Tom I just picked up an Eagle Premier 3.0 l PRV engine that I want to build up. Do you have a source for forged pistons over there? I'm looking at $1,000 for a set here in the states. Ian Yanagisawa On Jun 20, 2013, at 1:42 PM, "Tom" <dmctom@xxxxxxxxx> wrote: > Elvis is right. A simple calculation of the voltage, current and resistance > can easily prove this. > The resistance of the fuel pump stays the same and voltage will change. > Let's see what happens with the current. > This is just an example as I don't know the actual resistance of the pump. > > Let's assume that ideally the pump runs at 12.5V and its resistance is 1.5 > ohm. A simple formula of I=U/R (current = voltage divided by resistance) > will help determine the current. Thank you Mr. Ohm ;) > I = 12.5 / 1.5 > I = 8.33 > So, under ideal conditions our example pump will use 8.33 amps. > To calculate power use we can multiply voltage by current. Thank you Mr. > Watt ;) > P = 12.5 * 8.33 > P = 104.125 Watts > > Now, if the voltage drops due to bad connections, weak battery, failed > alternator the result will change. So, lets assume that the voltage at our > example pump drops to 10.5 volts. > I = 10.5 / 1.5 > I = 7 > The current drops to 7 amps. > And the total power.... > P = 10.5 * 7 > P = 73.5 Watts > > You can check my math to make sure I got it right. > As you can see from these calculations if the resistance stays the same and > the voltage drops the current will drop with it. As a result the power use > will drop and the power OUTPUT will drop as well. This means lower fuel > pressure and lower fuel volume. As some point the engine will simply stall > because of lack of fuel. > > Greetings from Poland! > Tom Niemczewski > Vin 6149 plus 2418, 3633, 5030, 16473, 17086 > Google earth: 52°25'17.66"N, 21° 1'58.40"E > > -------------------------------------------------- > From: "Elvis" <elvisnocita@xxxxxx> > Sent: Thursday, June 20, 2013 4:38 PM > To: <dmcnews@xxxxxxxxxxxxxxx> > Subject: [DML] Re: She starts (painfully), she runs (mostly), she doesn't go > anywhere... > > > > > Gentlemen, > > > > there is nothing inside the pumpt that controls the output power of it ! > > This is a stupid brushed motor that spins depending of the counterpressur > > that it sees. > > > > The unused pressure is transformed into fluid flow by the pressure > > regulator. > > > > And - a higher resistance (bad connector, thin wire, oxydized fuse, melted > > fuse holder) reduces the current. > > > > > > NO need to believe me, I just make my money with fans - which is nothing > > else but an air-pump. > > BTW - powerfull fans do have electronics inside to limit the max speed by > > PWM - therefore they can keep the power constant. When the voltage goes > > down - in certain limits - it draws more current. > > Again - nothing like this in a fuel pump. > > Yes, I even cut an old pump open to see how it works. > > > > Oh another example - the interior fan - it uses resistors to reduce the > > power, position 1 and 2 don't even require an extra relay...strang if - > > according to you - the current goes up ?!?!?!? :-P > > > > Have fun ;-) > > Elvis & 6548 > > > > > > > > --- In dmcnews@xxxxxxxxxxxxxxx, Ian <texas.twister@...> wrote: > >> > >> Ditto! > >> > >> Ian Yanagisawa > >> > >> On Jun 18, 2013, at 12:53 PM, JP Hindin <jplist2008@...> wrote: > >> > >> > > >> > > >> > On Tue, 18 Jun 2013, Elvis wrote: > >> > > This is a very strange theory, that a lower voltages kill something > >> > > and draws more current. > >> > > >> > This one I /can/ answer - the work of the pump doesn't change, so it's > >> > fixed - the laws of physics state that by lowering the voltage, the > >> > amperage must go up (Volts x Amps = Watts). This damages the pump > >> > because > >> > it's not designed to run at higher amperages, which would require it to > >> > be > >> > more sturdy with heavier duty wiring and stators, thus it burns out. > >> > > >> > > Anyhow - is the piston in the fuel distributor stuck ? > >> > > > >> > > Push the air metering plate down and you 'll see. > >> > > >> > I'll check this also, thank you. > >> > > >> > I've never actually dug into the engine bay - I only redid the tank - > >> > so > >> > I'm a little gunshy of tearing off covers and digging into it. I guess > >> > I'd > >> > best get over it and get cracking. > >> > > >> > - JP > >> > > >> > > --- In dmcnews@xxxxxxxxxxxxxxx, Ian <texas.twister@> wrote: > >> > > > > >> > > >... > >> > > > The low voltage ends up requiring more amperage to run the pump. > >> > > > This will eventually burn out the pump. There have been several > >> > > > threads on this issue. ... > >> > > > >> > > > > > > [Non-text portions of this message have been removed] ------------------------------------ To address comments privately to the moderating team, please address: moderators@xxxxxxxxxxx For more info on the list, tech articles, cars for sale see www.dmcnews.com To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnewsYahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/dmcnews/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/dmcnews/join (Yahoo! ID required) <*> To change settings via email: dmcnews-digest@xxxxxxxxxxxxxxx dmcnews-fullfeatured@xxxxxxxxxxxxxxx <*> To unsubscribe from this group, send an email to: dmcnews-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/