Last summer I had a sump installed in my stock tank. It was from Competition Engineering. The reason it was installed, is because when I was at full throttle down the 1/4, I would run out of fuel when it went into 2nd. I would let off, and then it would come back hard, and then when it went into drive, it ran out, until I let off, and then pushed the pedal down again to finish the race. This only happened at 1/2 tank of gas, or less. Now the same thing happens with the sump. If I have a half tank or more, no problem, it runs strong all the way thru the gears. Should I use the foam baffles? I was considering a fuel cell, but after reading what everyone else posted about the trouble that you have to go to installing a firewall, and venting, it seems like a lot of trouble and more $$$. So basically, the question is about the foam baffles. Will they help keep the fuel from sloshing? I think that is what is happening, but maybe some of you guys have been through this and are in the know! :Smarty:
Are you using an electric pump? I have the same sump with Mallory 140 and -8AN lines and have no starvation problems.
Gary, Yes I am using an electric Barry Grant Hot Rod 220 pump. I know on the Competition Engineering sump kit, that the directions indicate the holes need to be drilled in a particular pattern, and that they are a certain diameter. If they did that wrong and located it too far back, or not far enough, then... I know that the holes were very important in where they were located, because if you didn't put them in, then the fuel would go to the back of the tank easier. Nothing to hold it back. Looks like I will be pulling the tank now to double check. How far was yours welded back? Do you use the foam baffles?
Just a thought, if you're running a Holley, do you have jet extensions in the secondaries? Without them, it can cause a fuel starvation problem at full throttle.
Phillip, No, I do not have jet extensions. Do you think that is the cause? Are they recommended for this kind of application? Racing? I have about 7 lbs of pressure on the gauge at the regulator. We even bumped it up to 8 and was told that it was not a good idea to go much more than that. It didn't help with the fuel starvation either anyway. I can't figure why at a half tank or less, it will act like it is running out. Above a half tank, I never have any problems. We have checked for pinched lines, etc.
Just a couple ideas: Where is the pump mounted? Electric Pumps, especially BG's, do not work well if they have to pull AND push. Is the pump lower than the bottom of the tank? Is it behind the back of the tank? Make sure the pump inlet is gravity fed at all times. Also you can check your fuel flow. Unhook the the last fitting before the carb, put it in a measured metal one gallon container, turn on the pump until the can is full, and time exactly how long it takes. I don't know how much HP you're making or kind of carb you have, but you should be filling it in at LEAST 30 seconds, and that's for a typical 12 or 13 second car. A quicker car will need 20-25 seconds. Maybe something here will help. Have fun.
Yes, jet extensions are a great thing. They are also only about $8 or so for a pair at Summit/Jegs. When you launch all the fuel, in the tank as well as the carb, sloshes to the back. On the carb the jets for the secondaries are forward ie. closer to the center of the carb. The jet extension will keep the jets in the fuel at all times, especially under hard acceleration. Here's the link at Jegs for those: http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=722&prmenbr=361 Jeff is also correct about placement of electric fuel pumps. They should be as far back and as low as you can put them. They are much better pushers of fuel than pullers. That's why you see a lot of race cars with the pumps mounted out back under the gas tank. Gravity helps get the fuel to the pump. Also, make sure you put a filter BEFORE the pump to keep it from getting locked up by accidently sucking something in from the tank. Cars, always something else to check on:stmad: Good luck. Phil
