Fuel Pulsation Dampener.

[Dirtleg]

So this is a subject I've not found much info on relating to our EB engines.

Sure there are the recall issues from the 2.0 for pulsation dampener issues a few years back but that's not what I'm focused on. At all. In fact I'll just say it right now;

Please lets keep this thread on point in the event there is any interesting discussion here at all. Thanks.:cheers:
So back to my original topic.

While doing some research of our DI fuel system I've found on here and other places some pictures of the cam/pump actuator and also read about fuel pressure consistency problems in specific rpm ranges. I am not sure if it coincides with the 5200-5500 rpm chatter I've seen in the stock dyno charts but my mind can't get away from the idea they may be related. I could be just flat out wrong here and if I am so be it.

Well it's obviously not pump cavitation as it clears up at a higher rpm. So it got me thinking about resonance and at what frequency the fuel, or fuel system became unstable. At this point in my understanding of things my ideas are all theoretical and should not be taken as fact FYI.

As is the case with every component on our cars, the fuel pulse dampener on these engines is a cost vs performance compromise. I'm thinking the simple addition of a displacement based dampener downstream of the fuel pump might smooth out the fuel pressure issues. This would provide a consistent flow for the injectors if it could reduce the resonance effect on the pump. Being that it's displacement based it could even provide extra (stored) fuel in the event of a momentary pressure drop.

So with that said what are other peoples thoughts in this area?

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[Juben]

I'd say Alex could add some valuable insight on this one. What do you think, HemiCouple?

 

[LeonBorden]

What I don't understand is how FRS guys are making 600hp on their stock DI pump by just having an a1000 or 270lph lift pump.... And ours which is designed for an extra 100hp, can't.

 

[dragonacc]

What I don't understand is how FRS guys are making 600hp on their stock DI pump by just having an a1000 or 270lph lift pump.... And ours which is designed for an extra 100hp, can't.

The FRS is DI and PI.

 

[RoryTate]

But still one pump.

 

[Dirtleg]

Right now I'm pissed because I had a very long and thorough reply about some important issue with our HPFP typed up and my computer locked up and I lost it. A solid 35 minutes worth of typing. :doh:

I cannot type it all again so I'll try and do the short version.

Our HPFP is a piston pump. It works in a linear fashion by moving up and down. This by design creates resonant frequencies in the system. Sometimes the frequency is at a point where it pushes back off itself. Think of waves hitting a wall and bouncing back, interrupting the flow of the incoming waves. If they get far enough out of sync the flow can be restricted by this issue alone even though the pump is technically putting out more flow. To make matters worse, when going from the 2.0 to the 2.3 they increased the number of actuator lobes from 3 to 4 in the interest of increasing volume, increasing the potential for this to happen. Hence the factory installing a pulse dampener in the first place. Wonder if it's the same dampener as on the 2.0's. I would like to see a chart that could show the pulses in the fuel system to see how effective the factory fuel dampener is. At say 5500 rpm the pump is being actuated 183 times per second. That is a lot of "noise" in the fuel lines. I'd like to know how much of this is reaching the injectors. This is why I think a displacement based dampener would at least smooth out the flow at the injectors.

And I believe that a gear driven positive displacement pump would be a better solution if our fuel were capable of providing sufficient lubrication to prevent reliability problems. Not so much a problem with diesel but gas... I'm sure it can be done but at what cost? It would eliminate the resonance problem however.

Okay that was a weak attempt at re-creating my earlier lost post but you get the idea.

 

[Dirtleg]

The FRS is DI and PI.

But still one pump.

If they're also increasing the size of the port injectors, there's your answer right there. In that case the extra HP wouldn't be coming from the DI at all.

 

[arghx7]

I don't understand this concern - interwebz tells me that the 2.0 pulsation dampener related problem was attributed to a manufacturing problem.

Seeing how this is an entirely different and newer engine, why would you anticipate this to be a possible weak point?

 

[Dirtleg]

I don't understand this concern - interwebz tells me that the 2.0 pulsation dampener related problem was attributed to a manufacturing problem.

Seeing how this is an entirely different and newer engine, why would you anticipate this to be a possible weak point?

From my first post:
Sure there are the recall issues from the 2.0 for pulsation dampener issues a few years back but that's not what I'm focused on. At all.


Not weak as in going to fail, weak as in not up to the task of getting more power out of these cars with the stock fuel system. As in it's a choke point by itself and how can we easily and potentially inexpensively improve things.

And I don't know the answer hence this thread.

 

[Alex]

Hi Everyone, thanks Juben for the invitation. I've worked with the 2.0 EB extensively as well as the 2.3 Mazda DI motor before it so DI is something I've had lots of exposure to and perhaps can shed some light on the strengths and shortcomings of the system.

Ford has done a very good job on the DI system in these motors. The early DI motors (and some current ones) are susceptible to pressure drops that cause knock and LSPI which is the bigger "engine killer" in the DI world.

The Mustang 2.3 has 4 lobes on the cam while the 2.0 has 3 lobes for driving the HPFP. Given the larger displacement and turbocharger in the 2.3 along with the 4 lobes there is more HPFP flow available for this motor than the 2.0 which runs out somewhere around 360-380 ft lbs of torque to the wheels.

On the 2.0 the HPFP runs out first quickly followed by the injectors ... all in we are looking at running out of fuel around 380-400whp or so if really stretched so I expect the 2.3 to offer more than this on DI alone. The in-tank pump on the 2.0 flows plenty more - just had it tested it is good well north of 400whp and I expect the same here.

The 2.0 and 2.3 power curves look quite similar in shape with power dropping off in the upper RPM. The higher the RPM the more fuel the HPFP can deliver so what you end up doing is running out of HPFP in the lower RPM (peak torque) and out of injector in the upper RPM (high engine speed and smaller injection window). The power drop up top is due to saving the catalyst and the efficiency of the turbocharger dropping off. That doesn't mean power can't be extended up top and the aftermarket tunes take care of this.

I am going to be sorting through 2.3 data to get an even more exact idea of what the fuel system is capable of but my experience with the 2.0 tells me that you will run out of turbo before running out of fuel up top. Down low, E85 mixes will challenge the HPFP.

Overall the system is very robust with plenty of failsafes which is a great starting point.

 

[Dirtleg]

Alex, in your experience has there been any feedback/research into potentially reducing the resonance from the pump pulses to smooth out the fuel flow to the injectors?

Or am I now that "Quack on the Interweb" for suggesting it?

 

[Juben]

Alex's post is still there for me.

 

[Alex]

Alex, in your experience has there been any feedback/research into potentially reducing the resonance from the pump pulses to smooth out the fuel flow to the injectors?

Or am I now that "Quack on the Interweb" for suggesting it?

It's a good question and it is not something that is of great concern generally speaking. Fuel dampeners were used to keep pressure steady during injector firing on PI cars. Large volume rails as well as fast rail pressure regulation (this is done via a solenoid and spill valve on the HPFP) generally take care of this quite well. On top of all this the injectors in DI motors are open for less time than PI injectors having less of an effect on the overall flow of fuel from the rail.

The concern with the HPFP is dropping rail pressure which you can monitor live or in datalogs. Dips in pressure during WOT indicate that at that particular RPM the fuelling demands exceed the flow capacity of the HPFP. Fuel pressure drops if not very severe are indications that you are approaching the edge but the injector opening time will widen to make sure AFRs are met.

 

[Dirtleg]

Alex's post is still there for me.

What do you know. Now it's back. I better go do something else for a while. Things are getting strange around here.

 

[Juben]

What do you know. Now it's back. I better go do something else for a while. Things are getting strange around here.

I think it's the mods doings.

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