stock fuel lines for 'bigger' injectors

[cjridert1]

I have 680s and am maxing them out; I have base FP set to ~43. Are stock lines fine if I bump FP up to 48 base then retune?52? Anybody running increased FP because they are cheap too? Any other foreseen problems? Thanks guys

 

[snowborder714]

A lot of high horsepower cars are still running on the stock fuel lines, so you should be fine.

 

[dsmnightracer]

just run the stock lines, it will be fine.

 

[cjridert1]

Are there any other reasons to not run higher fuel pressure? Thanks for the replies guys

 

[tkelly27]

I'm guessing you want to turn the fuel pressure up so you can turn the boost up some? The combination of fuel pressure and boost are additive. Lets say you're running 30psi boost and 40psi fuel pressure, that's 70psi at the rail. 30psi of boost and 50psi of fuel pressure makes 80 at the rail. Fuel pumps drop off linearly normally.

 

[cjridert1]

I'm guessing you want to turn the fuel pressure up so you can turn the boost up some? The combination of fuel pressure and boost are additive. Lets say you're running 30psi boost and 40psi fuel pressure, that's 70psi at the rail. 30psi of boost and 50psi of fuel pressure makes 80 at the rail. Fuel pumps drop off linearly normally.

Correct. So a hypothetical 80 psi is fine for the rail/lines is my question along with if there are any other reasons I should be thinking of not doing this. Thanks much

 

[Splitpi]

Fuel pump flow rates is not a linear drop. It is actually an exponential decay. As pressure rises, the fuel pump flows less. The way around that is to lower base fuel pressure. Which puts the flow range in a higher position. The problem then is that the injectors flow less. So you then need larger injectors to compensate.... etc... There are like 10 different ways to skin this cat.

If you bump up the fuel pressure, then the injectors will flow more than normal. I.e.

48 base psi on 680's = ~714 cc/min
52 base psi on 680's = ~743 cc/min

However, your fuel pump will start having issues flowing that much at that high of pressure.... remember the fuel pressure will be Base Pressure + Boost Pressure in order to maintain the pressure differential inside the Cylinder. As far as worrying about the fuel rail pressure... I think it will be ok. If you are looking at doing this, then I would Highly recommend a minimum Fuel Pump of a Wally 255 lph (High Pressure model) with a re-wire.

 

[Mitsumaniax]

I would keep the Stock Lines if you are not running nothing bigger than 1200cc Injectors, a bunch of our customers have stock lines with over 600hp with no fuel starvation.

 

[need2boostpsi]

only reason i replaced my fuel lines was because the stockers rusted out on me and squirted fuel everywhere, otherwise i think most people would be fine with the stock fuel line minus the line from the filter to the rail, have you ever looked in one of those, the rail hole is tiny.

 

[cjridert1]

Fuel pump flow rates is not a linear drop. It is actually an exponential decay. As pressure rises, the fuel pump flows less. The way around that is to lower base fuel pressure. Which puts the flow range in a higher position. The problem then is that the injectors flow less. So you then need larger injectors to compensate.... etc... There are like 10 different ways to skin this cat.

If you bump up the fuel pressure, then the injectors will flow more than normal. I.e.

48 base psi on 680's = ~714 cc/min
52 base psi on 680's = ~743 cc/min

However, your fuel pump will start having issues flowing that much at that high of pressure.... remember the fuel pressure will be Base Pressure + Boost Pressure in order to maintain the pressure differential inside the Cylinder. As far as worrying about the fuel rail pressure... I think it will be ok. If you are looking at doing this, then I would Highly recommend a minimum Fuel Pump of a Wally 255 lph (High Pressure model) with a re-wire.

Thats really good info man. I have a 255 (not the HP and not rewired), do I dare turn up base to 48 with 24psi?

 

[mikEclipse99]

the stockeys will work just fine