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Better flow through Cat/exhaust manifold replacement?

Discussion in 'Modifications' started by jcuyckens, Sep 11, 2016.

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  1. jcuyckens

    jcuyckens Copenworld Member

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    Toyota Corolla 2004
    Rover 45 V6 2005
    Daihatso Copen 2006
    BMW R850RT & R850R
    Yamaha GTS1000 1993
    Hello,
    I was wondering, how to get a better gas flow through the exhaust manifold without installing tuning parts. I do want the engine bay look original.
    Then I notecid that some daihatsu's have in some years different exhaust manifolds on the 1.3 engines. I also saw they use the same manifolds for 1.3 en 1.5 engines.
    Since I use the 1.5L engine in my copen with original 1.3L manifold, I want to improve flow by installing a YRV/Sirion 1.3L exhaust manifold.
    But i would like someone with more knowledge to confirm that the swat would be an improvement. I've added two pictures to show the difference.
    Any thoughts?
     

    Attached Files:

  2. jez77

    jez77 Copenworld Regular

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    2000 Toyota RAV4
    The Sirion one looks to be far superior judging by the angle of the pipes going into the collector. I'd go with that one on looks alone, the factory stamped manifold looks terrible. Better check if it will fit, Copens are known for there expansive engine bays.
     
  3. Khalid

    Khalid Copenworld Newbie

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    Daihatsu Sirion Rally II, Daihatsu Copen 1.3
    I'm really curious to know if this is even possible. The Sirion/ YRV manifold seems superior in its flow design.
    The big question is if it would fit on 1.3 Copen engine bay and line up with the stock exhaust system?
     
  4. jcuyckens

    jcuyckens Copenworld Member

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    Daihatso Copen 2006
    BMW R850RT & R850R
    Yamaha GTS1000 1993
    I bought one and it just bolt on the engine, dimensions are equal, I tested it.
    Now I'm purchasing an HJS sport cat to be welded in the Sirion/YRV exhaust manifold.
    see pictures.
     

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  5. Khalid

    Khalid Copenworld Newbie

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    Hi jcuyckens.

    I imagine it would bolt on perfectly onto the engine. Does it line up a the bottom too for the exhaust?

    With the better flow design, did you notice any difference or improvement in performance?
     
  6. Kopen

    Kopen Copenworld Newbie

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    Hi,

    I am new to the forum, but I am not new to power gains via fitting high flow cats or removing them completely. My experience includes several different types of car. In each case the result was the same. The increases in performance from changing or removing cats has been Zero. My best advice is save your time and money. One thing I would recommend is treat your car to a bottle of Cataclean, it is simple and cheap to use and will ensure that the standard cat is working as it should.
     
  7. Salieri

    Salieri Copenworld Veteran

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    Our greek friend with the cat-less exhaust header would probably say otherwise :D
     
  8. Khalid

    Khalid Copenworld Newbie

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    Hi Kopen.

    I actually don't have any intention of removing the Cat, because as you say it makes little difference. Besides I don't want to harm the environment too much.

    I was just keen on exploring the idea of a better flowing exhaust manifold over what looks like a terrible design.

    If this just bolts on and it can help the engine breath better then I think it could be beneficial.

    Cataclean is a brilliant product. I used to use it on my Sirion Rally II and you could really notice a difference in performance and mpg!... downside is that it's expensive liquid science, but very good for the engine.
     
  9. marinos_84

    marinos_84 Copenworld Member

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    Dear Salieri,
    My copen have 91,4hp only one manifold(hand made),remove the catalyst and I posted a free filter.If you want to see my car,i have dyno.My car radically changed!!!
    Next week i will put parallel ecu Greddy and new dyno for my car.Stay tuned my friend..;)
     
  10. marinos_84

    marinos_84 Copenworld Member

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    I like talking with evidence.. ;)
     

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  11. Salieri

    Salieri Copenworld Veteran

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    What did I tell you? :D
    91hp at the wheels is nice, the engine is probably making 100-110 horsepower now
     
  12. Khalid

    Khalid Copenworld Newbie

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    Wow! That's really impressive. The car must feel completely different.
     
  13. Khalid

    Khalid Copenworld Newbie

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    How did you get on with YRV/Sirion Exhaust Manifold? Did you notice any improvement?
     
  14. jcuyckens

    jcuyckens Copenworld Member

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    Yes and no, i think acceleretion improved slightly, small difference in sound also. No major inprovement. I also installed a HJS sport catalyst inside the YRV manifold tocreplace the restricting original one.
     
  15. Khalid

    Khalid Copenworld Newbie

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    Thank you for the update.

    That's interesting.

    I've been thinking of getting a YRV/Sirion 1.3 exhaust manifold and doing a straight swap on my Copen 1.3 for a few bhp... If the improvement isn't so noticeable then it doesn't make much sense.

    With a sport catalyst of 200 cpsi there will be some improvement. It is claimed that it could give between 4 and 10bhp... I suspect it'll be in the lower end because the engine is small.

    What was the HJS catalyst converter size you had welded on?

    I want to look into the cost of doing this modification.
     
  16. jcuyckens

    jcuyckens Copenworld Member

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    Daihatso Copen 2006
    BMW R850RT & R850R
    Yamaha GTS1000 1993
    You are correct, it is noticable in the low end, more torque. I will check the type of HJS i have installed.
    Remark, i am using the 3szve engine.
    Link to HJS:
    HJS Universeel Substraat Katalysator HF+ Euro 4 200 CPSI tot 250 hp D108 L130
     
    Last edited: Jul 11, 2017
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  17. Khalid

    Khalid Copenworld Newbie

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    Thank you for sharing that. It becomes quite an expensive modification buying this and getting it welded on to the exhaust manifold professionally.

    Presumably new gaskets will need to go on and the front bumper etc will need to come off to get access.
     

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