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CHEF |
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Bert wrote: Also as a final though some fuel injectors do not increase fuel delivery in a progressive fashion with pressure increases and pintle injectors are know for poor atomisation with excessive pressure. An example of poor atomisation is 13B or 12A rotary injectors, its hard to get a smooth idle on them in a piston motor (tuning them with a Microtech hides this mostly). I'm using RX7 series 4 13B 550cc with the Wolf and they idle fine, the injectors your talking about are the larger secondary injectors found in 12A turbo motors, and yes, are not suited to piston motors. The Series 4 13B injectors are a commonly used upgrade in many nissan RB motors. I have a friend that runs them in a mpi starion (4cyl 2lt turbo) and has no idle problems Funny you should mention this as I was told the same thing by an EFI/Dyno specialist when I wanted them to smooth out my tune... they couldnt get it to run under 3000 without being overly rich so there solution was to either replace them with smaller S/C commodore injectors, or change to Haltech... I have sinse tuned it myself again |
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Bert |
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Maxxr6 wrote: bert one thing you forget is that fuel pumps will pump anything upto 80psi with no hastle plus when the rising rate reg is shut and you see your so called 120psi dont forgt that the injectors are letting fuel out of the rail so the pump cant push the presure to 120psi maybe you need to fit a pressure guage to a car and see what i mean
So what you are saying is then is that the pump cannot handle the pressure and you now have a disproportionate fuel pressure curve?? If the pressure is not there then either the relief (reg) or the pump is at fault. Also chef what I am infering to is actually not too big an injector but poor atomisation/fuel delivery. Couple this with a course fuel map and this can make the idle rpm slightly rough. I actually gave a poor comparison but what I was trying to say is that pintle injectors start spraying the fuel very poorly with too much pressure. The injector needs to be rotated close to 90 deg to airflow to help with atomisation. If the injectors were truely too big and caused and over rich condition at 3000rpm then the car would almost not idle. I have met a person who ran 8 batch fired 75lb injectors in a V8 and it idled fairly smooth (large cam). Yet chiptorque said it could not be done. |
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Maxxr6 |
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Age: 43 Posts: 50 Joined: 20th Aug 2005 Ride: ED XR6. XF twin turbo ute. Location: melbourne |
bert what i am saying is that a rising rate preure reg will keep the fuel presure up to what you need when you get boost the reg closes the more boost you make the more it closes if all you do is clamp you standard reg in a vice you will have a high presure at idle and a low presure at top end because it will still alow fuel to return, as the injectors open they release fuel as you know when they release fuel presure will go with it, when you have six or eight or even four the presure will drop this is why you need a rising rate presure reg to stop that.
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Bert |
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Maxxr6 wrote: bert what i am saying is that a rising rate preure reg will keep the fuel presure up to what you need when you get boost the reg closes the more boost you make the more it closes if all you do is clamp you standard reg in a vice you will have a high presure at idle and a low presure at top end because it will still alow fuel to return, as the injectors open they release fuel as you know when they release fuel presure will go with it, when you have six or eight or even four the presure will drop this is why you need a rising rate presure reg to stop that.
Read what I have written again. All regs raise the the fuel pressure at a rate of 1:1 with boost pressure. A rising rate increases this at a rate greater than 1:1, these are the mallapassi brand regulators. The vaccum line is there to ensure the reg gets feedback so the fuel pressure at the nozzle of the injector is always constant regardless of what the absolute pressure is wrt atmosphere. Vaccum in the manifold opens the reg and lowers the fuel pressure, WOT is virtually no vaccum and hence more fuel pressure. What you are saying if that the fuel pressure cannot be maintained. This means the pump is NOT suppling enough pressure through volume. I work on forklifts, the hydraulic system works basically like an efi fuel system. If what you were saying was corrct everytime I went to lift the forks in the air they would lift great off the ground then slow down as they rise then stop before they reach the mast's maximum height BECAUSE the pressure is not being MAINTAINED. |
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Maxxr6 |
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Age: 43 Posts: 50 Joined: 20th Aug 2005 Ride: ED XR6. XF twin turbo ute. Location: melbourne |
you work on forlifts! well sorry
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Maxxr6 |
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Age: 43 Posts: 50 Joined: 20th Aug 2005 Ride: ED XR6. XF twin turbo ute. Location: melbourne |
bert on your forklift what happens when you rev the engine when you are lifting the load, i think it goes up faster because you are increasing line presure like closing the reg at high rpm
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Bert |
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I work on forklifts because that actually pays better than the car industry. The aftermarket car industry is full of dreamers, s**t artists and ripoff merchants, I got feed up after 3 months. Car dealerships are boring, pay poorly, and train you so you have no future propects. Its funny how I now service/repair the forklift of my old dealership. In addition I get treated well, car, phone and fuel. It was a job I fell into.
