850 on a 35R ???
Originally Posted by twinscrewed
I doubt that. They sold me the 880's and when it was found that they were at their limit, they offered to exchange them for 1000's. I'm just sharing my experience. Take it fwiw.
This is almost certainly why I've seen several AEM EMS users talking about having to use unusually large injectors to make things work. The reality is a 720cc injector will provide enough fuel to support at least 550 bhp if the correct injector drivers are used.
I have been using tiny little 72 lb/min injectors (What Buschur sells as 780cc) which are in reality pretty much Rochester 750cc injectors. I have ran it past 35psi with meth without going over 100% (Extremely close but not over). Without the meth I have ran them at 24 lbs on pump with pretty high duty cycles as well.
Depending on the BSFC of your vehicle (Mainly decided by gas type) you would be OK for anywhere from 550-650. This also depends on your boost and fuel pressure and fuel pump capabilities.
Go here and at the bottom there are some tabs, go to the one that says fuel chart:
www.thedrunken.com/excel/
Depending on the BSFC of your vehicle (Mainly decided by gas type) you would be OK for anywhere from 550-650. This also depends on your boost and fuel pressure and fuel pump capabilities.
Go here and at the bottom there are some tabs, go to the one that says fuel chart:
www.thedrunken.com/excel/
Last edited by TrinaBabe; Mar 17, 2006 at 11:28 AM.
The way to read the chart is the X Axis is the fuel flow and the bottom axis is the HP (x10) & Fuel Pressure. The HP line shows you the required fuel flow for xxx HP, the pump and injectors show you the flow vs fuel pressure.
As you can see your fuel pump is technically the weakest link. The injectors outflow the pump. The easiest way to test that is to look at your fuel pressure guage (If you have one) while on a dyno or if you have an electric sender you obviously dont need the hood open. Then watch your fuel pressure... most likely it will not be 1:1 (1 psi/fuel:1psi/boost).
As you can see your fuel pump is technically the weakest link. The injectors outflow the pump. The easiest way to test that is to look at your fuel pressure guage (If you have one) while on a dyno or if you have an electric sender you obviously dont need the hood open. Then watch your fuel pressure... most likely it will not be 1:1 (1 psi/fuel:1psi/boost).
Last edited by TrinaBabe; Mar 17, 2006 at 11:46 AM.
Originally Posted by TrinaBabe
I have been using tiny little 72 lb/min injectors (What Buschur sells as 780cc) which are in reality pretty much Rochester 750cc injectors. I have ran it past 35psi with meth without going over 100% (Extremely close but not over). Without the meth I have ran them at 24 lbs on pump with pretty high duty cycles as well.
Depending on the BSFC of your vehicle (Mainly decided by gas type) you would be OK for anywhere from 550-650. This also depends on your boost and fuel pressure and fuel pump capabilities.
Go here and at the bottom there are some tabs, go to the one that says fuel chart:
www.thedrunken.com/excel/
Depending on the BSFC of your vehicle (Mainly decided by gas type) you would be OK for anywhere from 550-650. This also depends on your boost and fuel pressure and fuel pump capabilities.
Go here and at the bottom there are some tabs, go to the one that says fuel chart:
www.thedrunken.com/excel/
Can you also tell if those (Rochester) are the same as Fuel Injector Clinic's 750cc ?
Im not sure but since the Rochester 72 lbs/min = what most people would call 750cc injectors I would say the flow is the same. The voltage required to open/close them may be slightly different but the flow should be the same.
The reason the PTE Injectors are called 780cc I would assume is because they tested them at a higher pressure than most which is 43.5 psi of pressure.
The reason the PTE Injectors are called 780cc I would assume is because they tested them at a higher pressure than most which is 43.5 psi of pressure.
If the 880cc/min injectors are rated at 43.5 psi than I would say a 625 safely (With a little headroom in duty cycle) but it really depends on how rich you run your car and if the fuel pump can actually keep up.
The chart shows you thier flow if they are rated at 43.5 psi. Assuming your base pressure is 45+35psi boost = 80psi of fuel pressure = 428 lbs/hr at that pressure.
To hit 650 HP you would need: 422 lbs/hr... you can see there is not much room for error there.
