    Stock are:
    16. 45.000 15.000 -6.000 -10.000
    42 145.000 85.000 43.000 17.000

    How to tune Driver Demand Engine here:
    http://www.hptuners.com/forum/showth...254#post297254

    Mine are:
    16 140.000 120.000 70.000 -10.000
    42 145.000 150.000 90.000 17.000

    Just set this as you like.

    Now we have to tune VCT...

    I found that my cams make lot of stress (i heard it, it's nearly like soon before knock occurs) when i seen cam retard at more than 40 deg.
    so i cuted this values to max of 35 and removed 30% to up 0.6 load.
    This gave me better good part throttle torque. This is best to tune on the road with butt dyno, due You can't change tune on the fly on dyno to monitor what is best, so feeling is best friend here for You.

    Mine after looking at MPG and part throttle and wot runs are very simple and getting best overall performance. What I found finally to compensate for compression lost it's good to run them 0 deg retarded till 3000 rpm, so with above timing and bellow VCT i get same or better MPG and same or better part throttle TQ, wot I lost 20lb ft, but it's normal, it's not possible to not lost any TQ like some cams are described - it's nature of overlap. As they describe, You can lost over stock and compensate with CAI, but be sure You lost in compare to max tuned car with CAI.

    VCT:

    0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000
    0.000 0.000 0.000 0.000 0.000 7.000 8.000 9.000 10.000 10.000 11.000
    0.000 0.000 0.000 0.000 0.000 6.000 7.000 8.000 9.000 9.000 10.000
    0.000 0.000 0.000 0.000 0.000 5.000 6.000 7.000 8.000 8.000 9.000
    0.000 0.000 0.000 0.000 0.000 4.000 5.000 6.000 7.000 7.000 8.000
    0.000 0.000 0.000 0.000 0.000 3.000 4.000 5.000 6.000 6.000 7.000
    0.000 0.000 0.000 0.000 0.000 2.000 3.000 4.000 5.000 5.000 6.000
    0.000 0.000 0.000 0.000 0.000 1.000 2.000 3.000 4.000 5.000 6.000
    0.000 0.000 0.000 0.000 0.000 1.000 2.000 3.000 4.000 5.000 6.000

    Now goal is to tune WOT cam retard. This best has to be done on dyno, or You can try Virtual Dyno app
    http://www.bradbarnhill.com/projects/VirtualDyno/
    which is very usefull in tuning, and read perfect HPT logs.
    My results are in above VCT table.

    Finally You can same way as above tune Your timing, this is mandatory with any new cams too - as all above.

    I've seen some tunes from market for cams, non of them had changed more than 17 deg VCT WOT at and and idle air...

    With above setup car is driving better than stock, here You can look and it was with only basic tune:
    http://www.youtube.com/watch?v=_z2qqIHCPVM

    Thats all I think... but this post will evaluate since I get better information form my tests.
    Last edited by caniggia; 03-09-2013 at 05:55 PM.
    Eastern and Central Europe American Muscle and Harley-Davidson tuning
    www.hd-customs.pl
    http://www.facebook.com/hdcustomspl

  2. #2
    Potential Tuner
    Join Date
    Sep 2010
    Posts
    1
    Great and very helpful post!

  3. #3
    Tuner in Training
    Join Date
    Jul 2012
    Posts
    34
    Thanks for the information!

  4. #4
    Tuner in Training
    Join Date
    Feb 2013
    Posts
    21
    Could you upload your tune to looks at?

  5. #5
    Last tune before turbo.

    Lumpy cams, walbro 400LPH fuel pump running mixed mode (returnless with variable voltage), 39LB injectors, Gt500 tb, JLT110, 91 octane, adjusted fans and so on...
    Due to different intake, some of above tables are different.
    With turbo and cams it's completly different, still not have final version (as written in another topic).
    Attached Files Attached Files
    Last edited by caniggia; 10-14-2013 at 07:34 AM.
    Eastern and Central Europe American Muscle and Harley-Davidson tuning
    www.hd-customs.pl
    http://www.facebook.com/hdcustomspl

  6. #6
    Advanced Tuner
    Join Date
    Aug 2009
    Location
    Naples, FL
    Posts
    339
    Very nice writeup!

  7. #7
    To complete cam tuning, throttle needs to be tuned too:

    http://www.hptuners.com/forum/showth...le-tuning-Ford
    Eastern and Central Europe American Muscle and Harley-Davidson tuning
    www.hd-customs.pl
    http://www.facebook.com/hdcustomspl