Flexible Marine Exhaust

Discussion in 'Performance Mods' started by Muso, Nov 14, 2011.

  1. Muso

    Muso New Member

    I really don't like the look of copper exhaust pipes so I've been looking at my options. At first I thought I could use high temp silicone tubes but learned that they probably wouldn't hold up in direct contact with the high temps put out by a 2-stroke. I've seen (but stupidly didn't bookmark!) one inch diameter flexible exhaust designed for marine applications. Has anyone had experience with these? I don't want to waste cash to find out what someone (hopefully) could tell me. If I don't get any solid fact's I guess I'll be the guinea pig and let everyone know how it turns out.

    Are there other options I'm overlooking?


  2. Al.Fisherman

    Al.Fisherman Active Member

    Attached Files:

    Last edited: Nov 14, 2011
  3. motorpsycho

    motorpsycho Active Member

    I think that stuff in the link is not for engine exhaust.
    I think it's for extraction (like for a factory) to suck fumes out of a room.
    the walls of it look too thin for engine exhaust, and this kind of exhaust tubing will just pull apart if you tug on it hard enough.
    you need to look at the hardware stores because i have seen 3/4" - 1" flex pipe made for engine exhausts. this stuff is made for gas powered air compressors and welders where you need to locate the exhaust outside of the building or truck.
    heck, if you have a conduit bender, you can bend up your own pipe out of conduit in no time and it would be a one off design.
    the hardest part will be the exhaust flange to bolt the pipe to the engine, but that could easily be done by using the one from the stock exhaust.
  4. GasX

    GasX New Member

  5. Muso

    Muso New Member

  6. olow

    olow Member

    :idea:psycho has it right conduit bender and pipe plus welder:cool2:
  7. Muso

    Muso New Member

    Its been forever, but here it is.

    Well, I was able to get some 1" flex pipe through Napa. It was $1.80/ft and came in a 25' length. I fit it onto my engine pretty easily but it was also pretty ugly. The best angle I could get was what is best describe as a big 'C'. I also used (not sure if I needed) LOTS of exhaust tape mixed with high temp epoxy to join the exhaust port and the expansion pipe intake. After three layers of that it still leaked exhaust around engine port (the tape became 'gummy' under high temps). And the flex pipe itself leaked where it was at the most extreme angles. To top it all off, the **** pipe is starting to rust. Anyone want to buy 23 feet of rusted, unsealed, flex pipe?
    It was a valuable learning experience, if not expensive. "People do it this way for a reason!".

    But I did find a 5' length of flex gas line in my girlfriend's parents garage...
  8. MikeJ

    MikeJ Member

    Hi Muso -

    If the gas line is too fragile, keep in mind water heater copper flexible tubing. I used about 5 feet of it on a previous build and it works well for small engines. It is about 3/4 inch in diameter and can be bent to shape a few times (then it might start cracking). Use that and some copper pipe elbows and U-shaped bolts and bolt it together. All parts are from a decent hardware store like Ace. The joints will not be perfectly tight, but you won't be affected by the exhaust anyway. Attach it to your frame so it does not flop around all over the place or fall off.

  9. tooljunkie

    tooljunkie Member

    1" silicone hose was used on ford exhaust systems,it connected to the catalytic convertor.the heat in that area is quite high.
    maybe something found in a BBQ,the bendable tubing used to connect burners?
  10. lowracer

    lowracer Member

    I bought some of what you seek at Lowes (if my memory serves me right) for around $2.50 for 1'. It was well hidden in the duct work aisle. I've been using it with success & if it ever leaks its cheap enough...