mad_science said:
- Fork out like $1500 for a Radium FCST unit or similar from DeatschWerks and be done with it.
^^ This one.
Rationale ==> Think of all the entry fees, testing time, and frustration you've had. What's that time and resource worth? Wouldn't it be more fun to just race the thing as intended?
"Insanity is doing the same thing over and over, expecting a different result"
"Buy once, cry once"
Any reason you can't retrofit an OE unit like the 2002 camaro unit shown above?
Shavarsh said:Any reason you can't retrofit an OE unit like the 2002 camaro unit shown above?
Only unmodified OE fuel tanks or legit fuel cells (with no external surge) allowed. Lemons racers are in the bad overlap of the ((Creative // Unskilled)) Venn diagram.
One other option if I really don't want to just spring for the FCST unit, what about just dual lift pumps on opposite sides, with check valves and a Y-connector to the HPFP? Probably wouldn't drain to the last drop, but does give a standalone pick up on each side.
This ATL surge tank might work?
Just got off the phone with Holley tech support.
Their take is that the fuel cell foam is the issue: it's both pushing down on and wicking fuel away from the mat. The recommendation was to remove the foam completely.
I'm probably not going to do that, but I could see cutting one or more channels out of the bottom of the foam, allowing for an uncompressed path for the fuel to get back to the outlet fitting.
Interesting, good to know and try. I've used the foam to hold the hydramat in place, maybe another plan is needed there.
A friend of mine had this issue on his truck and the first thing he looked at was tank positioning. Its possible that because the cell is tilted down in the front, fuel might be pooling away from the Hydramat during acceleration. Even if it covers 85% of the cell, if fuel is pooling in that 15% over and over again, that could cause some issue. Not saying its the whole reason but it could play a part.
So glad I stumbled on your thread, we have a 22-gal cell in our Lemons Ranger, and have the exact same issues and hydramat. The other owner of the truck apparently found it on heavy discount because that NASCAR truck series is changing cell designs. It doesn't quite hit every edge of the cell.
Same exact problem for us- once we get to around half a cell, we start fuel starving coming out of right-handers. Our setup is a little weirder than yours as our cell is above the frame rails so there's notably more head pressure feeding our 044 pump (the fuel level is always WELL above the pump so it only has to start the siphon). I also made sure the return fitting was dumping straight onto the mat on the opposite side of the pickup.
So far Gingerman, Road America, and NCM we've had the issue with varying degrees of severity. My ideas for solution have been:
Personally I'm leaning towards option 1 or 3, but it would be nice to see some other successes with this issue.
I saw this thread was bumped, so I thought I’d provide an update. We participated in two Lemons races this season but still can't use more than 15 gallons of fuel before hitting fuel cut. Since the gas tank has multiple pickup points, we created new fuel lines to utilize all of them and moved the pump inside the tank.
Additionally, we removed some of the foam and left a small channel for fuel flow. Hydramat was then tested by adding half a gallon of fuel and jacking the car up on different corners, then dropped it quickly. With a fuel line running from the filter to the rail, we didn't observe any bubbles, and the fuel pressure remained stable. The Hydramat also covers 100% of the bottom of our cell.
On track, it made a slight improvement as we didn't get fuel cut in spots we had it before but it still happens around 15 gallons. Not sure what else to try.
Honestly, I'd get rid of that mat and build a proper fuel system. I built one with an in-tank sump with one-way doors and in-tank pump. Tank partitions guided sloshing fuel into the sump through the doors. Return fuel dumped back into the sump, keeping it full. If the sump overflowed, the fuel simply fell back into the outer sections of the tank. Never - not once - did I have any fuel delivery issues during multiple track events.
I run a 22ish gallon ATL cell in lemons with only a half size hydramat (1 fitting only) in the bottom center of it, we starve in long corners at around 3 gallons to go.
The one time we suffered fuel starvation that wasn't a low fuel level condition was a pre-pump filter getting plugged up.
To me it sounds like your problem lies elsewhere, but reading the thread you've checked most the boxes
In reply to PseudoSport (Forum Supporter) :
Damn.... That's basically all the ideas I had. We struggled at NCM with the same behavior around 12 gallons left (estimated, we don't have a level sender).
It sounds like manufacturing a surge "tank" that drops in as part of the filler is the best possible option. The crap part is that our cell doesn't have a standard size filler flange so it will all have to be custom made, but because of strange rules interpretations we had to enclose our cell in metal and swapping it out now would effectively be a "rip it out and start over" process. Unfortunately they also informed us we need to add an extended filler neck thanks to a mid-year rule change (that wasn't detailed on the actual rules) so that adds some complication, especially if we want to put the pump internal. Might need to bite the bullet and cut a new hole in the cell.
If not for the lemons rules, I would have installed an external surge tank years ago. It worked wonders on my FB RX7, and I even had to retrofit that for an internal feed pump.
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