fordfreak4life
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i suppose ill swing it with no input except im glad to see on of the originals still in here. id rather spend time here than facebook. F that place.
Heui Injection
- Thread starter Charles
- Start date
lincolnlocker
Well-known member
Back from the dead as well! Welcome back!
BrewTown
Member
Seeing that the "pump" camshaft spins at half crank speed, and Charles mentioned 50° of advance (although that seems entirely too much?) that translates into 25° BTDC of crankshaft for camshaft for lobe start. Not taking into account any initial ramp or delay.
Is 60% of injection BTDC a decent assumption for lobe design? That puts us at a ramp incline of roughly 42°. Someone with injection pump camshaft knowledge would need to point out my errors in assumption here. Keeping that incline ramp close to that figure should allow the most fuel with the smallest PW while still servicing the full SOI advance. Meaning, it would only be stroking the pump where there's possibility of using the fuel it's pumping.
Is there benefit to injecting after 17° past TDC, meaning 34° crankshaft?
If that is correct, knowing the unit pumps stroke, and cc's per distance could get us some idea if realistic SOI and PW gets us the volume necessary.
My whole concern with that is a unit pump designed for 1800 rpm having enough variability to operate at idle and at whatever RPM the goal is.
Pressure and velocity at high RPM the other side of this.
The other option that would complicate things, is if the pump cam advanced with RPM. Doing this would do 2 things, increase the lobe lift useable at each RPM (as in steeper camshaft lobe being available sooner at higher RPM, but also later at low rpm if pumped volume is too low in some scenario), and possibly allow an existing cam lobe, like the stock E7 one.
Pick this apart. I'd like to learn something...
Is 60% of injection BTDC a decent assumption for lobe design? That puts us at a ramp incline of roughly 42°. Someone with injection pump camshaft knowledge would need to point out my errors in assumption here. Keeping that incline ramp close to that figure should allow the most fuel with the smallest PW while still servicing the full SOI advance. Meaning, it would only be stroking the pump where there's possibility of using the fuel it's pumping.
Is there benefit to injecting after 17° past TDC, meaning 34° crankshaft?
If that is correct, knowing the unit pumps stroke, and cc's per distance could get us some idea if realistic SOI and PW gets us the volume necessary.
My whole concern with that is a unit pump designed for 1800 rpm having enough variability to operate at idle and at whatever RPM the goal is.
Pressure and velocity at high RPM the other side of this.
The other option that would complicate things, is if the pump cam advanced with RPM. Doing this would do 2 things, increase the lobe lift useable at each RPM (as in steeper camshaft lobe being available sooner at higher RPM, but also later at low rpm if pumped volume is too low in some scenario), and possibly allow an existing cam lobe, like the stock E7 one.
Pick this apart. I'd like to learn something...
Charles
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The beauty is..... it's tied to crank....
So no matter what speed you spin it, the fuel goes in the hole in the same degrees crank for the same cc's of fuel... and you move that window forward in time with the SOI timing with the stock Ford timing table.
As for comparing the E7 to the 7.3 on airflow, bare in mind, the E7 isn't running 150lbs of boost. Boost is literally displacement. You ARE moving the air..... not air volume, VE stays constant but air MASS. Each of the cubic feet you move might weigh 4 times what each cubic foot weighs going through the E7 at stock boost.
A 12v head flows crap compared to a 7.3, as unbelievable as that sounds.... but at 120 to 150 lbs of boost they will move enough air MASS for 1500+ hp. And that is with crap for injection pressure and 2 LESS INTAKE PORTS, valves, cylinders and injectors. Stockish heads.
VE is nice but boost from compounds WILL push the air in the hole. Not MORE air.... the same CFM through the port.... but really HEAVY air. The CFM INTO the first stage compressor however will be dramatically high. Need over 100mm certainly. The flow INTO the first stage will be 2 or 3 Mack engines...
