Topic: Fuel jug air breathers

Hi, sorry if this has been beaten to death but the search function yields chaos!

Ran my first Lemons race, Our team was very slow at fueling, I know a Fuel cell would help but with or without a cell we struggle with the jugs (vp fuel jugs)

If we take the air bleeding cap off they spill fuel out the air cap with the cap on fueling is slow.  I saw teams with hoses off the air cap to act like a snorkel and not spill.  I cannot find a cap with nipple for sale. 

What are yall doing to fuel fast without spilling.  Even with fuel cell and a big hose we still would need to solve the air vent spill issue.

Re: Fuel jug air breathers

The technique without the hose: tip the jug into the filler until fuel starts to flow, then open the vent a turn or so. This makes physics work with you instead of against you.

The ones I have seen with the hose don't have a cap. The house goes over the threads and is held on with a jubilee clip. I haven't paid too much attention to how the open side of the hose is held to the can.

That guy

Re: Fuel jug air breathers

A hose on the vent is very typical direction. Hose over the vent and down all way to the bottom of the canister.

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Re: Fuel jug air breathers

Ah just clamp it on, OK.

I was doing the tip it up and then open the cap a couple turns method which avoided spilling, then a car pulled into the pits after us and filled 10gal before we finished 5 and we had a head start.

We can be 10sec faster per lap and loose due to fueling, I mean we aren't trying to win but it's annoying to loose so much time fueling

Thanks.

5 (edited by rb92673 2022-11-20 09:00 PM)

Re: Fuel jug air breathers

Hose size matters too.  Take a hole saw to the top of your fuel inlet restrictor and get a giant hose on your jugs.

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Re: Fuel jug air breathers

Everything about your car and your team has to be dialed before the fueling part of pit stop times matter. All of the tracks I have been to, your pit stop lap is three laps long because the timing loop doesn't usually go across pit lane.

I'd bet actual money that a bone stock 2003 Hyundai Accent with a 22 gallon fuel cell and a decent fuel pickup (good brakes and good tires will help) would only have to be refilled once per hot track day, so your stint length is really only limited by your bladder capacity. If you only do driver changes when you fuel (because "racing") that probably puts you in the top ten assuming no breakage or black flags.

That guy

7 (edited by Zacks 2022-11-20 10:14 PM)

Re: Fuel jug air breathers

DirtyDuc wrote:

Everything about your car and your team has to be dialed before the fueling part of pit stop times matter.

Possibly,  but I'm not sure you realize quite how slow our fueling was lol.

I mean none of it mattered cause turns out our oil pan sucked and doesn't do well with cornering g forces so we blew the motor on day 2, but hey live and learn

Either way a tube on the gas can is like a 30cent fix to pick up time, and the oversized fill tube isn't too much either

8 (edited by DirtyDuc 2022-11-20 10:58 PM)

Re: Fuel jug air breathers

Zacks wrote:
DirtyDuc wrote:

Everything about your car and your team has to be dialed before the fueling part of pit stop times matter.

Possibly,  but I'm not sure you realize quite how slow our fueling was lol.

I mean none of it mattered cause turns out our oil pan sucked and doesn't do well with cornering g forces so we blew the motor on day 2, but hey live and learn

Either way a tube on the gas can is like a 30cent fix to pick up time, and the oversized fill tube isn't too much either

I know how slow fueling can be... and certainly seem. The go to answer for Lemons is Hunsaker fuel jugs, which have gigantic vents. There are even improvements there, because technique plays a role in not spilling. I'm saying that if everyone is giving up 4 minutes whenever they pit, pitting less is more of an advantage than it might seem compared to lap times.

The way I see it is, if you are truly depending on pit times to be competitive then you have built the same car as someone else. Before they instituted hot pit fueling everywhere, the diesel Porsche was theoretically competitive at cold pit tracks despite being 30-50 seconds off pace (I had a lot of time on my hands).


