MK4 on Order: Fuel System Questions

[Jim Doak]

I placed an order for a MK4 complete kit on May 10th. I selected several options with my order; however, I did not select Factory Five's EFI in-tank fuel system. (I plan on running a Holley Sniper 2 fuel injection system.)

It looks like the Factory Five EFI fuel system utilizes a 255 lph pump, a fuel pressure regulator, and a -4 size return line. It also includes a fuel filter and a charcoal canister.

I'm not sure of the quality of the fuel system components and a -4 return line seems somewhat small; plus, I don't need a charcoal canister.

Do you think I should opt for Factory Five's EFI fuel system option or should I build my own system?

Thanks.

[gbranham]

When I was planning my fuel delivery, I was left with the impression that the FFR-supplied pieces are a bit lackluster or perhaps undersized if you're going with something larger than a standard 302. I ended up building my own system, based on the research on the forum. I used a Walbro 255lph pump (which I think I may switch out to a larger pump, now that I've pivoted from Coyote to 427 small block), the Pro-M pump hanger with 3/8" -6AN feed and return fittings, stainless braided PTFE lines, and Aeromotive fuel filter and regulator. I'm building my own vapor can with charcoal and PVC, as many have done here on the forum.

[Mike.Bray]

Build it yourself, it's easy and less money. You don't mention what engine/HP so can't recommend an exact pump. The 255 l/hr most likely will work but there's a 340 l/hr also. Just call Forte, they can help you decide and supply a pump that literally just drops in.

-6 (3/8") lines are best. If you go ahead and run two lines from the pump to the engine compartment, supply & return, you will future proof your car in case you're like Papa Dave and one day switch the Sniper to stack EFI or something.

I used a Holley 162-554 10um inline filter but there are lots of good filters out there.

I believe the Sniper has a built in pressure regulator and I've not heard good things about it. I'm old school, supply the injectors with full pressure and regulate the return line. This gives the most consistent pressure to the injectors. Again there are a number of good quality regulators out there, Forte can help.

Happy building!

[gbranham]

Build it yourself, it's easy and less money. You don't mention what engine/HP so can't recommend an exact pump. The 255 l/hr most likely will work but there's a 340 l/hr also. Just call Forte, they can help you decide and supply a pump that literally just drops in.

-6 (3/8") lines are best. If you go ahead and run two lines from the pump to the engine compartment, supply & return, you will future proof your car in case you're like Papa Dave and one day switch the Sniper to stack EFI or something.

I used a Holley 162-554 10um inline filter but there are lots of good filters out there.

I believe the Sniper has a built in pressure regulator and I've not heard good things about it. I'm old school, supply the injectors with full pressure and regulate the return line. This gives the most consistent pressure to the injectors. Again there are a number of good quality regulators out there, Forte can help.

Happy building!

I agree with all of this, and it's what I'm doing. I have read the new Sniper 2 has dispensed with the internal regulator due to high failure rates, so I've built mine with the external Aeromotive regulator on the return line, as many have suggested here on the forum.

[JJK]

I do not disagree what others have said but wanted to mention a few additional things. I purchased and used the FFR EFI completion kit with my 347 Sniper setup. I was originally concerned about the -4 return lines, as many have noted as well as Holley, that the supply and return lines should both be -6. However, at the end of the day the EFI only wants two things from the fuel supply: volumetric flow rate and pressure. For the volumetric flow, the 255lph pump and -6 supply lines are sufficient for my engine. If I were using a 427 I am not certain that this would be the case as the pump may need to be bigger and the return lines may need to be stepped up to -6. My external fuel regulator mounts on the firewall and has three lines, the -6 supply, a -4 return, and a -6 deadhead line to the Sniper. The Sniper's return port is plugged so it only receives fuel from one of the inlets and does not have a return, the return is handled by the regulator. As others have noted, Sniper's have historically had issues with their internal fuel regulator, so I wanted the external for robustness. But, I agree that I think the Sniper 2 requires an external regulator. Another issue with the FFR system is the stock mustang fuel pickup, which is the most restrictive part of the system. I drilled out my pickup and return tubes to open them up a bit, but they are still smaller than the -4 return line. For a higher hp system with more fuel requirement, the Pro-M hanger solves this problem.
You can most likely cobble together something yourself for less money and bespoke it to your specific needs at the same time. But, for folks that do not have a lot of experience with this sort of thing, the FFR EFI completion kit is an easy and adequate solution for small to mid-range hp.

[Jim Doak]

Thanks for the feedback.

On my first build (2117), I eventually installed an in-tank pump with braided feed and return lines. Back then I had to adapt AN fittings to the hanger ports. (Kind of a hassle.)

I think I'll do as suggested and skip the FFR system and build my own. Like some others, I also read that the new generation Sniper 2 doesn't have an internal fuel pressure regulator like the original version did. (My first generation Sniper was somewhat problematic; I hope the current version is better.)

[Rebostar]

I strongly recommend you build the fuel system yourself. This way you can choose quality components that will work together. I did not install the EFI system, I'm running a 4150 Brawler 750 cfm carb. In doing the invantory I did not like the quality of ANY of the FFR supplied fuel system parts. I bought all quality parts from Summit and a couple other vendors.

Happy Trails
Allyn

[Buzzsaw]

I agree with the majority decision build your own system. The guys commenting before mme have done a good job of explaining the advantages. In regard to your choice of EFI system, you may want to look into the Edelbrock Pro Flow 4 system. It’s more expensive but I have never seen a complaint about the system.

[GFX2043mtu]

Call Glenn’s performance. He provides nothing but the best kits and parts at a very reasonable cost. His kits utilize carbon lined PTFE lines that dissipate static charge and will never seep fuel. His stuff is a once and done and it flat out works.

