Results 1 to 2 of 2

Thread: losing boost? Please help

  1. #1
    Junior SCH Member
    Join Date
    Nov 2003
    Location
    Welland ON
    Posts
    1

    losing boost? Please help

    Has anyone ever encountered this before?

    Vehicle setup:
    stock 60K mile shortblock
    AFR 165 heads
    B303
    GT40 intake with 1" spacer
    42# inj's
    no fmu
    255 lph pump
    Snow water/meth inj
    MSD 6BTM
    spout out set at 30' always with 1' pull out per pound
    BD11A with 11 # pully that has never made 11#'s max ever of 10
    BOV - 1st Gen DSM
    Pro M 77 cali'd for 42's

    blower has about 4k miles on it. the car is only a weekend car.
    Best time to date:
    11.7@118.59mph

    Here's the deal:
    last year - made 9-10 psi depending on temperature outside. If i step on it at about 2500-3000 rpm the boost would instantly jump to 5 psi and climb to max boost as rpm increases.

    this year: (beginning of the summer)
    max boost about 7.5 psi. 2500-3000 rpm full throttle amybe 3 psi and slowly builds to 7.5

    now - (end of the summer)
    max boost 4.5psi 2500-3000 rpm tromp and it jumps maybe to 2 psi.

    I took the blower off the car last week to check it out. Internal belt looks like brand new. opened up both sides. nothing looks wrong. dam! i was hoping to find the problem.

    I tried another boost gauge, and it reads the same. (did not use the same vac line, i ran it off the back of the intake.

    The car feels flat when it is under full throttle. when i say flat, it feels and sounds as if the car was tuned for boost and none is here to save the day... just like the time my serp belt flew off. Just flat. no power

    Vacuum is same as normal and steady at about 12" (B303 cam)

    The serp belt last year was loose as heck (thats why the belt flew off - ONLY once though and that was while passing someone on the way back from the track after running repeated high 11 sec passes).

    With my boost problem i went and got a new belt. Its tight.

    Replaced the discharge tube with the factory plastic one with no BOV just to see if the 1st gen DSM BOV was leaking. Nope same crap.

    Off bost, the engine runs just like normal. Not boost it just doesn't seem to do much more as little to no boost is happening.

    I don't know where to look next. I planned on upgrading to an S-Trim, BUT if i can just figure out the damn problem with this BD11a i can sell it to help fund the S-trim.
    Anyone got an S-tirm for sale ?

  2. #2
    SCH Moderator "SN Guru" speedytang's Avatar
    Join Date
    Dec 2002
    Location
    Marengo, Ohio
    Posts
    2,028
    Sounds to me your blowing past either a sleeve on one of the pipes or your blowing past your rings. Do a compression check and you will probably find a weak ring.

Posting Permissions

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