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Thread: Is it my Vanos??

  1. #1
    Join Date
    Apr 2009
    Location
    chicopee
    Posts
    267
    My Cars
    08 335i Single Turbo

    Is it my Vanos??

    Hey guys, i have a 01 325i, and just the other day i kinda raced my friend on his jeep that has alot done to the engine(haha who does performance upgrades on a jeep lol). So he started coming up beside me fast so i dropped it into 3rd and gund it. i brought it up to about 5.5k rpm and switched but before i switched i got a bog/a major loss of power. So i pulled away before he could pass me. but when i got home i knew something was not right. I started the car in the morning and it did not seem to sound like i remembered it to sound like. it has a little rattle/knock when at idle. you can hear it inside the car and it not to loud. you have to try in order to hear it. My question is, is it the vanos or is my valve train making the noise? I also have a e36 328i 1998 that i just droped an engine into and it sound horrible. It sound like a deisel. im thinking about doing the vanos but dont know what i need to buy. do i need the rattle and seal kit? thanks vic


  2. #2
    Join Date
    Jan 2009
    Location
    Chicago, IL
    Posts
    431
    My Cars
    2001 330i and 2005 330i
    I may be full of potatoes, but it's my understanding that the VANOS issues are mainly related to lower rev conditions, under 3K and that sort of stuff. Because the original seals get brittle, the VANOS pistons can't react as quickly as they should. In the upper rev range, the adv/ret timing returns to default: advance intake, retard exhaust. Net effect, the VANOS is essentially a passenger when you wind 'er out.

    It is also my understanding that dual VANOS (like yours and mine) are not subject to the rattle; that is a single VANOS issue. You might have loosened something during the 'race' that now makes a harmonic. Put your head under the hood and have a friend bring up the revs slowly. See if you can pinpoint the source.

    The shunt you felt is probably more the computer system than the VANOS seals. (Not to say that you shouldn't replace the seals anyhoo.) I remember seeing a graph of HP chacteristics with a before/after line for a programming mod. Both graphs had a flat spot in the upper range...
    Johnny Murray

  3. #3
    Join Date
    Dec 2008
    Location
    Jackson, Wy
    Posts
    85
    My Cars
    04 330xi
    I recall reading in the manual that the car will not let you over red line it by reducing engine output or something like that. Maybe that was all it was, just a guess.

    Good luck.

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