BIG A CODE INJECTORS?

[907DAVE]

Originally Posted by FARMBOY22

What you said makes sense though i believe it would be the increased flow of the oil needed not the pressure that would restricts it. I know in a normal hyd. systems that flow in harder to maintain than pressure. You can actually have pressure without flow(bad pump) but normally can,t have flow with out some pressure. On a high horsepower and/or rpm engine that makes sense. There are pros and cons to both, but i still wonder if on an engine making less than say 450hp at normal operating speeds if the A code would have an advantage??? Who knows i sure don,t?

I have a hard time following this.......without volume there cannot be any pressure, pressure is basically a measurement of restriction (to the flow/ volume).

I am sure you can have 450HP with some A's, but it wont be as easy as you could with a set of Hybrids.

[FARMBOY22]

Lets say you have a backhoe that the hoe wont lift as much as it should. If you put a flow meter inline on the main pressure hose coming out of the pump you can check pressure and flow. The system will have a min spec of what GPM at a set PSI the pump should maintain. Lets say it should be 50GPM@3500PSI you check it at no load (usuaully less than 100PSI) and it's pumping 60GPM. Looks good at first, but the GPM starts drop in as you increase the load (flow meters have built in adj restrictor to load systems) the gpm drops. It's possible that the flow completely stops 0GPM and the pump be making say 2500PSI the machine will stall. Thus can you have pressure with no flow and the system still work till you till the load gets to heavy. Make sense

[907DAVE]

Not trying to argue, but lets take a look at a basic example.......

The Garden Hose: With a regular spray nozzle on a regular garden hose you will have high pressure when the nozzle is half-closed, creating a high pressure jet with higher velocity. Open that same nozzle all the way and observe much more flow, but far less pressure. Higher flow = more friction loss = less pressure.

See it now? Restriction to flow = pressure........ no restriction= no pressure.

Lets look at some other definitions of pumps and pressure......

Taken from Hydraulic Pumps

Tutorial on Hydraulic Pumps

A pump converts mechanical energy, typically produced by an electric motor, into hydraulic energy.

The pump does not generate pressure, only flow. Pressure occurs when the flow from the pump meets a resistance, such as a cylinder attached to a load.

The mechanical action of the pump creates a vacuum at the inlet port, which allows atmospheric pressure to force liquid from the reservoir into the pump. The mechanical movement of the pump then forces the liquid into the hydraulic system.

Positive Displacement Pumps

Most hydraulic pumps are 'positive displacement' pumps. 'Non-positive displacement' pumps used in other applications generate slippage, causing the output to decrease as a load is applied.

A positive displacement pump has an extremely close fit between the pumping element and the pump case, resulting in slippage that is negligible compared to the pump's output. If the output port were plugged, the pressure would immediately rise to the point that the pumping element, case, rotor, or driving motor would fail.

Types of Pump

The displacement of a pump can either be fixed or variable. Variable displacement permits the output during a pumping cycle to change. This is accomplished by altering the geometry of the displacement chamber with an electrical or fluid control system.

Pumps are classified by the type of element that transmits the liquid. The most common elements are gears, pistons and vanes. By their nature, piston pumps lend themselves to variable as well as fixed displacement operation.

Taken from Centrifugal Pumps

The kinetic energy of a liquid coming out of an impeller is obstructed by creating a resistance in the flow. The first resistance is created by the pump casing which catches the liquid and slows it down. When the liquid slows down the kinetic energy is converted to pressure energy.

* it is the resistance to the pump's flow that is read on a pressure gauge attached to the discharge line

A pump does not create pressure, it only creates flow. Pressure is a measurement of the resistance to flow.

[FARMBOY22]

All of that is very true and completely blocking flow is the ultimate restriction. When you shut off the nozzle on that garden hose there is still pressure in that hose behind it even though there is no flow ie you have pressure with no flow.

Not trying to be smartass just trying to get you to see my side of it.

[907DAVE]

Lets go back again and see if we can figure this out.......

Originally Posted by 907dave

I have a hard time following this.......without volume there cannot be any pressure, pressure is basically a measurement of restriction (to the flow/ volume).

With that garden hose blocked off there is pressure in it, but only because there is a pump trying to push volume behind it. The greater the restriction to the flow, or the larger the volume trying to overcome that same restriction.......the higher the pressure.

The purpose of a hydraulic pump is to supply a flow of fluid to a hydraulic system. The pump does not create system pressure, since pressure can be created only by a resistance to the flow. As the pump provides flow, it transmits a force to the fluid. As the fluid flow encounters resistance, this force is changed into a pressure. Resistance to flow is the result of a restriction or obstruction in the path of the flow. This restriction is normally the work accomplished by the hydraulic system, but can also be restrictions of lines, fittings, and valves within the system. Thus, the pressure is controlled by the load imposed on the system or the action of a pressure-regulating device

Taken from Chapter 4 Pumps


Having fun yet?

[FARMBOY22]

Originally Posted by 907dave

I have a hard time following this.......without volume there cannot be any pressure, pressure is basically a measurement of restriction (to the flow/ volume).

I am sure you can have 450HP with some A's, but it wont be as easy as you could with a set of Hybrids.

