Technical Gas tank baffles in a wedge shaped tank.

Y'all feel free to me this won't work, but include the why please.

So here's what I came up with for the filler end, gas needs to go in and air needs to get out of this area. I'm not sure how gas thinks but I'd imagine the gas being happy with this.
The filler tube goes into the end panel-Mostly.


Here's what I'm thinking on the pic up end. It's in a drop down recess, yet to be cut. The holes are smaller, may be I put too many?
I could put a smaller cage around the pick up tube/pump.



I've got no plan for back here in the wedge yet

 

Ok immo do that just for you

 

I think it all depends on if the entrance to your shop is an approach from the north or the south. You don't want to get it wrong.

Sent from my SM-T377V using The H.A.M.B. mobile app

 

I'm thinking during filling that fuel may not be able to pass through all the small holes on the bottom fast enough and that first chamber might fill faster until it reaches the larger holes and spills over into the rear chamber. Might not cause any problems.
Also wondering if some of the top holes should be opened up to the very top or you might get an air pocket at the top of the rear chamber.
If your happy with the outside shape, and have a bunch of time to waste it would be neat to weld it up, and then use some plumbers putty and clamp on some clear lexan side plates and fill it with water to watch what happens

 

Well....if it was me, I'd triangulate the top portion in relation to the bottom portion, then flip it on it's side. Run a strap around the top, secure it to the car somewhere, the furthest away spot would be good, don't forget to weld some wrenches on the bottom for support, maybe triangulate them for looks? Sorry about using all the big words, just trying to be helpful. Probably get an extra few gallons in it that way, more ideas are better? By the way, that's how my friend does it, it hasn't ever broke........

 

You know I never thought of that!

Probably because I don't think like that.
But I understand exactly what you're telling me.

Where's that light bulb moment
graphic?

 

That. Would be interesting
.

 

Ok now your just fucking with me.
I have a round-about to get there.

 

I would think of it like the gate flaps around the oil pump pickup in a road race or left turn oil pan. Some gates in that baffle would keep the fuel from flowing rearward and still allow fuel in the rear compartment to flow to the pickup.
Not really sure if your upper holes should be there at all. They will allow some slosh and should not be necessary. Gravity will see to that as long as you have enough flow through the bottom passages. Just food for thought!

 

I think your over thinking this. The purpose of the baffles are to slow down the gas flow away from the pickup on hard acceleration or cornering. The two intended baffles should do that nicely. No need for anything else, unless that tank is much bigger then the 15-20 gal it looks to be. The distance of the fuel pickup from the bottom of the tank will have more of an effect on running out of fuel, or not running out of fuel, then the baffles will have. If you have a 1/2" fuel pick up tube, fuel starvation occurs when the pickup tube end is no longer submerged. With a 1/2" pick up tube on the bottom of the tank sump, you will need the 5/8" to 3/4" of fuel covering it at all times. Guessing by the pictures of your tank, that would equate to about a gallon of fuel. If you experience fuel starvation, maybe you need to add more gas, or sink the pickup tube in a well below the bottom of the tank.

If the baffles have holes at the bottom of each one, the fuel will quickly find a level consistent throughout the tank. Filling the tank with the baffles shown will not create any fill issues.

The big 24 gal wedge shaped factory tank, 36" front to back, 20" wide, and about 8" deep at the deepest point, that was in my old 70s big block Monaco did not have any baffles at all and it worked well for over 150,000 miles. The only time we experienced fuel starvation was the one time my wife ran out of gas. Gene

 

This tank has chamfered corners to allow air to be displaced when refueled with similar chamfers on bottoms baffles to limit fuel movement and allow it to be filled.

 

I see you've already made your baffles. But here's something a lot of you probably never heard, clunk. It is commonly used on RC Planes to allow the pick up to always be wet. Since you have a ramped floor on your tank all you need to do is imagine thing's in motion and standing still to see what a clunk would do. But this isn't the right answer either so don't ever post using it ever.

 

Vicky, I built a similar fuel tank for the floor of my 32 behind the seat. I had a can surrounding the pickup with a 3/8" hole facing forward, with a small sump. Didn't work worth a shit even with baffles. I had the pickup in the far right front. I believe that was the MAIN problem. Should of put the pickup in the center. That SS steel tank after all the work to clear the QC is in the scrap. built a SS tank vertical behind a bulkhead in back of the seat. Right hand turns would starve the pickup.

 

Thanks !

