While researching my latest no start condition I came across threads with pics showing sumps welded to stock gas tanks. All showed what looked like fairly large holes cut in the tank to let fuel drain into the sump. My thought is that a smallish hole would be better. I'm thinking of a slot about 3 inches long centered near the back of the sump with the sides bent down into the sump to make the slot about an inch wide. This should allow plenty of fuel to drain into the sump but during hard transient cornering or breaking would prevent a lot fuel sloshing back out of the sump. Any thoughts on that? Because if I have to drop the tank again I think I would go this route with an external pump etc.

 

Yours is a 91? As long as it's the factory tank, you should already have a sump in it.

Edit: oops they're actually baffles. Please ignore me.

 

For my "sump" all I did was drill a half inch hole in the bottom of the tank and weld a 8an fitting the the bottom of the tank, then 8an line to an external pump, then 6an to the fuel rail. ***NOTE this is not the 'correct' way to do it but I really didn't see the point of an elaborate sump system being my car is a street car. No problems with this setup with spirited street driving. If I was autocrossing or at the dragstrip pulling 1.3 second 60' times I could foresee some issues.

 

Interesting but not really a comment on my suggestion.

 

It kinda depends on other factors, like if your pump is too good will it suck the kinda small sump area dry faster than gravity fills it? I agree you don't need super large holes or to cut the entire area out, you want it to act like a baffle to keep fuel in the sump But if G's are making the entire tank slosh then they are also working against draining into the sump while your pump is still going all out. Even a sump bucket around an E-pump will starve if the tank is low enough.

Sumps work best in drag racing and I even prefer to mount the tank at an angle than flat. The angle won't let me fill the tank as much but drag racing is not a high volume fuel sport. Maybe you should look into a surge tank setup if your trying to make a tank last longer.

 

I sumped mine, and cut holes that the instructions said to do.
I used an external pump.
Mine combo is for drag racing tho