The fuel pump however at that pressure can only flow 264 lbs/hr. The pump would not sustain the pressure. So you drop the fuel pressure to an unknown number which results in the injectors not operating at the same pressure which decreases flow.
It is kinda a dillemma when it comes to fuel systems for this reason. Fuel pumps flow less at higher pressure, injectors flow more at higher pressure. So as pressure goes up, injector flow goes up, pump flow goes down. The most safe pressure you should run is when the injectors flow runs into the pumps flow.
Which with the Whinebro pump and true 880cc injectors is only about 50psi of fuel pressure. Which is not much fuel pressure... you would need your base pressure to be about 20psi (Most people run 40's) and be running 30 psi of boost. This results in a total flow of 330-340 lbs/hr for that setup. 340 lbs/hr = 525 horses. Your injectors may still be maxxing out but it is because they are not sustaining the correct fuel pressure. Increase the pump flow is your best answer. Say you ran another pump inline (Like the Whinebro inline that most do). Your new flow would be theoretically 492 lbs/hr at whatever fuel pressure you dare to run (Within reason).
Your new chart would now have the pump flow in the 850 horse range, but your fuel pressure would need to be raised to take full effect of the dual pumps but if you left it alone your injectors would then be the weakest link maxing out at 428 lbs/hr (45 base + 35psi of boost) which would yield in the range of 650 horses before getting close to running them static.
I hope all this makes sense to people.
The chart shows you thier flow if they are rated at 43.5 psi. Assuming your base pressure is 45+35psi boost = 80psi of fuel pressure = 428 lbs/hr at that pressure.
To hit 650 HP you would need: 422 lbs/hr... you can see there is not much room for error there.
The fuel pump however at that pressure can only flow 264 lbs/hr. The pump would not sustain the pressure. So you drop the fuel pressure to an unknown number which results in the injectors not operating at the same pressure which decreases flow.
It is kinda a dillemma when it comes to fuel systems for this reason. Fuel pumps flow less at higher pressure, injectors flow more at higher pressure. So as pressure goes up, injector flow goes up, pump flow goes down. The most safe pressure you should run is when the injectors flow runs into the pumps flow.
Which with the Whinebro pump and true 880cc injectors is only about 50psi of fuel pressure. Which is not much fuel pressure... you would need your base pressure to be about 20psi (Most people run 40's) and be running 30 psi of boost. This results in a total flow of 330-340 lbs/hr for that setup. 340 lbs/hr = 525 horses. Your injectors may still be maxxing out but it is because they are not sustaining the correct fuel pressure. Increase the pump flow is your best answer. Say you ran another pump inline (Like the Whinebro inline that most do). Your new flow would be theoretically 492 lbs/hr at whatever fuel pressure you dare to run (Within reason).
Your new chart would now have the pump flow in the 850 horse range, but your fuel pressure would need to be raised to take full effect of the dual pumps but if you left it alone your injectors would then be the weakest link maxing out at 428 lbs/hr (45 base + 35psi of boost) which would yield in the range of 650 horses before getting close to running them static.
I hope all this makes sense to people.
Also remember though, when running dual inline pumps you could run alot more pressure without dropping the fuel flow nearly as badly. This means with the same 880s you could run 10 more psi of base pressure which would increase the flow to match the dual whinebro pumps perfectly.
55 base pressure + 35psi boost = roughly 482-492 lbs/hr (Also where the dual pumps would be rated to) which would result in right around the 800 hp mark before getting close to running them static. All this extra power with the same exact injectors and fuel pumps.
55 base pressure + 35psi boost = roughly 482-492 lbs/hr (Also where the dual pumps would be rated to) which would result in right around the 800 hp mark before getting close to running them static. All this extra power with the same exact injectors and fuel pumps.
There are a whole string of ways to make the fuel system up to par and everyone likes doing it thier own way.
I bought an A-1000 which has the problem where it too, like most pumps, drop alot of flow when you get to high pressure situations.
If you buy another intanke pump you would need to do some fabrication to make it fit and make the outlet the correct size.
