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    Fuel Cooler?

    So A friend of mine has an old Yamaha XS650 Street tracker and I noticed the other day he has some kind of an insulation tape on the bottom of his fuel tank. He said it helps to absorb the radiant heat coming from the motor to help keep from his fuel getting too warm. He claimed that cooler fuel burns better and gives better performance. On top of that he had an oil cooler that he was thinking about running his fuel line through to make the fuel even colder before it gets to the carb. His only problem was it's a gravity-fed system so there was no way to get the fuel from the cooler back to the carburetor without the use of an electric fuel pump. On top of that if you pressurize fuel into a gravity fed carburetor you run the risk of flooding the carburetor. Has anybody ever heard of anyone else doing this or trying this to get cooler fuel for better burn?

    #2
    FWIW you don't want material to absorb heat, but rather deflect or reflect heat. That is why radiant heat panels work in roofing.. Cooler fuel does burn better but personally I would never mix a cooler for fuel and oil. It may seem to be convenient until it fails, your gas mixes with the oil and your bottom end spits out the bearings from lack of lubrication.

    If you are OCD about it and want some level of radiant barrier on the bottom of your fuel tank you could go to Lowes, buy some of the aluminum foil tape that is used on duct work and use it on the bottom of the tank, but to be fair the nature of fuel in the gas tank is probably already doing most of the work as far as acting like a cooler, especially a metal tank, which acts as a large heat sink in a manner of speaking. Some time take your finger and dip it in the gas tank and you should feel the difference between the temp of your fuel and the air temps (meaning the fuel will feel cool to the touch). Just be sure to wash your hands afterward

    If your friend is flat tracking he probably isn't filling his tank up all the way either, so in effect keeping the fuel cooler as well as the bike lighter.

    Heat soak is a real thing in track racing and most often the fuel is kept in the shade as much as possible to help keep it cooler as well.

    AS far as street riding goes, I doubt you will really notice any difference and it's not worth it overall in my opinion but that may vary from bike to bike, especially if you are going from metal tanks to composites.

    In his case he could use a low pressure vacuum pump to push the fuel through the system (similar to what we use on Hawks) not just electric, but you are trying to solve a problem that doesn't really exist. The best thing you can do if you want a source of cool fuel in your gas tank is to ride more and fill up more frequently. You'll find the fuel in the ground supply will be much cooler than what is in your tank and if you ride about 100 to 120 miles your tank will need a refill on a Hawk. It's a self fulfilling prophecy (pun intended).

    88 Blue Hawk GT - Under construction but rideable (guest approved)
    89 BlackHawk 2.0 - On the lift and being assembled
    90 Hawk GT (color as to yet be determined) - Still on the shelf in crates

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      #3
      He's not racing it it's fully Street legal. He wanted to use an oil cooler with nothing but fuel inside of it to cool the fuel down. So it would be a separate cooling system dedicated just for fuel with no oil in that cooler. Is an electric fuel pump bad to use in a Honda Hawk gt?

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        #4
        It's not bad, it's just the vacuum one has always been popular on Hawks and if you don't already have a power circuit for a fuel pump (or no longer want one) then vacuum pumps need no power and are easy to rebuild..
        88 Blue Hawk GT - Under construction but rideable (guest approved)
        89 BlackHawk 2.0 - On the lift and being assembled
        90 Hawk GT (color as to yet be determined) - Still on the shelf in crates

        Comment


          #5
          Air temp through the carb will totally dominate fuel temp. The only real concern with fuel temp is A) colder fuel means you can squeeze more into a tank (higher density) but that isn't a concern here, and B) too hot and it'll boil away, again I don't think a real danger of that happening either. He's never going to be able to measure or feel the perf diff from chilling his fuel.

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            #6
            The Hawk has a big plastic airbox to block engine heat from heating the tank. Without the airbox, most of the air above the engine is getting drawn into the motor thru the pods. And warm intake air is probably a bigger problem than warm fuel.

            This sounds like a pretty elaborate solution in search of a problem. The only thing I could think of using an external fuel cooler for is the extra volume (and range) it would provide.

            If you were looking for a support group you're barking up the wrong tree. This place is fulla enablers dude. - Shooter77us

            The bitterness of low quality lingers long after the thrill of a low price has gone. - RacerX450

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              #7
              Every race car I have ever built has had a "cool can", where the fuel, after the fuel pump, goes through a heat exchanger packed with ice to cool the fuel.
              It works, no discussion about it. Cooler fuel is good in many ways, cools the valves and seats for better flow, drops cylinder temps for better compression, less pre-ignition as well as more dense fuel.
              Every race car I have ever built is operating at the edge of maximum performance and we will fight to stuff more fuel down it's throat.
              I don't know what you're doing with your hawk, but I bet you're no where near that edge, so if you want more fuel, jet up.
              Same end result.
              When I'm at the track and the bike is just sitting, I'll put a wet towel on the tank to cool the fuel and the fuel lines on my hawk run down the frame rails to keep them away from engine heat. Just cuz.

