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  1. #1
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    Wastegate conversion for stockframe turbos?

    Posted this on N54tech, but figure it would get more response here.

    Planning to upgrade the stock snails in the foreseeable future. But aside from the usual quality control issue with the CHRAs that gets vented on these forum all the time, the wear rate on the wastegate assembly (flapper valve and pivot bushings to be more specific) on these stockframe turbos is a bit of concern as well. From my understand, the excess wear and eventual play, which causes the awful rattle that high mileage N54 is known for, is mostly due to the actuator setup on these turbos.

    Instead of staying close at idle and low load scenarios, the wastegates on our turbo would stay open and only fully close during spool. This demands a lot of back and forth movement on the assembly over time and leads to the rapid wear on the stock assembly, and even on the so called upgraded ones on the aftermarket ones. I mean, come on, how come wastegate rattle and excessive play is so common with n54 turbos, but not nearly as much on other platforms's OEM turbos with internal wastagates that have been around even longer(VAG, Evo/STI, etc.)

    So why don't we just convert the stockframe wastegate to the usual setup, by using mac solenoid used for the single turbo setup, and an aftermarket wastegate actuators like one of these (http://www.turbosmartdirect.com/Prod...ate-Actuators/). Can imagine this would be a difficult thing to do, since one only need to modify the existing brackets for holding the stock actuator, and fabricate the pushrods connecting the actuator to the wastegate lever.

    So here are my questions

    - How can we set up the vacuum line for this to work? I suppose we can just bypass stock boost solenoid all together and hook up the MAC solenoid, the one that is being sold on BMS with the PnP adaptor, directly to the WG actuator and the vacuum pump.

    - The diagram on the N54tech thread (http://www.n54tech.com/forums/showthread.php?t=20406) shows that the vacuum source is the inlet port of the turbo compressor, which doesn't produce a constant vacuum pressure, instead of the vacuum pump, which does. Would that affect things?

    Please guys, don't convince me to go single turbo instead, lol. As much as I like having incredible top end and ridiculous amount of peak hp, I have plenty of reasons to stay with stockframe hybrid and below 500whp instead. Hell, I don't even plan on installing inlets, lol.
    Last edited by cloud9blue; 05-30-2016 at 02:45 AM.

  2. #2
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    I don't think an upgraded waste gate wears out fast enough to warrant the effort, expense, lack of oem control, safety etc of the conversion

    Lots of effort for minimal change really
    boop

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    1 out of 1 members liked this post. Yes Reputation No
    I'm in a similar situation. I have decided to make my own wastegate parts. I am currently researching the best suitable stainless steel for this application.

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    Other platforms don't share the same wastegate rattle?!?!? VAG? Really?!?!? VW/Audi made a $#@!ing clip that goes around the wastegate pushrod/actuator linkage to help eliminate the rattle. Lol. Stock turbos are just junk man. If you want low end response and don't care for big power, but want longevity and reliability, then get Jake to pair a small 500hp turbo to the Motiv kit and just replace their vacuum lines with some hard lines from Payam.

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    Yes, I am well aware of the issue with the VAG 2.0T and the clips that were used on that platform, which is also used by many on our engines. But on what I can gathered, the rattle is made significantly worse on our car, especially on decel and low boost spooling, due to its open default position. Converting the stockframe's wastagate shouldn't be all that expensive, mac solenoid and actuators are all pretty cheap off the shelf items, that hardest part is fabricating the linkage, which really isn't hard at all...

    Motiv is $8k, and I am not a fan of the replacement passenger side motor mount that is required on all the quick spooling bottom mount manifold, which just doesn't seem all that sturdy for road course use. Nor I am convinced about the mid range and transient response of these non-twin scroll manifold, no matter how small of a turbo you run... And there is the issue with the O2 overheating. As I said, lol, I have a million reasons against going single turbo for my particular use of the car. Top mount, please, that's a horrible idea for track cars with all the heat up top next to the plastic valve cover...

    JB4 can already do the boost control once the mac solenoid is in place. Curious how does the Motiv kit control the boost on theirs without JB4?

    Would be nice if Pure or Hexon can think about this alternative wastegate config for their upcoming BB twins.

