I received the new updated fuel tank for my 818 and the design and instructions seem like an afterthought. Here are some issues I had with the process so far.
They provided no bolts to hold in the OEM pump and level sensor.
The subaru uses 2 level sensors in the tank and the area they are to be reused makes the level sensors sit on top of eachother and not work. I had to modify the mounting holes and flip the sensor around to point in a different direction in the tank.
There are no mounting tabs on the new fuel tank. So there is no way to secure it to the frame. The new firewall they provided holds down parts of the tank, but if the car were to release enough load on the suspension I feel like the tank would be able to move.
I am making some straps to tie down the tank as well as some rubber padding to prevent rattles.
Anyone with the new tank experience anything like this yet? I haven't seen many posts of people who have installed it yet. I will update as I complete the tank installation with any tips.
RE your second point, I was planning on just rotating the stand-alone level sensor to where it wouldn't interfere with the other one built into the pump, and bending the arms as-needed to get clearance, but I saw the same thing.
I agree on the mounting issue. I am going to weld angle brackets to it that will allow me to bolt it to the steel tube frame but I know that isn't an option for everyone. If that's not an option, I would suggest using a good strong adhesive on the bottom of the tank.
Can't offer more than that though as you are further along than me! The only other thing I noticed is that for my donor (2007), the fuel pump bracket is actually taller than the tank will allow for. Not much... just 1/8". I'm planning on bending the fuel pump bracket just a bit to get the top to sit flat on the flange.
Mine didn't come with bots either. Available at Lowes for cheap though.
I know the floats sit close to one another, but when there is fuel in the tank, will they interfere? I just quickly looked and tried to fit my small hand in there and it seemed like they will be fine when they lift off.
My fuel pump bracket was also slightly taller, but when I tightened all the bolts it went flat, I guess it won't be moving around much in there...
Another change that is required for the new fuel tank is that you can't run your brake and clutch line next to the tank as outlined in the manual. You will need to run it like Mike Everson did on the outside and over the rear trailing arm mounting. I would also recommend making sure that the radiator tube and hose is at least an inch or two above it.
I decided that I am going to weld the entire firewall as a solid piece. I already welded some tabs on the back of the firewall panel to keep it rivet free.
One thing is that the panel on the passenger side fits very tight on the floor, so don't put your weather strip too low on that side or you will just scrape it off with the firewall when you press it down.
Thanks for sharing your experience. I picked up some bolts at Lowes and they seem to work just fine.
I don't have access to a welder for the firewall but I think that is a great solution.
As far as the floats, if they are sitting on top of eachother won't the readings be off as the tank begins to empty and they start to touch again? Your gauge may go from 1/4 full to empty once they touch. I'm not 100% on that though bc I don't know exactly how both inputs work together on the float.
Thanks for the firewall advice. It looks like a very tight fit already so I am going to put down padding where I can.
As far as securing the tank I have changed my plan and I am going to strap it down using seat belt material from the donor. Since we only use 2 of the seat belts I figure the other ones can make a good strap.
I am finishing the tank this weekend so I will post up how it goes.
Summit sells metal gas tank straps that are universal. I would recommend that as it would be easier to secure without chances of seat belt fraying or getting sliced on a sharp edge. They're cheap too.
I read in another thread where someone is adding a breather to the top of the tank. Soon as I saw this it struck me. The filler pipe is lower than half a tank and there is no other venting available after this port is covered with fuel. I know the instructions say to cut off the venturi line making this a vent line. I plan to use this connection for the third pipe on the engine fuel line trio. Just for fun I tried to blow into this vent line on the engine and could not generate any flow. So I am not really sure how this Subaru engine "vent" line is supposed to work. If it wont flow air with the engine off while we are filling the tank then it will be impossible to add fuel above the point where air trapped in the tank overtakes the weight of the fuel trying to get in. The point is we will need to add an air vent. My kit included a brass vent with check valve that looks like it was intended for this purpose. However the tank has no provision for installing it. This weekend I will try to drill and tap a mounting location into the (smaller) fuel level cover. If this works I still need someplace to vent the hose. Others have welded a bung to the top of the fuel filler pipe. This works great while filling the tank but - Is our fuel filler CAP breathable? I doubt it. So as the fuel level drops there is the potential for low air pressure and fuel starvation. It seems like a small thing but proper engineering by FFR would save us many hours of trial and error as we find and solve these issues. Clarification from FFR would be appreciated.