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Re: Fuel jug air breathers

DirtyDuc wrote:

I'd bet actual money that a bone stock 2003 Hyundai Accent with a 22 gallon fuel cell and a decent fuel pickup (good brakes and good tires will help) would only have to be refilled once per hot track day, so your stint length is really only limited by your bladder capacity. If you only do driver changes when you fuel (because "racing") that probably puts you in the top ten assuming no breakage or black flags.

The guys with the Prius are pretty much proof positive that running cleanly and efficiently can get you into the Top 10 even in a 140-car race.

There's a little more to it than that; they run REAL RACE CARS™ and ran the Prius on a few test runs while they had the track rented out to test their real cars. So they had their race engineer figure out fuel-burn rates and what kinds of lap times they need to run to maximize efficiency and hit their stint lengths to get the most out of each day. BUT that's nothing that most teams who are paying attention can't figure out after a couple races. The lap time data is all out there for you and if you just scribble down some super-basic notes about how much fuel you put in the car to compare against lap times, you're already doing more race engineering than 95 percent of Lemons teams.

Before you even get there, though, I agree that you have to have the whole team on board with staying out of trouble and showing almost excessive mechanical sympathy before you worry about stint lengths, lap times, pit times, etc.

Eric Rood
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Re: Fuel jug air breathers

Fuel cans are heavy, I like to get the fuel out of them as fast as possible so I don't have to lift them anymore.  I only use the VP cans for storage and the Hunsakers for fueling the car.

There is no reason why they shouldn't try and be as efficient and fast as possible on their pit stops as long as they are safe.

Team whatever_racecar #745 Volvo wagon

Re: Fuel jug air breathers

I agree with everyone trying to argue that pit stops are not making or breaking your race, but I also see the fun in trying to make pit stops more efficient. It's nice to have them go quick just to avoid standing in the sun holding up that 5 gallon jug for a few extra minutes.


A few general notes. The Hunsaker jugs are the easy button. They aren't blisteringly fast as purchased, but some simple changes to the flexible hose will make them very quick. Practice to make sure you can stop fueling before you overfill. I tried modifying other fuel jugs, and ignoring that modified tanks are technically against the letter of the rules, they worked but required constant upkeep and repair. We bought Hunsaker jugs finally so we wouldn't have to think about them ever again.

Ideally you want the air vent feeding the bottom of the jug so that when you have it upside down the air is just cleanly flowing into the headspace, not having to bubble through all the fuel. That's why the Hunsaker jugs mold the vent down the side the way they do. You want a large air vent, but more importantly you want the air vent balanced to the fuel outlet. An oversized vent does no good if the outlet is your bottleneck.


Side musings. I wish the tuffjug ripper caps were faster. (https://www.tuffjug.com/products/ripper-caps.html). They make it impossible to overfill (if your setup has the jug fully upsidedown and stuck into your filler) because the air vent is built into the dump, so once the fuel level reaches the cap it just stops flowing. I love them with our fuel cell, but they are slow. Like at least a minute to dump each one. Now we tend to dump on average 2 Hunsaker jugs and then use a tuffjug to let us fill top the top without spilling a drop.

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12 (edited by duthehustle93 2022-11-21 09:45 AM)

Re: Fuel jug air breathers

The first race I ran, we were running the CA-compliant red jugs and refueling was PAINFULLY slow... like 20 minute pit stops for 10 gallons. But we were learning a lot and it wasn't really a big deal. We spend a lot of money to be out on track, not fueling, so I totally get a newer team wanting reasonable pit stops.

We implemented a few simple/cheap changes: we do some practice (it does help with speed, but mainly VASTLY improves safety), have a dedicated "pit mom" on the other side of the wall that keeps us organized during a pit, gutted the flapper from our fill neck (remove fill neck before gutting), and bought 2 hunsaker cans. I haven't tried modifying VP cans, but just get a couple hunsakers dedicated for fueling. Modifying anything fuel related isn't worth saving the money IMO, and if you do the math on how much your spending/hour to be at a race, the hunksaker cans pay for themselves in one race with how much additional seat time you gain.

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Re: Fuel jug air breathers

As a ridiculous benchmark, my Hunsakers would drop five gallons in seven seconds in free air.  I have seen jugs deliver five gallons into a fuel cell in between three and four seconds.  Those jugs had massive vents with check valves to reduce spillage.

