HPOP Options

[Jake P]

My HPOP is junk. I have stock injectors, and at WOT it holds 2100 PSI at 92% IPR DC. I think the junk HPOP is causing some of my other issues as well, such as poor fuel economy, and some odd driveability issues. With that said i am going to buy a new one. I just haven't decided what route i want to go yet. I will be getting better than a stock pump, since i plan on doing injectors soon. I don't know what size injectors i wanna get yet, but i have an idea. Basically i wanna know what HPO systems will handle up to about a 300cc hybrid while still maintaining a decent IPR DC with full pressure. I don't know if i'll be going that big on injectors, but just in case some day i do, i wanna have it covered. Just lookin for some ideas on the limits of different HPO options.

 

[Tree Trimmer]

fwiw, you do not buy a hpop for injector size, you buy a hpop based on nozzle size.

granted inj size matters, but not as much as nozzle size.

pick a nozzle, and then we can assist you better.

 

[Cat_rebel]

What if I want to run 160cc single shots with a 400% nozzle?

 

[Jake P]

Good point. I'll probably stick with a 200% nozzle so streetability and towability are still there with good tuning. I know any bigger than that towing is pretty much out of the question.

 

[Chvyrkr]

I think you'd be good with an SRP1 Jake, it'll probably be the best bang for the buck with any 200% nozzled injector.

 

[Jake P]

I'm really leaning towards that. I do remember Bill from PHP saying though that an SRP1 doesn't flow enough to run 250s, let alone 300's.

 

[Chvyrkr]

Really... I hadn't heard that.

I've heard 300/200 is gettin up there, but it handles it.

I think I've missed some data logs though.

 

[Jake P]

Id love to see a data log with ICP and IPR DC at WOT with an SRP1 and some 300/200's.

 

[V-Ref]

Bunch of numbers posted in this thread.
http://powerstrokearmy.com/forums/showthread.php?t=2979

If you've got a few extra bucks and don't want to wait, I'd think the used Stage 2 would be a good bet as well.

Here's a AE graphic with 400cc/200% injectors with fast fueling mods. Red is accel pedal position. Green ICP psi. Orange IPR DC %. Speed is vehicle speed. It's a very responsive pump.

 

[Jake P]

That really doesn't show a sustained WOT though. Actually never even hit WOT. I wanna see a data long from a stop all the way to like 80 MPH or more, WOT the whole time. That will show what that pump is really made of.

 

[CurtisF]

My HPOP is junk. I have stock injectors, and at WOT it holds 2100 PSI at 92% IPR DC. I think the junk HPOP is causing some of my other issues as well, such as poor fuel economy, and some odd driveability issues. With that said i am going to buy a new one. I just haven't decided what route i want to go yet. I will be getting better than a stock pump, since i plan on doing injectors soon. I don't know what size injectors i wanna get yet, but i have an idea. Basically i wanna know what HPO systems will handle up to about a 300cc hybrid while still maintaining a decent IPR DC with full pressure. I don't know if i'll be going that big on injectors, but just in case some day i do, i wanna have it covered. Just lookin for some ideas on the limits of different HPO options.

Before you start swapping out the HPOP, first look and see what kind of pulsewidth you're running when your pressure drops to 2100 psi.

Second, determine what size injectors and what power level you plan to achieve.

fwiw, you do not buy a hpop for injector size, you buy a hpop based on nozzle size.

granted inj size matters, but not as much as nozzle size.

pick a nozzle, and then we can assist you better.

This statement I don't get.

I ran stock injectors on a stock HPOP, and reached a little over 300 hp. Then I put 250/200's in with the same exact stock HPOP, and reached over 400 hp.

My power goal was over 400 hp on PMR's. I've reached it, and that's all I need. The stock HPOP at that power level holds 3000 psi rock solid.

In other words, nozzle size had absolutely zero to do my HPOP selection.

Besides, you can vary your injectors, but keep the same nozzle size across the board.... and different injectors will have different oil needs even if they have the same nozzles on them.

