Fuel tank mod

[nando]

Nice mod. Didnt the e21's and some vw have some sort of fuel "capacitor" thing? I swear I've seen something like that to battle our starvation issues.

that was a different thing altogether, and some E30s had them too. it was a fuel damper that was meant to reduce pulses/harmonics in the fuel lines themselves, because they were typically single batch fire fuel injection which meant that the pressure at the rail would vary wildly with each injection pulse.

[blueapplesoda]

Nice mod. Didnt the e21's and some vw have some sort of fuel "capacitor" thing? I swear I've seen something like that to battle our starvation issues.

[jlevie]

I had to trim one tab slightly to allow the pump to be in the desired orientation. A minute or so of work with a fill will get the job done.

[Snowmann]

Jim,

Did you modify the tank in anyway to fit the transfer pump to the driver side?

Mine when installed and spun to lock is indexed with the feed line facing to the drivers side (180 degrees from yours)

The tabs on the fuel pump hole in the tank are different sizes and appear to only allow the pump to index this way.

[Snowmann]

Well damn... That's the part of the puzzle I don't have... Looks like we're going that route.

[jlevie]

I'm assuming you just didn't want to weld as it was a used tank?

My plan is a npt weld bung with basically the same component list as yours...

Correct. While it is possible to weld on used tank by filling the tank with inert gas, it is easier to attach the fitting they way I did.

A better alternative, which I wasn't aware of at the time, is to replace the in-tank high pressure pump with one from a late production 318is. That pump has a return fitting which eliminates the need to fabricate same.

[Snowmann]

The bulkhead fitting is really pretty simple. I drilled and tapped a 2x2x1/8" piece of steel plate for 3/8NPT. The brass fitting is a 3/8" compression to NPT elbow. The NPT side (that winds up in the tank) was drilled out to accept 3/8" soft copper tubing which was soldered into place after bending and trimming. I formed that tubing to generally follow the existing fuel feed tube from the siphon.

I used JB weld on and around the threads of the elbow. The bulkhead plate was then attached to the tank with four pop rivets with JBweld between the plate and the tank.

I'm assuming you just didn't want to weld as it was a used tank?

My plan is a npt weld bung with basically the same component list as yours...

[jlevie]

Any close up pics of how you went thru the tank wall with the 1/8" plate? I'm assuming the fittings are compression style given the tube used... But trying to figure out how you successfullly created a bulkhead style fitting with this plate concept...

The bulkhead fitting is really pretty simple. I drilled and tapped a 2x2x1/8" piece of steel plate for 3/8NPT. The brass fitting is a 3/8" compression to NPT elbow. The NPT side (that winds up in the tank) was drilled out to accept 3/8" soft copper tubing which was soldered into place after bending and trimming. I formed that tubing to generally follow the existing fuel feed tube from the siphon.

I used JB weld on and around the threads of the elbow. The bulkhead plate was then attached to the tank with four pop rivets with JBweld between the plate and the tank.

[Snowmann]

Any close up pics of how you went thru the tank wall with the 1/8" plate? I'm assuming the fittings are compression style given the tube used... But trying to figure out how you successfullly created a bulkhead style fitting with this plate concept...

[JakeP]

They won't float around if you put enough in there. You need to pack it in!

[e30s50dan]

Yea. I checked out the site. They also sell small accumulator tanks. I'm afraid the small foam cubes would float around.... Damn,why can't someone come up with an EASY fix?

[JakeP]

You could buy some foam from Fuel Safe and just throw it in the top of your tank. They come in little cubes, easy to do.

[e30s50dan]

I quess there is no foam baffles on the market that could be squeezed in,that would keep the fuel close the pump,huh?

[jlevie]

An E30 tank has a cup built into it that surrounds the pump pickup, but it isn't very effective under high cornering loads.

[nrubenstein]

The E46 M3 has a neat little accumulator cup that sits over the pump intake and works remarkably well to limit starvation. I wonder how hard it would be to retrofit that or something similar to an E30?

(My 323, otoh, starves at 5/8ths f a tank.)