free mod, more fuel flow?

[2k05gt]

I was talking to a guy at a car show last week and he said that after his supercharger install he got better fuel flow by drilling out the inside flange where the fuel line clips in to the fuel rail. the hole is like 1/4 so he drilled it out to 3/8 inch. this allowed im to get close to 475hp without changing out his fule pump. anyone done this? does it help?

 

[94tbird]

i highly doubt it as the fuel pump is still flowing the same amount of fuel regardless of the sze of the hole. you need better pumps

 

[marcspaz]

If you don't change the flow rate of the pump, pressure drops as you increase the dia of the lines, not increase. He's full of shit... You need more pressure in the lines to keep a good spray pattern at higher volumes of fuel use.

 

[Androdz]

Ron I would think that getting a bigger hole will help you flow a little bit more of fuel thru it.

Andrew

 

[94tbird]

Ron I would think that getting a bigger hole will help you flow a little bit more of fuel thru it.

Andrew

Except since you have made no change to the tune. the pumps are electronically controlled and controlled by the tune. by enlarging the hole as Marc stated above, you are decreasing fuel pressure, not increasing it.

for example, take a mouthful of water and blow it out of a drinking straw. the small diameter of the straw allows you to build up pressure and shoot the water pretty far. Now take the same mouthful of water and blow it through a garden hose of the same length. the larger diameter of the garden hose doesnt allow any pressure to build up andthe water will just dribble out of the endof thehose

 

[Redfire]

I drilled it out as last year to allow more fuel flow as it is a pretty small diameter hole. I am not sure if it helped or not. I know Brad (Fin1) has the stock rails without the line drilled out and has a few 9.90 runs.

 

[94tbird]

I drilled it out as last year to allow more fuel flow as it is a pretty small diameter hole. I am not sure if it helped or not. I know Brad (Fin1) has the stock rails without the line drilled out and has a few 9.90 runs.

Im sure he has more than a stock fuel system though

 

[Androdz]

If you don't change the flow rate of the pump, pressure drops as you increase the dia of the lines, not increase. He's full of shit... You need more pressure in the lines to keep a good spray pattern at higher volumes of fuel use.

I was referring to this. I would think a bigger line without a little bottle neck will flow better. Remember he is not getting big diameter lines he is just getting rid of the bottle neck in the line.

Andrew

 

[94tbird]

I was referring to this. I would think a bigger line without a little bottle neck will flow better. Remember he is not getting big diameter lines he is just getting rid of the bottle neck in the line.

Andrew

If it were truly a bottle neck we would not be seeing 700rwhp msutangs on stock fuel lines. take al ook at the fuel lines on an 03/04 cobra. they are as thin as a drinking straw and make gobs of power. the tiny litle bit you drill out of the line isnt making a difference

 

[94tbird]

obviously a bit modified here but look at their fuel rail from the 03/04 cobra and compare it to ours

now if they can make power with that tiny rail, the hole your drilling wont make a difference

 

[Androdz]

If it were truly a bottle neck we would not be seeing 700rwhp msutangs on stock fuel lines. take al ook at the fuel lines on an 03/04 cobra. they are as thin as a drinking straw and make gobs of power. the tiny litle bit you drill out of the line isnt making a difference

How about the fuel lines from the pump to the fuel rails? I know you can increase the fuel pressure to be able to squeeze more out of the injectors but we know that is not the way to do it. Just trying to lower duty cycles thats all that interests me. Now I am rather curious on what fin has done to his system.

Andrew

 

[94tbird]

How about the fuel lines from the pump to the fuel rails? I know you can increase the fuel pressure to be able to squeeze more out of the injectors but we know that is not the way to do it. Just trying to lower duty cycles thats all that interests me. Now I am rather curious on what fin has done to his system.

Andrew

you increase that in the tune by changing the delta p for the fuel pressure. changing the lines to lager lines decreases pressure. you would need smaller lines to increase it. its a matter of physics

 

[Androdz]

you increase that in the tune by changing the delta p for the fuel pressure. changing the lines to lager lines decreases pressure. you would need smaller lines to increase it. its a matter of physics

So you are telling me I would then be better by putting smaller fuel lines because I would increase pressure? You would increase pressure but you would reduce flow and LPM. Putting larger fuel lines will increase fuel volume and you can increase the fuel pressure on the ems. For example I think I read on modular fords not far back about someone that has the gt500 fuel pumps over 90% and he changed the fuel lines completely and he dropped around 15% or so on duty cycle. I am not 100% sure if that was the # but I am 100% sure it did reduce the duty cycle.

