fuel tank vent
Thread Starter
Melting Slicks
Joined: Mar 2002
Posts: 2,164
Likes: 7
From: Beringen
fuel tank vent
I'm using a FI system on my car now and would like to install a larger fuel tank vent than the one that is in the cap right now. What are my options here.
Another cap ? Some plumbing.
Please note I'm not willing to take the tank out. I also have the unused fuel vapor line that I could use if necessary, but not sure if this is suitable.
Thanks for the input.
Yves
Another cap ? Some plumbing.
Please note I'm not willing to take the tank out. I also have the unused fuel vapor line that I could use if necessary, but not sure if this is suitable.
Thanks for the input.
Yves
Burning Brakes
Joined: Oct 2008
Posts: 1,037
Likes: 14
From: Mobile Alabama
Without removing the tank, the vapor line is the best bet. I am guessing that it is plugged off. I would open the vapor line and add a screen/filter to the open end. (fuel filter works well)
If you will be parking in an enclosed area and the fumes become too strong, you could add a vapor canister to the line. An alternative to this would be the smaller charcoal canister on some vacuum brake boosters.
If you will be parking in an enclosed area and the fumes become too strong, you could add a vapor canister to the line. An alternative to this would be the smaller charcoal canister on some vacuum brake boosters.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
If you have an operational vapor canister (and you wish to keep it), you do NOT want another tank vent. The canister IS the tank vent with that arrangement. An 'additional' vent to a working vapor can system will prevent it from working properly.
If you do not have [or want] a vapor canister included, about any sized tank vent will be fine. The vent only requires drawing in the volume of air that will replace fuel at the rate it is being used. A 1/8" diameter hole (or larger) would be more than enough, as long as it isn't blocked.
If you do not have [or want] a vapor canister included, about any sized tank vent will be fine. The vent only requires drawing in the volume of air that will replace fuel at the rate it is being used. A 1/8" diameter hole (or larger) would be more than enough, as long as it isn't blocked.
Le Mans Master
Joined: May 2003
Posts: 8,877
Likes: 3,556
From: Fernandina Beach FL
2023 Restomod of the Year finalist
2020 C3 of the Year Winner - Modified
Here's how I went about it- I am running a return line - and from my understanding at idle- over 90% of the fuel is returned- basically heating up the fuel and running back in the tank.
I have a non-vented cap- and from what I have read just changing over to a vented cap (designed for a carbs) will shorten the life of the pump (heat) and cause venting issues- not to mention that gas smell.
I looked at the vent on the Aeromotive Phantom Pump and the manual said the vent should be 6" above the tank and use a roll over valve. In a Vette to do this the vent would have to be a couple of inches above the rear deck!!!
I added a roll over valve- connected it to a charcoal canister ( used in GM cars for the brake vacuum line) and then a vent used in marine applications. I put the vent in the rubber neck at the gas filler. I also ended up going w/ Russel Synthetic rubber hoses to hopefully stop the permeation of the ethanol in the gas - and gas smells,
roll over valve
Vent for boat hulls-
How it's plumbed
So my thoughts- no gas smell- have a roll over valve if I am ever unfortunate to roll the car. I am also adding a Ford inertia switch to shut the fuel pump from an impact. Has a reset and was planning to mount it in the battery compartment -for easy access.
I have a non-vented cap- and from what I have read just changing over to a vented cap (designed for a carbs) will shorten the life of the pump (heat) and cause venting issues- not to mention that gas smell.
I looked at the vent on the Aeromotive Phantom Pump and the manual said the vent should be 6" above the tank and use a roll over valve. In a Vette to do this the vent would have to be a couple of inches above the rear deck!!!
I added a roll over valve- connected it to a charcoal canister ( used in GM cars for the brake vacuum line) and then a vent used in marine applications. I put the vent in the rubber neck at the gas filler. I also ended up going w/ Russel Synthetic rubber hoses to hopefully stop the permeation of the ethanol in the gas - and gas smells,
roll over valve
Vent for boat hulls-
How it's plumbed
So my thoughts- no gas smell- have a roll over valve if I am ever unfortunate to roll the car. I am also adding a Ford inertia switch to shut the fuel pump from an impact. Has a reset and was planning to mount it in the battery compartment -for easy access.
