Burst Panel Question.. need help asap

Every time the car launches and gets out about 300 feet it blows the burst panel out but its not an explosion that causes this. Ive done a running leakdown after this happens every time and everything is normal. ALso after it does this it balloons the fuel tank up and puts a million holes in it even though i have a vent tube. can anyone shed some light on this and how could i prevent the fuel tank from doing this? any help is appreciated... thanks in advance..

 

Not sure about the ballooning of the fuel pump, but the burst panels might be going because the straps on the spark plugs are too long, and are starting to glow, pre-igniting the fuel. Also, if your fuel shutoff isn't taped up or somehow prevented from partially shutting off, you should do that too. We banged the blower two runs in a row because the fuel shutoff was closing on the launch.

 

years ago i had a similar problem. in the pits, everything was fine. but when i would do a burnout it would blow the panel right out. i changed everything under the sun and it still did it. finally i took the whole fuel system to bill barrett and watched as he put it on his flow bench. as he sped the system up you could watch the main line to the barrell valve pulsate. he said that was from an air leak. even though no fuel was dripping it was sucking air at high speed and that was fixed with a new fitting under the pump. this might not be your problem but by putting it on a flow bench i was to find the problem without hurting any more parts during trial and error.

 

Thanks for the info but i wonder why it is pressurising my fuel tank and causing it to balloon up and get holes?

 

the vent is obviously not working , doesn't seem to be big enough to relieve the pressure causing the tank to swell and then pop. sounds like more fuel is returning to the tank than going into the motor.

 

is your burst panel moving in and out? this would happen when ever you let out of it ...as in the burn out or on the stand in the pits? what we do is on the back side of the panel were you see the seams i put a big bead of silicon on the seams..panels last a lot longer now..it takes out the weezing effect on the panel. hope this might help someone

 

You should check to make sure the spool is installed correctly in the barrel valve, if it is installed wrong it could be shutting off fuel flow and causing all fuel to return to tank. Doug

 

Burst Panel

I AGREE WITH ALL THE POSTS ABOVE SOMETHING IS CREATING A LEAN CONDITION CAUSING THE BLOW OUT. ON THE TANK IS THE VENT IN THE LINE OF FIRE COMING OUT THE BURST PANEL HOLE. SOMETIMES WHEN THE PANEL BLOWS AND THE VENT HOLE IS IN THE PATH OF FLAME COMING OUT IT CAN CAUSE A QUICK FLASH FIRE IN THE TANK INSTANTLY BALLONING THE TANK. IT MIGHT BE A WISE IDEA TO MOVE THE VENT OR USE A BURST PANEL DIVETER WHICH WILL CAUSE THE AIR AND FIRE TO TRAVEL DOWNWARD OR UPWARD WHICH EVER WAY YOU MOUNT THE DIVERTER. WE HAVE DIVERTERS IF YOU WANT TO SEE ON GO TO WWW.RBSSUPERCHARGERS AND TYPE IN PANEL DIVERTER UNDER THE SEARCH SECTION. GOOD LUCK ALSO CHECK ON YOUR LEAKDOWN AS IF YOU ARE USING A DUAL GAUGE SOMETIMES PEOPLE READ THEM BACKWARDS.

 

Fuel Tank Vent

RBS is correct; having the fuel vent in the wrong place on a funny car can be very dangerous. I have seen this happen, when a burst panel came out of a car at about the 1000ft mark the flame and heat followed the underside of the body and was sucked into the fuel tank causing it to explode, ripping a seam open from top to bottom and dumping about 8 gallons of alcohol on the car, burning it to the ground. When we examined the car, the fuel tank was also ballooned out just like what you’re describing. As far as why the burst panel keeps going, could be several things related to the fuel system. One thing to check would be the rubber hose(s) between the fuel tank and the fuel pump, make sure the hose isn’t collapsing as the fuel pump picks up speed, causing a lean condition.

 

These guys are right about the backfire igniting the fuel tank. Get that fixed. The suggestion about the fuel shutoff is also worth checking.

 

Just recently I saw a fuel system on a flow bench. It was from a TAD, they kept chucking blower belts. They tried everything and on the flow bench it was noticed that when they spun the pump up the fuel shut off would creep towards closed causing a lean condition that would backfire the motor and chuck the belt. It wasn't breaking the burst panel because there wasn't enough fuel to generate enough of a over pressure situation to pop the panel. If they hadn't ran the system on the flow bench they would have never seen it. Taping the fuel shut off open fixed it.

 

I've had a similar problem and it was the cam shaft phazed incorrectly, check cam install on 1 and 8 and make sure it reads the same or very close. if you check and it is retarded on 1 side of motor it will detonate because the plug will glow igniting the intake charge , it takes time for the plug to glow and that is why you maybe getting to 300ft and then having the problem I went through 30 panels to find this problem, fuel shut of coming on has happened and also intake hose sucking closed due to breather not being large enough, it's all a learning process.
Matt

 

We had a problem, ONCE, with the fuel shutoff vibrating toward the closed position. This cost us our one and only qualifying attempt. Fortunately our driver felt it nose over and clicked it off before it went BOOM. We now have a spring on the shutoff that clicks over center and prevents the valve from vibrating closed unintentionally. Tape and rubber bands are OK, but the spring will always repeat and can't be forgotten in the heat of battle.
Henry