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Thread: Alpina B7 Supercharger backpressure noise?

  1. #1
    Join Date
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    e39 '98 540i6, 2007 B7

    Alpina B7 Supercharger backpressure noise?

    UPDATE:

    The "backpressure chug" issue is confirmed as a bad "charge air pressure controller" which is the throttle body before the supercharger.

    The hesitation at light throttle was a crack in the intake tube at the curve just before the supercharger.

    The puff of smoke under hood was confirmed the oil from valve cover gasket dripping on exhaust. Gasket kits been replaced and problem gone.
    __________________________________________________ __________________________________________________ ____________________
    Original post:

    07 and 08 were sc years. My 07 is making what I would call a chug-chug-chug sound/feel as you let off the gas after you are over 3k rpm or more. It is louder at higher rpm and follows the engine speed as it slows until you cant hear/feel it under about 3k. To me it sounds like backpressure from the sc but I swear I don't recall hearing it before. Most sc and turbo systems have a blow off or bypass valve to allow excess pressure to excape when you let off the throttle, but my understanding is that Alpina's system is different and relies on the Valvetronic system and pre/post sc butterfly valves to modulate that pressure without a bypass valve? See this article here

    http://myautoworld.com/BMW/cars/bmwc...07-alpina.html


    Also, i usually get a single puff of light smoke come out the right front when I come to a stop. Not out the tailpipe. No visible signs of fluid spray/leak under hood or from underside on exhaust etc. The only other symptom is that when you are BARELY on the throttle (like just touching it), the car stutters and hesitates. This is more frequent when you are on flat ground on cruise control (barely on the throttle to maintain speed) It will do this in any gear at any rpm and it more noticeable at higher rpm. Other than that runs great and hard!

    This is an N62 engine platform but with some different Alpina-specific internals and sc components.

    Things done/observed lately:

    Changed plugs (correct kind) - no effect
    Changed ccv diaphrams - no effect except stopped excess oil vapors getting pulled in
    Changed rubber seal plates for eccentric shaft sensors - no effect
    Did the electronic reset of the adaptive transmission (step on gas for 25 sec while ignition on) - no effect
    Intake is clean and clear
    Mechanic found bmw vacuum code and cleared it. No other codes or errors. Was not specific enough to locate if at all current. Manual search indicates no broken hoses, pipes, etc in crankcase ventilation or otherwise.
    SC operates fine, no noises or leaks

    I feel ok driving it but the hesitation issue is a pain and I'm not convinced is normal. Wondering if the backpressure can be damaging or maybe that Valvetronic system is not working the exhaust valves properly.
    Last edited by MontanaRob; 01-04-2016 at 06:08 PM.
    1998 (9/97 production date) 540i 6 Speed Sport / black on black / shadow trim / debadged / black-out grill / Carbon fiber roundels / 80w Yellow Fogs / 2.81 non- lsd diff. / 17" BBS Sport Style 19 wheels/ 245 all around tires / modified CDV / Stage I Dinan software / 5w30 synthetic/ 244k miles and counting

    E65 2007 Alpina B7: Black on Black, Supercharged autobahn eater, 500hp/515trq, 245/295 tires, 141k miles with major systems rebuilt/replaced!

  2. #2
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    I can't really help your situation, but just so you know, valvetronic is only on the intake valves. Vanos, however, is on both cam gears.
    ASE and BMW Master Certified Technician

  3. #3
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    ok thanks
    1998 (9/97 production date) 540i 6 Speed Sport / black on black / shadow trim / debadged / black-out grill / Carbon fiber roundels / 80w Yellow Fogs / 2.81 non- lsd diff. / 17" BBS Sport Style 19 wheels/ 245 all around tires / modified CDV / Stage I Dinan software / 5w30 synthetic/ 244k miles and counting

    E65 2007 Alpina B7: Black on Black, Supercharged autobahn eater, 500hp/515trq, 245/295 tires, 141k miles with major systems rebuilt/replaced!

  4. #4
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    The "backpressure chug" issue is confirmed as a bad "charge air pressure controller" which is the throttle body before the supercharger.

    The hesitation at light throttle was a crack in the intake tube at the curve just before the supercharger.

    The puff of smoke under hood was confirmed the oil from valve cover gasket dripping on exhaust. Gasket kits been replaced and problem gone.
    1998 (9/97 production date) 540i 6 Speed Sport / black on black / shadow trim / debadged / black-out grill / Carbon fiber roundels / 80w Yellow Fogs / 2.81 non- lsd diff. / 17" BBS Sport Style 19 wheels/ 245 all around tires / modified CDV / Stage I Dinan software / 5w30 synthetic/ 244k miles and counting

    E65 2007 Alpina B7: Black on Black, Supercharged autobahn eater, 500hp/515trq, 245/295 tires, 141k miles with major systems rebuilt/replaced!