 

For you tb33.33333333 Figured 2 ways, by the number (math) and off the drawing. Verified correct by measuring the tank.
Angled baffle would fit either way, converging at the center fore or aft.

 

I spent 10 years working for a fuel tank manufacturer. When stop/start was first considered, there were a lot of complaints for noise when the car came to a stop at a traffic light and the motor shut off.....it sounded like two young kids playing in the bathtub. We did lots of trials trying to make the sloshing go away. A horizontal baffle has the biggest benefit. It keeps the gas that started in the bottom of the tank....in the bottom of the tank. Fuel can't run to the side and then climb the side of the tank, the horizontal baffle suppresses the wave from forming. A couple of flat baffles would be best....one does a whole hell of a lot.

 

I can put a sump in the tank,
And really - What's another floor pan modification at this point


But if I look at this first hand experience of it not working who wants to build scrap.

Dave do you think a better baffle system or better cage around the pick up would have or could have solved your issue? There's obviously some science to this stuff.

 

Thank you !
When you say "flat" what exactly are you referring to?

 

These guys are real serious road course racers, the only way they ever drive this car is pushing it to the limit.

They were having fuel starvation in when going left once the tank got a bit below 3/4 full.
What they started with and how they solved it.






They closed the holes, added air transfer tubes, pinched the fluid transfer tube and added hinged gates.

Setting up hinged baffles would be easy enough

 

is there room to put a small tank under the floor with the fuel pump in it? then gravity feed it with the big tank. it will give you more capacity and solve the baffle/pickup issue.
maybe make it an octagon with a oval air coolant hole dissecting it off to one side?

 

Horizontal. Parallel to the top of the tank... like floors of a high rise building.

 

Yes there's some room under there.
It's pretty clean, sanitary and uncluttered

My thoughts are to leave some flexibility and ability to run a pick up or an In tank pump if I want. If I keep the 392 in here I can run a mechanical pump, but I'm seriously tossing the idea of putting the blown 421 hemi in it. Then I need an electric fuel pump. I haven't made that decision yet but it's on the table. So it stays with capability for both And that part is not really an issue. Stomping on the loud pedal and creating a fuel starvation issue would be a concern with either and being able to get a cooler in my trunk was another.

 

Ok ! I get it

 

Something like this?

 

Yep. Go all the way across and front to back with just holes for fuel level sender to travel and fuel pick up to pass through.

 

I would guess it would help more to have it in the larger section to the left of your vertical baffle to keep the fuel from sloshing up the sides of that large area

 

Awesome! I think I need the vertical to keep the tanks shape. So the horizontal would be two parts.
The section on the left of vertical no holes and stopping short?
The section on the right of vertical end to end ? how many holes, what size and where? My guess would be a small hole on pick up end (a drain back hole) and a larger hole on the filler end, opposite the pick up for filling and refilling fuel chamber.

 

It needs to be attached pretty good, but not water tite. A little seepage around the baffle isn't a deal breaker. You are just trying to control the surges. You need to allow free movement of the gas gauge sending unit and fuel pickup. Otherwise, it will take minimal holes to let the gas seep to the lowest levels.

 

Vicky, I think my main problem was the pickup in the far right front. I have an electric in tank pump, and a fuel pressure gauge on the dash. When I had the low tank I was on the way to Louisville and the long right hander to get on the 270 bypass. The pump starved and froze. I had a spare pump, and made it there and back. But I never took my eyes off the pressure gauge. When the pressure would drop to zero I would shut off the pump till the slosh settled down, then switch it back on. I believe if I had the pickup in the dead middle of the tank, I would of been ok. Originally I wanted to access the drunk from behind the seat. But after a year of hearing the QC scream and exhaust fumes getting sucked in thru the trunk I changed. I made a plywood bulkhead behind the seat and covered the trunk side with sheet metal. Built a 16 gal vertical tank behind the bulk head. Can't remember the dimensions, Maybe 39"x25"x4". Make the pickup accessible so you can remove the whole assembly. Like a 4" or 5" hole. The suggestion on the horizontal baffle makes a lot of sense, I wish I knew that before. I can run the tank dry now, and the gauge never moves. I ran out of gas before. Now I have an aircraft float switch that lights at 2 1/2 gallons. And carry a M/C spare gas can in the trunk. Took the low tank to the scrap yard this morning and got $9.

 

To complicate things even further...
http://engj.org/index.php/ej/article/viewFile/806/434