14

Re: Fuel jug air breathers

+1 for Hunsakers.  They can be modified but, even out of the box, are oh so much better than the VP cans. 

I picked up a dozen modified VP cans on the cheap to store gas on race days.  The leaky speed-modifications make them barely worth the mess when refilling the Hunsakers between pitstops.  I actually find the much-hated five gallon EPA cans to be better for refilling.  Slow but at least they don't make a mess once one gets used to how they work. 

I greatly sympathize regarding slow filling being a major drag.  Yeah, there are a billion other things to work on but time spent fueling is literally time the car isn't being driven around the track.  Simple math - shorter fuel/pit stops equal more fun.

Re: Fuel jug air breathers

Thanks for all the info, I'll check out the hunsakers.

Fixing the vps to be quicker would be at least quicker. 

After we warmed up we actually put down some competitive times.  (Until we blew up)  If we can just fix the oil pan, the fuel starve and the refueling, and avoid blowing up we still won't win, but maybe we can be in the fight.

16 (edited by chaase 2022-11-22 06:01 AM)

Re: Fuel jug air breathers

We use the Hunsaker jugs but if you don't have a fuel cell, it will only be a limited benefit. The jug needs proper venting AND the fuel tank needs it as well. A fast fill jug is basically useless if the fuel tank doesn't have venting capable of supporting it.

The last thing I would worry about right now is fuel jugs. Once you can keep the car on the track, without getting black flags and not breaking, then you can think about how fast you fuel up.

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Re: Fuel jug air breathers

Well I was all exited about the 11 gallon hunsaker thats on sale right now, bam one jug to fill our 12gal tank, but my teammate reminded me of the 5 gal limit for fuel jugs, and I'm not buying 2 of those expensive suckers yet, so hose on the vp it is!

I just wanna try and fix all the errors, If we fail or miss something, so be it, I just don't see the harm in trying.  Especially when it's a hose from home depot for cheap.  I'm not going insane and trying to install a dry break or something, just grabbing low hanging fruit.

Re: Fuel jug air breathers

Adding a vent hose is pretty low risk, no reason not to. Just test it all out with water once or twice to make sure there aren't leaks and then you're good to go.

When I modded jugs I actually cut holes and added a big bulkhead fitting to add a vent to a jug that didn't have one. It was fine for 2 races then the "gas safe" adhesive started breaking down and leaking. That was not fun.

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19 (edited by Bricoop 2022-12-06 12:37 PM)

Re: Fuel jug air breathers

Zacks wrote:

Well I was all exited about the 11 gallon hunsaker thats on sale right now, bam one jug to fill our 12gal tank, but my teammate reminded me of the 5 gal limit for fuel jugs, and I'm not buying 2 of those expensive suckers yet, so hose on the vp it is!

I just wanna try and fix all the errors, If we fail or miss something, so be it, I just don't see the harm in trying.  Especially when it's a hose from home depot for cheap.  I'm not going insane and trying to install a dry break or something, just grabbing low hanging fruit.

Investing once is cheaper than buying twice.

With fast fueling, the most important thing is making sure your tank can vent quickly enough. I’ve found that to be the limiting factor. We went from 8 minute stops to sub-3 minute for 18 gallons. Each jug drains 6 gallons in <30 seconds. Making sure everyone knows their job during a stop. Focus on doing your job well, not fast. Rushing slows you down (eg, snapping in one of the harnesses backwards, you have to release the Cam lock and redo them). You’ll learn more tricks along the way.

Re: Fuel jug air breathers

We went the VP jug route when we started due to limited budget and Hunsaker cost.  We've upgraded our VPs over time and don't see the need for Hunsakers at this point, but then we aren't in contention for a Class A or B win any time in the foreseeable future. If your budget is unrestricted, the Hunsakers are the way to go. Since you already have VPs, I have a few suggestions.