Tappet design is a question. Getting the unit pumps to follow the cam at double the design rpm is a real issue. Increased spring pressure, rollers with limits to keep them from going all CP4 sideways..... I have even wondered about going cp3 style with an eccentric. The good news is that we can spin the pumping units far slower.... a cp4 has to fuel the engine from 2 pumping units spinning fast, dual cp4's have 4 total pumping units and dual cp3's have 6.... MEUI 7.3 would have 8. It could deliver the same fuel at lower cam operating speeds. The plunger sizes appear similar.
The similarities between a Meui pump and a CR pump are obvious. CR pumps hold 2 or 3 pumping units making 25 - 30k psi, and 4 or 6 units for dual pumps. A MEUI pump on a 7.3 would house 8 pumping units at 25 - 30k psi.
But..... you can't drain the rail. The more you ask for, the more violent it gets
So no matter what speed you spin it, the fuel goes in the hole in the same degrees crank for the same cc's of fuel... and you move that window forward in time with the SOI timing with the stock Ford timing table.
As for comparing the E7 to the 7.3 on airflow, bare in mind, the E7 isn't running 150lbs of boost. Boost is literally displacement. You ARE moving the air..... not air volume, VE stays constant but air MASS. Each of the cubic feet you move might weigh 4 times what each cubic foot weighs going through the E7 at stock boost.
A 12v head flows crap compared to a 7.3, as unbelievable as that sounds.... but at 120 to 150 lbs of boost they will move enough air MASS for 1500+ hp. And that is with crap for injection pressure and 2 LESS INTAKE PORTS, valves, cylinders and injectors. Stockish heads.
VE is nice but boost from compounds WILL push the air in the hole. Not MORE air.... the same CFM through the port.... but really HEAVY air. The CFM INTO the first stage compressor however will be dramatically high. Need over 100mm certainly. The flow INTO the first stage will be 2 or 3 Mack engines...
Tappet design is a question. Getting the unit pumps to follow the cam at double the design rpm is a real issue. Increased spring pressure, rollers with limits to keep them from going all CP4 sideways..... I have even wondered about going cp3 style with an eccentric. The good news is that we can spin the pumping units far slower.... a cp4 has to fuel the engine from 2 pumping units spinning fast, dual cp4's have 4 total pumping units and dual cp3's have 6.... MEUI 7.3 would have 8. It could deliver the same fuel at lower cam operating speeds. The plunger sizes appear similar.
The similarities between a Meui pump and a CR pump are obvious. CR pumps hold 2 or 3 pumping units making 25 - 30k psi, and 4 or 6 units for dual pumps. A MEUI pump on a 7.3 would house 8 pumping units at 25 - 30k psi.
But..... you can't drain the rail. The more you ask for, the more violent it gets
BrewTown
Member
I believe the 7.3 is basically the same on air flow as a stock 12v. Numbers I find are 140-150 cfm @28" for a 12v, and 110-115 cfm @28" for a 7.3. So average 12v over 2 revs hitting all 6 cylinders means 840-900 cfm, and 7.3 over 8 cylinders moves 880-920. I don't know about swirl, and I know the lack of runner length is poor design. Either way, that "should" put us on par with 12v power per boost capabilities. At least it won't be dramatically different. I don't know what ported 7.3 heads flow, but I'm not sure this is the worry currently. This is only intakes, so not the whole story...
How do we go about finding how much travel the pumps are capable of, and what that equates to in fuel? I agree that different springs, with higher pressures and without coil bind in the travel necessary. Anybody have access to a spintron?
Is CNC Fab making p-pump conversions also? I wonder if some of their parts would be available, like valve covers and anything for injectors. I know they have a front cover with their name on a pulling truck, maybe more. I didn't see anything on their site though. I thought Corey had p-pump conversions he talked about, just not sure.
Roller lifters have tie bars to keep them from spinning. Link bar lifters, whatever you'd like to call them. An idea anyway.
If you just look at power output with nitrous, 300 or 350cc injectors have done like 1200+ hp right? The only reason they don't without the bottle is air flow. Whether that be compounds with really high boost, or great flowing heads and a little less boost. Either way, nitrous is only cooling the charge and adding oxygen, it isn't fuel. Yes RPM range is a factor here too, but you get the idea...
