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Thread: M10 Boost creep issues

  1. #1
    Join Date
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    M10 Boost creep issues



    So i finally finished my turbo setup for my m10 and started tuning it. The setup is as follows:

    Otis manifold
    Borg Warner s252sxe .63 hot side
    Tial 38mm mvs. Open dump. 5psi spring. 6mm reference line from compressor housing to bottom port.
    3" exhaust with vibrant resonator

    Ms2x running wasted spark and batch fuel. I run around 15 degrees of timing at full boost and afrs stay in the mid 11s


    I am trying to keep it below 15psi until i build the block. However boost creeps to 20-23 psi by 5.5k rpm. I tried both 7psi and 5psi springs without much difference.


    Diaphragm was not pinched or damaged.

    Here is the manifold.



    I know that wastegate outlet is not ideal and i am running fairly large turbo on low boost but damn it creeps almost 20psi over the spring.

    The only thing that i yet have to try is remove WG completely or remove the spring and see what happens.



    Any ideas?


    Thank you










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  2. #2
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    Not enough flow is leaving the manifold prior to the turbo. You can try restricting the exhaust, or by adding a second larger waste gate.

    Quick experiment would be to reduce your exhaust at the end from a 3 inch to a 2 inch. This back pressure will force more flow out the waste gate.
    Capital Driving Club Car # 102
    How to turbo your car:
    Step one. Install ecu and learn to tune and or have it tuned.
    Step two. Install injectors and retune.
    Step three. Install turbo parts and bits. get it running with out leaks. DO NOT DRIVE IT. Idling should be ok
    Step four. Retune car
    Step five enjoy

  3. #3
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    Quote Originally Posted by euro2fast4u View Post
    Not enough flow is leaving the manifold prior to the turbo. You can try restricting the exhaust, or by adding a second larger waste gate.

    Quick experiment would be to reduce your exhaust at the end from a 3 inch to a 2 inch. This back pressure will force more flow out the waste gate.
    I guess choking the exhaust should help a bit and i totally don't need 3" for only 15psi. I just wanted to prep for future when i build the block and run e85.


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  4. #4
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    Quote Originally Posted by Retoropak View Post
    I guess choking the exhaust should help a bit and i totally don't need 3" for only 15psi. I just wanted to prep for future when i build the block and run e85.


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    Its probably cheaper then adding a gate. Unless you plan on operating at 8 to 7 psi in the future once you have a built bottom end.
    Capital Driving Club Car # 102
    How to turbo your car:
    Step one. Install ecu and learn to tune and or have it tuned.
    Step two. Install injectors and retune.
    Step three. Install turbo parts and bits. get it running with out leaks. DO NOT DRIVE IT. Idling should be ok
    Step four. Retune car
    Step five enjoy

  5. #5
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    Quote Originally Posted by euro2fast4u View Post
    Its probably cheaper then adding a gate. Unless you plan on operating at 8 to 7 psi in the future once you have a built bottom end.
    7 psi build block and e85 don't belong in on sentence. It will be closer to 30psi


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  6. #6
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    Looks like you could fit another gate on the front of the collector if you can get the oil drain around it. That's probably the easiest and most effective solution. Welding a fin above the wastegate port in the collectorto help direct gasses to the wastegate would help too. Mabey it's telling you how much boost it wants? A 2 inch exhaust will kill it


    86 325es, 2.8L m50, S476sxe, ProEFI 128 ecu, e85, solid rear axle, TH400 trans, 28x10.5w slicks, zip ties, popsicle sticks, tape
    best time 9.06 @ 151.8 mph, best 60 foot 1.30

  7. #7
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    Ill try recirculating WG first and i might finish my exhaust. Exhaust terminates just before the driver seat.

    If it wont help i might weld a baffle above the wg port. But i am worried it will kill the spool. It is inly 1.8 liter pushing fairly big turbo.


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  8. #8
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    I don't think a small baffle in there would hurt it. Velocity is your friend for spooling


    86 325es, 2.8L m50, S476sxe, ProEFI 128 ecu, e85, solid rear axle, TH400 trans, 28x10.5w slicks, zip ties, popsicle sticks, tape
    best time 9.06 @ 151.8 mph, best 60 foot 1.30

  9. #9
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    If you are running e85, I don't see a problem with a stock m10 running 25psi. Personally, I would get a larger turbine housing which will lower boost pressure and let it eat. Also, your timing (15*) might be weak if you are running e85, thus acting like a rolling anti-lag.

    If if you build an engine latter on, I would weld up the water channel on the back side of the combustion chamber of the head to stabilize it from deflecting. Obviously keep a small hole in it for water circulation.
    WOT

  10. #10
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    Quote Originally Posted by hsvturbo View Post
    If you are running e85, I don't see a problem with a stock m10 running 25psi.
    No e85 yet and i have half tank of 87 there hence fairly conservative timing

    I thought that bigger hotsides like to creep more?

    Quote Originally Posted by hsvturbo View Post
    If if you build an engine latter on, I would weld up the water channel on the back side of the combustion chamber of the head to stabilize it from deflecting. Obviously keep a small hole in it for water circulation.
    Any more info on this?



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  11. #11
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    M10 Boost creep issues

    I just tested it without the wastegate. It made 10 psi at 5.2k rpm.



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    Last edited by Retoropak; 07-26-2017 at 11:15 PM.

  12. #12
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    Quote Originally Posted by Retoropak View Post
    No e85 yet and i have half tank of 87 there hence fairly conservative timing

    I thought that bigger hotsides like to creep more?


    Any more info on this?



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    A bigger hot side requires more exaust gas to spool. So you should have less boost creep.

    Weld info in post 2 on the below link.

    https://www.bimmerforums.com/forum/s...up-H2O-jackets
    WOT

  13. #13
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    Quote Originally Posted by Retoropak View Post
    I just tested it without the wastegate. It made 10 psi at 5.2k rpm.



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    Sounds like you need to check the spring and or waste gate for damage.
    Capital Driving Club Car # 102
    How to turbo your car:
    Step one. Install ecu and learn to tune and or have it tuned.
    Step two. Install injectors and retune.
    Step three. Install turbo parts and bits. get it running with out leaks. DO NOT DRIVE IT. Idling should be ok
    Step four. Retune car
    Step five enjoy

  14. #14
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    Quote Originally Posted by euro2fast4u View Post
    Sounds like you need to check the spring and or waste gate for damage.
    What wastegate? I removed it completely. Leaving the wg port in the manifold open and it still build almost 10 psi of boost.






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  15. #15
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    wtf?????????
    unbelievable. joke thread. april fools.
    Last edited by Robocop; 07-27-2017 at 11:06 PM.

  16. #16
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    Ok so i welded couple baffles right above the wg port to redirect the exhaust to wg. And it did not work. So i swapped the wg to 44 mm and it steel crept to 20 psi (4psi spring) but at higher rpm this time.

    So i figured it is bbq time and tossed some snails on grill.





    Preheated the hotside to around 700F welded schedule 40 stainless pipe using 316L and left it overnight on hot charcoals to slowly cool down.




    Just need to add vband for tial 38mm and it should be good to go.


    Hopefully it will work and it wont crack.




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  17. #17
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    Tested it and it does awesome job at keeping the boost under control.

    It holds the boost steady all the way to the redline





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