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Thread: Modify tune for turbo

  1. #1
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    Default Modify tune for turbo

    I have a 2002 camaro and before i had headers, dual exhaust, with some sort of cam (had it in when i bought car so don't know what it is), and then i put a racetronix fuel pump in and had setup and tuned it on e85.

    Now I built a turbo kit for it with cast manifolds, swapped out the stock 28lbs injectors for some 1000cc injectors (1155cc at 4bar). I put a second pump in the tank, removed fuel pressure regulator, and set it up as a return system with a regulator after the rails. Car is still on e85, and i removed the maf. Running a 3 bar map.

    I took the tune that was running in the car from before and followed the custom os tutorial to copy and paste it into cos 5. I can not get the car to stay running under about 2000rpms. If i hold the throttle to the floor it will start up and then i have to hold rpms at 2000 or it will die. I think it is something with my injector flow rate.

    To tune the car on e85 originally I was lazy and modified the IFR table by 30% less so I didn't have to change all other tables, and i got it tuned in and running really well. How i did this is i took all the vales in the IFR and multiplied them by .7

    My question is if the stock injectors are rated at 28lbs at 58psi? Since the tune I'm starting with is setup based on a 30% less IFR do i set my regulator to 58psi then take 1155 (rating of injectors at 58psi), and multiply them by .7 and enter that value? So my IFR table would have a value of 76.909 and this value would be the same throughout the table since it is a rising rate regulator? Because i tried this and still can't get car to idle.

    any and all idea's are welcome, i was actually thinking about swapping back the 28lbs injectors to see if that would work and put the tune back in it had before. Since i'm not running the maf anymore if i put the old tune in would it be good enough to start up and idle?

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    Also once i do get the engine running, will I perform calc.vet just like before and it will also work on the new Boost VE Table A0009?

  3. #3
    Joe (Moderator) joecar's Avatar
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    VE/MAF were tuned for IFR set to .7 x actual flow...?

    Try this:
    - set B4001 IFR back to previous value,
    - B3601 Stoich AFR for E85 (9.7),
    - multiply B0101 VE by (1/.7)=1.429.


    No, do Calc.MAFT to correct Main VE and Boost VE tables (ignore the MAF calculation part of it)...

    read thru both Calc.VET and Calc.MAFT threads first (make sure you understand both) and then do Calc.MAFT;

    Calc-VET-correcting-MAF-and-calculating-VE-(in-single-log)
    Calc-MAFT-correcting-VE-and-calculating-MAF-(in-single-log)-gt-reverse-of-Calc-VET
    CALC-VET-Summary-Notes
    Summary-Notes post #29

    you will need the calc_pids.txt from either of those threads (the pid CALC.DAT is important).

    do you have FlashScan V1 or V2...?

    which wideband do you have...?




    idea: in scantool create a single map that looks like B0101 and A0009 placed side-by-side...
    (this allows you to use a single transient filter, and you just copy/paste the appropriate portion of the map into B0101 or A0009).
    Last edited by joecar; June 13th, 2013 at 07:32 AM.

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    Quote Originally Posted by joecar View Post
    VE/MAF were tuned for IFR set to .7 x actual flow...?

    Try this:
    - set B4001 IFR back to previous value,
    - B3601 Stoich AFR for E85 (9.7),
    - multiply B0101 VE by (1/.7=1.429).


    Yes, do Calc.VET on Main VE and Boost VE tables. edit(joecar): sorry, I meant to say do Calc.MAFT here
    When doing calc.vet on the boost table I'm assuming the best method would be to make a second map that starts where the regular calc.vet map leaves off. that way you create new values for both b0101 and A0009?

    Ok, i will try this tonight. I assume multiplying B0101 by 1.429 is to compensate for the previous B4001 table that was 30% less than it was suppose to be?

