Fuel Accumulator......

[Jim Nilsen]

Won't work. If the regulator is set at 45psi then the pump is never pushing more than that. Hence, the accumulator will only get to 45psi. This means that fuel pressure will only go down from there.

Several aftermarket EFI systems will only accommodate +/-10% fueling changes from the table values even in closed loop. That's a fine line to live with, and then throw in fuel pressure fluctuations, and your pistons might not be too happy.

Carburetors with mechanical engine pumps are easier in that there is a reserve built in. The line from the tank to the pump acts as a reserve, plus the volume of the bowls. I never had a problem at the track with carburetors. EFI is another story.

What corner pickups did you use?

Todd,

How much HP is your engine making, and what fuel tank/cell do you have?

It all depends on what side the regulator is on to the accumulator.
From my experience with accumulators you always have a higher pressure pump and the accumulator is always at a higher pressure than the down side of the regulator, especially if it was a bypass regultor to keep the volume up. The accumulators I have worked with were fed by air pumps and they tend to pulse so bad that with out the accumulators you would not have a consistent pressure to the regulator. With an electric or hydraulic pump the pressure is more consistent we usually didn't need an accumulator. The accumulator would still work the same and when you needed to go from one tank or batch to another while filling you would have the accumulator to make sure you didn't have any fluctuations in the fill line.

The big drawback to an accumulator is space and weight.

The good thing about this whole thread is that it is bringing more out about fuel systems in general that still needs to be discussed.

I like the sound of the low pressure pump from a big tank to feed the small one like Jeff uses in the Ultimas. We just need to get a list of parts and prices to make it easier to do without a lot of guesswork and research. Tanks that are simple are not as costly as baffled tanks and I have enough room for two tanks of the right propotion and then the other side of all this is for someone to make a divided tank, not baffled but divided to make strapping then in a lot easier.

For now I am happy to just be able to go below half a tank of fuel and not run out. Having to drive into a town to fill up before every time out on the track is a pain.

For those that want to know, my tank is a circle track cell and had the pickup in the right rear and when you go to a track with mostly right hand turns you really have problems. I had totally forgot that my pickup tube was there after 10 years of waiting to get my car on the road, the pickup tube went in at the front right hand corner. Yea I know it was a dumb mistake but it is much better now and we will see how good at Gingerman.

I think we can all safely say that the accumulator is not going to be the way to go but I wanted to hear others thoughts since it makes us think and from that other problems and solutions come.