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Length of Fuel Lines

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DarthRacer

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Is there a minimum or maximum length my fuel and pressure lines should be to help rule out any strange tuning problems?
 
I don't think it matters. I don't that much. Some people have line wraped around everything. Shouldn't make a difference.
 
The only real rule of thumb is that they should be close to equal in length.

Some general guidelines are:
1. Make them between 7-9 inches in length.
2. Longer pressure line means engine will tend to run lean or possibly starve for fuel.
3. Longer fuel line means the engine will tend to run leand and stay running longer when inverted.
4. Shorter pressure line means the engine will tend to run rich.
5. Shorter fuel line means the engine will run rich and for a shorter time inverted.

Taking these guides and experimenting, you will find combinations can give you some of the strengths and minimize the weaknesses of both. Regardless, you will need to tune your engine accordingly to compensate for fuel and pressure line lengths.
 
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Good tips Sky. I never thought the length would matter. Is that why you have your line wrapped around the body post? I'm gonna investigate mine 2morrow. THANX:thumbsup:
 
I now have the fuel line wrapped around the shock tower to keep it out of the way. I moved it from where you see it in the image in the gallery. On my T-Maxx I have the excess coiled under the fuel tank.

Regardless, I have used the guidelines above to great success and have little trouble keeping my engines running (upright or otherwise).
 
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Most of the manufacturers will recommend what length to make the lines for each kit or RTR.

I have found that all the Manufacturers **except Traxxas do a good job of making sure the lines are tuned for the stock or recommended engines.

Sky outlined the basics for the most part.
Its fun to play around and see what happens.
 
Sky is correct with what he said happens when you lengthin or shortin the lines. The only one I touch is the pressure line. If you mess with this, you will effect the mid range of the motor. I like to lengthin it to about 10", depending on the engine and perfomance, to help the mid. I geared my car high on the second gear so there was a little lag in the mid. Leaning out the mid by putting a longer pressure tube cleared that up.
 
from what i have been told - a longer pressure line will decrease the pulsing action from the exhaust, thereby reducing the foaming properties of agitated fuel. Just my 2 cents. Also, sky is right, by having a longer fuel line, the engine will run slightly lean, but it helps alot in the event of the vehicle being overturned
 
NitroNewbie,
If you want to solve the foaming fuel problem, Christian had a good tip that works. Just a spritz of Armor All in the fuel (the gallon) solves the foaming fuel problem.

Originally posted by Çh®i§tiªñ
Spray only 1 spritz of armor all into your 'new' gallon of fuel. This will cause the bubbles to cease. I dont know of armor all causing any harm and even in looking at its chemical composition, find no reason it cannot be used. A LOT of people in this are have used it for a long time and have had no problems ever, including myself.

Get one of those little spray bottles of armor all (looks like a womans hairspray pump bottle) and JUST 1 SPRITZ! No more than that. No more bubbles

Dont spray it in the tank though. That would be too much in my opinion.
Click to expand...
 
No problem. That's what they keep me around for...that and the entertainment value of me blowing my top every now and again...:devil:
 
Originally posted by SkyMaxx
No problem. That's what they keep me around for...that and the entertainment value of me blowing my top every now and again...:devil:
Click to expand...

That, and your eloquently worded, seven paragraph posts. :write:
 
I'm with NCNitro - although skymaxx has very valuable info - I sometimes feel as if I am reading a novel by Leo Tolstoy. :smart:
 
Wow, good info guys. Armor All, who would have guessed. I wonder if anyone has ever compiled this stuff into a book. I know I'd buy it.
 
Thanks for the tips!!

I'll be checking my lines tonight fer sher!! :thumbsup:


Oh, BTW, when my engie idles you can see the pressure waves at the top of the fuel in the tank from the pressure line. It tends to foam up the fuel a bit. I wonder if this is why air is getting into my fuel lines to make my engine stall.......
 
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Originally posted by nitronewbie
I'm with NCNitro - although skymaxx has very valuable info - I sometimes feel as if I am reading a novel by Leo Tolstoy. :smart:
Click to expand...

Tolstoy was a great author, so I'll take that as a compliment...with one suggestion...if you don't like to read, then steer clear of my posts. I like to pack as much info in as possible and sometimes that makes for a long post. Saves on the twenty questions game...
:write:

Originally posted by DarthRacer
Thanks for the tips!!

I'll be checking my lines tonight fer sher!! :thumbsup:


Oh, BTW, when my engie idles you can see the pressure waves at the top of the fuel in the tank from the pressure line. It tends to foam up the fuel a bit. I wonder if this is why air is getting into my fuel lines to make my engine stall.......
Click to expand...

Could be...but I believe we have given you two solutions to both problems. 1. Armor All for the foamy fuel, and 2. longer pressure line to reduce the pressure to the tank.

Regardless, let us know how you solve it.
 
I'm just :stick: fun at cha, I havnt read a post of yours yet, where i didnt learn at least one thing.,
 
I know...but you know the saying about poking the bear with the short stick...=devil

Just kidding. :D
 
:stick: wwhatcha gonna do, eh eh ?:stick: eh?


LOL -- what a website, good information, good topics, good sense of humor
 
I was tuning my recently acquired Ultra MBX Pro and had problems wuth the Hyper 8 dying with around 1/4 tank left. First I started richening the fuel mixture just a tad but it screwed up the engine performance. I ran a search and came up with this topic, read it, and cut around 1.5" (in short 1/4" increments) from the pressure line, it really improved a lot.

Then I cut off around 3/4" from the fuel line and voila'. Full tank of gas and no more engine dying.

Thanks for all the tips!
 

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