Burning Brakes
Joined: Oct 2010
Posts: 1,160
Likes: 23
From: Prescott AZ
Here's how I went about it- I am running a return line - and from my understanding at idle- over 90% of the fuel is returned- basically heating up the fuel and running back in the tank.
I have a non-vented cap- and from what I have read just changing over to a vented cap (designed for a carbs) will shorten the life of the pump (heat) and cause venting issues- not to mention that gas smell.
I looked at the vent on the Aeromotive Phantom Pump and the manual said the vent should be 6" above the tank and use a roll over valve. In a Vette to do this the vent would have to be a couple of inches above the rear deck!!!
I added a roll over valve- connected it to a charcoal canister ( used in GM cars for the brake vacuum line) and then a vent used in marine applications. I put the vent in the rubber neck at the gas filler. I also ended up going w/ Russel Synthetic rubber hoses to hopefully stop the permeation of the ethanol in the gas - and gas smells,
roll over valve
Vent for boat hulls-
How it's plumbed
So my thoughts- no gas smell- have a roll over valve if I am ever unfortunate to roll the car. I am also adding a Ford inertia switch to shut the fuel pump from an impact. Has a reset and was planning to mount it in the battery compartment -for easy access.
I have a non-vented cap- and from what I have read just changing over to a vented cap (designed for a carbs) will shorten the life of the pump (heat) and cause venting issues- not to mention that gas smell.
I looked at the vent on the Aeromotive Phantom Pump and the manual said the vent should be 6" above the tank and use a roll over valve. In a Vette to do this the vent would have to be a couple of inches above the rear deck!!!
I added a roll over valve- connected it to a charcoal canister ( used in GM cars for the brake vacuum line) and then a vent used in marine applications. I put the vent in the rubber neck at the gas filler. I also ended up going w/ Russel Synthetic rubber hoses to hopefully stop the permeation of the ethanol in the gas - and gas smells,
roll over valve
Vent for boat hulls-
How it's plumbed
So my thoughts- no gas smell- have a roll over valve if I am ever unfortunate to roll the car. I am also adding a Ford inertia switch to shut the fuel pump from an impact. Has a reset and was planning to mount it in the battery compartment -for easy access.
Le Mans Master
Joined: May 2003
Posts: 8,877
Likes: 3,556
From: Fernandina Beach FL
2023 Restomod of the Year finalist
2020 C3 of the Year Winner - Modified
Thanks....
actually here's some updated pics- since the stereo is just in the dash for looks- the sidepipes will be my music-
I moved the vent to the antenna hole-
The other thought I am contemplating is putting a fuel cooler on the return -a few OEM new cars have it- can't imagine it would hurt - or help...
Richard
DSCN4419
DSCN4420
actually here's some updated pics- since the stereo is just in the dash for looks- the sidepipes will be my music-
I moved the vent to the antenna hole-
The other thought I am contemplating is putting a fuel cooler on the return -a few OEM new cars have it- can't imagine it would hurt - or help...
Richard
DSCN4419 DSCN4420
Burning Brakes
Joined: Oct 2010
Posts: 1,160
Likes: 23
From: Prescott AZ
Thanks....
actually here's some updated pics- since the stereo is just in the dash for looks- the sidepipes will be my music-
I moved the vent to the antenna hole-
The other thought I am contemplating is putting a fuel cooler on the return -a few OEM new cars have it- can't imagine it would hurt - or help...
Richard
DSCN4419
DSCN4420
actually here's some updated pics- since the stereo is just in the dash for looks- the sidepipes will be my music-
I moved the vent to the antenna hole-
The other thought I am contemplating is putting a fuel cooler on the return -a few OEM new cars have it- can't imagine it would hurt - or help...
Richard
DSCN4419 DSCN4420
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Just FYI that vapor line needs its check vlv to prevent slosh going into the charcoal canister. I changed from non-vented to vented cap because my carb system uses a continuous return that i installed and discovered that it pressurized the tank from the return fuel and vapor. Then with a right turn and a full tank of gas it sloshed into that vent and forced fuel all the way to the charcoal canister. Yes fuel was coming out the top of my charcoal canister right next or eve onto the exh header. Wow what a scary experience.
What im saying is that with a pressurized fuel return line any tank vent has to be at the highest point in the tank and protected from any slosh.
Richard has the best tank vent i have ever seen or imagined - though not a "simple" fix. Nice work Richard.
What im saying is that with a pressurized fuel return line any tank vent has to be at the highest point in the tank and protected from any slosh.