You don't need to worry about the filler pipe being lower than the top half of the tank. Liquid is self-leveling. As the level in the tank passes the top of where the filler neck connects to the tank, the gas you continue pumping into the filler neck will not be displacing the air in the filler neck, instead the gas in the tank will rise. There will be some displacement as the overall level of fuel rises (the level in the filler neck will rise at the same level as in the tank.... probably 1/4" per 10 seconds or so), but it is so small that the air will escape past the filler nozzle.
Cutting off the venturi line will make a workable breather. I've tested it on mine. You said you blew into this vent line on the engine and couldn't move any air. Are you sure you had the right line and was it connected to anything else? Did you try just connecting some hose to the venturi line on the pump top and blowing into that hose? It works fine on mine. You can see how I routed that vent line to a home made charcoal can. The vent line is small though.... you aren't going to displace enough air through it to solve venting issues while filling. That's why I and others added a larger diameter vent specifically for filling and it just vents out the filler neck (note that this vent only works when the gas cap is off and you are filling the car - it is not intended to be anything other than a filling vent). The "venturi vent" allows enough venting for temperature expansion/contraction and for adding air to the tank that's displaced by the fuel your engine consumes. With the new tank, you can make two vents by using the metal line on the second fuel sender as a vent as well (would require you to cut it off just below the pump top like the venturi vent).
You are right; there is no place to install the FFR provided vent/rollover valve. There was on the old tank. They need to just stop shipping them with the new tank since they aren't compatible. I added a 3/8" inline rollover valve in the vent line on mine (from the venturi vent). Details in my build thread.
The fuel cap is not breathable and you don't need it to be with a working vent line.
TL;DR:
- The vent off the new pump top works fine as the main vent
- The added vent I and some others have added (connects the top of the tank to the top of the filler neck) is only for fast-venting while filling and is not intended or needed to vent with the gas cap on
- The low connection point of the filler neck to the tank is not an issue
As I understand the Subaru fuel system the top pipe is for pressurized fuel from the fuel pump. The middle pipe is for unused fuel return to the tank, and the lower pipe is labeled vent. If I blow or suck on any of these I do not have air flow. I hesitate to discard the vent pipe as it must serve some factory engineered purpose. So connection from my OEM fuel pump cover to these 3 pipes leaves me without a fuel tank vent into free flowing air. I suppose I could TEE off of the vent line to a free air location such as a charcoal canister. The second (smaller) OEM tank cover has a pipe which supports the fuel level sender. I cut this short but it still gets covered with fuel several inches from the top of the tank. I'm thinking an additional vent is required.
The third (lowest) pipe goes back under the intake manifold to the egr valve. I think on the wrx it was plumbed into the charcoal canister. If you remove the egr valve you will be able to blow through it.
One other thing with the new tank/firewall is that there is also a new tunnel cover that I didn't receive. I'm guessing they sorted that on the later kits but when I received the new tank/firewall it didn't come with the new tunnel cover. I emailed Vinny and found out about the new tunnel cover.
The third (lowest) pipe goes back under the intake manifold to the egr valve. I think on the wrx it was plumbed into the charcoal canister. If you remove the egr valve you will be able to blow through it.
One other thing with the new tank/firewall is that there is also a new tunnel cover that I didn't receive. I'm guessing they sorted that on the later kits but when I received the new tank/firewall it didn't come with the new tunnel cover. I emailed Vinny and found out about the new tunnel cover.
You have to modify the pump assembly.
See page 64 of 818 manual rev 1o
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Originally Posted by NBinSD