How do we go about finding how much travel the pumps are capable of, and what that equates to in fuel? I agree that different springs, with higher pressures and without coil bind in the travel necessary. Anybody have access to a spintron?
Is CNC Fab making p-pump conversions also? I wonder if some of their parts would be available, like valve covers and anything for injectors. I know they have a front cover with their name on a pulling truck, maybe more. I didn't see anything on their site though. I thought Corey had p-pump conversions he talked about, just not sure.
Roller lifters have tie bars to keep them from spinning. Link bar lifters, whatever you'd like to call them. An idea anyway.
If you just look at power output with nitrous, 300 or 350cc injectors have done like 1200+ hp right? The only reason they don't without the bottle is air flow. Whether that be compounds with really high boost, or great flowing heads and a little less boost. Either way, nitrous is only cooling the charge and adding oxygen, it isn't fuel. Yes RPM range is a factor here too, but you get the idea...
Charles
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I think with the reality that ports don't flow into open air and that there is a piston in the way, as air pumps, the 7.3 and the 12v should move air similarly, cylinder per cylinder. I don't agree that having 2 more cylinders will basically wash out. As bad as the 7.3 flows, it should still outflow a 12v in terms of total air in, per minute at any given rpm by a fair bit more. This is one reason why even at low power outputs, the larger displacement is such a burden in an inducer limited pulling class for instance. The 7.3 needs much larger compressor than the 5.9 for the same compressor efficiency for any given flow and pressure ratio because it moves so much more volume. Look at it in terms of VE. The VE should be very similar between both 2v engines with similar valve sizes and port flows but one of them displaces 5.9L and the other 7.3L.
Stock, the units move 400cc I think. I haven't taken one apart but they make 1650ft/lbs on only six units on a stock truck meeting full emissions regs. 8 units at that same BSFC is 2200ft/lbs. If they never were capable of more, I don't care. But no OEM maxes out the hardware for a stock OTR engine.
I would like to run the stock front cover. Mech pump guys can't just choose which way to spin the pump with an idler in the hpop spot and the mech pump turning "backward" because it would require a custom cam on an already unicorn 8 cylinder pump. I want to see about using the hpop spot as an idler/ aux drive and then a MEUI pump above it running another 7.3 cam gear.... right back to 50% crank with no special gears or covers
Yes something would have to limit the roller's freedom of motion or just go flat, or something.
Nitrous on a 7.3 changes the burn RATE..... giving you the ability to get an otherwise poorly atomized, slow injection event sped up so much after the fact that it can produce the bmep it never could without the oxidizer.
Mech pump 7.3's have proven that the platform can burn fuel in time without the oxidizer if you can simply get it INTO the engine in time. And I don't know that the pumps they are running are achieving the kinds of pressures the MEUI does stock..... and.... they have fixed timing.
Stock, the units move 400cc I think. I haven't taken one apart but they make 1650ft/lbs on only six units on a stock truck meeting full emissions regs. 8 units at that same BSFC is 2200ft/lbs. If they never were capable of more, I don't care. But no OEM maxes out the hardware for a stock OTR engine.
I would like to run the stock front cover. Mech pump guys can't just choose which way to spin the pump with an idler in the hpop spot and the mech pump turning "backward" because it would require a custom cam on an already unicorn 8 cylinder pump. I want to see about using the hpop spot as an idler/ aux drive and then a MEUI pump above it running another 7.3 cam gear.... right back to 50% crank with no special gears or covers
Yes something would have to limit the roller's freedom of motion or just go flat, or something.
Nitrous on a 7.3 changes the burn RATE..... giving you the ability to get an otherwise poorly atomized, slow injection event sped up so much after the fact that it can produce the bmep it never could without the oxidizer.
Mech pump 7.3's have proven that the platform can burn fuel in time without the oxidizer if you can simply get it INTO the engine in time. And I don't know that the pumps they are running are achieving the kinds of pressures the MEUI does stock..... and.... they have fixed timing.
