Aux fuel... Why has no one just made a high flow fuel pump?

I see all these aux fuel systems coming out but why has no vendor just made an aftermarket fuel pump and injectors (if needed). This is my first newer car (use to old foxbodys and my srt4. But I mean if an almost 30 year old mustang can run e85 with just an upgraded fuel pump and injectors. What is stopping us?

The fact that these cars are direct injected, and bolt in replacement injection pumps of higher capacity are either nonexistent or very hard to come by. From what I read in another thread here, stock direct injectors are generally capable of considerably more power than the hp rating of the engine they're installed in. Despite this, bigger injectors are available for our cars. Which then leads us back to the pump...

From what I understand the stock HPFP in our cars cannot really be upgraded, and it would be a huge undertaking for a company to produce a new one that would still be limited by some other factors. I don't really know much about it but I remember reading about this a while back. I'll see if I can find the post I'm referring to.

Tune+ said:

The pump doesn't share share it's same design with any other vehicle. It's one of the few HPFP'S on the market that is oil fed, and it is fed with a feed line. It does come apart, however there is nothing to be upgraded or changed in its current housing. Max pump lift is being achieved and the factory camshaft is 4 lobed instead of 3 like most vehicles in this family.

The current cost of a production run of an upgraded fuel pump is 300k for roughly 650 pumps. That is cost, you'll have to mark up to make it worth your while and nobody is going to ever sell 650 upgraded HPFP'S that will still have a limitation due to factory lift height. You would need to pair it with an upgraded exhaust camshaft with a larger lobe lift height in order to get more lift out of the pump, or even more duration. A lot of R&D will be needed, and it won't be cost effective as there are already port fueling options available and more to come.

There is a billet upgrade that is being tested but the company doing the testing is going to shit the bed for sure when I comes down to making power.

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http://www.mustang6g.com/forums/showthread.php?p=1140884

I wonder if someone will make an adapter plate or something to mount a bigger pump onto our engines, one that moves more fuel per stroke than the stock one does. If such a pump doesn't use forced oil feeding, then cap the line off.

So basically at some point when cost comes down there will be one.

Slow89 said:

So basically at some point when cost comes down there will be one.

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The pump is driven by the cam. Ours is a 4 lobe design without much lift. Any replacement pump will likely also need a corresponding cam to go with it. Changing cams is not easy on these cars either.

Slow89 said:

I see all these aux fuel systems coming out but why has no vendor just made an aftermarket fuel pump and injectors (if needed). This is my first newer car (use to old foxbodys and my srt4. But I mean if an almost 30 year old mustang can run e85 with just an upgraded fuel pump and injectors. What is stopping us?

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there are higher flowing DI Injectors on the market already that flow enough to empty the rail since the OEM HPFP can not keep up.
So they are basically useless at this point
As far as an upgrade to the HPFP, that's a tall order due to its sealed design. Much different than the VW and Mazda applications that allow for internal upgrades.

There are opportunities to upgrade the OEM in tank low pressure pump (that feeds the HPFP) but due to the limitations of the HPFP, there hasn't been a need.

If you are tapping into the low pressure fuel feed to supply fuel to a nitrous system or aux fuel rail you may need to upgrade the low pressure pump at some point.

This hasn't been an issue from our testing so far but it's a factor to consider.

The best solution so far is adding a dedicated fuel system for aux fuel or nitrous so the entire OEM fuel system can function on its own.

I'll be posting some installation pics and experiences here really soon - stay tuned:cheers:

The key is to just leave it be for now until the tech catches up.

I've reached the maximum limit of the stock in-tank pump already with a 5558 and E85. I'm putting in a full returnless system using twin Walbro 465's much like the 1000hp systems on the GT's. The only difference is I'm using a 4 port regulator to feed the HPFP and aux rail.

Once it's done the car will gain much of it's volume from the aux and that should allow the DI system to fine tune the mixture.

The EBM is at a weird spot. Lots of new stuff coming, some of it is going to work, some is going to be trash. But if done carefully there will be BIG things coming in the next 6 months. The shit is about to get realish.

Slow89 said:

I see all these aux fuel systems coming out but why has no vendor just made an aftermarket fuel pump and injectors (if needed). This is my first newer car (use to old foxbodys and my srt4. But I mean if an almost 30 year old mustang can run e85 with just an upgraded fuel pump and injectors. What is stopping us?

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Because making a HPFP to support is a $300,000 project. There is only one company that is going to put that amount of money into it, and unfortunately I can't disclose who that is just yet. I should have the unit in my hand next month and testing finalized by the end of June but there are a few drawbacks.