If you want to greatly speed up your VP jugs, look for 3/8" or 1/2"  "through-hull brass fittings" on ebay or Amazon. They will flow far more air than the factory port.  Use good fuel proof washers on both sides - Viton if you can find them, Nitrile would be second choice). Cheap washers won't seal for more than a couple of days and your jugs will leak next race. You can buy clear PVC hose at Lowe's or Home Depot.  Put the vent pretty high up.  Drilling the hole is easy, the hardest part is finding someone with small enough hands to reach inside the VP jug mouth with the inside of the jug part of the fitting and then getting a wrench on the fitting and ensuring the fitting is tight.  An 18" to 24" vent hose can be bent down from the fitting and zip-tied to the handle. A vent tube from the inside fitting to the bottom of the jug will help, too. That smooths the airflow instead of having it bubble up through the gas.  If you use the inside vent tube, be sure to loosen the stock vent cap slightly when the can is full and in the sun at the track - and of, course, tighten it completely before heading to the pit to fuel.  Loosening the stock vent cap will prevent the can from pressurizing as it heats up in the sun and self-siphoning the fuel out of the can and into your drip pan or fuel wagon (speaking from experience).

As mentioned, test with water, then dry out and test with gas in your daily driver or tow vehicle so you won't have surprises at the track.  This is an easy mod, and will make a noticeable difference in your fueling.

You can gain even more time by going to a larger fuel tube/cap at some point in the future when you think it may further help your pit times. And by "further help your pit times" I mean after several races when your team has gotten a good handle on pitting duties, focus, and efficiency, because those areas are the real low-hanging fruit.  You can bore out your fuel filler port with a hole saw to accept larger diameter fuel hoses and use larger through-hull fittings on the fuel jug caps.  We did that and found a 1 1/4" inside diameter fuel hose flowed faster than our car's stock fuel system could accept due to it's plumbing and vent design, and had to back down to 1" filler hoses.  Since the flow rate increases dramatically  with the hose diameter, a 1" hose flows way more than a 3/4" hose does. However, don't get carried away on that end -  I have heard rumors that Lemons may limit fuel hose diameters soon. I'd think that was aimed at the teams using 2"  and 2 1/2" fillers in their fuel cells, but can't say for sure so don't rush on that mod.

Re: Fuel jug air breathers

Bought the "4x flow cap" from jegs.
https://www.jegs.com/i/JEGS/555/80219/10002/-1

Drilled out the vent to 13/32 which leaves the stock look and the Cao still works ect, then shoved some 5/8 ID vinyl hose over the vent and taped it down

So no risk of any seals leaking or glue failing ect.  And pretty cheap.

Anyway timed it with water, 5 gal in 16 sec.

So faster than we need lol,  seems worth the low investment

Thanks for the tip on just clamping the hose over the vent threads, I was way overthrowing that part.  And it really doesn't spill out just tip it up and away we go!   This is really gonna make refueling easier (not just faster)

Re: Fuel jug air breathers

Zacks wrote:

Anyway timed it with water, 5 gal in 16 sec.

It's unlikely to be 16 seconds going into the fuel tank,
as you still have to vent the air out of the tank as the fuel goes in.

Also, be very careful about using the can vent on your last jug of fuel.
With the can vent open, there is noting to stop the fuel from overfilling
the tank and spilling. I know this from experience.

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Re: Fuel jug air breathers

Oh yeah, I know it won't be 16 secs, but it will be faster than last time!  I have no dreams of f1 pit times lol5

And yeah I was just talking to my team mate about how we have to figure out/be careful since the tank vent is probably lower than the fill neck if it backed up...

Wish I could just change the vent so that wouldn't be a problem  (as much problem) but I guess that all can't be touched per the rules.

Re: Fuel jug air breathers

we had the same problem with the vp cans not filling fast enough. We ran button willow in the fall and got killed at the fuel stops. it took about 7-8 minutes to fill the car with just normal vp cans. We finished 9th but we figured with the time saved we could have done better. We bought two hunsaker fuel jugs and got just some pipe for the hardware store to make bigger spouts on them. we are going to use them at thunder hill but in testing they seem to be way worth the money.