From: Peter Cremasco on 8 Feb 2007 16:19
On Thu, 08 Feb 2007 13:22:59 GMT, "Knobdoodle" <knobdoodle(a)hotmail.com>
>"Nev.." <idiot(a)mindless.com> wrote:
>> Ok so I tested it myself.
>> 5.7 Lt EFI Holden in diagnostics mode.
>> All Lights off idle speed ~803
>> All Lights on idle speed ~803
>> All lights off fuel rate 2.68L/hr
>> All lights on fuel rate 2.68L/hr
>Hey Nev; what's it do when the air is switched on?
>Does the idle drop or stay the same?
>Of course aircon is a much larger load than just headlights but it might
>indicate if your engine computer is automatically compensating or not.
Strangely enough, the Camira engine speed increases when the a/c is
switched on. I think that's the ECU overcompensating for the extra load,
PeterC [aka MildThing]
'01 Yamaha FJR1300
From: Dale Porter on 8 Feb 2007 16:22
"Peter Cremasco" <FirstName.LastName(a)bigpond.com> wrote in message news:ms4ns2duvu4b7tvncuicr1vedevs58cnjj(a)4ax.com...
> On Thu, 08 Feb 2007 13:22:59 GMT, "Knobdoodle" <knobdoodle(a)hotmail.com>
>>"Nev.." <idiot(a)mindless.com> wrote:
>>> Ok so I tested it myself.
>>> 5.7 Lt EFI Holden in diagnostics mode.
>>> All Lights off idle speed ~803
>>> All Lights on idle speed ~803
>>> All lights off fuel rate 2.68L/hr
>>> All lights on fuel rate 2.68L/hr
>>Hey Nev; what's it do when the air is switched on?
>>Does the idle drop or stay the same?
>>Of course aircon is a much larger load than just headlights but it might
>>indicate if your engine computer is automatically compensating or not.
> Strangely enough, the Camira engine speed increases when the a/c is
> switched on. I think that's the ECU overcompensating for the extra load,
That would be due to the air-con compressor not being driven by the engine, more the other way around. It starts up and runs at a
higher speed than the engine does at idle.
GPX250 -> CBR600 -> VTR1000 + VT250F-J
From: jlittler on 8 Feb 2007 17:23
On Feb 9, 12:56 am, Hammo <hbaj2...(a)aapt.net.au> wrote:
> On 9/2/07 12:34 AM, in article
> YFFyh.4682$sd2....(a)news-server.bigpond.net.au, "Knobdoodle"
> <knobdoo...(a)hotmail.com> wrote:
> > "Nev.." <i...(a)mindless.com> wrote:
> >> I think you've been reading too many physics books and you've lost sight
> >> of reality. Are you saying that if I measure something once per second
> >> and then multiply that by 3600 my result is not an accurate measure of an
> >> hourly rate? Do you think the computer controlling the fuel rate just
> >> guesses?
> > No; it actuates the injector the exact amount that it's been told to for the
> > conditions it's measured.
> > It then displays the exact mpg (L/Hr, Km per kilojoule or whatever) that's
> > it's been told to display too.
> > But it doesn't have any idea what a litre actually is and it certainly
> > doean't have any ability to actually measure one!
> It's measured, but it can't measure?
No, it's calculated based on what actually is "measured" (or more
accurately specified by the efi).
The efi opens the injector for a period according to what it's lookup
table tells it is the right amount given the parameters it has sensors
measuring. It ASSUMES the fuel pressure (and hence fuel flow) is
correct (unless there has been some new fangled advances in EFI I'm
not aware of). I know of no cars that measure actual fuel flow, they
usually calculate your fuel consumption based on the amount of time
they've opened the injectors, and the number of KM's travelled. Those
two parameters are based on a number of implicit assumptions:
- the fuel pressure is correct
- there are no blockages restricting fuel flow
- the size of your tyres are as specified and hence the number of K's
calculated is correct
it's a reasonably accurate estimate and more than good enough for the
purposes for which it is used. That doesn't mean the actual fuel flow
From: jlittler on 8 Feb 2007 17:31
On Feb 8, 3:35 pm, CrazyCam <crazy...(a)ar.com.au> wrote:
> GB wrote:
> > Answer me this one:
> > You take a fridge and put it in a temperature sealed room. You
> > lock the door to the room so that Johno can't upset the test by
> > coming in and getting beers for people every two minutes. You
> > leave the fridge door open, and the fridge running.
> > Does the ambient temperature inside the temperature sealed
> > room rise or fall?
> This is, of course, a trick question.
> Everyone knows that a fridge is simply a heat pump, gathering heat from
> inside, and moving it outside, but... with the fridge door open, the wee
> light will be on, thus heating up the insides of the room.
While all true, you missed that the electric motor of the fridge is
less than 100% efficient and hence some of it's power is also becoming
heat. Hence the room will be heated up by motor heat generated plus
From: Theo Bekkers on 8 Feb 2007 17:30
> Excellent, and I'll bring the oscilloscope!
I've got a 40 year old Tektronix 422 in the shed somewhere.