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  1. Rick360

    Bernoulli - Intake vs Exhaust Flow

    Well I think I have the answer for those who are interested. I'll see if I can explain it like it was explained to me. The flow can exceed the 146cfm/in² in the exhaust direction because of pressure recovery due to the exhaust port and attached pipe acting as a conical diffuser downstream of...
  2. Rick360

    Bernoulli - Intake vs Exhaust Flow

    dgallup, Yes, air is supplied to the cylinder/chamber under +28"wc pressure above atmosphere. Could you expand on the "why" and if Bernoulli predicts a limit much higher, how high? Thanks, Rick
  3. Rick360

    Bernoulli - Intake vs Exhaust Flow

    Yes, patprimmer is correct about my question being about measured flow on a flowbench @28"wc d/p, not on the running engine. Since the original post I tried flowing an exhaust port in the reverse direction...from atmosphere back into chamber/cylinder on flowbench, just to see how much it could...
  4. Rick360

    Bernoulli - Intake vs Exhaust Flow

    I have seen in many places the calculated (using Bernoulli theory) limit of airflow of 146cfm/in² with a D/P of 28"wc. This holds very true when flow testing intake ports on cylinder heads. The very best intake ports can flow close to 140cfm/in² at the throat area (mcsa) of the port. Why is it...
  5. Rick360

    Voltage-Limiting Op-Amp

    Sorry for my limited op-amp knowledge. VE1BLL wrote: "Oscillation is often caused by too much gain (waaay simplified...) - not too little gain" Why would the specs say it is stable @ Gains >4 and have a different part for gains <4? VE1BLL wrote: "Your stated requirements do not appear to...
  6. Rick360

    Voltage-Limiting Op-Amp

    I have a need for a circuit that has an input range of 0 - 5 VDC with an adjustable output voltage limit and adjustable(near unity) gain for an output between 0 and 5 VDC. Single rail 5V-10V Power Supply needed. I found a couple of TI op-amps (opa688 or opa689) that should do it except the...
  7. Rick360

    Hi-lift flow vs Mid-lift flow

    Larry, Thanks for the info. I checked out the spreadsheet to see the formulas involved and I have a question about the disch coef. The basic formula is FLOW/(CURTAIN AREA * 137.7). What is 137.7 for? a constant for something? Is this constant different depending on test pressure? Rick
  8. Rick360

    Intake Manifold Temperature

    With a drop in pressure there will be no change in the amount of heat contained in a given mass quantity of air, but since this constant amount of heat is expanded into a larger area, due to the drop in pressure, the temperature will drop. Rick
  9. Rick360

    Boiler economizer on watertube boiler: Good idea?

    I beleive the ID fan would require a change if one is required. The FD fan flow, Sec duct and windbox pressure shouldn't change because the furnace pressure would control at its normal setpoint, therefore the FD fan would see no difference. Since furnace pressure would be the same the ID fan(s)...
  10. Rick360

    Hi-lift flow vs Mid-lift flow

    There are things that can help at certain lift ranges on some types of heads. What I would like to know is which is more important. Is it the highest .100" that matters most given equal port sizes, as I have calculated? Rick
  11. Rick360

    Hi-lift flow vs Mid-lift flow

    When porting a set of heads there are ways to enhance high, mid or low lift flow characteristics. I realize the ideal is to gain at all lifts but sometimes there is a tradeoff. Which one would you trade for what other one? and why? I profiled a cam which has .800" net lift thru its entire...
  12. Rick360

    Bailey INFI90 HMI upgrade

    "Upgrade" is always ABB's recommendation. Our plant uses Alphastation 255 OIS-43's running Conductor VMS 4. I found a power supply(refurbished) on website (using google) to repair one and had a bad motherboard on another and Compaq field service came out to repair it. After the buyouts and...
  13. Rick360

    sudden loss of speed.

    Pressing ctrl-alt-del will show a list of the current programs running. Ad-aware will create a list of processes running during a scan. The "Show logfile" button will display this. It gives details about process file location etc. Unless the harddrive is nearly full, as MacGyver suggested...
  14. Rick360

    sudden loss of speed.

    Look at your task list to see the processes and programs that are running. If your OS is NT or W2000 Pro I beleive it shows the processor time % for each. Knowing what and how many processes are running would help in isolating the culprit. Ad-aware lists the running processes after a scan...
  15. Rick360

    sudden loss of speed.

    Try using a anti-spyware program such as Ad-aware or spy-bot. There are many websites that install programs that aren't a virus, they are &quot;spyware&quot;, but slows your computer down by using your resources for itself, sending your surfing habits back to the owner etc. Ad-aware is a free...
  16. Rick360

    Dyno Operation Control Problem

    Was the power co. test done at the main breaker box? I assume it was. If the full drop in voltage on one leg adds to the opposite leg, then the neutral feed is creating the full voltage drop, so it has significantly more resistance than the other wires (probably poor connection at the...
  17. Rick360

    Dyno Operation Control Problem

    Sounds like it might be a bad neutral. Did you measure the voltage from neutral to both sides of the 240 when it is malfunctioning? If the 120V legs fluctuate in volatge when the individual 110V phases load change then that is whats going on. The bad connection could be from the dyno to the box...

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