There are no jobs on the Gold Coast/Brisbane in Electrical Engineering that pays enough money that you can live on. No I am not s**t you I have one in Electrical/Communications. You are obviously a very arrogant person who thinks they are better than everyone else because they just simply opened their mouth and breathed. I APPOLOGISE I give really bad analogies that you can't understand. I bend over so you can paddle my a** for my mistake. I will try to explain it to this last time. A fuel regulator serves one purpose, to maintain a constant fuel pressure as the fuel is discharged into the manifold. Therefore it has to be able to go down when the mainfold is showing vaccum and up when it is showing pressure (boost). This is achieved by connecting a vaccum line to the diaphram of the regulator. You check the base fuel pressure with the line disconected. The fuel pressure goes down at idle and cruise, hook up a pressure gauge and look yourself. Now the magic part. The base fuel pressure is set on the factory Bosch regulators by spring pressure onto the diaphram restricting the fuel return. Pressure is pressure regardless whether I am pushing on the diaphram with my finger, a spring or pressure (fluid or air). I have proved that the factory Ford regulator will go up in pressure to AT LEAST 50psi. Regardless of me squeezing the regulator in a vice in order to apply more spring pressure or via manifold pressure to the fitting on the diaphram the fuel pressure WILL rise. I refuse to reply to anymore of your pointless posts in this thread so don't get b**ch because you still have not properly read what I wrote earlier that CHEF instantly understood. |
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ToranaGuy |
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Nice to know that the factory reg will cope with 50psi. This means someone else wanting to build a mild turbo setup, has one less part to replace.
A question i have tho, what does it flow like @ that pressure, is the flow a linear equation, or does it drop off? Cheers ToranaGuy
_________________ I am the ToranaGuy!|74 Lh Torana Turbo|78 Hz PanelVan|86 Mighty Boy Ute|93 EB2 Ghia,GT Mockup,5spd,LPGI,Full Leather|2 x EB Xr8 5spd's|FS [VIC]: Wrecking - Eb XR8 - Parts available |Build Thread|Ebay Items - Ford Parts| |
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Spork |
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Thanks for clearing that up bert.
So if the standard fuel pressure is about 34 Psi this means that you could run up to 16Psi of boost on the standard fuel reg and it will still be able to control the pressure accross the injectors at a constant 34 psi. Summary: Unless your injectors are undersized there is no need for a "rising rate". Especially with aftermarket EMS as this will make tuning more difficult.
_________________ Manual EL Gli.
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Bert |
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I said at least 50psi. I expect it will do higher than this and I will find out when I get around to turbochaging my car, hopefully by November. I only raised my fuel pressure to ensure enough flow and get (hopefully) better atomisation with my disc injectors.
A rising rate reg will always give a skewed fuel table. This is very bad if your ecu tunes by VE not injector rate. |
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sickd |
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ok so i could run 10psi out of a turbo on my ef xr6 with the reg its got
??? dont flame me i just want a confident yes that there will be no problems at all
_________________ BA XR8 BOSS 260
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CHEF |
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Yes, I am and its fine
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bogan |
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hey CHEF what turbine and compressor A/R's are you running and when does boost come on.
cheers
_________________ THATS TOPS MATE |
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CHEF |
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Ex is 1.04, comp 0.60. Boost gets to positive (0 psi) at 2200, 14psi ( or whatever max boost is set to ) at aorund 3000 rpm.
Basically, soon as you touch the throttle it get on boost and hits max very fast |
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sickd |
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my turbo is a ex 1.06 and .50 or .60 will this boost up fast ?
_________________ BA XR8 BOSS 260
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