The website is most likely created/maintained by Marketing rather than Engineering... so who would you trust the most...? :DQuote:
Originally Posted by pkincy
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The website is most likely created/maintained by Marketing rather than Engineering... so who would you trust the most...? :DQuote:
Originally Posted by pkincy
Hi gang!
I agree with your thinking. :)Quote:
Originally Posted by joecar
It helps to understand the uneven/odd PSI values when one realizes fuel system values are originally spec'd in the metric 'Bar'. To go back and reconvert the PSI values (provided they had not been rounded off) back to Bar makes those values easier to understand and more logical. A problem surfaces when the values are rounded off after converting to PSI. This makes 'close' acceptable. I once had a difference of opinion with a forum guru that was convinced 1 bar and 1 atmoshpere could be interchanged because they were close. Convince a sprinter it is acceptable to call his 100 meter run a 100 yarder.
More to the point of the quote, 40 PSI may have been used to flow test the injectors, but I am confident that PSI value is not the correct flow rating spec of the injector. I believe the Ford injectors are spec'd at 2.7 Bar. It makes it easier to understand when noting the 2.7 is an even value, whereas the 40 PSI is an 'odd' value.
I don't believe it is greatly abused in this industry, but because marketing is paid first and foremost to sell a product, accuracy/integrity of advertising is usually the exception to the rule. :rant:
EDIT: BTW 'joecar', in post #3 you posted MANVAC = 80 kPa = 11.5 psi: IFR = 53.088 lb/hr = 6.689 g/s
In case this is an error, what conversion equation was used to achieve the 11.5 PSI = 80 kPa? Thanks.
Gary
I was making the point that we have all seen too many variations on rating standards for those injectors... :D
Oh, I went: 80kPa / 101.3kPa * 14.5psi = 11.5psi since 101.3kPa == 14.5psi
80kPa == 11.5psi
Sanity check:
11.5psi of vacuum = 11.5psi * ~2inHg/psi = ~23inHg
and then:
80kpa/101.3kPa ~ 78%
23inHg/29.3inHg ~ 79%
With the above statement I again agree. Obviously, most variations were incorrect. :) The internet is a great info source, but unlike books, there is no peer review of internet info to increase accuracy.Quote:
Originally Posted by joecar
Regarding the equation above... please bear with me.
101.3kPa = 14.69 PSI (1 atmosphere)
100kPa = 14.5 PSI (1 bar)
so.... any value of kpa will also be the % of 14.50 PSI (Remember, it's the metric logic.)
.8 * 14.5 = the answer. Agree? Take care.
Sorry for what appears to be a mountain out of an ant hill. :frown:
Gary
Oh, I see, in error I used 101.3 instead of 100 (or 14.50 instead of 14.69); I see, gotcha, thanks...;)
(101.3kPa == 14.69psi != 14.50psi)
ok, I think I get this, very good info. Butt.....
I have a system designed at 43.5lbs
Running 22lb injectors
I have idle pressure set to 46.
It is vac regulated pressure system.
Is this chart designed for a fixed pressure, or vac regulated?
So, my base 0kpa needs to be entered as 2.85 correct? I just need to know if the chart adjust for my style system. Or I need to take a pressure reading at each kpa mark and enter it in this calculator.
So you have:
- injectors rated as 22 lb/hr @ 43.5 psi,
- vac referenced pressure regulator;
Do this:
- engine running,
- remove vac hose from regulator,
- measure railpressure (in psi).
(--> remember to reconnect vac hose when done).
Then calculate this: IFR = 22 * sqrt(railpressure / 43.5)
The result is in lb/hr; if want g/s then multiply by 0.125998.
Paste the resulting value into B4001 all across in all cells (i.e. flat table).
ok. Will work on that this weekend as I'm going to fix my oil leak tonight/tommorow.
But lets just "assume" its 46psi
IFR=22*sqrt(46/43.5)
IFR=22*sqrt(1.05747)
IFR=22*1.02833
IFR=22.6233
then
22.6233*.125998
so all would be 2.85.
So spread sheet is correct, I just need to measure with line off, rather then on.
Yes, correct.
I just did a fuel reading. Same with vac on as vac off.
How much is 2.91 to 2.85. Is that alot, or a little?