Boomer

I think that the best answer would be to run the shortest non-tight fuel line you can reasonably run, and run several loops for your pressure line. On my NTC3 I run three loops around the handle thingy.

Just do what's reasonable. Having too much or too little is not going to kill you, unlike having an extra or less turn in your carb. . .

popsracer

wahturi;

What you should find by lengthening the pressure line, is that there should be less foaming in the fuel tank, most noticablely at idle. One nice gentle loop should be enough, the EXACT length is not important. (just like Boomer said)

Boomer

You know, it's amazing how much we agree on Pops. . .

speedoo

Don't cut your fuel line too short. A too-short line from the tank to the carburetor will not get the fuel to the engine quicker; use a long piece. The fuel pick-up is usually at the bottom of the tank; when the car flips over, the fuel pick-up isn't fed any fuel and the engine uses only what's left in the lines. A short line will run out of fuel more quickly.

Pressure tap. Here's another line that you should keep long to equalize the exhaust pulses that pressurize the tank. A short line transfers the pulses to the tank and can cause the fuel to foam.

Darkseid

iTrader: (9)

Thats the way I always thought of it. I've seen some people with some really short fuel lines, and when they flip over, their out before the marshall can even reach them. Now, I'm not saying make it crazy long, but I think a little extra wont hurt and may actually help.

Of course if you never crash, then its not an issue!

patelladragger

I don't know if this is true or not. I know the offroad guys used to say this a lot, but I run my fuel line short as possible and have been upside down before plenty times and never ran out. I think the pressure may feed the carb whether the tank is upside down or not.

On the lines it was more important to loop a longer line when running the rear exhaust ntc3. Other cars I've had no issues with pressure lines of varying sizes.

Paris site says you can actually fine tune performance characteristics with the length of pressure line but I have enough variables to get a handle on without fooling with that one.

Darkseid

iTrader: (9)

I HEAR THAT!!!

popsracer

Boomer;

Well we sort of got our R/C feet wet at Showtime together.

A 2" difference in length can be felt by an experienced racer.
A LONG line will hold more bubbles that will stall your engine.
There is NO EXACT length for any given Car/Engine combination.
All that Boomer and I are trying to do is give everyone a starting point. From there, experiment and see what works best for your application.

speedoo

From what I have been reading 8" minimum to 12" maximum on the exhaust retune line. The shorter the line the faster the top end speed up to a point. Each engine and tuned pipe have different responses to lengths before the fuel starts to foam. The best thing to do is start long and cut off a little at a time until you find what is best for you.