longer fuel tank back pressure line?

[Jmacca]

I was just wondering why people like to have really long fuel back pressure lines? what does it do to the pressure in the tank?

no explanations i have found are very good, hopefully someone on here can tell me.

 

[olds97_lss]

Since the tubing we use is fairly soft, it will expand when pressure is applied. The engines run and pressurize the line with puffs of air vs a constant pressure. The longer line absorbs the puffs (supposedly) by either expanding or just by virtue of being longer and having more air capacity and makes the pressure more even in the tank when the engine is running.

It's kind of like having an air compressor with an air tank vs a line directly off the compressor pump itself. That tank gives you a consistent pressure even when the pump is running due to it's volume.

 

[Rolex]

I couldn't have said it better myself....
Well, actually I could, but the results would have been the same.

 

[Jmacca]

thanks for the info ^^

 

[exmark93]

so will a longer pressure line give me better fuel economy?

 

[olds97_lss]

No. Just possibly more consistent tune.