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Custom Exhaust

Discussion in 'Performance' started by Dj1house, Jan 17, 2021.

  1. Dj1house

    Dj1house New Member

    I was playing around with the idea of taking my Sambar to an exhaust shop to have a full custom exhaust done. I have a few questions though. Since I have a KT6 with the EK23 2 cylinder, what diameter exhaust should it be? 2"? 2.5"? I assume it needs to have an expansion chamber like the stock one has, correct? Any advice is welcome.
  2. SDK1968

    SDK1968 Active Member

    not sure about that engine vs my K6A....

    but i ran 2" from the flange right behind the O2 sensor all the way out the back. it made a huge difference in how it ran.

    it is a little bit louder though. sounds like a side x side now.
  3. Jigs-n-fixtures

    Jigs-n-fixtures Well-Known Member

    For a naturally aspirated engine, there is an equation to size the exhaust tubing based on the exhaust valve diameter and the max rpm the engine will run at. The exhaust tubing acts as a ram, and increases the actual airflow through the engine. Too large of tubing and you loose the ram effect, decreasing the scavenge, and hurting torque.

    On a supercharged or turbocharged engine, the exhaust need to be as large as possible to reduce back pressure, which will increase the scavenge.

    On my naturally aspirated Hijet, I am planning 1-1/4-inch tubing from the manifold back, and installing a tuneable exhaust tip, from SuperTrapp. Upside of that is that the SuperTrapp is a spark arrestor when I’m off road.
    Limestone likes this.
  4. Dj1house

    Dj1house New Member

    My EK23 is a N/A engine, so I'll try to work out what size I need for the exhaust. I was thinking about trying to get equal length headers to optimize the scavenging. But in the case of that big drum expansion chamber (if that's what it even is, I'm thinking in terms of 2 stroke here) can I just get rid of it? I wanted to remove the cat and just make it headers through to a muffler, but I don't know about that bug drum. Trying to free up some ponies here.
  5. Dj1house

    Dj1house New Member

    Looks like yours is a 660cc whereas mine is a 550, so 2" is probably too big for my little 2 cylinder. But you didn't change the exhaust manifold? And you're running no muffler?
  6. SDK1968

    SDK1968 Active Member

    If you are talking to me & not Jigs?

    correct. 2" straight pipe, no muffler... but i still ran it all the way to the back bumper. no worries about burning a valve or starting a fire.
  7. Dj1house

    Dj1house New Member

    I just took the Sambar to a reputable exhaust shop, said they could handle it. They said that they would be using 2" stainless from the manifold back and taking out the cat/muffler thing. I'm worried about it if the carburetor will have to then be tuned? And also there's 2 pipes running to the cat that would need to be addressed, one tube that runs to the air intake and one that is some sort emissions pipe. Not sure how the truck is going to perform after the modifications...
  8. SDK1968

    SDK1968 Active Member

    i didnt have a carb model on the exhaust change.... there were ZERO negatives on mine. EVERYTHING was better. low end, midrange, high end all good on torque(feel) all good on power.

    top end speed went up about 10kmh too. on my Zuki: it can breath in & now it can breath out.

    oh the only drawback is its a little louder.

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