    Does modifying B3601 to 9.7 affect the tune in anyway? I always wondered that value was actually used. Such as in the future possibly the e85 mixture is only 70% ethanol i can skew the B3601 stoich ratio to get afr back where it should be?
    Last edited by joecar; June 13th, 2013 at 07:41 AM.

  5. #5
    Joe (Moderator) joecar's Avatar
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    Sorry, I pressed Reply too soon... do Calc.MAFT, not Calc.VET.

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    Joe (Moderator) joecar's Avatar
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    Quote Originally Posted by gpr View Post
    When doing calc.vet on the boost table I'm assuming the best method would be to make a second map that starts where the regular calc.vet map leaves off. that way you create new values for both b0101 and A0009?

    Ok, i will try this tonight. I assume multiplying B0101 by 1.429 is to compensate for the previous B4001 table that was 30% less than it was suppose to be?

    Does modifying B3601 to 9.7 affect the tune in anyway? I always wondered that value was actually used. Such as in the future possibly the e85 mixture is only 70% ethanol i can skew the B3601 stoich ratio to get afr back where it should be?
    Do Calc.MAFT.

    If you're using wideband only, then in calc_pids.txt you want SELBEN to use wideband only, this is done by setting the CLC for CALC.CL to "0".


    Yes, x1.429 is to unscale the VE table (from being scaled by tuning with IFR set to x.7).


    Setting B3601 to 9.7 causes the final fueling to be richer (it does what IFR x .7 does, but cleaner (leaving VE correctly modeling airmass).

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    Are you sure i should take my Ve table and multiply it by 1.429? This seems like it is making it very very rich as some of the VE values are above 140% which doesn't seem like the car naturally aspirated would be anywhere close to that effecent.

    Wouldn't changing the B3601 to 9.7 and then changing the IFR table back to actual injector flow rate make the compensation needed?

    BTW, thank you for your help. I'm going to go read through all those threads again, its been a while so i need a refresher, and for some reason some of my maps and dashboards disappeared.

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    I'm still stumped. Tried all your recommendations, even tried putting VE with 30% smaller values and nothing works. It will start if i have the throttle wide open but i have to hold it open and if it drops under 1500rpm it dies because it is so rich.

    It seems no matter what i do it has no affect on how the car runs. I have tried decreasing fuel pressure, decrease and increase VE, changed the IFR table. I also thought maybe it was trying to use the TPS VE Table as A0003 was enable, so i disabled that and zero'd out the table. Still no change, so i have no idea why it isn't working. I'm debating on either putting a regular tune back in so it will start up and run, or put my stock injectors back in to see if possibly these new 1000cc injectors are bad.

    Here is my tune with the cos5, and here is the short log file I got tonight. Also i have attached the file which i started from and what i was running before i told everything down to do the turbo.

    Also why do all the custom calibrations show up as "Out of Range" even though they are set at or in the limits?
    Attached Files Attached Files

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    I think I might have found a possible cause. B3647 Commanded fuel vs rpm was set to show AFR, and it had values of less than one in there. I'm guessing that was commanding the car to be stupid rich? I put the values from the COS tutorial, but i'm guessing they were talking about lambda.

    Anyway i put the following values in the attache screen shot. Will this work as it is using the stoich a/f of e85, or should i put 14.7 for stoich and have it richen up to 11 or 12?
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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  10. #10
    Joe (Moderator) joecar's Avatar
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    Quote Originally Posted by gpr View Post
    Are you sure i should take my Ve table and multiply it by 1.429? This seems like it is making it very very rich as some of the VE values are above 140% which doesn't seem like the car naturally aspirated would be anywhere close to that effecent.

    Wouldn't changing the B3601 to 9.7 and then changing the IFR table back to actual injector flow rate make the compensation needed?

    BTW, thank you for your help. I'm going to go read through all those threads again, its been a while so i need a refresher, and for some reason some of my maps and dashboards disappeared.
    Trythis first and see what it does.


    Also, view your VE table in g*K/kPa units (then you won't have any problem with >100%).

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