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Discriminator valves!!


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The radium one although a great company has one key part missing. It’s not clear. With the ATL you can physically see when your getting to the full mark and can ease off on your dump rate. We’re not allowed dry breaks so when the vent closes you would get the splash back as the fuel has no where to go. 
 

Personally I would try and make the ATL work.

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1 hour ago, Mopar 4 Life said:

The radium one although a great company has one key part missing. It’s not clear. With the ATL you can physically see when your getting to the full mark and can ease off on your dump rate. We’re not allowed dry breaks so when the vent closes you would get the splash back as the fuel has no where to go. 
 

Personally I would try and make the ATL work.

But all fuel lines must be metal or covered by metal right Right! so you should not see it when fuel?

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3 minutes ago, DRVOLKS said:

But all fuel lines must be metal or covered by metal right Right! so you should not see it when fuel?

 

I know you’re joking, but for new people on the forum, only fuel lines within the driver compartment must be metal/encased by metal. If it’s behind a bulkhead separating the driver compartment it’s legal. If it’s visible during fueling it helps the fueler to not make a big spill. 

 

i run the ATL valve. It’s a big boy and I used some fittings from McMaster to scale it down to 3/4” (https://www.mcmaster.com/5372K168)

 

 

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37 minutes ago, KoneKillah said:

Can someone learn me what this is why you would want one?

 

General comment: Bigger fuel vent ID = faster fuel can go in. 

 

Answering the Q: This particular valve prevents fuel escape if you find yourself upside down. It “discriminates” between air and liquid. 

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Harmon Racing sells one also, uses -10 an fittings iirc.  I use it on 146.  246 has the atl one which has 1.25npt threads I think.  It was much harder to fab an enclosure for.

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17 hours ago, KoneKillah said:

Can someone learn me what this is why you would want one?

 

In addition to the roll-over safety noted above, we had to add one because for the first few laps on a full fuel load the cornering g-forces would still force fuel out of the over flow. This cured that problem. 

 

To add to the safety conversation - in the event of a partial roll over, the internal rollover valve might not fully close, thus this is a great secondary check valve as the two pingpong-style balls should still fully close even if the internal steel ball doesn't get over enough to close. Yes the ATL disc. valve is big, as noted above we just used reducers to get it down to a normal sized vent hose. 

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17 hours ago, MichaelPal said:

 

General comment: Bigger fuel vent ID = faster fuel can go in. 

 

Answering the Q: This particular valve prevents fuel escape if you find yourself upside down. It “discriminates” between air and liquid. 

There are two separate items which sorta do this. 
1) rollover valve does what you describe. It is generally in or mounted to the fuel cell. Often made from a heavy metal sphere which seals when flipped over but will not stop fuel from rising past it during fueling or while on track. 

2) discriminator valve prevents sloshing and g-force fuel movement from escaping out the vent tube. Often made from a hollow, floating ball which seals when upright and fuel buoys it up into the seal. 
 

A discriminator valve is not necessary if your vent tubing runs high enough and vertical enough to prevent fuel loss in corners. A rollover valve is required per the rules. 

Edited by enginerd
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I was able to make the atl one work. While we are talking about all this stuff I have never understood the banning of dry break type fittings with the 5 min pit stop requirement. Seems like that would be a safer setup than the fuel pushing back out the tube at you once it’s full and running everywhere. 

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On 1/27/2020 at 12:15 PM, enginerd said:

There are two separate items which sorta do this. 
1) rollover valve does what you describe. It is generally in or mounted to the fuel cell. Often made from a heavy metal sphere which seals when flipped over but will not stop fuel from rising past it during fueling or while on track. 

2) discriminator valve prevents sloshing and g-force fuel movement from escaping out the vent tube. Often made from a hollow, floating ball which seals when upright and fuel buoys it up into the seal. 
 

A discriminator valve is not necessary if your vent tubing runs high enough and vertical enough to prevent fuel loss in corners. A rollover valve is required per the rules. 

 

So I opened up the ATL unit a while back and while both balls are very ping-pong in nature. The bottom one is heavier/more dense. When the unit is flipped upside down it acts as a rollover valve as well and did not let any fuel out.

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6 minutes ago, MichaelPal said:

 

So I opened up the ATL unit a while back and while both balls are very ping-pong in nature. The bottom one is heavier/more dense. When the unit is flipped upside down it acts as a rollover valve as well and did not let any fuel out.

 

And - to add to that - I took an old one apart a few years ago (see Camaro build thread) and tested other alternatives VS the ATL balls in an attempt to build my own. For anyone thinking of building vs buying, regular ping-pong balls do not hold up to gas. 

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On 1/26/2020 at 4:17 PM, MichaelPal said:

 

I know you’re joking, but for new people on the forum, only fuel lines within the driver compartment must be metal/encased by metal. If it’s behind a bulkhead separating the driver compartment it’s legal. If it’s visible during fueling it helps the fueler to not make a big spill. 

 

i run the ATL valve. It’s a big boy and I used some fittings from McMaster to scale it down to 3/4” (https://www.mcmaster.com/5372K168)

 

 

It was not a joke in my car the cell and all pumps and lines are in the metal box per rules . the filler is metal to as rules so for use their is no way to see the fuel stack up . some car can open the trunk to view the valve. We run the vent higher then the filler cap opening then back down below the filler so the pan can catch fuel spill. When filling when it spits back a little we are full. I still think not letting us use a clear reinforced filler tube like other clubs makes it more dangers  on filling and added cost. 

old pic 

7W81cug.jpg

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5 hours ago, pintodave said:

 

And - to add to that - I took an old one apart a few years ago (see Camaro build thread) and tested other alternatives VS the ATL balls in an attempt to build my own. For anyone thinking of building vs buying, regular ping-pong balls do not hold up to gas. 

I have used wood balls in my waste vac pump and they last about a year and tested in gas do not swell up. I found a cheap valve on eBay and swayed out the balls and tested it in gas it  lasted never tested on the car

New Sch 80 PVC 3/4 Inch True Union Ball Check Valve Socket New Sch 80 PVC

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