              Comment


                #8
                Originally Posted by bitzz View Post
                Every race car I have ever built has had a "cool can", where the fuel, after the fuel pump, goes through a heat exchanger packed with ice to cool the fuel.
                It works, no discussion about it. Cooler fuel is good in many ways, cools the valves and seats for better flow, drops cylinder temps for better compression, less pre-ignition as well as more dense fuel.
                Every race car I have ever built is operating at the edge of maximum performance and we will fight to stuff more fuel down it's throat.
                I don't know what you're doing with your hawk, but I bet you're no where near that edge, so if you want more fuel, jet up.
                Same end result.
                When I'm at the track and the bike is just sitting, I'll put a wet towel on the tank to cool the fuel and the fuel lines on my hawk run down the frame rails to keep them away from engine heat. Just cuz.
                Your mistake is trying to apply a Car thing to a Bike.Kurlon is right,the carbs heat the shit out of the fuel.But so are you. I have only known of one example of this principal in a Hawk. A couple of renowned(in some groups) manics
                who built a racebike or 2 laid up a fiberglass cool-air box right in a Hawk frame on an engine w/o the carbs. Then they replumbed everything that stood in the way of enclosing the carbs and fed them cool air from a snorkel over a lowered radiator. This purportedly gained a few HP on the seat-of-the-pants Dyno.....but they were making 80-90hp.

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                  #9
                  Cool(er) fuel will cool the intake charge more as the fuel evaporates. (heat of vaporization) This is the main gain from running a fuel chiller on a car and it will give a measurable improvement. Also, in a class where you are limited on fuel volume carried, cooled fuel allows you to stuff a bit more in the tank. F1 has (and I believe MotoGP as well) limits on fuel temperature. There are diminishing gains, because the colder the fuel, the harder it is to atomize so you start losing combustion efficiency at a certain point. All that being said, I sure don't see the point on a XS650. Other than maybe installing a reflective barrier on the bottom of the fuel tank, which is pretty easy. I do that on a lot of max effort racebikes.
                  J.D. Hord
                  Keeper of Engine Nomenclature, 9th Order

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                    #10
                    Official Race track reflective barrier!!!! LOL

                    https://www.lowes.com/pd/3M-2-5-in-x...ape/1002947412
                    88 Blue Hawk GT - Under construction but rideable (guest approved)
                    89 BlackHawk 2.0 - On the lift and being assembled
                    90 Hawk GT (color as to yet be determined) - Still on the shelf in crates

                    Comment


                      #11
                      Originally Posted by Hordpower View Post
                      Cool(er) fuel will cool the intake charge more as the fuel evaporates. (heat of vaporization) This is the main gain from running a fuel chiller on a car and it will give a measurable improvement. Also, in a class where you are limited on fuel volume carried, cooled fuel allows you to stuff a bit more in the tank. F1 has (and I believe MotoGP as well) limits on fuel temperature. There are diminishing gains, because the colder the fuel, the harder it is to atomize so you start losing combustion efficiency at a certain point. All that being said, I sure don't see the point on a XS650. Other than maybe installing a reflective barrier on the bottom of the fuel tank, which is pretty easy. I do that on a lot of max effort racebikes.
                      Now this is actual technospeak of the Nomenclature,as opposed to a transcribed tale from my hazy recollections.

                      Comment


                        #12
                        The DEI gold stuff is

                        Originally Posted by rpcraft View Post
                        Official Race track reflective barrier!!!! LOL

                        https://www.lowes.com/pd/3M-2-5-in-x...ape/1002947412
                        J.D. Hord
                        Keeper of Engine Nomenclature, 9th Order

                        Comment


                          #13
                          DEI is the king of heat sheild stuff for sure. I use it to protect fuel and AC lines in my K5 engine compartment but I never really thought much of needing it on a bike for sure though. I have learned though that the aluminum tape is really good for blocking radiant heat doing some powder coating, believe it or not.
                          88 Blue Hawk GT - Under construction but rideable (guest approved)
                          89 BlackHawk 2.0 - On the lift and being assembled
                          90 Hawk GT (color as to yet be determined) - Still on the shelf in crates

                          Comment


                            #14
                            I've always been a little conflicted on aluminum. On one hand, reflective. OTOH, also highly heat conductive. Depends on the situation and type/quality of backing material I guess.
                            J.D. Hord
                            Keeper of Engine Nomenclature, 9th Order

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                              #15
                              honda VFRs have thick heat blankets under their fuel tanks.
                              "It's only getting worse."


                              MY rides: '97 VFR750, '90 Red Hawk, '88 Blue/Black Hawk, '86 RWB VFR700 (3), '86 Yamaha Radian, '90 VTR250, '89 VTR250 (2), '73 CB125, '66 Yamaha YL-1

                              Sold: '86 FJ1200, '92 ZX-7, '90 Radian, '73 CB750, '89 all-white Hawk, '88 blue Hawk, '86 FZ600, '86 Yam Fazer 700 , '89 VTR250, '87 VFR700F2, '86 VFR700F.

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