FUEL CELL, FUEL STARVATION, can't figure this one out Options

[kart54]

Well, the only (hence fastest, (I am kidding here)) G prod SCCA porsche made its debut at Willow Springs for practice on Friday. One day I'll even get pictures for you guys. Anybody who says a 1.8 can't be fast come on out and drive this car, I dare ya. I was able to run with almost everything there except a couple of open wheel pro Mazda cars and a $180,000 or more GT3 cup car. Its' amazing to me how much people spend on a sport that is basically just for fun.
Once the Goodyear slicks heated up it was basically put it to the floor and leave it there except the lefthander going up the hill which was a third gear down shift. Other than that a little left foot trail braking in a couple of spots and leave it floored. Want a true thrill; go through turns 8 and 9 at Willow flat out, on the rev limiter with a taller 5th gear and never lift. Took me about a third of the day to get that much huevos, plus some suspension adjustment and when I did it was a real rush. Then repeat at turn 1, a narrow left hander same type of rush.
But, once the slicks heated up and my fuel burned off to between two thirds and half remaining a very strange problem arose. This didn't happen at low speeds or with a full tank.
My fuel cell sits where the original gas tank did. The fuel pickup is on the passenger side and the return is on the driver's side. The hose for the pickup is all the way to the bottom of the tank (I checked and tested the hose for any holes) and I run foam in the tank to help prevent sloshing, the fuel return is about an inch and a half into the top of the tank.
With the fuel burned off when I went into the left hander the car would stall out like it was fuel starved, once I got back on the straight or into a right hander it would run great. It also ran great for 5-8 laps when it was full of fuel.
Here's the odd part; in a left hand turn the fuel would be sloshing toward, not away from, the fuel pickup and away from the return line. Is there any reason the return line needs to be immersed in the fuel?
This has me completely baffled. I disassembled everything at the track. There are no air leaks of any type on the fuel pickup side all the way past the fuel pump and the fuel pickup hose goes to within a 1/4 of an inch of the bottom of the tank. Nothing gets in the way of the fuel pickup and the fuel vent works properly.
The problem only occurs under very hard left hand cornering with a half to two thirds full tank.
Any suggestions and possible solutions will be greatly appreciated. This one's got me.
Erik (Thorshammer), Chris (Tangerine racing), John (south of the border Rodgers) et.al any sugestions?
Randy
"Car 54 Here I Am" G prod Porsche 914 The fastest in the U.S. (Ok, Ok, the only one in the U.S. so it's also the slowest)
Ventura, CA.