Fast Fill Mod

jschildm · Jan 30, 2013

I purchased the F-SuperDuty Roll Over Valve from someone on this site, as well as some modified filler necks to do the fast fill mod. I got it installed last week and filled up the rear tank for the first time today (front tank is still full). It worked great, and I was able to have the nozzle all the way on (granted it was a slow nozzle). However, it ended up clicking off and I saw fuel in the neck (or at least foam). It wasn't as much fuel as I thought it would hold, but figured I would call it good. When I got in the truck, it said that it was only 3/4 full.

I know the back tank sits high enough that you have to be really careful with the breather hose routing. There might be a slight sag in it near the top of the filler neck, but not much. I am guessing some kind of sag is the problem, but it worked so well, and then acted full. Others that have done this, if you had a sag in the breather line, is this similar to your experiences?

Thanks.

kramarj · Jan 30, 2013

On our work trucks we have the TransferFlow filler necks and from what I understand, they do about the same job. Ours do the same thing unless you fill it real slow. Not sure if there is a fix, I got it to fill a lot better by running the breather higher, but still only fills to 3/4 most of the time. Might just be the nature of the beast.

old man dave · Feb 1, 2013

I have the TFI tank setup and my buddy has the do it yourself version. All of the tanks fill within the last 1/2 gallon or so without slowing down using the big truck pumps (wiith the big nozzles). You have to make sure the vent and fill lines angle at an upward angle. If it gets near horizontal, then it slows filling fast. The vent fitting on the filler neck is near the top so the vent hose angle is as steep as possible, the filler hose has no kinks in it.

PsRumors · Feb 1, 2013

After mine click off it will take about another gallon and it is a little slower getting that last gallon in but it but still much faster than stock. I have the transfer flow kit.

On the roll over valve, there is some extra plastic on the end that goes in the tank, maybe three inches or so. Did you cut that extra off? It allows the tank to fill higher prior to filling the neck with foam.

jschildm · Feb 1, 2013

I think the front will be better, since the tank sits lower relative to the filler neck/breather. Also, I did trim the plastic piece some on the roll over valve on the front, but not the back. I tried to keep as steep of an angle as possible, there just isn't a lot of room on the rear, with the filler neck being so flat. I might have to take the bed back off to trace a wiring issue anyways, so if I do, I might trim the plastic portions that fit down in the tank some.

I was also wondering if I could bring the breather up over filler neck, and then down to the connection on the fill hose. This would allow the vent to go up higher, and fuel wouldnt collect because if happen to push up that high, it would drop down to the filler neck. I don't know that it woudl really do me much good anyways though. Anybody have thoughts on that?

PsRumors · Feb 1, 2013

I forgot to mention, the transfer flow kit has you space the rear tank down by about a 1/4" using 4 nuts. That 1/4" might help.

jschildm · Feb 1, 2013

It worked like a champ until then though that's for sure. This is one of the few mods my wife really approved of. She hates when I have to fill up when she is with me, haha.

kramarj · Feb 1, 2013

PsRumors said:
I forgot to mention, the transfer flow kit has you space the rear tank down by about a 1/4" using 4 nuts. That 1/4" might help.

We have two of their kits and I don't remember anything about that. Maybe it said it in the instructions and I overlooked it? They still work with out doing that. Did you do that on yours? If so did it help?

I should also say that on our trucks we have utility boxes so our results are a little different than on a regular truck box as they probably mount a little different. Either way, they are a better setup than stock.

old man dave · Feb 2, 2013

Utility beds generally have the fillers lower than stock and that creates filling problems.

My TFI kit did not have the nuts and my buddy did not space his tank down either. I installed my kits maybe 12 years ago.

Some of the diy guys used PVC pipe fittings in place of the rollover valve (cutting a groove for the tank seal) so there would be minimum protrusion into the tank.