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.

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.

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.

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).

As far as living and learning... I do many dumbs.

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.

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.

+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.

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.

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.

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.