Hello,
I noticed something odd..

I did some math calculations and stuff, and I noticed that the
Injector Pulse Width, is LONGER then the time for the intake
stroke. This is at Higher throttle settings, but below 5000 rpm
What the hell? I think Im missing something.

 

I'm no tuner, but I would imagine that it's still spraying fuel into the combustion chamber in the compression stroke and doesn't stop spraying until microseconds before the spark.

Just a guess, not actually sure.

 

Do our injectors spray directly into the cylinder? Or into the intake manifold behind the intake valve?

Also here is from a spreadsheet to calcualte intake stroke times.
I started with RPM, then converted to RPS (revolutions per second) then, converted that to seconds per revolution
Then, miliseconds per revolution, then by dividing by 4, we get the miliseconds that the piston is on intake.
I need to do another RPM/PW Record pull on my Interceptor again to get the PWs for the RPM at WOT or Part Throttle.
But what pulse widths do you guys have for these RPMs?

RPM RPS SPR mSPR Intake mS
1000 16.67 0.060 60.0 15.0
1500 25.00 0.040 40.0 10.0
2000 33.33 0.030 30.0 7.5
2500 41.67 0.024 24.0 6.0
3000 50.00 0.020 20.0 5.0
3500 58.33 0.017 17.1 4.3
4000 66.67 0.015 15.0 3.8
4500 75.00 0.013 13.3 3.3
5000 83.33 0.012 12.0 3.0
5500 91.67 0.011 10.9 2.7
6000 100.00 0.010 10.0 2.5
6500 108.33 0.009 9.2 2.3
7000 116.67 0.009 8.6 2.1
7500 125.00 0.008 8.0 2.0
8000 133.33 0.008 7.5 1.9

 

@ 4800 RPM my PW was 17.2 mS
That is spraying LONGER then it took for the entire engine to rotate once. (12.5mS @ 4800RPM)

 

They spray into the head.

 

So the injectors are not pulsed in frequancy / harmonic with the engine revolution?
If not, what is the Injector Frequancy vs PW? Is the Frequancy Constant and varied by PW?

Also did some calculations,
With an AFR of 11.5:1 I calculate that the 42.29 Lb Injectors from Lucas can keep up until a maximum MAF of 32.42 PPM at wich point they will become static.
60# Injectors max out at MAF of 46 while the stock 35s will max out at a MAF of 26.83PPM

A guy at work said thers no way im close to maxing out my injectors and you guys say I am close, so I figured id do the math. I'll have to do a RPM/MAF Pull and record with the interceptor to find out though. But looks like I am getting close... last record I peaked MAF at 21.87 @ 4870 RPM

Not sure if my MAF would be reading correctly since I'm tuned for a K&N Typhoon intake and I currently have a ZZP 3" Intake. But I don't think it would be off by a large margin though.

 

.... and as I search with google I found the following information:

Delphi / Lucas
42 lb / hr. '009' Disc Injectors
Part Number Delphi 01D030B (Lucas old 5208009, Lucas New 621031)
Static Flow Rate: 42.29 lb/hr @ 43.5PSI (300kPa) or 320gm/min
Dynamic Flow Rate: 9.96 gm/pulse - 2.5ms pulse width and 10ms repetition rate
Coil Resistance: 15.9 Ohms / High Impedance / High-Z (No ECM driver modifications required)
Additional Information:

Top feed disc injectors use a small disc with six holes around its circumference. The disc rests on a short chimney that surrounds a metering hole. As the disc is raised off the chimney by magnetic force, fuel flows through the holes in the disc, over the walls of the chimney, and out the metering hole to form a full, finely atomized cone.

Performance advantages over pintle injectors (i.e. Ford / Bosch & Accel types) as listed by Delphi:
• The flat mating surface ensures that no excess fuel is present to evaporate and therefore, no deposits or clogging can occur.
• Compatible with alternative fuels (i.e. Methanol)
• Longer service life
• High-speed disc action allows wider dynamic flow range for improved idling
• Quieter operation
• Revolutionary disc design resists build up deposits which can affect fuel flow.
• No Fuel leakage for quicker starts

This means I'm going to have to refine my calculations AND Measure my Fuel Pressure as well since that seems like it would have an effect also.

 

your pulse widths at in the 17's at 4800 rpm? :-\ Thats getting awfully high awfully early.. What are they by redline?

 

Also, you car only fires each cylinder every other revolution. So you have twice the individual revolution time between spark events.

Next, the intake valve opening is what allows the fuel and air into the cylinder, It actually starts to spray a few moments (ms) before the intake valve opens and gets dumped in when the valve opens.

 

Forgot about that, yes you are correct and that makes sence now!


Ok that makes sence too,
Thanks,
Ill have to do a Long pull in 2nd gear to find out what my redline PW is, I have to find an area of road where I can get it up to 70...

 

 

Just got done installing 60s. Now to wait for UPS to deliver my PCM back to me after reprograming at ZZP.

 

dont forget fuel pressure is 58psi

 

Think most of the time the injectors spray onto the back of your closed intake valve(s). Once it opens the whole mixture is sucked in. Available time is 2 complete engine revolutions for a 4-stroke. ;-)

 

I saw that when I looked in the holes from when I pulled out the 42# injectors before in installed my 60# Injectors