pxctoday

» Log in

User Name:

Password:

Not a member yet?
Register Now!

» Find OEM Parts

» Jobs

» wallpapers

Results 1 to 7 of 7
  1. #1
    Frequent Poster
    Join Date
    Feb 2006
    Location
    ITALY
    Age
    52
    Posts
    193

    pipes performance on the dyno

    Hi Bill,
    my request is made for personal information only!!
    The motor is a twin 1050 SS with the same setup (carbs, Mpem, etc). Which ex. system makes the most top power and what is the hp difference between:
    a) Single pipe Coffmans system.
    b) Double Factory Pipe system.

    From what I know and this is I think common knowledge a multicylinder two stroke equipped with a pipe per cylinder delivers the most power.
    Speaking instead with some tuners here in Europe they stated that in the case of the Rotax BB twins the differences between a single pipe system and a double one are not very noticeable!!
    What is your point of view?
    Michele

  2. #2
    Tech Guru PWCToday.com Is My Home Away From Home Watercraft Magic's Avatar
    Join Date
    Feb 2004
    Location
    Glendora, California
    Posts
    25,321

    Re: pipes performance on the dyno

    Personal information? On a open website? LOL!

    If your Miller 1050 is properly ported for twin pipes it can produce more HP with a twin pipe setup. But if it was ported for a Coffman pipe, it will not produce more HP with twin pipes.
    email Chris at Watercraft Magic cdofixr1@live.com

  3. #3
    Frequent Poster
    Join Date
    Feb 2006
    Location
    ITALY
    Age
    52
    Posts
    193

    Re: pipes performance on the dyno

    Hi Bill,
    Maybe that I have expressed myself in the wrong way with the words "personal information".
    I wanted only to say that the requested infos were only to increase my personal technical knowledge about the problem!! I have absolutely
    no problems to share infos with everybody here in the forum.
    You stated that each pipe needs its specific porting to give optimum performance and this is out of discussion for a SS package in which you are permitted to modify the porting.
    But if I work in a Limited setup where porting can't be changed which pipe pipe system gives the most power output?
    Thank you
    MIchele

  4. #4
    PWCToday Regular
    Join Date
    Sep 2005
    Location
    Loganville, Georgia
    Posts
    62

    Re: pipes performance on the dyno

    Bill,

    Also, can a 1050 ported set of cylinders for a coffman be modified to the run the twin setup?

  5. #5
    Tech Guru PWCToday.com Is My Home Away From Home Watercraft Magic's Avatar
    Join Date
    Feb 2004
    Location
    Glendora, California
    Posts
    25,321

    Re: pipes performance on the dyno

    Michelle,
    On a unported limited race motor, the FPP long chamber twin pipes will probably produce about 10 hp more than the Coffman pipe. There will be a substaintial increase in the midrange power for accelleration, with a bit more HP at the very top end.

    I suggest that if you are a really good tuner, you can get good results with the twin pipes, but most guys will not necessarily be all that much better off than if they ran the easier to tune Coffman setup. Some would even say that the Coffman setup is better, especially if they have modified their exhaust manifold with some creative porting and milling equiptment.

    An example of the power differences between the C pipe and the twin pipes is with the oem 951 engines. A stock RXX was rated 160 HP from the factory. That is an increase of 30 HP over stock 947's that make 130 hp.
    A coffman exhaust on an otherwise stock 974 makes about 150 HP, a gain of 20 hp.
    email Chris at Watercraft Magic cdofixr1@live.com

  6. #6
    Tech Guru PWCToday.com Is My Home Away From Home Watercraft Magic's Avatar
    Join Date
    Feb 2004
    Location
    Glendora, California
    Posts
    25,321

    Re: pipes performance on the dyno

    Quote Originally Posted by bonus
    Bill,

    Also, can a 1050 ported set of cylinders for a coffman be modified to the run the twin setup?
    Yes we do upgraded porting to make a Coffman ported clyinder work with the twin pipes.
    email Chris at Watercraft Magic cdofixr1@live.com

  7. #7
    resident guru mandriva's Avatar
    Join Date
    Sep 2009
    Location
    montreal,quebec
    Age
    40
    Posts
    1,015

    Re: pipes performance on the dyno

    Long live for great info..thank you! This post answer my question
    Rossier 7250 rpm
    110 mid pipe/200 stinger
    Head 43cc/45 squish
    Strak swirl 17/22

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Powered by vBadvanced CMPS v4.2.0