Results 1 to 17 of 17

Thread: S52 turbo 8psi 12.1 afr with 21lb injectors

  1. #1
    Join Date
    Mar 2015
    Location
    New Jersey us
    Posts
    11
    My Cars
    BMW 328i

    S52 turbo 8psi 12.1 afr with 21lb injectors

    Finally finish my turbo install. I’m running the 540i 3.5” maf in blow thru way. 21lb injectors. Trm chip for obd1 for s52. Precision entry level turbo. 60 trim.

    Here is my question. Running 8psi and at wot afr goes to 11.6 than 12.2. How is that possible? I did a quick pull. Once I saw the afr at the 12s. Went a little hard on it. Afr still 12.2-3. So, I floored it real quick and let go. Afr 11.6. After seeing those number Went for a full run. Afr 12.1 accross the rpm at wot.
    I know numbers are correct. Gauge and sensor brand new. I got 30lb injectors on the mail. As well as a emanage blue. I would definitely install them for better afr. But can someone with experience explain why with 21lb injectors I’m still able to get those afr numbers?

  2. #2
    Join Date
    Mar 2012
    Location
    Renton, Wa
    Posts
    5,429
    My Cars
    98 m3
    Ok, so this will definitely blow your motor up. Please consult a tuner.


    Sent from my iPhone using Tapatalk
    1989 535i - sold
    1999 M3 Tiag/Dove - sold
    1998 M3 Turbo Arctic/black - current
    2004 Built motor TiAg/Black - Sold
    2008 E61 19T Turbo-Wagon - current
    2011 E82 135i - S85 Swap - current
    1998 M3 Cosmos S54 swapped Sedan - current

    1998 Turbo: PTE6870 | 1.15 ar | Hp Cover, Custom Divided T4 bottom-mount, 3.5" SS exhaust, Dual Turbosmart Compgates, Turbosmart Raceport BOV, 3.5" Treadstone Intercooler, 3.5" Vibrant resonator and muffler, Arp 2k Headstuds | Arp 2k Main studs | 87mm Je pistons | Eagle rods | 9.2:1 static compression, Ces 87mm cutring, Custom solid rear subframe bushings, Akg 85d diff bushings, 4 clutch 3.15 diff, , Poly engine mounts, UUC trans mounts W/ enforcers, 22RPD OBD2 Stock ECU id1700 E85 tune, 22RPD Big power Transmission swap w/ GS6-53

  3. #3
    Join Date
    Feb 2012
    Location
    Birmingham, Alabama, USA
    Posts
    8,369
    My Cars
    1995 BMW M3
    Wut?

  4. #4
    Join Date
    Jun 2005
    Location
    New England
    Posts
    25,402
    My Cars
    F90 M5; E36 M3 Turbo
    It is possible you don’t have a very good turbo system and are making only about 300 rwhp at 8 psi, and the 21 lb injectors can actually support about that much. I’d be worried about ignition timing related detonation if you are running a turbo on a stock tune.

  5. #5
    Join Date
    Mar 2012
    Location
    Renton, Wa
    Posts
    5,429
    My Cars
    98 m3
    You may be able to see those afrs because you’re not in boost. While out of boost the car isn’t any different really.


    Sent from my iPhone using Tapatalk
    1989 535i - sold
    1999 M3 Tiag/Dove - sold
    1998 M3 Turbo Arctic/black - current
    2004 Built motor TiAg/Black - Sold
    2008 E61 19T Turbo-Wagon - current
    2011 E82 135i - S85 Swap - current
    1998 M3 Cosmos S54 swapped Sedan - current

    1998 Turbo: PTE6870 | 1.15 ar | Hp Cover, Custom Divided T4 bottom-mount, 3.5" SS exhaust, Dual Turbosmart Compgates, Turbosmart Raceport BOV, 3.5" Treadstone Intercooler, 3.5" Vibrant resonator and muffler, Arp 2k Headstuds | Arp 2k Main studs | 87mm Je pistons | Eagle rods | 9.2:1 static compression, Ces 87mm cutring, Custom solid rear subframe bushings, Akg 85d diff bushings, 4 clutch 3.15 diff, , Poly engine mounts, UUC trans mounts W/ enforcers, 22RPD OBD2 Stock ECU id1700 E85 tune, 22RPD Big power Transmission swap w/ GS6-53

  6. #6
    Join Date
    Mar 2015
    Location
    New Jersey us
    Posts
    11
    My Cars
    BMW 328i
    I’m in boost. Reading 7.65 to 8psi at wot.

