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Old 05-17-2011, 12:58 AM   #1
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Default Fuel tube lengths?

What is the benefit of running huge amounts of fuel tube like I see some buggys with? Is it purely for an extra bit of run time? Or is there any benefit to it?

I have just run mine straight to the carb with as little tube as possible due to not having much tubing. Should I consider making a few loops for it, or just stick with short and simple?
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Old 05-17-2011, 01:04 AM   #2
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you will hear many theories about this, but i believe you should keep fuel lines as short as possible, this increases fuel pressure.
some people run a heap of fuel line to increase the run time upside down but even short amounts of fuel line will keep you running 10-15 seconds if you don't rev the hell out of your engine, hope this helps
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Old 05-17-2011, 01:40 AM   #3
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you also dont want to much pressure in the fuel line or you run the risk of flame out on re fuelling, when shutting the lid it can force a large charge of fresh fuel into the engine and force a cut.

Tbh there are not huge gains to be had with huge lengths of fuel line and the gains in run time are not massive, it was a long time ago we checked but im sure the length needed to gain 1cc of fuel was probably longer than you would think, run as much as is necessary but try not to keep it really short.

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Old 05-17-2011, 03:48 AM   #4
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Mostly the extra fuel line is for when you are on your lid waiting to get marshalled.

With people either running a clunk style tank (Losi and Hot Bodies) or modding a tank to have a clunk, the extra line that people ran isn't needed as much. If you want a little more run time, add in a couple of fuel filters (with the guts removed) to gain some extra fuel. Depending on the filter you can gain 3 to 5 cc's. For club racing you could get away with that, but at larger events adding in the extra filters or fuel line could put you over the max. fuel limit.

If you really feel the need to do either of the above, be sure to check the length of the exhaust line.

My theory is that if you add in a bunch of fuel line or filters, you may need to shorten the exhaust line to compensate for the added fuel line or filters to keep the system in balance. If you run a short fuel line, adding some length to the exhaust line will help to balance the system.

As stated in the first responce, there are many theories and mine is but one. I'm sure that there are plenty of people that could better explain the effects of longer/shorter fuel/exhaust lines.
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Old 05-17-2011, 07:46 AM   #5
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The least amount necessary and make sure the fuel line and pressure line are the same diameter. IMHO the more line you run the more chances you are taking in the long run to get air leaks and then the tuning issues begin.......
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Old 05-18-2011, 12:36 PM   #6
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The caveats others mention above (pressure, clunks, etc) apply but the only thing I can think of that *might* be a reason to run longer lines is to reduce the temp of the fuel going into the engine for longer run times (allegedly). Like a poor man's version of exhaust coolers you see sometimes from pipe to fuel tank.

Whether or not they are functional or if you'll even notice a difference is debatable.
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Old 05-18-2011, 03:40 PM   #7
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I could see a longer fuel line in between the exhaust and the tank so it doesn't heat up the fuel but I run an exhaust cooler to my tank on both my
D8 and D8T and I run a fuel filter in between the tank and the engine as well. I noticed an increase in the performance with the exhaust cooler and my fuel lines are as short as I can get them. I run a little longer from the tank to the fuel filter and then to the engine but I only do that for a clear nicely looped line that decreases a chance of pinching or breaking the lines, I've run the same fuel lines for the past year with no cracks or breaks in the lines but I also keep them clean and blow them out when I can. Works for me.
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