nozzel feed lines

Her`s a question for all the fuel injection gurues, ever since i can rember, the lines goin to the nozzels were 5/16 in size all the other lines have been made bigger, so how come the nozzel lines weren`t made bigger (Less resistance)?????

 

Fuel Lines

Typically On A Blown Injected Motor You Are Trying To Achieve Fuel Pressure As Well As Fuel Volume. The 5/16 Lines Supply Enough Volume And Are Easier To Fill With Fuel To Create The High Pressures Needed To Make A Motor Run Good. Also Smaller Means Lighter If You Increased All The Lines In Size It Would Add Up In Weight Fairly Quick.

 

Thats a good answer , But i cant buy it ,most all the guys i know that run TA/FC run the rubber lines because they flow more fuel, the inside diamater is larger than the steel lines, and being rubber i`m thinking that they strech and or balloon under presure, i never weighed one but i`ll bet the rubber lines are heaver.

 

Fuel Lines

RBS is correct , the rubber lines are made for convenience and in a lot of cases are a hazard and can contribute to problems in a fuel system. The stainless lines are stable , even in flow and direct as well as fire retardent. As a side note to RBS' comment pressure is built through orifice and restriction but it does not always sacrifice flow , but in some cases can actually improve the metering of it .Yes the rubber is heavier and deteriorates from the inside out .
The stretch and ballooning of the lines you talk about makes me shiver to think that makes sense to you as a benefit or bonus (fuel cars 550# and alcohol 100-250 #) ....... Boy I hope they are not Stretching/Ballooning !!

 

Les, I agree with you,my point is that they use the rubber lines because they are bigger inside diamater,ergo better fuel volume, thats the question why not make bigger steel nozzel lines, i dont buy the presure and or weight thing, i think 1/4 in. stanless would weigh the same as the rubber ones flow more fuel and the nozzels would take care of the pressur, look at the cars with 16 port nozzels they got two times the weight, and i agree they are a fire hazzard,

 

Rubber vs steel lines

I have burned up rubber lines when the motor blew the burst panel but I have also seen steel lines crack from shake. Both have advantages and disadvantages.

 

Random thoughts on nozzle Tubing versus hose:
> Average ID of 3/16 nozzle hose end (you did mean 3/16?) is .135
> Average ID of 3/16 stainless tubing is .129
> Tubing is safer but hose is more convenient sometimes.
> Hose should probably be replaced every year.
> Some racers prefer whatever their mentor or hero uses.
> Hose has 9.5% more area than the tubing and technically has no 90d bends.Therefore, it can flow more. However, often times the length of rubber hose required is longer than tubing. The extra length, a lot to times, can offset any flow gain.
> Hoses do flex and move as the pressure increases. It is a scary thing to watch on the bench.
> When switching from a tube to a hose the curve changes a little. The flex and expansion causes a "cushion" as the hose expands via the pressure.
> Bigger ID is not always the right choice where flow is concerned.
> If the larger ID of the rubber hose is "trick", I ask if anyone is running a nozzle big enough to max out the stainless tubing?
> The 3/16 tube is actually too big in most cases but it's all we have.
> Inspection of the flared ends between races can catch flare splitting problems. A new tube once in a while is a small cost.
> Where long tubing lines might "dance" under tire shake a little dab of clear silicone between the lines somewhere in the middle will stop that. With a little finesse it can be done neatly so not to appear too "back yard". The tye wrap deal also works as well as custom made seperators.
> Personally, I prefer the tubing if the engine is in front of me.
> It doesn't matter which is used once it is dialed in on the bench or at the track.
Dave Koehler
www.koehlerinjection.com

 

It`s intresting that you say the line is longer and the flow is reduced, Being that you have a flow bench, have you ever tryed to make all the lines equial lent`s like say a ex. headder?

 

Nope, that is not what I said. It's a "can" thing, not an absolute.

Sure, and just as quickly I quit worrying about it.

Headers: The only truely equal length headers I have ever seen are dragster zoomies. Should they be equal? Perhaps not.
Dave Koehler
www.koehlerinjection.com