  7. #7
    Join Date
    Mar 2012
    Location
    Renton, Wa
    Posts
    5,429
    My Cars
    98 m3
    We maxed out pink tops on the Dyno yesterday naturally aspirated. There’s not much headroom. Probably refer to Phil’s post


    Sent from my iPhone using Tapatalk
    1989 535i - sold
    1999 M3 Tiag/Dove - sold
    1998 M3 Turbo Arctic/black - current
    2004 Built motor TiAg/Black - Sold
    2008 E61 19T Turbo-Wagon - current
    2011 E82 135i - S85 Swap - current
    1998 M3 Cosmos S54 swapped Sedan - current

    1998 Turbo: PTE6870 | 1.15 ar | Hp Cover, Custom Divided T4 bottom-mount, 3.5" SS exhaust, Dual Turbosmart Compgates, Turbosmart Raceport BOV, 3.5" Treadstone Intercooler, 3.5" Vibrant resonator and muffler, Arp 2k Headstuds | Arp 2k Main studs | 87mm Je pistons | Eagle rods | 9.2:1 static compression, Ces 87mm cutring, Custom solid rear subframe bushings, Akg 85d diff bushings, 4 clutch 3.15 diff, , Poly engine mounts, UUC trans mounts W/ enforcers, 22RPD OBD2 Stock ECU id1700 E85 tune, 22RPD Big power Transmission swap w/ GS6-53

  8. #8
    Join Date
    Mar 2015
    Location
    New Jersey us
    Posts
    11
    My Cars
    BMW 328i
    My set up.
    T3 precision turbo .63 ar turbine housing 76 trim. 60ar compressor. 2.5” charge pipe. 3” cold pipe. 12x33x3 intercooler. Bottom mount. 39mm precision wg.

  9. #9
    Join Date
    Nov 2013
    Location
    VA
    Posts
    1,156
    My Cars
    E36
    Need a proper tune bro. Base map will put you around 10.5 to 10.9 afr and revisions you should be closer to 11.5 afr. Anything higher imo is pushing it.

  10. #10
    Join Date
    Mar 2015
    Location
    New Jersey us
    Posts
    11
    My Cars
    BMW 328i
    Thanks for the advice. Upgrading injectors and getting it tune. I was just surprised that with the small injectors I was getting 11.6 afr.

  11. #11
    Join Date
    Jun 2005
    Location
    New England
    Posts
    25,402
    My Cars
    F90 M5; E36 M3 Turbo
    I think you were heading for trouble. Hopefully you have not done any damage yet. I am not a tuner, though. You should pay more attention to Volosso,
    Last edited by pbonsalb; 05-09-2018 at 12:38 PM.

  12. #12
    Join Date
    Mar 2015
    Location
    New Jersey us
    Posts
    11
    My Cars
    BMW 328i
    I’m taking all of you guys advices. Won’t be running the car with stock injectors/tune. That was just my test run. Was just confuse/surprised as how the 21lb injectors were able to keep the afr at 11.6 at wot. With 8psi of boost.

  13. #13
    Join Date
    Jun 2005
    Location
    New England
    Posts
    25,402
    My Cars
    F90 M5; E36 M3 Turbo
    You are running a small turbo so it may be that you are not adding as much power as you think.

    Also, the S52 is very efficient, so the usual 0.50-0.60 BSFC that you rear about as the recommended number for boost is probably too high to use for these motors. I would guess more like 0.45 BSFC. Rough math is 6x21.5=129 lbs/hr and 129/0.45=287 crank hp. However, I recall reading of people making about 300 rwhp with these injectors.

  14. #14
    Join Date
    Mar 2015
    Location
    New Jersey us
    Posts
    11
    My Cars
    BMW 328i
    That sounds about right. Thanks for the input.

  15. #15
    Join Date
    Mar 2009
    Location
    TX
    Posts
    3,423
    My Cars
    97 M3/4/5, MCS
    You should probably consult your tuner first before purchasing those injectors. I could be wrong though.

  16. #16
    Join Date
    Mar 2015
    Location
    New Jersey us
    Posts
    11
    My Cars
    BMW 328i
    The 30lb injectors?

  17. #17
    Join Date
    Jun 2005
    Location
    New England
    Posts
    25,402
    My Cars
    F90 M5; E36 M3 Turbo
    30s are for low power assuming a safe duty cycle. You should look at 42s or 60s or whatever your tuner likes to work with. I am guessing that is you since you mentioned greddy emanage.

Bookmarks

Posting Permissions

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