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  #11  
Old 09-05-2005, 04:06 PM
Gert_ Gert_ is offline
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Quote:
Originally Posted by Richard L
For example, if an engine is running with rich air fuel mixture to maintain resonable egt level and and knock free - 10-10.5:1 is normally considered as a safe tune by most tuners now a days and manufacturers.
Are you serious?? Resonable egt level and knock free level with 10-10.5:1?? This is a power free level too, I suppose :?

Gert
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  #12  
Old 09-05-2005, 04:16 PM
Gert_ Gert_ is offline
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Default Re: nozzle flow rate

Quote:
Originally Posted by dsmtuned
RPM is one of the factors that determines injector duty cycles. :wink:

Craig
To calculate duty cycle:

(60 / (RPM / 2)) * 1000 = Msec ( maximum injector time available at this rpm)

To find duty cycle:
(Inj time / Msec) * 100 = Injector Duty.

If you want to know exact duty cycle at any rpm, you have to know the exact injection time, so you must have some logging tool.
Now, if you have logging files, you can make an excel sheet, and calculate what fuel is injected, and how much water is needed at any * percentage.
That is not an garantue that it is working correct right away, at least, not at my car. After the math, there are some adjustments needed, based on knock, and intake temps.

Gert
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  #13  
Old 10-05-2005, 10:10 PM
honki24 honki24 is offline
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well, Its just nice to know I'm running in the 10-15% w/f ratio, rather than .11% :lol: now... how to figure out the afr I want w/o a piggyback or any means of knock detection...
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  #14  
Old 13-05-2005, 08:41 AM
Santo Fontana Santo Fontana is offline
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Default Re: nozzle flow rate

Quote:
Originally Posted by hotrod
I think you need to throw out that math and start over your numbers are WAY out of the ball park!
Quote:
then I have 13,200,000cc per minute of fuel
That is 13,200 kilograms of water or about 29,040 lbs of fuel ---- I don't think so

At max rpm, WOT the injectors are nearly running continuously. Forget how many times the engine fires, ( a 4 cycle engine only fires each cylinder once every 2 revs anyway ).

You will find that the WI nozzle is probably rated in gallons / HOUR

For a gallon/hr nozzle just multiply the gal/hr by 63 and you have cc/min flow. In your case your spray nozzle flows about 246 cc/min

Your fuel injectors flow 550cc/min MAXIMUM at 100% duty cycle. So the max fuel you can flow under any conditions is 2200 cc/min. If you car runs a max injector duty cycle of 85% ( that's typical max on a factory set up) your max fuel flow is 2200 x .85 = 1870 cc/min. 15% of that is 280.5 cc/min.

Your 3.9 gal/hr nozzle will give you about 13% water to fuel at max fuel injector duty cycle and the WI spray wide open.

Larry
If you were using a simple single stage with a solenoid, wouldnt you want to take your IDC at your tourque peak, or whereever you plan on starting the spray, and figure out your fuel flow at that point? It seems to me if you if you size your nozzle at max idc, then you wouldnt want to turn it on until then.
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  #15  
Old 16-07-2005, 12:39 AM
RX-Heven RX-Heven is offline
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Injector setup is 2x720cc primaries and 2x1600cc secondaries.

To run 15% water to fuel at 70% IDC, I calculate this way:

(IDC) x (Total fuel cc's) x (Target % water) =
(.70) x (1440 +3200) x (0.15) = 448 cc's of water

Then, also assuming the water nozzles operate at 70% DC and one 0.9 mm WI nozzle flows 315cc (max), I get:

(15% water to fuel) / [(WI flow rate) x (IDC)] =
(448) / [(315) x (.70)] = 2

So I would need two 0.9 mm nozzles to meet my 15%.

Alternatively,
The water (mixture)-to-fuel percentage is roughly 10% with one .8mm nozzle and one .5 mm nozzle in my setup.
Here is how to find that:
To run 10% water to fuel at 70% IDC (assuming), calculate this way:

(IDC) x (Total fuel injector cc's) x (Target % water) =
(.70) x (1440 +3200) x (0.10) = 325cc's of water

Then, knowing the water nozzles operate at 70% DC (from our assumption of IDC) and one 0.8 mm WI nozzle flows 280cc (max) and one 0.5 mm WI nozzleflows 180cc (max), I get:

(required cc's of water) / [(WI flow rate x IDC)] = 10%
(325) / [(280 x .70) + (180 x .70) ] = 10%
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  #16  
Old 05-01-2013, 08:36 PM
james-g40 james-g40 is offline
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Default Re: Calculate your correct injection Percentage !

I know this is an old topic but this might be the answer im looking for.

Going by the math provided this should be correct:

4 x 250cc injectors = 1000cc

1000 x .85 = 850

15% of 850 = 127.5

Im planning on running the smallest injector my kit come with which was 0.5mm. Is this too much?
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  #17  
Old 05-01-2013, 08:44 PM
Richard L Richard L is offline
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Default Re: Calculate your correct injection Percentage !

0.5mm injects aboiut 200cc/min. If you ad about 25% methanol as an antifreeze, You are not far off the ideal.

Since we have stopped the production of the 1s system six years ago. Look after it well as there are no more spares available.
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  #18  
Old 07-01-2013, 09:55 PM
james-g40 james-g40 is offline
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Default Re: Calculate your correct injection Percentage !

Ok, i will make sure its well looked after.

Im going to be using a 50/50 mix.

Would a 0.4 be better? Or i can run 2 x 0.3's but that gets more expensive but will help if one injector gets blocked.
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  #19  
Old 07-01-2013, 10:41 PM
james-g40 james-g40 is offline
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Default Re: Calculate your correct injection Percentage !

Richard, i spoke to my mapper as he logs/stores it all and he said that my 250cc injectors are running around 75-78% duty cycle on 1 bar boost above 2500rpm or so.
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  #20  
Old 07-01-2013, 11:05 PM
Richard L Richard L is offline
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Default Re: Calculate your correct injection Percentage !

In this case, 0.4mm may be just about right.
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