I think we have gotten away from the subject a little. The only point I was trying to make was that if 3000PSI is demanded from your HPOP the HPOP doesn't know or care which injector is in front of it. The HPOP will pump as much volume as it takes to try and maintain that 3000PSI which will be the same as the intensifier pistons are the same. It's the additional oil flow or volume the A code will need to maintain that 3000PSI for a longer time because its barrel is smaller and the plunger must travel farther to inject the same amount of fuel and also taking more time that will hinder it. There by flow not so much as pressure is the problem on high HP engines ,but shouldn't be as much a problem on lower HP engines. Of course if the HPOP can't keep up the pressure will also be low. I was wondering at what point or HP range is the Hybrid truely at an advantage. I know at stock levels the A is best and at 600HP+ Hybrid is better, but where is the split between the two as to which one is better?

[907DAVE]

Originally Posted by FARMBOY22

I think we have gotten away from the subject a little. The only point I was trying to make was that if 3000PSI is demanded from your HPOP the HPOP doesn't know or care which injector is in front of it. The HPOP will pump as much volume as it takes to try and maintain that 3000PSI which will be the same as the intensifier pistons are the same. It's the additional oil flow or volume the A code will need to maintain that 3000PSI for a longer time because its barrel is smaller and the plunger must travel farther to inject the same amount of fuel and also taking more time that will hinder it. There by flow not so much as pressure is the problem on high HP engines ,but shouldn't be as much a problem on lower HP engines. Of course if the HPOP can't keep up the pressure will also be low. I was wondering at what point or HP range is the Hybrid truely at an advantage. I know at stock levels the A is best and at 600HP+ Hybrid is better, but where is the split between the two as to which one is better?

Agreed!

That is probably a question better suited for an injector builder, or someone with some time on a flow bench.

Sorry I am no help.

[FARMBOY22]

Originally Posted by 907dave

Agreed!

That is probably a question better suited for an injector builder, or someone with some time on a flow bench.

Sorry I am no help.

Hey I like a good debate as much as anyone. If nothing else it was still fun.

I'm still curious though.

[FARMBOY22]

The whole reason I brought it up is that I'm pretty well at the mechanical limit of of my stock engine. I want to lay out a plan to have a engine with an efficient tune at 350-375HP I can tow heavy with truck and trailer grossing 30,000lbs+ heavy, but still have a tune at 450-475HP that I can play with. For reliablity reason that's as far as I want to go as I don't want to fill the block or fire ring the heads and may be pushing it there? I'm looking to get a new HPOP anyways as mine will only hold about 1800PSI on a full throttle 60 to 90+ MPH run in OD on a 3% uphill grade with the Edge race tune and will set SES light in about 4sec.

[F-127]

Although somewhat sore on the subject(only cause I spent a pretty good length of time writing a post earlier today... only to be interrupted a few times... then being logged out automatically... attempting to post... then finding out I needed to resign in and have my work disappear), I'll try again.

I'll agree, the definitive break point on when an A code is better or a hybrid is better is certainly left to the injector builders, and even they might have difficulty coming up with the answer. I'll give my thought, if your going for the HP(or under) of what a 160cc/100% A code injector can provide, go for it. If your shooting for more HP than that, then hybrids are probably the way to go as you're probably building a 'performance' engine to have a high HP(and RPMs usually).

Situation asked, if your looking for a 200cc/100% injector and utilize the size of the injector often there are probably two situations:
Go with a 200cc/100% A code(if found), and a HPOP upgrade
Go with a 205-238/100% hybrid, HPOP upgrade not always needed

The hybrids may cost more, but if you use the total cost for injectors and the HPOP upgrade when using an A code, that route would probably be higher. If A codes are more efficient, how long before the increased efficiency of the A code would pay off?

I don't know for sure, but I ran 238cc/100% Rosewood hybrids in my 97 for quite a while and I averaged 15 MPGs with all my driving. I was fairly happy because some other side notes include: lifted, oversize tires, a non-streamlined bumper and even having some fun with it often. I even had a high of 17.9 mpg. I'm not sure how much better an A code could have done.

Now into some injector 'theory', some may already know parts of what I'll say, but I'll cover more for others. Some 'theory' is what I've read, as well as some of my own. With the combination of A code and B code parts we have the hybrid injector that flows more fuel volume per oil volume(but reduced pressure) when compared to the A code. See part details here.

The heart of the discussion: (which may have already ended)


Areas A,B,C referenced from image.
General accepted thought, lower HPs=A code, higher HPs=hybrid. Here's my attempt at explaination. At higher HP more RPMs are usually utilized. At some point the need for the intensifier piston movement is so fast, that the oil can't flow through area B and into area C fast enough. A pressure drop occurs over the intensifier piston when compared to the rail pressure(area A) and fuel injection pressure suffers. Raise the rail pressure to flow through B faster? Can't go much higher or the poppet valve will float. Another option? Hybrids, by flowing more fuel volume per oil volume, area C needs less expansion in a hybrid than the A code for equal fuel amounts. The fuel injection pressure drop is then somewhat less with the hybrid at higher RPMs. This giving the advantage to hybrids at higher HP. This is a thought on why hybrids, although "supposed" to inject at lower pressures than A codes, might actually inject at higher pressures in certain situations.

Is what I said above right? Not sure. Have I been 'inside' injector? Unfortunately not. Do I have more injector thoughts? Yeah, this is probably enough for one time though. Didn't really feel like entering debates on PSN, a little more friendly here. What's it mean when you answer your own questions again?