Jump to content

Search the Community

Showing results for tags 'Fuel pump'.



More search options

  • Search By Tags

    Type tags separated by commas.
  • Search By Author

Content Type


Forums

  • OzFalcon
    • OzFalcon News
    • New Member Introductions
    • Site Feedback
  • General
    • The Pits
  • Merlin's Metalcraft Emporium
    • Panel Beating Tech
    • Paint Tech
  • Technical
    • 6 Cylinder Tech
    • V8 Tech
    • Forced Induction Tech
    • Exhaust
    • Body and Exterior
    • Transmission and Differential
    • Steering, Suspension and Brakes
    • Cooling System
    • Interior and Car Audio
    • Auto Electrics
    • LPG Tech
    • Cortys and Eskys
    • Effies
    • Wheels and Tyres
  • Projects
    • Extreme Builds
    • Member Builds
    • Showroom
    • DIY
  • Trash 'n' Treasure
    • The Car Yard
    • The Wreckers
    • Non Car Related Sales
    • Wanted

Find results in...

Find results that contain...


Date Created

  • Start

    End


Last Updated

  • Start

    End


Filter by number of...

Joined

  • Start

    End


Group


AIM


MSN


Website URL


ICQ


Yahoo


Jabber


Skype


Location


Interests

Found 2 results

  1. I could not Find an appropriate section for fuel related topics so it's going here. The following is written specifically for Crossflow EFI but can be adapted for pretty much any petrol fuel system across all cars. The following guide can be used for troubleshooting various problems with fuel supply and also determining maximum supportable HP/KW Lets get started: Go to your car. (Off to a good start ) Follow the fuel return line from the pressure regulator on the fuel rail, to where it terminates to the return hard line and disconnect it. Run the return line from the regulator into a 2L bottle. You may need to make an adapter to plug the line into and run the line out of the engine bay. Try not to make the line longer than needed, the line should not have any kinks or restrictions. The line will not be under high pressure so regular fuel line is fine. Hardwire the fuel pump by either shorting the main current pins on the fuel pump relay connector (preferred method) with something like the jumper the pic above. Or running some 10A (or greater) power wire directly to the pump from a strong 12-14V source. A fully charged car battery will work. If not already done, lift the carpet in the boot and remove the fuel pump access hatch to gain access to the fuel pump. Put a multimeter nearby so you can measure voltage at the pump. What your trying to do, is simulate the the fuel pump running normally. This is why shorting the relay is better if possible, as this will test it's power supply. In addition, having the battery on a charger during the test will ensure a strong voltage closer to that of when the alternator is running. Note: If you are doing this test not for the purpose of troubleshooting, but to find maximum supportable hosepower, then running the pump at a stable 12v is best. This will give you lower performance figures for the pump and this is what you want. A fully charged lead acid battery should sit around 12-12.4 v after a short period of use. When this is all done power up the fuel pump, after a slight delay fuel will start running into the bottle. Time how long it takes to fill the bottle. Watch for a steady flow, it should not fluctuate. While the bottle is filling you will have a few seconds, A stock XF EFI pump takes approx 60-80 seconds. Quickly go to the fuel pump and take a voltage reading and write it down and do the same with the cars battery voltage. If you do not think you have time to take this measurement you can either use a larger container to catch the fuel, or do it after reconnecting the fuel return line at the end of the test. If you are doing this test for troubleshooting and you are having issues that take a few minutes of driving to occur, it could be duty cycle or even tank related. If the tank is not breathing properly it can cause suction on the pump and reduce performance. Grab a 20 liter jerry can and put the return line in it, Carry out the test, again timing how long it takes to fill. Obviously for this test you will need at least 30 liters of fuel in the tank. Throughout the test monitor for steady, regular flow. There should be no pulsing and flow should be consistent right till the end. Measuring a large quantity like 20L will give you a more accurate flow rate measurement. Simply divide the seconds by 10, to align the result with the other test. Continue to monitor the voltage at the pump, compare it with the voltage at the battery. The difference between Pump and Battery voltage is your voltage drop and this indicates any supply issues to the pump. Voltage drop should be low. Under 0.5v is good. As a final test you can, again, measure the time it takes for 2 liters. It is best to do this test without stopping the fuel pump at all, transfer the line from the 20 liter container straight to the 2 liter bottle whilst it is operating. if possible measure the voltage. The voltage and time taken should be equal or very close to the fist time you measured the 2 liter bottle. If it is not the same, then it could be sign of an issue. Quickly remove the fuel tank filler cap and repeat the test. If the issue is resolved, then you most likely have a breathing issue with the tank. Another cause may be low battery voltage, Ensure the voltage during the second test is equal or very close to the voltage of the first test and that the voltage drop has not changed dramatically. You now know a couple of things: You know voltage X. Voltage X is the voltage the pump gets during operation. The lower or higher the voltage, the lesser or greater fuel it can