Competition Injector line question...

[Morse]

My injection pump flows well over 800cc's, and my fuel pressure should be up to par as well. . Have 66, BB twins. . What size injector line would be best for a drag/play truck for my 12 valve. I also have a large nitrous system. Can't decide between . 093 or . 120. Haisley reccommended . 120, Enterprise said . 093. I'd say some other guys out there could possibly give me some tips on this. . Larger sounds better, but for the drags I'm just not sure. Anyone here had the same delimma?

 

[crawler]

Injector Lines

To use the 120 lines it better be just track use.



The 093 lines will behave much better for street/strip use.



Been there done that.



~Wes~

 

[Bobcat698]

To use the 120 lines it better be just track use.



The 093 lines will behave much better for street/strip use.



Been there done that.



~Wes~

At what power level would going with bigger injection lines be needed? Surely not at my power level?

 

[crawler]

I actually only use . 08? lines on my little truck.



I'll let you guess on the ?



Jim Fulmer has experimented quite a bit with the . 093's and doesn't really like them for the street and I have to agree with him. We both have experienced a lot of "governor bounce" at light throttle or cruising.



Jim has something else that he is going to try with the . 093 lines to try and make them liveable. But, I prefer the . 08? lines for my use. Now that's not to say that I don't have some other lines with their own holders, wrapped in plastic ready to go on my truck at a moments notice

Sometimes you have to have a little extra.



Some people will disagree with me on the line sizes for street trucks, but this is just my preference. Everybody will have to find what works for them.



~Wes~

 

[Morse]

I've bought parts from a lot of shops out there, and have asked this question. . Scheid and haisley said if your injection pump is flowing over 600, you should go with larger lines. The thing I don't really understand is when the fuel reaches the fuel injector. If you only have injector with tiny holes compared to the line, what's the benefit of the larger line. Small line with more pressure seems to be a better answer, but why would some of the big guys be running them if that were the case? Hmm...

 

[RSlaughter]

ill guess 0. 084

 

[fest3er]

... If you only have injector with tiny holes compared to the line, what's the benefit of the larger line. Small line with more pressure seems to be a better answer, but why would some of the big guys be running them if that were the case? Hmm...

Were I to hazard a guess, I might surmise that the bigger line could result in a faster rise in pressure. This would allow you to change to a higher pop-off pressure with a corresponding delay in the injection timing. Remember: the number one rule in diesel injection is that fuel atomization increases with injection pressure; with better atomization, the fuel will burn quicker/better.



However, if you go with too big of a line, the fuel will have to accelerate a lot more in the injector. Too small, and you can't get the fuel through the line fast enough (boundary resistance, you know: the fuel at the walls flows much slower than the fuel in the middle of the line).



Ponder this: if you flow a lot of fuel, you might want to try a slightly smaller line with thicker walls. Thicker walls means the pressure is transferred directly to the injectors, rather than being partially wasted stretching the tubes. Smaller ID means the fuel is already flowing that much faster when it reaches the nozzle: less energy is expended accelerating the fuel to get out the holes. (Sure, it might not be *much*, but it's still something. )



It all boils down to:

• how much fuel you flow,
• what your pop-off pressure is, and
• how much fuel can efficiently pass through different size lines

Figure those out, and you can select the best line for the task at hand.



Geez, I'm starting to sound like Mr. Cameron. :-laf

 

[COMP461]

I run a . 083 line

 

[crawler]

Morse in answer to your question.



Run the 093 line. It will work just fine for you.

 

[Mhannink]

Were I to hazard a guess, I might surmise that the bigger line could result in a faster rise in pressure. This would allow you to change to a higher pop-off pressure with a corresponding delay in the injection timing. Remember: the number one rule in diesel injection is that fuel atomization increases with injection pressure; with better atomization, the fuel will burn quicker/better.



However, if you go with too big of a line, the fuel will have to accelerate a lot more in the injector. Too small, and you can't get the fuel through the line fast enough (boundary resistance, you know: the fuel at the walls flows much slower than the fuel in the middle of the line).



Ponder this: if you flow a lot of fuel, you might want to try a slightly smaller line with thicker walls. Thicker walls means the pressure is transferred directly to the injectors, rather than being partially wasted stretching the tubes. Smaller ID means the fuel is already flowing that much faster when it reaches the nozzle: less energy is expended accelerating the fuel to get out the holes. (Sure, it might not be *much*, but it's still something. )



It all boils down to:

• how much fuel you flow,
• what your pop-off pressure is, and
• how much fuel can efficiently pass through different size lines

Figure those out, and you can select the best line for the task at hand.



Geez, I'm starting to sound like Mr. Cameron. :-laf

i have to agree w/ fest3er i think its all a matter of what application and what your looking for my feeling is that it is just like the any motor you can't simply slap on power adders and expect them to function perfectly they need to be tuned and calibrated for each application to get the most performace. when everything on a motor is tuned and calibrated to work w/ everything else thats when you make maximum power.

 

[crawler]

I talked to morse the other day for a pretty lengthy period of time.



From, what was said in that conversation I felt the suggestion of the 093s would be appropriate.



I took into consideration his mods, his goals, and his uses for the truck.



~Wes~