VW type 3 fuel pumps
-
jaywithtype3
- Posts: 16
- Joined: Thu Dec 13, 2012 1:36 pm
Re: VW type 3 fuel pumps
to Nate et al;: look yourself: 255 is not a part number. NOW i see on amazon Walbro GSS392 listed as inline, not seen before; GSS 342 is NOT listed as any type; no one above said get GSS392; above record shows that & that i guessed i wanted GSS342; no one redirected. thanks where thanks is due. jay
-
jaywithtype3
- Posts: 16
- Joined: Thu Dec 13, 2012 1:36 pm
Re: VW type 3 fuel pumps
update to all : part number above is supposed to be GSL392, & that has been ordered. Testing of "wrong" pump GSS342 (surely identical in performance) reveals again cant be too thoughtful. It uses ~35 W at 7 volts, for full pressure 28 psi & plenty flow, & fuel soon warm. At 12 volts fuel will heat more (80 watts); this is 3x original system power; can there be consequences from heating fuel tank on warm day? jay (my access to Net even less now, could be weeks before see posts)
-
raygreenwood
- Posts: 11907
- Joined: Wed Jan 22, 2003 12:01 am
Re: VW type 3 fuel pumps
This has been discussed at length. I used sensitive equipment numerous years ago to disprove any worries about fuel heating from either the pump or time in the fuel loop.
Theoretically...sure...doing "work" to the fuel is adding energy (heat)...that being said....the amount of temperature rise in the fuel even from running all day would be un-measurable on any thermometer you could afford for less than about 5X the cost of the car. Its totally insignificant.
You have cooling and heat transfer from the fuel into the lines, sloshing and evaporation in the tank and other areas....plus the fact that the fuel charged into the loop spends a grand total of much less than a minute full loop (what does not get used by the engine).
Also that 80W...is what is consumed driving the pump motor. That does not mean that 80W of work is all being transferred to the fuel. The work imparted to the fuel is NOT the sole reason why one pumps wattage is higher than the other. It is the armature design more than work imparted. One motor has higher pressure capability even with the same roller cell chamber design. In order to deliver that required torque to overcome higher restriction....which is imparted by the check valve...not the fuel....a given pump motor will draw more amps. It needs heavier windings, magnets and armature to do this.
Dont worry about this. Its not significant. Ray
Theoretically...sure...doing "work" to the fuel is adding energy (heat)...that being said....the amount of temperature rise in the fuel even from running all day would be un-measurable on any thermometer you could afford for less than about 5X the cost of the car. Its totally insignificant.
You have cooling and heat transfer from the fuel into the lines, sloshing and evaporation in the tank and other areas....plus the fact that the fuel charged into the loop spends a grand total of much less than a minute full loop (what does not get used by the engine).
Also that 80W...is what is consumed driving the pump motor. That does not mean that 80W of work is all being transferred to the fuel. The work imparted to the fuel is NOT the sole reason why one pumps wattage is higher than the other. It is the armature design more than work imparted. One motor has higher pressure capability even with the same roller cell chamber design. In order to deliver that required torque to overcome higher restriction....which is imparted by the check valve...not the fuel....a given pump motor will draw more amps. It needs heavier windings, magnets and armature to do this.
Dont worry about this. Its not significant. Ray