Supra generations

    The Toyota Supra Community for all Supra generations

    Toyota Supra A90

    Owners of the fifth generation Toyota Supra are thrilled about that car

    Toyota Supra MKIV

    In July 1993, the fourth and so far last generation of the Supra came on the market. Internationally, this type is called " Supra MKIV ".

    Toyota Supra MKIII

    In early 1986, the third generation of the Supra was introduced. It is also the first that has not been marketed with the suffix Celica.

    Celica Supra (MK2)

    The second generation was presented in the fall of 1981 and had a completely independent drive with the new (170 hp) 6-cylinder engines.

    2000GT & Supra MK1

    The first Supra built from spring 1978 to summer 1981 was still offered as a top version of the Celica first in Japan and later in the United States.

    BPU Tuning Erklärung | Forum

    Topic location: Forum home » Supra MK4 » Tuning
    Spoony
    Hi
    habe im englischen forum diesen informativen bericht gefunden, original von Homer geschrieben und von der www.mkivsupra.net homepage.
    Finde das ganz interessant, damit sollten keine fragen mehr zum BPU offen sein!!!
    wer langeweile hat kann das ja gerne ins deutsche übersetzen, ist aber super einfach zu verstehen :wink:

    Name:
    BPU

    Also known as:
    Basic Performance Upgrade
    Full decat

    What is it?
    BPU stands for “Basic Performance Upgrade”, a term coined by US firm Suprastore for a basic upgrade package for the TT Supra. BPU is essentially what other marques refer to as "Stage 1” engine modification.

    The BPU upgrades allow the engine to produce more power by raising the boost pressure the turbos produce.

    In stock form, the TT produces 0.76bar (11psi), however this can be raised its is generraly acceptd that the stock ceramic Jspec turbos will handle 1.2bar (17.4psi). The Export spec (UK/Euro/US) has steel blades so will, in general, survive at higher boost pressures. 1.4bar (20.3psi) is not unheard of.

    1.2bar is the "accepted" safe limit with regards to a) detonation, b) actually getting more power, and c) some level of longevity. It is also accepted that you are spinning the cylinder and pulling the trigger each time you use them, but 1.2bar you have one loaded chamber, 1.4bar you've got three
    There are limitations with pressures above 1.2bar, the turbos are already outside of their efficiency range and the additional heat generated will raise the intake air temperature considerably – thus negating the effect of increased boost pressure.

    In both Jspec and export spec, BPU will raise engine power to around 400bhp. Not only will it release more power but it allows much quicker turbo spool-up, which vastly increases drivability.

    How it works
    In stock form, the boost pressure the turbos produce is controlled by back pressure in the exhaust system (I.e. highly restrictive catalytic converters and exhaust system). There are two approaches to BPU dependant on the model of car; as such the next section is split between Jspec and Export spec:


    Fundamentals of BPU

    Jspec:
    To raise boost beyond the stock level the restrictive catalytic converters are removed, thus allowing the turbos to spin faster and produce more boost pressure.

    There is a down side to this. With both cats removed the turbos will in fact over speed far past their safe limit and reach over 1.6bar (23.2psi). This is due to the small size of the jspec wastegate which cannot cope with the increase in exhaust gasses.
    At these pressures the ceramic blades in the turbo can become detached from the shaft and therefore cause catastrophic failure of the turbo.

    In order to add some restriction back in to the exhaust a restrictor ring is added to the exhaust system. A restrictor ring is simply a metal plate that fits normally between either between the 1st and 2nd decat pipes, or the 2nd decat and cat-back. The centre of the restrictor is drilled out to a smaller diameter than the exhaust itself (normally around 2inches). A properly sized restrictor should bring the maximum boost pressure down to 1.2 bar or less.

    UK/Euro/US (Export) spec:
    To raise boost beyond the stock level the restrictive catalytic converters are removed, thus allowing the turbos to spin faster and produce more boost pressure. Different to the jspec, the export spec has a larger wastegate which can handle the increase in exhaust gasses.
    Therefore boost pressure will be maintained at only slightly above stock levels, typically 0.85bar (12.3psi). In order to raise this further it is necessary to install a Boost controller to change the way in which the wastegate opens.
    A restrictor ring is not required on the export spec

    Note: On both models it’s possible to raise the boost with simply adding a Boost controller or Bleed valve; however this is not recommended since the huge resistance of the cats is still in place. This will result in significant extra heat being generated in the manifold and could cause serious engine damage due to raised exhaust gas temperatures.
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