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Old 02-11-2010, 04:45 PM   #1
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Default Too much fuel line?

will it hurt or effect anything running to much fuel line for extra runtime? will it be too hard to get the fuel from the tank to the carb?
thanks
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Old 02-11-2010, 05:13 PM   #2
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not good for racing cause too much fuel line may be illegal and if you are upside down too long it builds up a bigger air pocket so the motor will flame out, then when you come into the pits your pit guy will have your car on the box longer trying to prime it back up to run.
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Old 02-11-2010, 05:24 PM   #3
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Too much fuel line also lowers the fuel pressure in the line and the engine has to work harder to suck the gas out of the tank. Think of it like a straw, a short straw you hardly have to put any effort into, a long straw with lost of bends and twists requires a lot more work to move the same amount of liquid to the end.
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Old 02-11-2010, 06:05 PM   #4
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Quote:
Originally Posted by Frank L View Post
Too much fuel line also lowers the fuel pressure in the line and the engine has to work harder to suck the gas out of the tank. Think of it like a straw, a short straw you hardly have to put any effort into, a long straw with lost of bends and twists requires a lot more work to move the same amount of liquid to the end.
That's the same example I use.

What it means is you'll need to run richer carby setting to get the same amount of fuel as you do with a shorter line. So it's relative.
Air will move out of the line very quickly & you'd have to have a very large air bubble to cause a flame out. If you have a tank where the fuel pick up is locked at the bottom, so when upside down it sucks air, having a longer line will give you more time to get it turned over & as said, air moves very quickly, so when the air bubble hit the carby, it rushes through with very little resistance & there should be enough fuel in the motor to get past this, maybe with a few hesitations.
The negatives are - when your fuel capacity is measured at racing events they include the fuel lines. So you may be running with an illegal amount of fuel. Secondly, it may give the fuel more time to heat up, resulting in a less dense fuel.


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Old 02-11-2010, 11:24 PM   #5
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The longer the fuel lines the slower the reaction on the throttle..
When giving throttle exhaust pressure must build up and must speed up the flow with a lot of resistance in the lines.

With shorter lines the pressure is much quicker at the carb, with that you can lean out the LSN making the engine more powerful from the bottom and a better milage.
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Old 02-12-2010, 08:17 AM   #6
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All of the above
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Old 02-12-2010, 08:21 AM   #7
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So what is the correct length of fuel line you should be using ?
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Old 02-12-2010, 08:33 AM   #8
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So what is the correct length of fuel line you should be using ?
im sure its on a car by car basis, but i like to keep mine in the 6-8" range
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Old 02-12-2010, 01:08 PM   #9
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also too short isnt good either. you cant run it directly from the back of the tank right to the carb. find a way to make it around the tank once then make your way to the fuel nipple. not really any more than 10-12''.
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Old 02-12-2010, 01:19 PM   #10
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Old 02-12-2010, 04:37 PM   #11
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I don't run mine around the carb like that. It puts the fuel too close to the head for my liking and only increases the fuel temp before it enters the carb, not by much but it does.
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Old 02-12-2010, 08:37 PM   #12
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I'd be scared to have my fuel line that close to the brake linkage. It just screams "rip me!!"
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Old 02-12-2010, 10:56 PM   #13
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i run my fuel line exactly like that picture on my rc8, and i have had 0 problems, my buddy runs his the same way with no problems, the break linkage doesnt bother it and fuel might get warm but it doesnt affect it due to the fact it still the rest of the lone to go threw to it has time to cool off before reaching the carb fuel inlet barb.
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Old 02-12-2010, 11:00 PM   #14
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Originally Posted by Miniracer23 View Post
I'd be scared to have my fuel line that close to the brake linkage. It just screams "rip me!!"
i agree. heres mine. neat and clean

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Old 02-13-2010, 06:25 AM   #15
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Quote:
Originally Posted by Miniracer23 View Post
I'd be scared to have my fuel line that close to the brake linkage. It just screams "rip me!!"
ok thanks guys i just now remembered to check this thead. but yea i run my fuel line like the first picture of above. i drilled some holes in the top of the tank (not through the tank) and put zip ties there so the break linkage doesnt rip the fuel line because i actually had it almost happen. it was wearing grooves in the fuel line. so the zip ties hold it back good from that happening.
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