 

[Jake P]

Before you start swapping out the HPOP, first look and see what kind of pulsewidth you're running when your pressure drops to 2100 psi.

Second, determine what size injectors and what power level you plan to achieve.

I might do that today. Why am i checking PW? Give me some real insight to what i'm doing and why.

I already know that my goal is 500 horse, however, i might go with a bit larger injector than needed and just keep it detuned for now until i can get a larger turbo. So anywhere from a 238 to a 300/200.


This statement I don't get.

I ran stock injectors on a stock HPOP, and reached a little over 300 hp. Then I put 250/200's in with the same exact stock HPOP, and reached over 400 hp.

My power goal was over 400 hp on PMR's. I've reached it, and that's all I need. The stock HPOP at that power level holds 3000 psi rock solid.

In other words, nozzle size had absolutely zero to do my HPOP selection.

Besides, you can vary your injectors, but keep the same nozzle size across the board.... and different injectors will have different oil needs even if they have the same nozzles on them.

I can see where nozzle size will make a difference too, but flow is important too. With a larger nozzle its going to empty faster, so you are gonna have to be able to flow oil faster to keep ICP up.

 

[CurtisF]

I might do that today. Why am i checking PW? Give me some real insight to what i'm doing and why.

The short story: the longer the injector is open, the more oil volume is required.

Bit longer explanation: If an injector is empty in "X" amount of time, then there's no reason to hold it open longer than that specific amount of time. If you do, then oil pressure will drop, because the volume needed to keep it open that extra amount of time increases.

However, it's quite common to find higher HP tuning that holds injectors open for a VERY long time. In that case, it's typically an indication of tuning, not the pump, that is the issue.

I already know that my goal is 500 horse, however, i might go with a bit larger injector than needed and just keep it detuned for now until i can get a larger turbo. So anywhere from a 238 to a 300/200.

Then you may or may not need an HPOP. Get the injectors first, then see how your pump is holding up. If anything, it will save you money in the short term until your actual oil needs arise.

I can see where nozzle size will make a difference too, but flow is important too. With a larger nozzle its going to empty faster, so you are gonna have to be able to flow oil faster to keep ICP up.

What you're describing here is the internal workings of the injector, not the HPOP. The HPOP system, whether stock or modified, is a fixed displacement system. It's always going to provide the same oil volume for each revolution of the pump. Speed of the injectors don't matter to that system as long as the volume required by the injectors does not exceed the volume the pump can supply.

Adding more volume (via modified HPOP setups) simply increases the available oil volume to those injectors.

 

[Jake P]

The short story: the longer the injector is open, the more oil volume is required.

Bit longer explanation: If an injector is empty in "X" amount of time, then there's no reason to hold it open longer than that specific amount of time. If you do, then oil pressure will drop, because the volume needed to keep it open that extra amount of time increases.

However, it's quite common to find higher HP tuning that holds injectors open for a VERY long time. In that case, it's typically an indication of tuning, not the pump, that is the issue.

2 different tuners has the same issue though, so i would think that would kinda rule out the tuning. Im no expert though so i could be wrong. I didn't get the chance today to hook it up, ill shoot for tomorrow though and post my findings. Wont the PCM automatically compensate for low ICP and increase the PW though?

Then you may or may not need an HPOP. Get the injectors first, then see how your pump is holding up. If anything, it will save you money in the short term until your actual oil needs arise.


What you're describing here is the internal workings of the injector, not the HPOP. The HPOP system, whether stock or modified, is a fixed displacement system. It's always going to provide the same oil volume for each revolution of the pump. Speed of the injectors don't matter to that system as long as the volume required by the injectors does not exceed the volume the pump can supply.

Adding more volume (via modified HPOP setups) simply increases the available oil volume to those injectors.

