Fuel Hose Length

[Net-Jester]

hey guys I was just curious how long to you keep your fuel inlet line in relation to your exhaust pressure line? Right now I have 1 foot on each and I'm cutting to find the differences.

 

[El Pirata]

Most people will tell you between 7 - 9" I will vary the length of both lines depending on the application.

 

[militarymaxx]

I read somewhere that 8 - 10 inches is the standard. I run 8" on both of my lines.

 

[bkunar5356]

whoa crap. lol, mine are only as long as they need to be. about an inch on the carb and 2-3 on the exhaust. why do they have to be longer? I've got a bunch of extra, maybe ill re-run my lines tonight.

 

[El Pirata]

You don't have to make them really long or really short. My K-1 has a fuel line including dual filters that's about 10" long and 5/32" ID. My pressure line is 3" long and has a 1/8" ID.

 

[militarymaxx]

EP's right, no set rule, nothing in stone but there are the 'norms'.
A longer fuel line gives you two things. More fuel onboard for longer runs and more lid time. Personnally, this really benefits the racers where longer runs between fuel ups is a plus and more lid time in case those turn marshalls aren't paying attention. A short pressure line can cause a rich condition and just the opposite, a short pressure line can cause it to be lean. If your current setup is giving you good running conditions, leave it alone. But if you decide to change the lengths of either line, be prepared to adjust the engine.

 

[RatzoRC]

I like to keep a long pressure line. 12-15 inches. And a short fuel line. Might make your motor run a little hotter, but It will run better.
Thats my opinion.

 

[El Pirata]

That's not a short fuel line, this is a short fuel line:

 

[drummerjamesh]

man el p that it short

 

[HumboldtBlazer]

Originally posted by El Pirata
That's not a short fuel line, this is a short fuel line:

You kill me EP, always got to be different.

 

[El Pirata]

Funny thing is I've never had any problems as a result of that short fuel line.

 

[SkyMaxx]

The norm is between 8-10 inches for most buggies and MTs. Onroad I gather is about the same. Those lengths are for both pressure and fuel.

Longer pressure line gives steadier pressure but tends to cause a lean condition.

Shorter pressure line allows the pulsing of the engine exhaust to foam the fuel and could over pressure the system leading to a rich condition.

The same applies to the fuel feed line...longer means it will run lean...shorter means it will run rich.

Now...that all being said, you can run a longer pressure line and a shorter fuel line and even things out or vice versa...shorter pressure line with longer fuel line.

Personally, I think an even set up is the way to go, but many will tell you they are successful with variations and hybrids (El Pirata has perhaps the most hybrid I have seen in a bit and his stuff runs great).

 

[Diver6127]

Also differs from manufacturer to manufacturer. My NTC3 kit instructions stated 10" on pressure line and just enough fuel line from my tank to reach the nipple on the carb. I have run a short pressure line and got erratic tuning issues. Went back to the 10" line and all were resolved. I guess it depends on your engine and day to day tuning issues. I say, get a long peice of line and cut different lengths and see how she runs with different lengths of pressure line. As far as the intake line ... I have to say it doesn't matter to me. The pressure line should take care of variances in performance/tuning issues.