Can I delete all this from on top of my fuel tank and cap the holes in the tank? The charcoal canister is long gone and there are no emission requirements in New Zealand. Also when I remove the filler cap there is a lot of air pressure in the tank. Is this normal? Thanks in advance.
LS1/T56 ex GTO

 

Gas in your gas tank will expand as it heats up. It needs somewhere to go and vent, hence the vent system.

The thing is what vents is gasoline vapors which are VERY flammable. That's why that system is there. Stock it takes those vapors and injects them into the engine at certain low-load times to be safely burned.

There's really no good reason to remove all that. The weight is negligible, they aren't in the way, and the system works and works well.

If you cap the tank you will have odd fuel pressure problems, not recommended either.

Dale

 

Tank has got to be able to breath as Dale says. The later cars deleted the expansion tank entirely and just ran a line loop with 2 of the check valves......if you simply dislike that invisible clutter.

Even with no emissions requirements, the stink of lawn mowers, etc, free venting to atmosphere is annoying enough for me!

 

Leave the gas tank plumbing as stock. Remove the canister and the rest of the system under and in front of the TB elbow
The hose that goes from the gas tank to the canister, put some type of filter on it, let it hang or push it up into the chassis somewhere.
The tank will function normally now and any vapor will go to atmosphere under the left side of the car. Have run this for years without any smell of gas vapor. And the tank keeps vapor pressure as stock.
Now you have two gas line being used: (1) tank to injectors, (2) fp regulator to tank, and the gas vapor line unused.

Then you can turn these three lines into an upgraded fuel system where the now unused line becomes the fuel return line and the original return line is used as a parallel forward flowing fuel line.
The fuel pump outlet hose goes into a large fuel filter and when it comes out of the filter, split it into two hoses going to the two forward feeding lines. At the fire wall, you have two lines supplying fuel.
Either go back to a single joined line as stock or two separate fuel lines.
I used these two lines to separately supply fuel to the primary and secondary injectors for parallel flow. After supplying fuel to the injectors, the 2 hoses go to the FPR, then one hose from the FPR goes to the vapor line back to the gas tank.