Announcement

Collapse
No announcement yet.

My boredom = Fuel Rails (390cc DSM)

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • #46
    While you guys are spending all night at your computer arguing about a miniscule heat problem, there's others such as myself who are just going with the tried and true aluminum rails and building their cars faster than you. :lol: j/p
    1987 300ZX Turbo - http://www.z31performance.com/forum/vie ... php?t=3114
    2001 Tiburon Turbo 60-1 270whp/268tq

    No cupholders? Where am I gonna put my beer????

    Comment


    • #47
      Those tried and True rails are clear anodized? Like the Holley units are?
      Try not to be a Yahoo

      Comment


      • #48
        I've had this on my Tib for a while with no probs. Even holds the weight of the FPR on the end.
        http://img.photobucket.com/albums/v214/ ... /Rail2.jpg
        http://img.photobucket.com/albums/v214/ ... /Rail1.jpg
        1987 300ZX Turbo - http://www.z31performance.com/forum/vie ... php?t=3114
        2001 Tiburon Turbo 60-1 270whp/268tq

        No cupholders? Where am I gonna put my beer????

        Comment


        • #49
          I suppose someone could argue the point that hot fuel could maintain a more constant pressure at idle. This is due to the PV=nRT relationship. The fixed volume of the fuel system would show that P is proportional to T.

          The effect would be that after each pressure relief (regulator letting a small volume go by), the heat would act in conjunction with the pump to bring the pressure back up. If we looked at the pressure vs time on a scope, we would see this. Having a more constant fuel pressure would really help larger injectors that are trying to maintain a more precise PWM. Larger injectors must also be more precise in matching also. It is critical and anyone that moves up to larger injectors should get them flow matched I assume?

          Anyway, I do not believe that the FPR actually flows a constant return of fuel back to the tank. It would be a pulsing process of sorts. Needle gauges show this effect.

          Having a larger inner diameter in the aluminum fuel rail means more contact area with the hot aluminum by the fuel. So the fuel will pick this heat up very rapidly. Its also a larger reserve of hot fuel. So the FPR, if it bleeds off some amount of fuel, it should have to be a larger amount than stock.

          The main effect I would be concerned about is pre-heating fuel in regards to high power output. The ecu does compensate for this and I suppose other ecu solutions also offer some feedback system to do this also. At some point, fuel density and its relationship to fuel temperature will be an issue. The slow responding fuel temp feedback system on a stock car can not react to an event where there is little to no fuel flowing through the bypass system. Under a hard acceleration, when fuel flow through the injectors is at a maximum, the temp reading may not reflect the reality of the temp of the fuel going through the injectors themselves. Its a 'sensor-lag' event of sorts.

          Since I am planning a E85 based vehicle, I would actually want a higher fuel temp myself. Those of you that want the pure gasoline solution (as pure as they sell it), and the needed precision of metering that implys, would have to take fuel temp into account.
          Try not to be a Yahoo

          Comment


          • #50
            Shesh guys! I was actually enjoying reading this thread till the pissing match began.

            When it comes to automachanics i'm totally clueless and im trying to learn everything I can and keep an open mind to what I read. So the information was quite insightfull as to the workings of our fuel systems, heat buildup and such.
            Its all fun till you hit the doggie and do an endo into the wall.

            One willing to take his own life into his hands,
            Will not hesitate to take the lives of others.

            Comment


            • #51
              Actually on this subject of aluminum being a heat sink, That is the very reason its a good choice of material for fuel rails. Aluminum does absorb heat quite well but it also releases that heat very quickly as well. Thats why aluminum is used as heat sinks for almost every application where heat is needed to be wicked away from a substance. This is one reason why you see the finned aluminum fuel rails, the heat will flow evenly across the entire rail including to the fins. The fins being thin and more exposed to air will allow the heat to dissipate more quickly. this is why you see aluminum heat sinks used on computer chips
              Its all fun till you hit the doggie and do an endo into the wall.

              One willing to take his own life into his hands,
              Will not hesitate to take the lives of others.

              Comment


              • #52
                Aluminum can source or sink heat
                Try not to be a Yahoo

                Comment


                • #53
                  crowbar wrote: Aluminum can source or sink heat
                  Yes, and in a case like this, it is more likley to source it from the plenum/manifold rather than disipating any heat that would have been in the fuel from the lines, which is like, none.
                  85 Z31 6.0 LSX turbo 766whp/792wtq
                  04 GTO, LS6, big cam, porting, N20... underway for summertime daily driver.

                  Comment


                  • #54
                    That's why trannies are aluminum with heat sinks.
                    1987 300ZX Turbo - http://www.z31performance.com/forum/vie ... php?t=3114
                    2001 Tiburon Turbo 60-1 270whp/268tq

                    No cupholders? Where am I gonna put my beer????

                    Comment


                    • #55
                      There is the heat of pressurization but that is probably lost in the hard lines from the pump to the engine. The underhood environment, and proximity to the lower plenum, is the heat 'driver'.

                      I was putting my injectors in yesterday and realized that the FPR is attached to the lower plenum also. This will also drive the fuel temp sensor to a heated condition. I left out the screws and fasioned a plastic spacer to block this heat. I also removed the temp sensor and sprayed it with copper gasket spray and installed it. It should now track the fuel temp rather than the plenum temp.
                      Try not to be a Yahoo

                      Comment


                      • #56
                        crowbar wrote: There is the heat of pressurization but that is probably lost in the hard lines from the pump to the engine. The underhood environment, and proximity to the lower plenum, is the heat 'driver'.

                        I was putting my injectors in yesterday and realized that the FPR is attached to the lower plenum also. This will also drive the fuel temp sensor to a heated condition. I left out the screws and fasioned a plastic spacer to block this heat. I also removed the temp sensor and sprayed it with copper gasket spray and installed it. It should now track the fuel temp rather than the plenum temp.
                        you made a few assumptions over your past few posts, why don't you test out your theories?

                        I already asked you to get a thermal image of a running car with aluminum fuel rails pointing out your "hotness" .... so where is it? this would prove your theory ... or not

                        secondly just to be clear, you now care about the temperature of the fuel returning to the tank?

                        and lastly you say the extra heat in the fuel might build pressure on the fuel rail so as not to cause a problem, which is in direct contradiction to your whole constipated argument so far that heat is bad.... (I'm not agreeing with you on either point just mentioning it)

                        Comment


                        • #57
                          I don't really pay attention to you to be honest. And go back to the goatse pic. That face gives me the creeps.

                          Another heat concern would be the effect on the injectors over time. They are similar to electric motors and heat kills motors.

                          I have some LM34s so I can rig up a data taker
                          Try not to be a Yahoo

                          Comment

                          Working...
                          X