provide. The pumps operating range can be anywhere between 11-14.4V Operating pressure is the pressure in the fuel rail during operation. controlled by the fuel pressure regulator. Typically 43.5psi on a stock system. I'll talk more on pressure later. At operating pressure, at voltage X, it takes 'Y' seconds for your fuel system to fill the 2L bottle. On a completely stock crossflow EFI system a time less than 75 seconds to flow 2 liters is fine and will safely support up to 220RWHP Naturally Aspirated. We will use Y = seconds to fill the bottle. Z = Liters measured or liters in the container. Z*60/Y=LPM 2*60/75=1.6LPM (or 1600cc/min) Now you know what your pump puts out you can make an estimation of maximum supportable HP. All these calculators assume a few things, a lot has to do with assumptions of brake specific fuel consumption, which is a measure of efficiency. You don't need to know what that is, but just be aware that the calculators will get you in the ballpark but are not perfect. So always go on the safer side Go here: http://fuelinjectorclinic.com/hp-calculator We are treating the fuel pump like a single injector, to estimate how much power your LPH or cc/min can make. Select 1 cylinder. Select 85% duty cycle. Enter your pumps cc/min into the "injector full flow value" Set the remainder to your specific car. In my example i got 220RWHP. I'll take a moment to explain why I choose 85% for the duty cycle. When using the calculator the way that we are, the duty cycle is the % of fuel you want to use of the pumps total capacity (it's LPM). So for us, we can play with this figure to give a "safety factor" You don't want your pump on it's limit, because if something as simple as the alternator the pumps operating voltage will quickly drop below 12V and the fuel pump will pump less fuel. I have done my own comparisons on voltages and the stock pump. A drop in voltage at the pump from 12V to 11.5 took my pump from 66 to 74 seconds to fill the bottle. So 0.5v = a 8 second drop in performance. That works out to a 26HP difference. If you were running at full noise with the pump at 95% and then the supply voltage dropped 0.5v, you would loose operating pressure, leaning out the fuel mix and risk damage to the engine. SEGWAY The operating pressure of the fuel system is governed by the fuel pressure regulator. It's pressure is referenced to the manifold pressure. The purpose of this device is to maintain a constant differential pressure across the injectors. As manifold pressure changes the tip of the injector experiences changes in resistance to flow. The injection rail is at 44psi. If the manifold pressure drops 5psi because the throttle is closed, the injector now sees a differential pressure of 49psi, as a result injector flow rate increases and the engine will run rich. The counteract this, the fuel pressure regulator will drop the rail pressure 5psi, preventing any change in differential pressure on the injector. Increasing rail pressure increases the flow rate of the injectors. But, it reduces the flow rate of the pump. So, while you can get more fuel/power from injectors by increasing fuel rail pressure, You have reduced the ability for the pump to push fuel. This is why you need to find a balance between the fuel pump, the injectors and the fuel pressure. Altering fuel pressure too far outside manufacturers specs will interfere with the injector spray pattern and may have negative affects on economy and peak power. Testing fuel pressure is as easy as putting a pressure gauge somewhere in line on the high pressure side. Testing at the tank can be done, but is not ideal, as there will be some pressure lost through the line. It is best to test and set fuel pressure as close to the fuel rail as you can. Power up the system and ensure the fuel pressure meets the requirements of the injector OEM. To test the regulator you can disconnect it's vac line and suck/blow into it's reference port while watching the pressure gauge. Finally if you have followed everything so far, then you'll understand that working out injector sizing at this point, is pretty easy. using the links above and below you can roughly assume the amount of fuel you will need for your target HP, divide this for the amount of injectors you have and you get your required flow rate at 85% duty cycle. We never want to run injectors at 100% duty. Also do not choose injectors that are too big. as this makes it difficult to meter fuel at low values and leads to issues with idle and very low load and RPM, making tuning difficult. All bosch injectors have a part number stamped into the side. If you punch this number into google you should find information for flow rates and rated rail pressure. Also, Bosch EV6 and EV1 long body injectors, are interchangeable, the EV6 been the better performers with greater tolerance to different pressures and better spray patterns. You may also find this calculator handy: http://www.witchhunter.com/injectorcalc1.php Thats it.
  2. Crazy2287

    Retrofit intank pump?

    Hello all, Wont keep you long on this one, just throwing it out there for some discussion. I'm intending to upgrade the fuel system in my EFI 4.1 ltr to flow enough fuel to handle up to 95% ethanol mix. Stock pump only flows 1.9LPM on a good day so need to step it up. Was originally going to swap to a carby tank and mount an external pump, then i saw this: http://www.diyautotune.com/catalog/walbro-gss342-255-lph-intank-fuel-pump-p-348.html I cant imagine it will be beyond me to mods this onto the factory pump assembly, but its still a concern. Will be a bonus having the pump in tank as opposed to the logistics behind mounting it externally. Has anyone upgraded the factory intank pump before?
×