BIG A CODE INJECTORS?

[FARMBOY22]

I was curious how large cc wise an A code injectors can be built. Reason being it seems to me the higher injection pres of the A code would up the mileage and perfromance of an engine even though you would need more oil. Especially if you had a weak pump and were going to replace anyways. Would an 200cc/100% full A code not out perform a hybrid the same size? How much more oil would the A code need?

[907DAVE]

Originally Posted by FARMBOY22

I was curious how large cc wise an A code injectors can be built. Reason being it seems to me the higher injection pres of the A code would up the mileage and perfromance of an engine even though you would need more oil. Especially if you had a weak pump and were going to replace anyways. Would an 200cc/100% full A code not out perform a hybrid the same size? How much more oil would the A code need?

I am no expert on the subject but with injectors with such a high ratio things slow down. Performance HEUI injectors are all about fuel per time, the higher the ratio the longer it will take to move the fuel because of internal restrictions. This in itself can be harmful to your engine because of the advanced timing needed to deliver a full load of fuel within the "injection window". Hybrid injectors seem to be the better option as they are capable of delivering large quantity of fuel relatively fast, which means less timing, less cylinder pressure, and a much happier engine.

Yes you will loose injection "quality" with lower injection pressures, but gain the speed to deliver more fuel. Another benefit is that big oil systems are not always necessary with the Hybrids, that make it a bit easier on the wallet.

[FARMBOY22]

Originally Posted by 907dave

I am no expert on the subject but with injectors with such a high ratio things slow down. Performance HEUI injectors are all about fuel per time, the higher the ratio the longer it will take to move the fuel because of internal restrictions. This in itself can be harmful to your engine because of the advanced timing needed to deliver a full load of fuel within the "injection window". Hybrid injectors seem to be the better option as they are capable of delivering large quantity of fuel relatively fast, which means less timing, less cylinder pressure, and a much happier engine.

Yes you will loose injection "quality" with lower injection pressures, but gain the speed to deliver more fuel. Another benefit is that big oil systems are not always necessary with the Hybrids, that make it a bit easier on the wallet.

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?

[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.