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Recent content by schmidtj86

  1. schmidtj86

    EFI controllers

    I work for an EFI company in China, and we make LOW cost systems. Any interest?
  2. schmidtj86

    performance and fuel economy?

    Combustion chamber has to be one of the most important areas (think fast burn and low ignition timing). Then, reduce friction and reciprocating mass wherever possible. Get the most from the fuel used also = drive like a chinese guy = shift at very low RPMs (I've been in China for over a year and...
  3. schmidtj86

    Dyno Installation

    "Engine Testing Theory and Practice" second edition is a great SAE book by Michael Plint and Anthony Martyr. Covers almost all aspects of equipment choices and designs, building dyno cells, and engine testing. I highly recommend it.
  4. schmidtj86

    EGR and how it adds to fuel economy???

    EGR's obvious main purpose is NOx reduction (inert gas temperature cushion). Any HC benefit is secondary (heating intake charge thus improving vaporization (it's hot EGR) - the second go-around is kind of non-sensical in a steady state mode). CO benefits, uhh, maybe from better vaporization, but...
  5. schmidtj86

    Exhaust back pressure

    Could it be a "sanity" check? To see if your gauge is actually working (assuming factory system). Is there anything related to that spec, like "replace muffler if..."? Do any seals in the turbo require exhaust pressure to keep long-life seal?
  6. schmidtj86

    Fuel Injector polarity

    Maybe it's so that people don't ask "does it matter which way I connect the wires on the injector?" If you just tell them one way is right, with a simple mark, it may save a lot of emails and phone calls, and wasted time.
  7. schmidtj86

    BMW's throttle-less engines

    Also if you close the intake very early, there is no pumping losses when the piston goes down, because that same force that resists it going down, helps it come up (neglecting heat transfer, and friction). It can get the charge into the cylinder nearer to atmospheric pressure, but closes before...
  8. schmidtj86

    bsfc vs torque vs HP

    It's also a matter of spark timing/flame speed/knock limits, fuel vaporization, and the friction losses due to RPM (slinging all the oil, moving all the parts, etc...). The later the timing -required- for MBT, the higher the BSFC is. On the engine I'm currently working on, it's peaking (minimum)...
  9. schmidtj86

    Another engine oil question

    The difference between 0-5-10-15 is huge when it starts to get really cold (sub -20C). 15W will come out like honey, and the cranking RPM will be way down in the cold, making starting more difficult, and loads the battery down a lot, and if it's already weak, it may strand you. As long as it's...
  10. schmidtj86

    Turbochargers converting heat energy to rotational energy

    Is it a reversible expansion (like in a piston/cylinder assembly). Kind of like why doesn't the exhaust get cold expanding out of the exhaust valve, or why an intake manifold doesn't ice up (except at the high velocity around the throttle). I guess if you spin the turbine backwards, it would...
  11. schmidtj86

    One point of forced induction/NA SI engine comparison

    Do you want to compare 2 DIFFERENT engines? Like a 454 at 10:1 NA vs a boosted 350 with an effective compression of (i.e) 13:1 - Both taking in the same air mass? Torque is more than just pressure when comparing engines of different size.
  12. schmidtj86

    Catalytic Converter As Part of Exhaust Collector

    A kit that includes long tube header(s) and cat(s) and a heated O2 (or 2) could probably pass the emissions requirements, but it's expensive to take the official test for an EO#. It's also illegal to remove a functioning catalyst that is under a certain age and still functioning. That's probably...
  13. schmidtj86

    Catalytic Converter As Part of Exhaust Collector

    There are many close mounted cats in production now. Usually supplimented with another, unless the engine is so clean or so small that it's not needed. If supplimented, the first cat usually has less everything and is mainly used to light the second cat quicker, but also do a small bit of work...
  14. schmidtj86

    Fuel Pressure Regulator

    I think Ford may be using a voltage regulated pump in some applications. There are many OEM reasons to go to a deadheaded system (like no more engine bay heat being put into the return line to the tank, and one less line), but few aftermarket reasons. It takes lots of engineering to combat the...
  15. schmidtj86

    Throttle Body - What size do I need?

    Did you tune the Haltech? EFI out of the box is usually worse than a carburetor, but I've seen people do it (and don't take offense if you have tuned it - I'm used to the tech calls and have to start with the simplest possible solutions first, hehe). Are you running the 4 barrel with 8 MPI...
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