motorheaddown

My build is close to completion; so I wanted to share what I've done for the fuel system. When the car is done, I'll post the full project after achieving my objectives on the dyno.

My goal on the fuel system was to have a reliable setup that was quiet and capable of 1000 rwhp on E85. Additionally, I didn't want any fuel components in the trunk area; everything had to be either in the tank or under the car. Also, all components had to be E85 compatible; so, the fuel lines are either PTFE steel braided or Gates submersible.

First, I upgraded to the Walbro 450 lph pump and installed two in the tank that are y-blocked to an 8AN line. Note, use PTFE heat shrink tubing when rewiring the Walbros:



I used about 7" of Gates submersible line to create a service loop to clear the sending unit arm for its full range of travel:



Next, I replumbed the tank with PTFE 8AN feed and return lines. This required welding in two 8an bulkhead fittings. Note, I removed the fuel tank from the car and had an expert welder do the work. As a safety disclaimer, you MUST fill the tank with water to prevent the fumes from igniting.

This is the view from below:



And routed around the differential to the rear of the car:



Here are the feed and return lines inside the tank:



I routed the return line around to the back of the tank in front of the sending unit but clear of the float arm and dumped the fuel return into the back of the slosh bucket. You can see it at the top of this image:



The pumps are combined in a y-block and connected to the 8AN feed line. The line in the back is the return line.



The fuel feed line goes to rear of the car where the spare tire cavity was. Obviously, I cut out the spare to make room for the filter and remaining fuel system components:




The outlet of the fuel filter goes to fuel rail. So, this setup will support at least 850 rwhp on E85. Since my motor will make over 1000, I needed more fuel than what the Walbros could supply. So, I augmented the system with a Magnafuel 4303. When it's time to run nitrous, I'll simply reroute the Walbro feed line from the fuel filter to a sump tank that feeds the Magnafuel pump:



In both configurations, the sump tank is fed by the fuel return line as well, and the overflow (back side of sump) is returned to the main fuel tank. The return line also has a flex fuel sensor installed just prior to sump tank.

Admittedly, reconfiguring the fuel system is somewhat inconvenient, but I'll only run nitrous at the track. Plus, it only takes a couple of minutes to move lines around. The feed line coming from the tank is long enough to attach to both the filter and the sump tank; a different feed line is not required. Then it's simply a matter of adding the line between the Magnafuel and the filter. FWIW, the empty space to the right of the Magnafuel is for a second 4303 and sump tank just in case I decide to slap a monster turbo on the car. Or, I'll upgrade to a Weldon.

Those are the cliffs as I skipped over many details, but I think you get the idea. Basically, I run two Walbros on the street for boost only and then reroute the feed line to a sump tank that feeds a Magnafuel pump when adding nitrous.

Thanks,
-scott

CatManD3W

iTrader: (18)

Awesome writeup.....Im sure alot of other member will appreciate this.....

GTX580

iTrader: (3)

Awesome writeup. Just the info I need. Im buying a spare fuel tank and attempt to tig it myself.

SSmith

iTrader: (7)

Awesome set up and the work looks unbelievable. I will say it might be a bit overkill for what you needed at that horsepower level. Great job though.

Shane

t2d2

iTrader: (8)

I'm blown away that you were able to do all that work through such tiny access panels to the tank. Super clean work!

BTW, if anyone wants a cheap tank to try mods like that on, I've got one that leaks at the supply line at the bottom where the triangular shaped piece's weld spots pulled away. If you've got the ability to do all that other welding, that probably wouldn't be too tough to address.

motorheaddown

I appreciate the kind words from all who replied.

As mentioned above, the dual Walbros are good to at least 850 rwhp on E85. However, they probably won't get me to 1000 with margin; that's why I added the Magnfuel. Even then, I doubt the Magnfuel is good beyond 1200 rwhp on E85; so, I don't believe it's overkill. I simply want plenty of fuel for now and the future should I decide to go with a big-frame turbo.

Even if I went with the Magnafuel all the time, I'd still prefer to sump it; so, at least one in-tank pump is required. Adding a second Walbro was a no-brainer; plus, I'll use them 99.9% of the time except at the track. It dawned on me that I could have the best of both worlds by laying in the feed line next to the fuel filter and the sump tank.

FWIW, I hate dealing with fuel systems because it seems most set-ups (including my old one) are never reliable or adequate for growth. I believe this fuel system addresses both issues. Problems solved...

Thanks,
-scott

lexforlife

iTrader: (7)

2 of those 416 and id 2000 will do 1000on e85. ..a few buddies have done so at around 88%dc.

motorheaddown

That's good to know.

I only post numbers for things I've accomplished or direct personal friends who have dyno'd their cars. So, that's why I listed 850 and1000, respectively. I don't know what the upper end is for either setup, but I know I'm safe with margin to those numbers.

Thanks for another data point.

-scott

motorheaddown

Here's an update. After getting some time on the Wabro 450s, I took a look in the tank with the fuel pumps running, and this is what I discovered. The secondary pump was leaking.


It's leaking under the plastic barb assembly; so, I'm glad I found it. I was never a fan of plastic barbs; so, I ditched the Walbros and went back to 2 Densos. Plus, the Denso pumps accept PTFE lines directly over the barbs which means there's no rubber lines anywhere in the fuel system.

I also added a bypass value to switch between the Denso's and Magnafuel pump without changing lines. Plus, they all 3 feed a huge Y-block. So now, everything is plumbed in place.


​​​​​With the bypass valve and a flip of a switch, I can run two Denso's to the fuel rail, or two Denso's feeding the Magnafuel, or all three pumps feeding the fuel rail together. That'll make it good for 1500+ whp even on E85. On the street, I normally run the Denso's, only, so, it's nice and quiet. And those pumps provide enough fuel to make 850 whp on E85 all day long.

Thanks,
-scott

motorheaddown

I think you took my quote out of context. The disclaimer was only for welding the tank. The tank can't be welded empty; it must have an inert liquid or gas to keep it from combusting.

As far as corrosion goes, just cycle pump gas through every so often, and it'll be fine.

Thanks,
-scott