[Nigel Allen]

I built my car using the fuel lines, filter, as supplied by FFR, along with a 255lph Walbro in tank pump and standard hanger. I have a dash mounted (and calibrated) fuel pressure gauge. The pressure is measured on the firewall mounted regulator.
Running on the dyno, you can watch the fuel pressure (upper left gauge) in the attached video. Set point is 60psi as recommended by Lund tuning. Once rpm exceeds 4,500rpm the pressure begins to drop off. This run was to 6000rpm.
My winter project will be to go to 6AN lines, Pro-M hanger and a better fuel filter arrangement.

https://www.youtube.com/watch?v=BYSfEz3WX8g

As an aside, the fuel pump struggles with aeration when the Mustang tank is 1/4 or below. Braking or cornering will often see pressure momentarily drop to 30psi.

Cheers,

Nige

[JJK]

Nigel, your steering wheel is on the wrong side of the car AND you are driving on the wrong side of the street.
But seriously, did you use the FFR supplies hard lines or the EFI completion kit with flex fuel lines?

[Nigel Allen]

G'day JJK,

It certainly could be said that my car spends most of it's time on the wrong side of the road. Back when I received my kit, the fuel system consisted of the standard steel lines, plus the 'Coyote completion' kit, which added EFI hoses, clips and an barbed adaptor to interface to the coyote fuel rail.

[rich grsc]

I had the exact same issue with fuel aeration, the Pro-M hanger will solve that problem. Your upgrades are a good choice.

[CaptB]

Dump the FFR fuel system, build it. IMHO.

[Mike.Bray]

Once rpm exceeds 4,500rpm the pressure begins to drop off.

That's not good at all. EFI systems rely on the fuel being at a constant pressure, the ECU can only control the injectors with open time. It's why the pressure is regulated after the injectors and not before.

If the pressure is changing the amount of fuel being injected into the cylinder is not what the ECU thinks it is. In the case of the pressure dropping that means less fuel which means it's going lean.

[gbranham]

In regard to your choice of EFI system, you may want to look into the Edelbrock Pro Flow 4 system. It’s more expensive but I have never seen a complaint about the system.

This is pretty good info. I've been researching this system this morning, after I read your comment. It's actually cheaper in the long run than the Holley Sniper 2 setup, assuming you're building an engine from scratch like I am. By the time I buy the Sniper 2 system, the Hyperspark system, and an intake manifold, I'm at $2700. The Edelbrock system has all that (including the intake manifold) for $2260. Very compelling. Thanks for the info...I have a lot to think about.

[Mike.Bray]

That Pro Flow system is light years ahead of the Sniper. Save yourself future heartache and get the Pro Flow over the Sniper.

[gbranham]

That Pro Flow system is light years ahead of the Sniper. Save yourself future heartache and get the Pro Flow over the Sniper.

Thanks, Mike. I'm going to read up on it, for sure. Educate me...what makes it so much better? Is it's ECU just that much smarter?

[Mike.Bray]

Thanks, Mike. I'm going to read up on it, for sure. Educate me...what makes it so much better? Is it's ECU just that much smarter?

The Sniper is a brilliant idea, basically an electronic carburetor that bolts on to a standard manifold and with a few simple setup instructions you're ready to go. And with an O2 sensor it's self-tuning so your engine always runs perfect. And it's only about $1k ready to go. No wonder Holley is selling them by the truckload.

However, to do this Holley had to package everything in one box, kind of like the old stereo systems that had 5 or 6 different components in one box that all worked but none were great. There's the mechanical bits like a carb but also has 4 injectors, an ECU, TPS sensor, fuel distribution and pressure regulator, and other bits. The ECU is pretty basic as is the interface. And to keep the retail price down to around $1k they're not exactly throwing top quality bits into it. There are numerous forums on Sniper issues for a reason. To me you always get what you pay for.

The Edelbrock Pro-Flo has 8 port injectors, a separate ECU, more tuning capability, and the latest version can even be tuned from your smartphone. Everything about the Pro-Flo is a step up from the Sniper.

The next step up would be to build your own system with a port injector manifold (https://www.summitracing.com/parts/tfs-52400115/make/ford), a throttle body like this one (https://www.summitracing.com/parts/edl-4150), and a separate ECU like a Fast Sportsman or Holley Terminator (https://www.summitracing.com/parts/hly-550-943/make/ford). I'm running a Sportsman on a Borla stack system and I'm very impressed with it.

Kind of like Good, Better, Best

Hope this helps.

Mike

[gbranham]

Thanks, Mike. Very helpful as always! Much appreciated. I'm sold.

[rich grsc]

Mike, Borla 8 Stack & a Fast Sportsman.:cool: I really am happy with mine, love how strong it pulls.

[Mike.Bray]

Mike, Borla 8 Stack & a Fast Sportsman.:cool: I really am happy with mine, love how strong it pulls.

Same for me! Aftermarket EFI systems have come a long way from the old DFI systems I started with.

[Buzzsaw]

This is pretty good info. I've been researching this system this morning, after I read your comment. It's actually cheaper in the long run than the Holley Sniper 2 setup, assuming you're building an engine from scratch like I am. By the time I buy the Sniper 2 system, the Hyperspark system, and an intake manifold, I'm at $2700. The Edelbrock system has all that (including the intake manifold) for $2260. Very compelling. Thanks for the info...I have a lot to think about.

You’re welcome, and Mike Bray gave a good description of thr Pro Flow 4 EFI. I wanted a separate ECU that I could locate away from coil, distributor and any other interference. I also wanted real fuel injection and the multi port set up delivers it. I don’t know if the Borla 8 stack with the sportsman performs any better than the Pro Flow 4 but it sure dresses up the engine bay nicely. I hope to have the Borla setup someday!