So, I am in the process of building a 13brew and drop it in a rx8. I have a 20oz co2 paintball tank that i want to use to make a surge tank but my question is. What is the smallest size tank that can be used for this application?

 

I think you would need to see what your fuel pump delivers, then figure how long 20oz would last at that delivery rate.

I'd want 10-15secs worth of fuel at least. Also would need to make sure you can pick up all that fuel in the surge tank.

I'm pretty sure I've seen something like a CO2 bottle used as a surge tank before. May have been a nitrous bottle though.

 

Get some thing like this Integrated Engineering Billet Surge Tank- Submerged 044 Pump and run a Bosch 044 in it with the stock pump or even a Supra Denso feeding it.

Because the Intank pump is not regulated it will easily outflow the 044 that's having to fight the Regulator, so the Surge Tank should stay full even at WOT.

 

Another option for fuel pump inside the surge tank...this is what I'll be running.
Fully Enclosed FP34 044 Fuel Surge Tank - 034Motorsport | Performance Parts for Audi, Porsche, and Volkswagen

 

I already bought an inline fuel pump a1000. I really like the above set up. Clean and perfect for what i need. But since i have this pump already i want to build a small surge tank. Ive looked around but the ones ive found look cheaply built

 

Panda, I looked into that Tank and it does look good/well made but i was put off a bit by the Pick up. I'm using -8 feed's and they only recommend running -6 lines as the pick up is 3/8 instead of 1/2 minimum.

But that said it would be good if your using the stock feed 3/8 lines.