High pressure fuel line mod?

[BoostedST17]

I've read and seend this done on the Honda 2.0 and 1.5 liter engines. It supposedly helps top end with little to no known downsides. Has anyone here looked into trying this out?

Here's a video of the mod.

View: https://youtu.be/t16yhFh_XqE

 

[LilPartyBox]

1st thought...use a drill press with a clamp. Going freehand on a such a precision part of a mission critical system is risky. I would imagine it's introducing some turbulence to the fuel flow as well. That turbulence may not be a big deal, idk. But for an unconfirmed 10% increase it isn't worth molesting the fuel line. Also, Honda engineers might have had a good reason for using the smaller diameter.

 

[BoostedST17]

I agree it's not the most precise way of doing this modification. I have been doing a lot of reading on the FK8 forums and there seem to be tons of information as well as data logs. Some have experimented with even larger-sized holes.

I was just curious to see if this was something we could apply to this platform. I assume we may have a similarly designed HPFL, who knows, maybe our line could just be straight-through and wide open.

 

[Jabbit]

Isn't there potential to go too far, lose pressure, and run lean? Seems like more risk than reward here.

 

[BoostedST17]

Isn't there potential to go too far, lose pressure, and run lean? Seems like more risk than reward here.

Yes, but the real question is how big is too big? Baby steps and working with a known tuner would be my approach.

Isn't in a way upgrading to the Bosch 30% bigger injectors while leaving the rest of the hardware untouched similar? Are the injectors bigger internally by 30%?

 

[Jabbit]

Yes, but the real question is how big is too big? Baby steps and working with a known tuner would be my approach.

Isn't in a way upgrading to the Bosch 30% bigger injectors while leaving the rest of the hardware untouched similar? Are the injectors bigger internally by 30%?

In theory, yes similar. However a part engineered by Bosch vs a hole reamed out with a Bosch drill are about as far apart as you can get.

 

[BoostedST17]

In theory, yes similar. However a part engineered by Bosch vs a hole reamed out with a Bosch drill are about as far apart as you can get.

This quote made my day, I got a good laugh out of it. Very clever writing sir.

 

[BoostedST17]

Below is Dizzy's Tech article on the Bosch injectors.
https://dizzytuning.com/blogs/technical-documents/fiesta-st-bosch-30-uprated-injectors-part-1

In the article he describes fuel rail pressure drop caused by the upgraded injectors with a garden hose analogy. I think this mod would be like upgrading your water hose at a small scale.

Wouldn't this just increase the volume of the fuel available to the rail?

 

[LilPartyBox]

Speaking outta my butt but...perhaps it's the size of the hole that maintains pressure or spray pattern. Akin to the water hose analogy, squeezing the end of a hose makes it shoot water at a higher pressure. Release your grip, hole gets bigger and and the water flows at a lower pressure

 

[BoostedST17]

Speaking outta my butt but...perhaps it's the size of the hole that maintains pressure or spray pattern. Akin to the water hose analogy, squeezing the end of a hose makes it shoot water at a higher pressure. Release your grip, hole gets bigger and and the water flows at a lower pressure

I think this is exactly what happens when bigger injectors are installed. Hole gets bigger aka more volume of fuel however the pressure is dropped.

The injectors are like the nozzle at the end of the hose, the fuel rail and hard line would be the hose size and volume.

I also wonder if this system works like a hydraulic press, where a small amount of liquid in a small area is compressed (HPFL) and the pressure in the larger connected cavity is then multiplied (fuel rail)??

 

[BoostedST17]

I've seen several videos now on the Fiesta ST high pressure fuel pump replacement, and have pulled up images of the replacement line to get an idea of the line ID dimensions. I am 70% sure this is the case with our cars where one end has a larger ID compared to the fuel rail end.

I'm willing to be the guinie pig, but I still have to come up with a test that would prove this theory right or wrong. I know very little about turning cars, and I doubt a tuner would want to risk their reputation on such a silly mod.

My thoughts to measure this test are,
* log fuel pressure drop before and after
* log injectors duty cycle before and after
* increase ethanol % slowly until it leans out? E30 tune ?

I also ran into a nice post by razorlab, who did his own turning and found some power on the oem tune, by adding a couple of gallons of E85 to the tank. Maybe I could try something similar and see what the limits are before and after ??
https://www.fiestastforum.com/forums/fiesta-st-build-projects.77/

Honestly it sounds like I am on a path to blow my engine up by ghetto-rigging something instead of just buying injectors. $600 dollars for Bosch injectors are way cheaper than a new longblock.😅

 

[Jabbit]

There is also this "mod" that people over here don't seem to talk about, wondering if it really works - https://pumaspeed.co.uk/product-Pumaspeed-Racing-High-Volume-Fuel-Supply-Kit_17769.jsp

 

[BoostedST17]

Well, this thread is dead. The Bosch injectors thread linked a YouTube video of the install and in one of the shots you get a clear image of the hard fuel line. The line looks wide open.

 

[LilPartyBox]

haha may this thread RIP...