- Upgraded HPFP is limited to a very small space, you can't make the pump very large because of the engine bay constraints. If you look at the HPFP on your vehicle right now it is about .500" away from the firewall.

- Upgraded HPFP is also limited to the exhaust camshaft. The factory unit is almost at max lift inside the pump. So even upgrading the lobes on the exhaust camshaft that stroke the HPFP you aren't going to get increased flow. So if you make a HPFP that allows for more stroke/volume of fuel to be moved you are going to have to upgrade the exhaust camshaft as well to increase the lift height to take advantage of the new stroke.

- Direct Injected engines are designed to flow LESS fuel, that is the benefit of going direct injected for manufacturers as it gets better MPG and has a fuller burn which results in less emissions. So if you increase the amount of flow needed to support flex fuel you are going to start having fueling issues inside the combustion chamber, and in order to control it properly you are going to have to redesign the piston to allow for fuel control during a injection stroke. The current piston in these engines would not be efficient.

- The above point is really targeted towards a high horsepower build, say 500whp+. So even though there is going to be and upgraded pump possibly in the future it is going to be limited to stock turbo's and maybe some stock frame upgraded turbo's. I'm going to take a shot in the dark and say issues will start arising around the 420-430whp mark, and that is if we can even get enough flow out of it without changing the camshaft.

In the end, using the factory direct injection system to handle idle, part throttle driving, and transition is the best way to go in my opinion. Big horsepower cars need mega fuel and allowing it to come into the cylinder already atomized is going to be much more ideal for someone looking to make good numbers.

Interesting, I would have assumed that keeping as much fuel as possible delivered through the direct injection system would be ideal. So, if I understand what you're saying correctly, the greatly-increased volume of fuel needed for really big power will cause the burn to happen in ways that are not optimum due to the combustion chamber shape being designed for much lower volumes of fuel? Perhaps someone will design pistons to correctly handle that and release them to the market. One other question: If the stroke on the existing camshaft lobe pretty much maxes out the travel of available pumps, what about increasing the bore? (I assume a piston is being acted upon inside the pump.) A pump with the same stroke but bigger bore would obviously be able to move more fuel.

In my limited opinion I would say the volumes needed to support big HP would be better provided via port injection. You get exactly what Adam talked about- well atomized fuel.

Key to making power is getting the fuel to the chamber as a liquid (droplet) and allowing it to vaporize. Getting the fuel well mixed makes this much easier to accomplish with PI. A DI motor would be concentrating a larger mass of fuel right into the cylinder with little time to really vaporize much of the liquid.

If I could ditch the DI I would....

higdominator said:

In my limited opinion I would say the volumes needed to support big HP would be better provided via port injection. You get exactly what Adam talked about- well atomized fuel.

Key to making power is getting the fuel to the chamber as a liquid (droplet) and allowing it to vaporize. Getting the fuel well mixed makes this much easier to accomplish with PI. A DI motor would be concentrating a larger mass of fuel right into the cylinder with little time to really vaporize much of the liquid.

If I could ditch the DI I would....

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You said it right there. I would kick it immediately if I could.

v8440 said:

Interesting, I would have assumed that keeping as much fuel as possible delivered through the direct injection system would be ideal. So, if I understand what you're saying correctly, the greatly-increased volume of fuel needed for really big power will cause the burn to happen in ways that are not optimum due to the combustion chamber shape being designed for much lower volumes of fuel? Perhaps someone will design pistons to correctly handle that and release them to the market. One other question: If the stroke on the existing camshaft lobe pretty much maxes out the travel of available pumps, what about increasing the bore? (I assume a piston is being acted upon inside the pump.) A pump with the same stroke but bigger bore would obviously be able to move more fuel.

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I'm speaking in terms of E85 only. The pistons I designed for a customers engine has some changes with this exactly in mind, but a little different as most of the fueling is coming from my AUX fueling kit.

In regards to bore, that is more or less the route you have to take, increase the VOLUME of the pump itself without increasing the external dimensions. I mentioned above that I am testing an upgraded HPFP for the Ecoboost Mustang in the near future, just waiting on the manufacturer to replicate the same unit more than once.

Stupid question. Why can't an electric HPFP be made? Or belt driven?
Just a quick search I found where high HP diesel applications add a second HPFP to allow for more volume of fuel while keeping pressure where it needs to be. The article I saw showed the 2nd pump to be belt driven.

Picture is a diesel application.