Problem filling stock tank?

[Tilton]

What about issues when racers do this and then their car spews gas out the side or back when on track? Seems to me that would be a fire hazard but also could cause a slick spot on track. I have seen this before and mentioned it to a racer who just brushed me off with it. Should we be concerned?

Tilton-forgot to tell you this but I saw your car spewing gas out the back.

A number of people came over to let me know. I didn't think it was as bad as some were saying because the car wasn't using much more fuel than normal. Looking at Sean's R4 video it was quite a lot during the long left hander before the front straight.

First we thought it was a clogged vent line from when I went off early Saturday. After inspection the vent line was fine, but the problem seems to be my exhaust (without turn downs) which was heating up the gas tank. This will be changed before MSRC as well as a new gas cap.

[Pranav]

What about issues when racers do this and then their car spews gas out the side or back when on track? Seems to me that would be a fire hazard but also could cause a slick spot on track. I have seen this before and mentioned it to a racer who just brushed me off with it. Should we be concerned?

I'm unsure if removing the inlet check valve would cause an issue with my non vented cap if the tank is getting sufficient pressure venting on the other side.

To date, with my new venting setup that went in over the summer, I've no longer had issues with dumping on track, until this past event at MSRH.

Prior to MSRH, I was running a 3/8" hose to the bottom of a steel 1qt catch tank, and a combination of 1psi check valves at the top (one going in, one going out, both go to a breather hose on the back bumper), with a 3rd fitting going to a ball valve that I would open for venting during fueling. I had zero issues with dumping fuel on track (out the hose or cap), but then I took the overflow tank out and went to 1/2" hose as a misguided attempt to fix the fueling issue. According to Sean, I ended up dumping on track during the 30 min race because I had stuffed/overfilled the hell out of the tank and had no overflow. The overflow tank will be going back in before Cresson. I'll also return to having sufficient coiling/looping of hose to prevent a siphon effect...

I don't like dumping fuel on track either, it's a waste of money! Who cares about accidental combustion...

[BryanL]

Tilton-it was a pretty good spray that I saw in the same spot you mentioned.

Pranav-sorry I really don't grasp all the catch tank venting stuff you have going on. Don't really know why you are having trouble other than it seems like it all may have been messed with. Don't really see any issues when using the stock tank. Now what I did think I understood is you have a catch tank for GAS mounted somewhere with the breather hose going to the back bumper. I've burned enough hair off my body to know that some gas fumes with a hint of spark are going to blow up-so to me it is concerning that you have a hose full of gas fumes on your back bumper where you might get hit causing a spark or underhood fire from the car behind you. Also, guess its good that Burch isn't smoking cigs while racing anymore.

That being said I have zero idea how the stock tank works for venting or anything but I have a stock plastic tank in the backyard I'll check out this week.

[Pranav]

I won't name names but there are plenty of others here that have a straight hose going out back to a breather as well.

My overflow tank with 1psi valves stopped it from from spraying out all over the track and kept the situation pretty well contained for the 2 events I ran it. Only ripped it out for MSRH because I thought it was causing my fueling issue, which it wasn't (I manually flip a big ball valve to make a straight, unrestricted vent which bypasses all that crap when fueling in the pits).

Fumes from a hot tank on a return style fuel system have to go somewhere, they don't just disappear into thin air. Do you know where your tank fumes are going?

Only other solution I could think of is we all start running the factory EVAP hardware again.

[GlennCMC70]

The stock system uses the evap to run the fumes into the air intake, buring them. There is an air INLET valve (read as 1 way valve) that is OEM. The one for a 4th gen is a white plastic part at the end of a hose leading up to the tank. This allows air to replace burn fuel to prevent a vacuume being pulled on the tank.

I have this plugged on mine. It is only needed if the OEM evap system is in place. My evap line now runs to along the frame rail to the rear of the chassis. I have a small K&N style filter on the end that is made with a stainless mesh over it. It is a 3/8" line. This is plenty of volume for air in/out. It is high and centered. I also have a ball valve inline to close this vent off while being stored in the garage.

Don't run a vented cap on 4th gens. I have had major spillage w/ them.
I wouldn't knock out the ball at the bottom of the fill neck. My wish it was still there if you find yourself upside down.

I have plans to cut the OEM neck off and using fuel cell filler neck hose and a non-OEM cap to stop the leaks at the fill cap.

[Rob Liebbe]

Fumes from a hot tank on a return style fuel system have to go somewhere, they don't just disappear into thin air.

They don't? Somebody better alert the EPA.

[Pranav]

That being said I have zero idea how the stock tank works for venting or anything but I have a stock plastic tank in the backyard I'll check out this week.

The LS1 plastic tanks have all kinds of voodoo magic going on that I don't understand, good luck with that.

I wouldn't knock out the ball at the bottom of the fill neck. My wish it was still there if you find yourself upside down.

Was there a solution to that car you said earlier was having an issue with the ball valve or should I be looking into replacing the tank?

Currently running a non vented cap, have had no issues with fuel coming out the gas cap since I made that switch.

[Pranav]

Nevermind, I get what you were saying Glenn. Going to try play with some stuff when I get back to the garage later this week.

Bryan just for you I'm going to heat the tank up with a blow torch as part of my testing process. Don't wanna idle the car to simulate it, gas isn't cheap.

[Supercharged111]

Now you guys have me thinking because my car really reeks up the trailer. My "vent" is the factory hose zip tied to the filler neck next to the cap. Did the LS1 tank use a rear-mounted evap can?

[GlennCMC70]

The evap can on 99-02 fbodys is located on top of the tank.
LT1 cars have it on the driver side behind the rear tire hidden by a plastic shield.