THAT ARGUMENT AGAIN...  Is bigger better? err no...

4mm O/D Nylon (internal bore 1.7mm to 2.5mm) Nitrous line, Versus the Stainless Steel Braided 3.7mm ID Nitrous line argument... Which is the best one to use with your system. This pipe feeds Liquid Nitrous Oxide to your Nitrous Solenoid in the cars / bikes engine bay / area...

 
OK. The facts...

These are the two "normal" obvious possibilities. On the face of it it looks like a simple question - but its really not!

• The first common type - The "brake pipe" type of line, in braided stainless steel with a fairly big internal bore, and relatively high thermal mass.

• The second commonly used type (at least here in the UK) is the 4mm NYLON Outside Diameter or O/D with quite small internal bore inside, and low thermal mass "cheap" unprotected (no stainless armour sleeve) Nitrous line...

The Nitrous lines job is to deliver a constant flow of LIQUID Nitrous Oxide to the solenoid valve.

Advantages of the Braided stuff...

RED = DISADVANTAGE
GREEN = ADVANTAGE

• Its pretty to look at!

• Cost

• It STAYS pretty to look at after its been disconnected and re-connected hundreds of times!

• Its tougher, and more abrasion resistant because its coated with stainless steel braiding.

• Can stand very high pressures safely

• it has less "gassing" of the Nitrous (and stays in dense liquid form) as flow increases due to less pressure drop over the length of the tubing. This means easier more consistent jetting - especially where big Nitrous jets are used because the Nitrous arrives at a consistent density regardless of flow rates..
   

• It has more internal volume, so a short period of time goes by when activated, where all the "gas" that may be sat in the line (not liquid) gets pushed out  through the Nitrous solenoid and Jet. This effect is worse with small Nitrous jets and long pipe work runs. In racing use a "purge" valve can be used to ensure that the air/gaseous Nitrous is vented to atmosphere before the run.
   

• It looks more professional
   

• High thermal mass means it will cause gassing for longer wherever the pipe is hotter than the Nitrous leaving the bottle.
   

• Its more difficult to cut and fit the end fittings for if you have never done it before! But not too difficult.

Advantages of the 4mm O/D Nylon stuff...

RED = DISADVANTAGE
GREEN = ADVANTAGE

• Its not as pretty to look at

• Cost

• Its nuts and olives, and the pipe itself begins to look tatty after it is undone and redone lots of times!

• Its not as tough and abrasion resistant.

• Not designed to stand very high pressures safely. But is "ok"

• It has MORE gassing of the nitrous as flow increases. This is due to the pressure drop over the length which increases with the flow rate. This means less dense Nitrous Oxide delivered as the jet sizes go up or the pipe gets longe.. This makes it more difficult to estimate the correct jets without individual testing.

• It has less internal volume, so it "purges" the line of gas and air faster giving faster and smother "hit" of Nitrous. Little or no need for a "purge" valve except under extreme racing conditions.

• It looks less "professional"

• Its easier to cut and fit the end fittings

• It is small so can be run in side wiring looms, under carpets more easily.

CONCLUSION
There may be a few other minor considerations but basically this is what happens. So, if you are running a low power system in a street car, a nylon line is adequate. If you REALLY want braided here, with its bigger internal volume then it will work, but there will sometimes be a short delay between hitting the button and go! This matters less with bigger hitting systems because 150bhp system purges the line 6 times faster than 25BHP system! There is no "yes" or "no" answer. Horses for courses I am afraid... Personally for 70BHP and above I would use Braided, routed carefully away from heat... And on a bike where the line is short, I would ALSO use braided for 35BHP and above.

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