Dual feed ideas.

[Remps]

If a 12 valve producing 450+ horsepower is being fed (a potential) 150 lbs/min of air at 50-60 psi from compound turbos, but only actually requires 65-75 lbs/min to make 450+ horsepower, could excess volume/pressure be used to run an air over hydraulic case feed pump? Or possibly an air over hydraulic boost pump? (As of now unsure of the volume of air required to run these)

Lets say it has a working air pressure of 40-125 psi, consumes 12 scfm, and can pump 40 cubic inches of fluid per minute at 500 psi with 40 psi input. Pumped fluid pressure is pretty much stalled out at 1 cubic inch per minute at 5000 psi with 40 psi input, not really important for a secondary relieved pump case, lets say a 300 psi secondary case pressure bypass, with it's own return to the fuel tank.

How much of a drop in boost at wot would one see using boost pressure to run a pump like this, and would one see boost returned (and maybe increased) by the extra fuel provided? I'd guess that doubling or possibly tripling the case pressure (from a setup with huge injectors) has to have an effect on fill time/volume in the plunger, especially at higher rpms.

Also the timing piston would stay pegged at full travel where it should be when wot at 2700+ rpms. With the factory fuel inlet/vane pump providing the volume of fuel, and with case pressure above zero, the case is full, it just needs a low volume/high pressure pump to maintain pressure.

Any and all thoughts and ideas welcome, good or bad.

[Remps]

[url]liquidpumpcatalog.haskel.com[/url] The pump selection wizard there shows two pumps capable of 1 gpm at 300 psi with 45 psi input, at 5 and 9 scfm.

[Begle1]

I'm convinced that the end-game on VE pumps involves dual-feeding the head and rotor with an auxiliary pump that can maintain the case pressure.

But intake air is just as precious a resource as fuel, it seems counter-intuitive to use charge air to pump fuel when you can use an electric or belt-fed pump instead? On paper you might have more air than you need, but in practice I doubt it'd be worth the sacrifice.

I have no experience with air-over-hydraulic pumps, what's the application of those?


In my garage is a half-baked repurposed Cummins ISX gear-to-gear fuel pump along with a spare AC clutch and custom bracket that should allow me to mount it in the stock air conditioning compressor location. That's the direction I was going, but I really just wanted an excuse to justify my being too lazy to fix my air conditioning.

[matthewh]

Could you run a 12v electric fuel pump, and regulate the output using a boost reference regulator? Would that give you enough fuel psi to feed/keep up with the case drop?
What's more important, feed pressure or volume? Seems if you could feed enough volume, could you make up the difference of a lower psi?

Idk alot about the pumps, or hydraulics, just bits and pieces I've picked up over the years.

I do remember a guy who was feeding his pump with a converted P/S pump, but that seems like way excessive pressure

[DMan1198]

I find myself in agreement with begle. Charge air, even if excessive is something I wouldn't sacrifice to push fuel. I would much prefer to utilize the powersteering pump (there may be a case to add the pump off a common rail, or a small car as they're belt driven if you wanted to retain your full power steering from your case mounted pump).

[Begle1]

With all this case pressure datalogging and injector flow calculations certain members are doing nowadays, we should know exactly how much pressure and flow we need.

You also want it to be COOL fuel.

[Remps]

Matthewh, that was member TurboRam, his 12 mm ve on a 24 valve setup was directly feeding the head and rotor, so I don't think the case was seeing 1500 psi. Not sure if he had the vane pump and pump case completely isolated.
I suppose an air over hydraulic setup would just act like a boost leak eh? Micropump.com has gear pumps and electric motors that would probably do the trick for feeding the case 2-300 psi. To me, this sounds simpler than a setup like turboram had, though it wouldn't likely make as much power, it'd have a little more fuel and a better timing curve than it would with the vane pump alone.

[79Powerwagon]

Would there be a benefit to a dual feed in an engine with less than 450 hp?

I have a gear/gear pump off of a 3406E , regulated to 80-100 psi, spring could be changed for more pressure but I don't know how far it would go...


*also - is case pressure dropping off on higher hp 12mm pumps? Or mainly an issue for 14mm's?

[DMan1198]

It's an issue with big injector 12mm pumps.

[79Powerwagon]

Thanks.


Slightly off topic from the dual feed,

I know nothing as far as increasing volume/psi out of vane pumps, but what if instead of cutting down the circumference of the rotor, one machined cut outs similar to my crude drawing? (Areas in black) more fuel volume? Or grenade?

[PToombs]

I don't think you would gain anything from that design. The key is the rotor is in an eccentric, as it comes around the fuel is forced out by the chamber getting smaller. Your cavities carry more fuel, but there is no way to force it out.
If the eccentric is larger, more cavity on the open side, that would push more fuel thru it.

[79Powerwagon]

I see what your saying.

*Has anyone attempted more of an oval shaped eccentric?

Back to dual feed it is.

[Remps]

I've heard of a few people supposedly attempting to modify the vane pump housing, I don't recall anything successful though.

[79Powerwagon]

Anyone think the vane pump would benefit from more input fuel? Is the stock input a restriction?

I understand there isn't much to open up in the inlet passage but there may be a way to feed fuel almost directly into the vane pump instead of just that L shaped rough passage( in conjunction with stock)

[Begle1]

The vane pump itself is a restriction along with everything going into it. Pushing more into the vane pump helps as long as you keep that front seal in mind.