Richard has the best tank vent i have ever seen or imagined - though not a "simple" fix. Nice work Richard.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Le Mans Master
Joined: May 2003
Posts: 8,877
Likes: 3,556
From: Fernandina Beach FL
2023 Restomod of the Year finalist
2020 C3 of the Year Winner - Modified
I think the fuel cooler is a good idea. I was talking to a fellow just the other day about how he use to have a can under his hood that the fuel line ran through on his old drag car and he would put a bag of ice in the can and he said it made a noticeable difference especially on hot days and multiple runs.
Yes- I just have to figure out where to mount- I have my eye on one of these- like $80.
Just FYI that vapor line needs its check vlv to prevent slosh going into the charcoal canister. I changed from non-vented to vented cap because my carb system uses a continuous return that i installed and discovered that it pressurized the tank from the return fuel and vapor. Then with a right turn and a full tank of gas it sloshed into that vent and forced fuel all the way to the charcoal canister. Yes fuel was coming out the top of my charcoal canister right next or eve onto the exh header. Wow what a scary experience.
What im saying is that with a pressurized fuel return line any tank vent has to be at the highest point in the tank and protected from any slosh.
What im saying is that with a pressurized fuel return line any tank vent has to be at the highest point in the tank and protected from any slosh.
Look at the way the fuel is returned on the Aeromotive Pump I am using- The corrugated pipe and the rectangular spout- I'm sure the guys that designed this did it for a reason...probably not a bad idea to 'copy'!!!
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Well that w/s has some nice vent products and probably what i should do rather than just a vented cap - thx for sharing.
Well my 4th gen Z28 has an corrugated tube on the fuel pump but its on the feed/supply/outgoing line. Ive always thought that was needed for the sending unit as the pump mounts on the level sending unit which will bend the line as the level in tank moves up & down. But the return line is not a corrugated plastic line but some kind of thick black rubber like flexible product which has to flex also - and the pump vent has the same black stuff but vents inside the tank while another line on top of the sending unit vents the tank to a sealed canister. I dont know how the canister does it - think it has a high press relieve - but every time i open the fuel cap i hear a loud hissing sound. I swear it a sucking sound but others are convinced its fuel air/vapor rushing out. Anyways the chevy fuel sys is pretty much a sealed sys since the 90s. And that could be another option (to copy) as it should reduce gas fumes in the garage. But it looks like the vent needs to start at a high location on the tank regardless of the system.
Well my 4th gen Z28 has an corrugated tube on the fuel pump but its on the feed/supply/outgoing line. Ive always thought that was needed for the sending unit as the pump mounts on the level sending unit which will bend the line as the level in tank moves up & down. But the return line is not a corrugated plastic line but some kind of thick black rubber like flexible product which has to flex also - and the pump vent has the same black stuff but vents inside the tank while another line on top of the sending unit vents the tank to a sealed canister. I dont know how the canister does it - think it has a high press relieve - but every time i open the fuel cap i hear a loud hissing sound. I swear it a sucking sound but others are convinced its fuel air/vapor rushing out. Anyways the chevy fuel sys is pretty much a sealed sys since the 90s. And that could be another option (to copy) as it should reduce gas fumes in the garage. But it looks like the vent needs to start at a high location on the tank regardless of the system.
Le Mans Master
Joined: May 2003
Posts: 8,877
Likes: 3,556
From: Fernandina Beach FL
2023 Restomod of the Year finalist
2020 C3 of the Year Winner - Modified
There are several that have tried it...some degrees of success- but w/ different gas tank designs- where the vehicle has a long filler neck.
I just can't see it being a great idea w/ the Corvette's short filler neck- especially since gas is so volatile.
Richard
I just can't see it being a great idea w/ the Corvette's short filler neck- especially since gas is so volatile.
Richard
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Hey, Richard thats a great idea. Well maybe the GT/lemans style filler neck would work for this. Someone on the forum here used make a gorgeous lemans filler neck & cap but i think it was too unprofitable for his time & effort.
Now another item on my to do list.
Ooops i read the article and that filler cap was a fake covering the stock cap so i deleted the links - sorry.
Now another item on my to do list.
Ooops i read the article and that filler cap was a fake covering the stock cap so i deleted the links - sorry.
Last edited by cardo0; Jul 10, 2014 at 12:42 AM. Reason: big mistake