I've threatened for some time to post a thread on my new fuel system, this time with photos. I spent the holiday weekend building my new fuel supply system. 12 years ago I built a high G system using two pumps and a reservoir. I was never happy with the design. It was bulky and I spent alot of time re-engineering it to correct flaws. The new system provides all the benefits of a high G system with a single pump and simple plumbing. The system is more than this engine needs, although running 70psi rail pressure, the large pump is necessary. This system will serve the fuel needs of the 550hp 406 that I plan for the near future.

As you view the photos, you may notice the sump hangs a little low below the rear cargo pan. Ground clearance is 6" below the sump. I do plan to redesign the sump, making it 1.5" shorter, or 1.5" higher as the case would be. I'll need to relocate the fuel return to the side of the sump instead of the back. I'll probably tackle that job the weekend after next.

EDIT: You may notice my temporary exhaust. It was intended to get my by while I work out the new dual 2.5" system. The muffler is one of the powersticks that will be used with the dual exhaust. As is, this is way too loud for the street. I'll have to do something with it before I can drive the car even temporarily.

 

So no feedback at all? I thought I'd at least hear something about it being so low to the ground. I guess if it really sucked someone would have said something.

EDIT: After some careful consideration, and kicking myself for rushing the design process, I have decided to take about 2" off the depth and move the return to the side. The return will still feed back into the sump, but be further above the baffles, near the top of the sump. The redesign will fit the body much better and should still function the same. It looks like I've got plenty of clearance for the exhaust. I was thinking of notching the front of the sump to make more room if needed.

 

I actually think it's a really neat idea. Why would you need something like this though unless you're running Autocross? I can't, other than a "This is neat", see why I'd need a high-G system? What did you foresee needing this for when you built it?

 

Very nice work, but I also feel it's a solution looking for a problem. What do you intend to use
the car for that would require this setup?

 

Thanks guys for the feedback. I built this sump system to replace a bulky lift pump/pressure pump system that I built 12 years ago. This car has always had an issue with fuel cut off during hard cornering anywhere below about 1/3 tank. My 84 HO and 82 TA had the same problem. The chassis and suspension upgrades I did 15 years ago in the original build only made it worse. The simple solution is to sump the tank. Now it has a single pump, feed and return lines. Neat and clean. Another valid reason for this mod is that I'm OCD and can't help myself.

This weekend I revised the sump, removing 2" of depth and gaining 2" ground clearance. I moved the return to the side where it will still be above the revised heat shield that will find its way back on the car when I get to it. I also did a better job of venting the tank, using the original 3/8" supply tube, notched just below the lid, and the tube that had gone to the tank pressure control valve. The connect to 3/8" hoses that follow the fill neck and have filters.

I also got Dyno Don's Y-pipe installed and my temporary exhaust is now dual glass packs, the cheapest available from Summit. They remove and install in a few minutes which will make it easy to button things up at the end of a day fabricating the new exhaust. The new exhaust will also be designed for quick easy remove/install for ease of under-car service.

BTW, sorry the car is so filthy underneath. I live on a gravel road in farm country. Also, I would clean and paint the rear axle but I plan to replace it soon.

 

Being a retired aircraft mechanic, I'll bring up using a coarse foam inside the fuel tank as a way to keep fuel slosh to a minimum. We use it in military aircraft wing tanks to reduce the chances of a tank explosion from enemy fire, but it was also found to minimize fuel slosh in the tanks.

 

MSgt, I know about the foam. Racing fuel cells are generally filled with it. I had considered it for this car but installing it would probably have required cutting open the tank. At that point, the sump is no more or less difficult.

One other thing I want to bring up. The revised sump provides good ground clearance. The filter and supply line however still bother me. I'm going to work out a new design for that so it doesn't hang down below the pump. Generally though, I am very pleased with the how the system turned out.

 

I reworked the supply line today to fit in front of the pump and sit higher. I had looked at using a 90 on the sump outlet when I first redid the sump but at that time, I couldn't see how it would work. Today, I spent some time measuring and test aligning the hose ends and filter to the pump and sump outlet. You can see in the photo that I ended up with a pretty good bend in the short lengths of braided hose. Fortunately, while the braiding makes the hose fairly stiff to bend, it also prevents collapse. So, the hose maintains a large flow path through the bends.

I'm now much happier with the result. You may have guessed that I am very much OCD. I had great plans of getting this system just right the on first shot. Well, that didn't work out so much. However, like most prototypes, it is getting closer to where I want it with each adjustment. Some time soon, I'll modify the heat shield to go over the sump and button things up, then finish the exhaust. The one thing I was wishing today was that I had used an AN-10 male weld in bung at the sump outlet rather than the pipe bung with AN adapter. The AN-10 bung would have been much shorter so the 90 doesn't have to protrude so far out and down from the sump. Still, while the photo taken on the flat rack doesn't clearly show it, there is ample ground clearance. The filter hanging behind and below the pump was the one remaining concern that I had.

The photos below show the three stages. First design sump, new design sump with filter behind pump, new sump with filter tucked in front of pump.

 

I never did update this thread when my Aeromotive fuel pump failed. The pump in the photos is the Aeromotive A750. This pump has been through a tough life as part of my dual pump, reservoir system. It was run out of fuel, cavitated, and run low on power at least a few times each during its 9 years on this car. This is a very well made and durable pump that would work well for any engine up to 700hp running 45lbs rail pressure. Part of the problem it had in my system is the 70psi rail pressure that I run.

It seemed like, after the new system was finished, the pump would be okay. I ran a current ramp test on it with my labscope and current clamp and could see a little sign of commutator damage. But by the waveform, the damage looked minor. The current was high, 16amps@13.5V at 70psi and I knew from that the pump wouldn't be around for too long. It left me two and a half weeks ago. Drove the car to work and back on Monday. Parked it in the garage like always and the next morning the engine started and stalled as the pump died. Another current ramp test showed almost a total loss of contact on the commutator. One little bump of current each revolution. Once pressure comes up, the pump stalls and that's it.

I ordered the Fuel Lab 41401 to replace it. The two pumps look almost identical but the Fuel Lab pump is brushless(awesome) and has a low and high speed option(also awesome). With a duty cycle controller, like Fuel Lab's electronic pressure regulator, the pump becomes variable speed. The 41401 is a high pressure model rated at 125psi. It flows 105gph at 45psi and about 60gph at 70 psi. Current draw at 70psi looks to be about 9 amps. Tons of capacity for my future plans and an excellent design. In my current application, on the 355, I'll run it at low speed. When I install the 383 later, I'll add their regulator and go variable speed.

Fuel Lab is making these pumps to fill orders so I had to wait a bit to get mine. Heard yesterday that it was shipped and should be here by next Tuesday. Just in time for NAPA Day at the Drags on the 12th.

 

Fuel Lab 41401 pump got here today. It installed quick and easy where the A750 came out. Even fit in the same brackets. Note the yellow terminal with 18 ga wire connected to ground. That is speed control. Grounding it puts the pump in low speed. Even in low speed it's alotta pump.