  5. #5
    Join Date
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    2007 Alpina B7
    Quote Originally Posted by MontanaRob View Post
    The "backpressure chug" issue is confirmed as a bad "charge air pressure controller" which is the throttle body before the supercharger.

    The hesitation at light throttle was a crack in the intake tube at the curve just before the supercharger.

    The puff of smoke under hood was confirmed the oil from valve cover gasket dripping on exhaust. Gasket kits been replaced and problem gone.
    It looks like I'm resurrecting an old thread but I am having the same issues with my 07 B7 and have narrowed it down to secondary throttle body.
    MontanaRob, did you end up replacing yours? Cost is still astronomical and I can't find a repair kit for it anywhere.
    Just your 2 cents plz

    Sent from my ASUS_Z012DC using Tapatalk

  6. #6
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    The ultimate problem ended up being the plastic gears inside the throttle body. The second one right at the intake manifold is fairly inexpensive and common to other models. The first one before the supercharger is unique and very expensive and there are no other substitutes that I am aware of

    Sent from my SM-G900T using Tapatalk
    1998 (9/97 production date) 540i 6 Speed Sport / black on black / shadow trim / debadged / black-out grill / Carbon fiber roundels / 80w Yellow Fogs / 2.81 non- lsd diff. / 17" BBS Sport Style 19 wheels/ 245 all around tires / modified CDV / Stage I Dinan software / 5w30 synthetic/ 244k miles and counting

    E65 2007 Alpina B7: Black on Black, Supercharged autobahn eater, 500hp/515trq, 245/295 tires, 141k miles with major systems rebuilt/replaced!

  7. #7
    Join Date
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    2007 Alpina B7
    Same gear is broken in my B7, I am in process of manufacturing one. Ones I do one, I'll be able to make as many as needed, if anyone else needs it.
    Originally this gear is made out of plastic and will not last more than 50.000 km, I know because mine was already replaced under warranty. Whole secondary throttle body was replaced, $2000,00 Canadian. Its outrageous that 3 min of work to replace the plastic gear requires replacement of the whole supercharger throttle body.

    Quote Originally Posted by MontanaRob View Post
    The ultimate problem ended up being the plastic gears inside the throttle body. The second one right at the intake manifold is fairly inexpensive and common to other models. The first one before the supercharger is unique and very expensive and there are no other substitutes that I am aware of

    Sent from my SM-G900T using Tapatalk

  8. #8
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    Quote Originally Posted by Milan99740il View Post
    Same gear is broken in my B7, I am in process of manufacturing one. Ones I do one, I'll be able to make as many as needed, if anyone else needs it.
    Originally this gear is made out of plastic and will not last more than 50.000 km, I know because mine was already replaced under warranty. Whole secondary throttle body was replaced, $2000,00 Canadian. Its outrageous that 3 min of work to replace the plastic gear requires replacement of the whole supercharger throttle body.

    Gear has been manufactured and it has been in my car for 3 weeks now. Working like brand new again.

  9. #9
    Join Date
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    2007 Alpina B7

    Need that part

    Quote Originally Posted by Milan99740il View Post
    Gear has been manufactured and it has been in my car for 3 weeks now. Working like brand new again.
    I need the same part. Can you send me details to getting one?

  10. #10
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    '93 850Ci- Daily Driver
    Ditto...
    '93 850Ci - Mineralweiß Metallic

    2001 740iL - Titansilber
    ALPINA B7 -Alpinweiß III


    ...the price of cool ain't cheap!

  11. #11
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    We have 5 BMW's (Cars)
    Quote Originally Posted by TxGR8White View Post
    Ditto...
    Make that 2 (or is it 3??)
    1 E38, 1 E39, 2 E46's, 1 E65, 1 R22, 1 R75/5

  12. #12
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    Hi. Not sure if you need the gear or not. I think I've private messaged you. Gear is made by a local machine shop in Hamilton, Ontario. If you need the gear please message me privately. Tx

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  13. #13
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    Update.
    Unfortunately the shop that was manufacturing the gear is not in business any more. I was able to help nine Alpina B7 E65 owners and all of them had zero issues ever since.
    At least it is possible to make the gear, now someone else will have to figure out how.
    Milan

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