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  1. #1
    Geo. E's Avatar
    Geo. E Guest

    Default I have been thinking about th

    I have been thinking about the tempture in my engine compartment and the fact that the engine is breathing hot air.
    I am thinking about adding another vent hose from the outside air to the flame arrestor so that the carb can breathe cold air.
    I would like to get opinions as to weather this would help efficiency.

  2. #2
    Join Date
    Jan 2004

    Default " I suspect you would perform

    " I suspect you would perform slightly better. Maybe not enough to really feel but then again perhaps a little bit. Cold air going in sould result in the air/fuel mixture compressing slightly based on the temperature prior to being brought in by the intake stroke of the engine. This would produce a slight increase in the delivery of fuel to your engine. As for efficiency I will let someone else speak to that.

    Just my thought on the matter. I would be interested in how it works out if you proceed though.

    One more thought, ... if you position that extension such that when your under way the wind generated by your motion will blow into the end of it then you will have the most basic form of what is commonly called a tunnel ram. That added air presure helping to push air into the carb should also boost performance just a little. "

  3. #3
    croozertoo's Avatar
    croozertoo Guest

    Default "Additional ventilation into t

    "Additional ventilation into the engine compartment is a good idea, but in order to get the performance increase you want, you would have to build a fairly airtight housing around the flame arrestor and use non-combustible (metal) components. Coastie inspectors may take a dim view of such a modification and you may also want to check your insurance policy regarding engine mods.

    If you're running a high performance boat, it may be worthwhile pursuing, but anything like a family runabout or cruiser won't respond much to mod like this. The theory is good, but the practical application might not be worth it.


  4. #4
    Join Date
    Apr 2003

    Default Consider the problem of keepi

    Consider the problem of keeping water out of the intake especially if you attempt to ram air. Spray from rough seas and wind etc. Aldo

  5. #5
    Join Date
    Apr 2003

    Default " P.S. I use 3 blowers to exch

    " P.S. I use 3 blowers to exchange engine compartment air, apart from clearing fumes the amount of air moved reduces the compartment temp. I only use them at high R.P.M. Aldo "

  6. #6
    Dan Gavin's Avatar
    Dan Gavin Guest

    Default " Geo. ducting colder intake a

    " Geo. ducting colder intake air may not necessarily increase efficiency. Theoretically speaking, to increase the efficiency of any internal combustion engine (a heat engine in the world of thermodynamics) you simply need to increase the difference between the temperature of combustion (aka T1) and the temperature to which the combustion is exhausted to (aka T2). The efficiency of the Carnot Cycle, which is the basic ideal heat engine cycle is given by:
    eff= 1-T2/T1. Looking at the equation you can see that by increasing T1 you get a higher thermodynamic efficiency. Modern engine designs have moved towards greater Thermo efficiencies over earlier designs. Just consider the average coolant temps car engines run at today. Coolant temps have increased due to increases in combustion temps. Having said this, there may be some benefit to ducting cooler temp air to your intake from a practical sense. This benefit may come from the cooler air aiding a struggling combustion process caused by some defficiency (ie. preignition, poor fuel atomizing or otherwise poor fuel/air ratio( ideal is 14.7:1). Hope this helps, and sorry for the long post but I just had to chime in. Any body know of any cheap tandem axle trailers?

    Thanks and good luck! "

  7. #7
    poker casino346's Avatar
    poker casino346 Guest

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  8. #8
    poker casino902's Avatar
    poker casino902 Guest

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