Andrew

 

[fin1]

Im sure he has more than a stock fuel system though

Now I am rather curious on what fin has done to his system.

Stock FPDM, lines & rails. 60lb injectors, KB BAP, GT500 pumps with upgraded wiring.

 

[MikeVistaBlue06]

Guys, not to get into the middle of this, but I believe the rate limiting factor in the fuel system are the injectors themselves--they provide the biggest "resistance" to fuel flow. When you are running normally, you could have a fuel line on the car 1" in diameter and the fuel pump would fill it, and then build up pressure to normal levels.

Now at WOT that may be a different story. If one has 40#/hr injectors on the car, then at a 100% duty cycle (basically stuck open), that would be 320#/hour that the fuel pumps would have to supply. Assuming 6 pounds per gallon for the gas, then the fuel pump must be able to pump 53.333 gallons per hour or a little under 1 gallon a minute (0.89 gpm) under normal operating pressure.

Given 60#/hr injectors, this would jump the fuel flow up to 80 gallons per hour or 1.33 gallons per minute.

One other thing to consider is this, if there is another orifice in the fuel system the same size as the one drilled out, it ain't gonna do a damn thing to the system, since the smallest hole in the system will dictate how much flow there will be at a given pressure.

Hope this helps.

Mike

 

[Nickoli]

why risk/mess with it? aftermatket fuel rails are'nt that high and when your talking the safe power potential of a motor i would get a set...


----word to the wise = don't skimp on fuel systems-----

 

[Androdz]

why risk/mess with it? aftermatket fuel rails are'nt that high and when your talking the safe power potential of a motor i would get a set...


----word to the wise = don't skimp on fuel systems-----

The problem is when you are recommended to do this and that when you really don't have to... I mean almost stock fuel system except the fuel pumps and injectors... if it is enough to do 9's then it is enough for me... too many people recommend to do this and that but the problem is everything ads up and half the the things you don't need...

 

[marcspaz]

Well, along those lines...

You can add a complete KB supercharger kit that comes with everything you need to get in the 11's for about $5500. No exhaust mods, no fuel lines, no top-end or bottom end parts, no trans parts, etc.

The real question is what does it take to do it right and what will we truly benefit from? And THAT depends on the individual. The truth is, most of us fit into the group of the KB Kit doing the job and not really needing anything else. Unless you have million dollar sponsorship and you're winning $25k - $100k a race, none of the other shit matters. You don't need to milk every 1/1000 of a second out of your street car.

To throw something a bit more personal/human into the mix, Scott is a personnal friend of mine. I don't want to see him fuck his car up doing a mod that he does not need to even consider addressing. Especialy since the science behind the recommendation is flawed.

 

[94tbird]

The problem is when you are recommended to do this and that when you really don't have to... I mean almost stock fuel system except the fuel pumps and injectors... if it is enough to do 9's then it is enough for me... too many people recommend to do this and that but the problem is everything ads up and half the the things you don't need...

Stock FPDM, lines & rails. 60lb injectors, KB BAP, GT500 pumps with upgraded wiring.

I think you need to reread what Fin wrote. He is far from an almost stock system. the only stock parts he has are the FPDM, lines and the rails. he has GT500 pumps (plural) which flow a ton more than the stock pump does. 60lbs injectors which are approximately 3x the size of the stock ones. He has a boost-a-pump increasing the voltage to the FPDM to increase fuel flow and he has upgraded all of the fuel system wiring.

All of that helps to flow more fuel. just drilling out the stock line will not do this for you.

 

[2k05gt]

Scott is a personnal friend of mine. I don't want to see him fuck his car up doing a mod that he does not need to even consider addressing. Especialy since the science behind the recommendation is flawed.

the guy who told me about this also had a Supercharger, I would not do this on a N/A car anyway. I was thinking about the Saleen car at the Bamchips Dyno Day that ran out of fuel at 400hp. if he had 60# injectors and the fuel pump was able to push more fuel but the restriction was at the rail flange, could drilling out the hole and increase the overall flow help him get 450 before he starved the engine of fuel? thats my question.

Marc, BTW you also know this guy who told me this......