SLC fuel system

This is what we came up with on the fuel system. I think it is typical for the LS set up although I think I lost my mind when I emptied my Bin of 90 % of its AN fittings to do an all braided system. I have done it this way for r&r of any of the components. I tried to keep things accessible. I will find out next week when we put the body back on to check clearance for the rear bar how I did..............
slc fuel system 001.JPG
slc fuel system 002.JPG
slc fuel system 003.JPG
slc fuel system 004.JPG
slc fuel system 004.JPG
 

Scott

Lifetime Supporter
Malon,

It looks good. The location of your components is similar to mine. I suggest you consider installing a close out panel between the gas tank and the engine compartment. This will mitigate heat, noise and fumes entering the cockpit.

How are you planning to service the pumps and filters next to the fuel tank? Once the spider is on, you'll find it extremely difficult to do from the engine compartment. If you have a race car, it's easy to do from the cockpit. If you have an interior tub, you'd have to tear the car apart (i.e., seats, spider, cage, tub and close out panel. A simple solution is to cut an access panel into the floor as discussed in this post.
 
Thanks Scott. The one picture I took from the cockpit towards the engine compartment. I do have an access panel so I can get right to the pumps from the inside of the car. I do not have one of the later interior tubs that rcr offered so I at least don't have to worry about access problems with it We will see how easy things are to get to. I also have a panel for getting to the fuel sender and would be able to replace it if necessary..........m
 
Your pumps are located higher than their pick-up points coming from the main tank and the surge tank. These pumps generally like a little bit of head pressure otherwise there's risk of cavitation/overheating. Once the fuel level in your main tank falls below your low pressure pump it's going to have to start sucking/siphoning the fuel out of the main tank. Your high pressure pump may have some initial priming issues but once things are filled you shouldn't have a problem there. If there will be long periods between drives it *might* be possible for you to lose enough prime that fuel would drain back far enough so the HP pump's no longer fully primed.

I'd always be worried about having a low tank of gas and premature failure of the pumps - and you already know what my luck is with pumps! :(
 
Thanks Cam. I agree on the head pressure for the pumps and I realize these are pushing pumps [electric] not the old style mechanical pull style pump, as usual when I set these up it difficult to get the pumps as close to, and below the tank level for best performance my intent is to always try and keep at least 1/2 tank of fuel in the system which should give me the head pressure enough to keep the pumps in good standing. With the design of this system I think enough fuel should loop back to the tank keeping things cool but we will find out. I installed the shut off valve for the purpose of planning on the head pressure in the system in case or when any work has to be performed. I have read of your issues with this type set up and am aware of the changes you've made [thanks for posting that] I have set it up so if I have to change things I am hopping it wont be too difficult but we know how that goes...........m
 
its always ideal for external fuel pumps to sit below the level of fuel if the tank. As shared it prevents pump cavitation and keeps the pump primed. But in my experience its not as much of an issue as reported. My race truck has been running the same off the shelf walboro pump for 8 years. lots of offroad racers run the pumps the same way. My pump is a full foot higher than the fuel cell and it takes a few seconds with every start up to prime the pump. the pump has never failed. the second pump is a back up. there are check valves in the system so if one pump fails the computer switches to the second pump. they can also be cycled manually and can both be ran at the same time if desired.

Also note that there is no surge tank on this race car. one pump does all the work all the time.
 

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Dusty I understand the idea behind this fuel system design and it does make since to me but I have wondered if it is completely necessary. In all of my race cars I run single electric fuel pumps, they are all carbureted and I have never had any issues with any of them while racing or playing at the track. I run two pumps on my gt's but that is only because of the separate tanks. The slc is the first true fuel injected LS engine I am running so I am a little in the dark on what exactly I needed for the fuel system. I went with what others have tried and run, it makes since to me to go off of what they have used tested and learned. I look forward to your build and when you get to the fuel injection set up do share it! I am always looking for better ways to do things. I shocked myself with my use of army/ navy fittings on this one it set a record for me!................................m
 
surge tanks work and are reliable. yours looks clean and well constructed. These surge tanks just seem overkill to me and there is nothing wrong with overkill. That said, the end goal is to maintain constant fuel pressure even when fuel is sloshing around. It can be argued that there are simpler ways to achieve this goal. In tank solutions like baffles, well placed pickups, sumps, hydromats, and the like can accomplish the same thing without all the hoses, motors, wires and space used by surge tanks. surge tanks used to be more of an item in the off road race world but have been less of an item as newer technologies and engineering evolve.
 

Howard Jones

Supporter
Ya, I agree with Cam, move the pump to the floor of the compartment so that gravity will keep the pump full of fuel on startup. I think the pump will last longer that way. Easy to do now. Otherwise that really looks like the business!
 
...In tank solutions like baffles, well placed pickups, sumps, hydromats...
That's my plan next time I have the spider off. Put a sump in the bottom of the tank, add a few baffles, put the pressure pumps (2) in the tank with hydromat pickups. I'll probably extend the tank to fill the left side that is not used for plumbing.

Will simplify things noticeably.
 
I have mounted a lot of electric pumps in the best location possible and most of the times they seem to end up higher then the lowest point in the tank. The only times I have had a problem is when I am on the track and not kept enough fuel in the tank for that last hard session, these were all carbureted and no injected motors. I have never done this during an actual race because I am to anal and always make sure to top off the fuel to avoid this when it really mattered to me. Its nice to see the different ideas and opinions and I agree that a sump and baffles in the tank would be very beneficial because I am pretty sure injected motors don't like fuel starvation at all, but at this time not practical w/o a lot of extra work, so I have gone with a basic system. I run fuel cells in my fender to fender race cars for safety of course, and if I decide to go crazy with this car the fuel system is one of many that will have to be re-visited to do competition with it. Like Frank, I would like to simplify things. I know after some track testing because Howards is right, I should never drive this thing on the street to even near its potential. Changes are inevitable..................................
 
I would love that! Have looked at it several times. I have also been invited too run pikes peak hill climb but haven't [yet] been able to pull that one off.........................m
 
We went and watched Pikes Peak this year as we've been thinking about running it - though not in the SLC. We decided against it as it is a year of prep and then weather can stop you from having a run, or at least a dry run. We would have build a one-off car for it, so a LOT of work and testing to get ready. I say "we", but it would have been me paying the bills and doing 90% of the building with my son doing 90% of the engineering and 100% of the driving.
 
We are north of pikes peak and I know lots of people that do run it Frank. They seem to all say the same thing you are down there for a whole week you only run the whole course on race day, practice is broken up to three separate days with three separate sections and they say plan on 10.k to run it with the car already done and no major issues. I am retired now and it is still on my list, hopefully logistics will work out and I can make it happen at some point. They are going to start limiting entrance as my understanding is the run groups are full and more and more people want to try it now that it is fully paved.........m
 
I used to have a problem posting my work [pictures] but it seems they have made it a lot easier. nice work though John...........m
 
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