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  1. #1
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    Pushing the limits on a new platform.. too far?

    Hypothetically speaking, or not so, however you would like to take it. How do you know what a new motor can take?

    Take the N54 for instance, noone knows what its fully cpable of pushing yet.
    How do you:
    1. Find the fuel limitations:
    2. What parts of the motor are most likely to fail, and when
    3. How do you know when too much boost is, too much?
    4. What can you do to mitigate the risks?

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    Research and development. Blow a few of them up. I think Tuning is the Key though. If you can tune it properly that will minimize the damage that comes from it. The damage that does happen should show you the weak parts instead of a weak tune.
    Click here to enlarge

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    Click here to enlarge Originally Posted by LostMarine Click here to enlarge
    Hypothetically speaking, or not so, however you would like to take it. How do you know what a new motor can take?

    Take the N54 for instance, noone knows what its fully cpable of pushing yet.
    How do you:
    1. Find the fuel limitations:
    2. What parts of the motor are most likely to fail, and when
    3. How do you know when too much boost is, too much?
    4. What can you do to mitigate the risks?
    The fuel limitations can be found by monitoring cycle duty of the injectors. If they are at 100% then there is physically no way for them to open longer and add more fuel, besides running a higher rail pressure or swapping to higher flow injectors.

    "Too much boost" as you know can depend on a variety of variables, but normally you would want to stay near the maximum efficiency island of your turbo's compressor map, to keep from over-spinning your turbos and putting out a bunch of hot air. The N54 is cool because you can gauge when cylinder temps are getting out of hand by watching the ECU adjust ignition advance and see iats rise with data-logging.

    If you aren't octane limited/knocking, then it really depends on the hardware. I've heard of heads actually LIFTING OFF of the block and stretching head studs/bolts from so much boost/cylinder pressure, resulting in a blown headgasket and/or warped head! This can also happen when you have two different materials (aluminum head/iron block) heating up and expanding/contracting at different rates.

    Really, it's going to take a lot of boost to find the hardware limits of the N54, assuming proper tuning, fueling and after-cooling are not a factor.

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    after-cooling?

  5. #5
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    Click here to enlarge Originally Posted by LostMarine Click here to enlarge
    after-cooling?
    Yep. Early turbo cars did not have it. You can do it a variety of ways. Use a air-air heat exchanger, water-air heat exchanger, meth/water injection, etc.

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    oh, i thought you meant after combustion or something thats why i didnt understand, not post turbo.. ok ok, i got ya

    how you can find out the flow rateings for a turbo?

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    lots of money, a good shop, R&D. fueling can be the main issue

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    Click here to enlarge Originally Posted by LostMarine Click here to enlarge
    oh, i thought you meant after combustion or something thats why i didnt understand, not post turbo.. ok ok, i got ya

    how you can find out the flow rateings for a turbo?
    Here are some great links, I recommend reading all three: http://www.turbobygarrett.com/turbob...o_tech101.html
    http://www.turbobygarrett.com/turbob...o_tech102.html
    http://www.turbobygarrett.com/turbob...o_tech103.html

    The third link is what you are asking for, it will show you what a compressor map is, how to read it, and how to determine if you are under/over-sized for your HP level and engine size/efficiency.

    It will be harder for you to determine, since you have Modded stock turbos, maybe ask Rob Beck for what he thinks should be a similar compressor map? And remember, you are going to be calculating for 1.5 liters each, because you have two turbos. Click here to enlarge

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    Click here to enlarge Originally Posted by 05m3smg Click here to enlarge
    Research and development. Blow a few of them up. I think Tuning is the Key though.
    Exactly, trial and error.

    Somebody will find the limit and then you know. Thing is, that limit also changes as the tuning evolves. What you thought the internals could take may change if the tuner knows the limitation he is working with. Some motors get their reputation as being strong way down the line as the tuning would evolve. Look at the S54, people thought it was made of glass at first. Now, it can take 700 whp on stock internals and I bet it could take more.

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    Well, I guess im gonna take this 1 step further and stop there.. I just dont want to make a rookie mistake, an unkown factor im cool with and able to accept, a skipped, easy precation would piss me off.
    I'll Let someone else take the ball and run with it after this Click here to enlarge

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