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    Vargas has done this with the n55 turbo. Converted to a normally closed wastegate and a mac type solenoid. Not sure if he still has I available to purchase
    2010 AW/BLK 135i VM 6465 Single Turbo w/ OCDworks Modified T51r Housing, JB4 + MHD, VRSF CP & Tial, Big Tom, Fuel-It PI + Stage 3 + Return + Ethanol Sensor, BMW PE, MFactory LSD, Spec 3+ & MFactory SMFW, RB External PCV, ADV sensors, and many more....
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    2 out of 4 members liked this post. Yes Reputation No
    Click here to enlarge Originally Posted by BostonBeemah Click here to enlarge
    Vargas has done this with the n55 turbo. Converted to a normally closed wastegate and a mac type solenoid. Not sure if he still has I available to purchase
    not to be a fanboy or hater, but I won't buy anything from VTT lol.

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    I would be interested in this style setup on some stockers. The death rattle is the only real issue I have with my car.

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    Click here to enlarge Originally Posted by BostonBeemah Click here to enlarge
    Vargas has done this with the n55 turbo. Converted to a normally closed wastegate and a mac type solenoid. Not sure if he still has I available to purchase
    I tried that and it didn't work smoothly at all. Could make a ton of boost though.

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    For the cost of getting the Turbos out to replace the wastegate and put everything back, isn't it just going to be more cost effective to go to a stage 1/2 aftermarket turbo instead?
    Best:11.79@119mph on stock turbos.
    11.74@129 on GCs.
    FBO+Meth Port injection, GC Turbos, custom bucketless stage2, JB4, Trebila flash.

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    Click here to enlarge Originally Posted by AWSAWS Click here to enlarge
    For the cost of getting the Turbos out to replace the wastegate and put everything back, isn't it just going to be more cost effective to go to a stage 1/2 aftermarket turbo instead?
    Hard to argue against...
    Three sets of brand new 991.2 3.0 headers for sale: Kline, Fabspeed, and Vektor Ceramic Coated

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    Click here to enlarge Originally Posted by AWSAWS Click here to enlarge
    For the cost of getting the Turbos out to replace the wastegate and put everything back, isn't it just going to be more cost effective to go to a stage 1/2 aftermarket turbo instead?
    Guess I wasn't clear to begin with. yes, you are right. But it would be even more cost effective if the stage 1 and 2 turbos are converted to default-closed type of wastegates from the get go.

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    Click here to enlarge Originally Posted by cloud9blue Click here to enlarge
    Motiv is $8k, and I am not a fan of the replacement passenger side motor mount that is required on all the quick spooling bottom mount manifold, which just doesn't seem all that sturdy for road course use.
    Seriously? You do know the track abuse that motor mount gets put through on our award winning race car right?

    Click here to enlarge Originally Posted by cloud9blue Click here to enlarge
    And there is the issue with the O2 overheating.
    ADV sensors have solved this 100%.

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    Click here to enlarge Originally Posted by jyamona@motiv Click here to enlarge
    Seriously? You do know the track abuse that motor mount gets put through on our award winning race car right?



    ADV sensors have solved this 100%.

    I understand... Lets keep it professional here, I am not here to trash anyone. But I am just not a fan of having PU mounts that close to the hot parts. I have a set of blackforest PU motor mounts as well. The passenger sides started to deform within a month of light winter driving due to the heat from downpipes. Perhaps it is just bad materials.

    If you guys can show ensure that your PU mount can handle the radiant heat from the hot parts running right next to it, I might reconsider your kit. And honestly, the Motiv kit is only one I would consider if I do go single turbo.

    Going slightly off-topic, what is the recommend turbo pair for 450-500whp on pump gas while preserving the spool and transient response as much as possible.

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    Why wouldn't a heat shield work to protect your mount if it was an issue?
    Click here to enlarge

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    Click here to enlarge Originally Posted by Nugs Click here to enlarge
    I tried that and it didn't work smoothly at all. Could make a ton of boost though.
    Well your gonna have that issue on any normally closed wastegate unfortunately. There's no boost control until you hit the spring pressure or in your case, the adjustment level. You can adjust the nut on the rod to lower the spring pressure to allow more control at lower boost levels.
    2010 AW/BLK 135i VM 6465 Single Turbo w/ OCDworks Modified T51r Housing, JB4 + MHD, VRSF CP & Tial, Big Tom, Fuel-It PI + Stage 3 + Return + Ethanol Sensor, BMW PE, MFactory LSD, Spec 3+ & MFactory SMFW, RB External PCV, ADV sensors, and many more....
    RIP Click here to enlarge2008 AW/BL 135i
    Click here to enlarge

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    Click here to enlarge Originally Posted by B M W Click here to enlarge
    I would be interested in this style setup on some stockers. The death rattle is the only real issue I have with my car.
    Good point, but the failed mount that I had was suppose to be stock replacement. There really isn't a heatshield for the motor mounts in stock config, but the EPDM rubber used in the OEM mounts seem to handle the heat just fine.

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