Here is my last run when i hooked to the AE a few weeks ago. This is in PHP extreme tune, WOT. Green is RPM, red is ICP, green is IPR DC%

 

[CurtisF]

2 different tuners has the same issue though, so i would think that would kinda rule out the tuning. Im no expert though so i could be wrong. I didn't get the chance today to hook it up, ill shoot for tomorrow though and post my findings. Wont the PCM automatically compensate for low ICP and increase the PW though?

Yep, it's common.

And the reason the PW increases is because of what's being commanded.

I don't know why it's still the norm, but it is. There's really no reason for it, since the final result is always more smoke and higher EGT's.


And I'm not bashing anyone or any particular tuner. Just want to get that out of the way before anything comes up.

 

[Tom S]

The short story: the longer the injector is open, the more oil volume is required.

Bit longer explanation: If an injector is empty in "X" amount of time, then there's no reason to hold it open longer than that specific amount of time. If you do, then oil pressure will drop, because the volume needed to keep it open that extra amount of time increases.
However, it's quite common to find higher HP tuning that holds injectors open for a VERY long time.

If the poppet valve is against the upper seat and the injector is bottomed out where exactly is this extra lost oil going to?

I agree fully that I have seen some pretty long PW data logs from a variety of tuners at least from AE.

 

[Tom S]

Anyone???

 

[CurtisF]

If the poppet valve is against the upper seat and the injector is bottomed out where exactly is this extra lost oil going to?

I agree fully that I have seen some pretty long PW data logs from a variety of tuners at least from AE.

I think that would be best answered by those who have flow benches.


My take on it is that let's say you can make 315 hp on stock injectors at 3.8 ms of pulsewidth. At that pulsewidth, let's say the stock HPOP can keep injection pressures at or very close to 3000 psi.

Now let's increase PW to say 4.9 ms (no stretch of the imagination here, I've seen that and much more on a very common basis). Now ICP has dropped to 2000 psi. Power gain at the rear wheels? Call it 5 hp. But the side effects now are much higher EGT's and much more smoke at WOT.

To me, increasing PW that far just doesn't make sense. The end result of smoke and EGT's is far less desirable than the negligible power gain that you most likely won't feel at the SOTP, or even notice on the dyno or at the race track.

Anywho... that's my 2 cents on the matter :gun:

 

[Tom S]

I think that would be best answered by those who have flow benches.


My take on it is that let's say you can make 315 hp on stock injectors at 3.8 ms of pulsewidth. At that pulsewidth, let's say the stock HPOP can keep injection pressures at or very close to 3000 psi.

Now let's increase PW to say 4.9 ms (no stretch of the imagination here, I've seen that and much more on a very common basis). Now ICP has dropped to 2000 psi. Power gain at the rear wheels? Call it 5 hp. But the side effects now are much higher EGT's and much more smoke at WOT.

To me, increasing PW that far just doesn't make sense. The end result of smoke and EGT's is far less desirable than the negligible power gain that you most likely won't feel at the SOTP, or even notice on the dyno or at the race track.

Anywho... that's my 2 cents on the matter :gun:

I am pretty much on the same page as you on this. Next question since you dabble in tuning. How closely does the PCM follow the asked for PW in the tune. My casual observation is that PW gets really streched out when the HP oil demand is not met. Does the tuning software even allow you to set a PW or is it more like you are setting MFD or similar.

 

[golfer]

The short story: the longer the injector is open, the more oil volume is required.

true..UP TO the point of the mechanical limit of the injector...(IP stroke)

Bit longer explanation: If an injector is empty in "X" amount of time, then there's no reason to hold it open longer than that specific amount of time. If you do, then oil pressure will drop, because the volume needed to keep it open that extra amount of time increases.

not true. Or I should say, a properly built injector should not have any oil leakage at the upper poppet seat...

ie, an injectors' maximum oil use (bore x stroke of IP)...is the same regardless of time...leaving that injector "on" for eternity should use the exact same volume of HPOil as the minimum time required for it to empty.

If you can drop ICP with extended inj duration (ie more than minimum time to empty), then you have an inj issue related to the poppet valve...which is (unfortunately) very very common in the injector world...