The easiest way to do this is the buy an inline Whinebro pump and just cut the metal line and use high pressure hose/fittings to adapt the pump to pump into the stock lines. One pump feeds the other pump. This will pretty much get rid of the flow drop from pressure making the flow line almost completely flat compared to a biggie pump which pumps a whole bunch but the flow still drops badly with pressure.
The best way to do it is to run two pumps parallel. This brings into a big problem where we only have one fuel rail so you would need an good check valve at the inlet of the fuel rail or something like that. Either that or run another set of injectors with thier own rail and thier own injector driving... obviously not the cheap way but it is by far the best and your flow would be nuts.
I bought an A-1000 which has the problem where it too, like most pumps, drop alot of flow when you get to high pressure situations.
If you buy another intanke pump you would need to do some fabrication to make it fit and make the outlet the correct size.
The easiest way to do this is the buy an inline Whinebro pump and just cut the metal line and use high pressure hose/fittings to adapt the pump to pump into the stock lines. One pump feeds the other pump. This will pretty much get rid of the flow drop from pressure making the flow line almost completely flat compared to a biggie pump which pumps a whole bunch but the flow still drops badly with pressure.
The best way to do it is to run two pumps parallel. This brings into a big problem where we only have one fuel rail so you would need an good check valve at the inlet of the fuel rail or something like that. Either that or run another set of injectors with thier own rail and thier own injector driving... obviously not the cheap way but it is by far the best and your flow would be nuts.
Very good stuff Trina.
So you can confirm 43.5 PSI as stock pump pressure. Can you confirm 55 PSI for the Walbro?
Thanks a lot as I am trying to save money from actually buying a new rail and regulator. I can tune around this.
So you can confirm 43.5 PSI as stock pump pressure. Can you confirm 55 PSI for the Walbro?
Thanks a lot as I am trying to save money from actually buying a new rail and regulator. I can tune around this.
Im sure there are alot of how-tos on how to make an external inline pump fit with stock metal lines but the easiest way I can see to do it is with a flaring tool and a few fittings:
Cut the stock metal line as close to the output of the first pump as possible, leaving a little room of metal line on each side of the cut.
Slide whatever type of brake of fuel fittings are required to mate with the pump (Flare type). Then flare each line with the flaring tool, and then simply tighten the fittings to the pump and run the power / ground wire to the new pump. Should be relatively simple... you also need to remember the stock fuel lines will soon become a restriction as well though. Im not sure the stock line size but I would assume at most it is a -6 (3/8" OD). This will get you up past 600 by a little bit before it starts to hold the flow back some. Then again, how much power you plan to make
Cut the stock metal line as close to the output of the first pump as possible, leaving a little room of metal line on each side of the cut.
Slide whatever type of brake of fuel fittings are required to mate with the pump (Flare type). Then flare each line with the flaring tool, and then simply tighten the fittings to the pump and run the power / ground wire to the new pump. Should be relatively simple... you also need to remember the stock fuel lines will soon become a restriction as well though. Im not sure the stock line size but I would assume at most it is a -6 (3/8" OD). This will get you up past 600 by a little bit before it starts to hold the flow back some. Then again, how much power you plan to make
Originally Posted by Ev0ikon
Very good stuff Trina.
So you can confirm 43.5 PSI as stock pump pressure. Can you confirm 55 PSI for the Walbro?
Thanks a lot as I am trying to save money from actually buying a new rail and regulator. I can tune around this.
So you can confirm 43.5 PSI as stock pump pressure. Can you confirm 55 PSI for the Walbro?
Thanks a lot as I am trying to save money from actually buying a new rail and regulator. I can tune around this.
The pressure is based on the regulator (And boost). If you have a 1:1 fuel pressure regulator the fuel pressure goes up 1 psi for every 1 psi of boost. I think the stock base pressure is around 43 psi but Im not positive. You could put an A-1000 fuel pump and the pressure would still be 43.5 psi (Just with a whole bunch more flow).
The fuel pump does not change the fuel pressure (Unless the first pump could not flow enough to keep the pressure where you want it).
Fuel pumps flow xx amount of fuel at xx pressure. You change the pressure, not the pump. The pump just changes the flow at that pressure. At that same website I pointed you to, click on Pump Flows. That should show you what I mean.
www.thedrunken.com/excel/