Return fuel line. - Toyota Yaris Forums

abstractmethod · 02-25-2014, 03:22 AM

Any one running a return fuel line with an aftermarket fuel rail and fuel pressure reg or is it not important... Would love to hear every ones opinions. TIA

dj92 · 02-25-2014, 08:35 AM

As the fuel is scarcely compressible, I see no advantage in moving the pressure regulation circuit from the tank to the engine.

abstractmethod · 02-25-2014, 08:49 AM

Thanks for your reply. I'm more concerned about whether or not a return fuel line is necessary. If I don't have one will there be to much pressure in the fuel rail?

CTScott · 02-25-2014, 08:52 AM

When upgrading the fuel system for forced induction systems, a return fuel system upgrade allows you to install a 1:1 fuel pressure regulator. That allows you to have the fuel pressure increase by 1 PSI for 1 PSI of boost (to compensate for the plenum pressure).

For my supercharged Yaris, I modified a stock pressure regulator to increase the fuel system pressure to 6 PSI (which is the max boost for the S/C). I also increased one to 60 PSI for fnkngrv for his turbo setup.

abstractmethod · 02-25-2014, 09:36 AM

Thanks mate

fnkngrv · 02-25-2014, 02:12 PM

what is your goal here?

abstractmethod · 02-25-2014, 06:41 PM

My goal is to find out how necessary a return fuel line is for turbo application on a 1nz-fe..

CTScott · 02-25-2014, 08:25 PM

Quote:

Originally Posted by abstractmethod

My goal is to find out how necessary a return fuel line is for turbo application on a 1nz-fe..

In a perfect system one with a 1:1 regulator would be used. For most typical applications (up to about 8 psi) it isn't essential, and very few of the boosted Yaris owners go that route. With the stock fuel pump one is not required, but with an upgraded fuel pump you may find that the manufacturer says that one is required. With a closed system there are spikes in pressure (that can shorten a pump's life) when the injectors close. With a return system those spikes are significantly reduced, since the regulator is close to the valves (injectors).

So, the question is how much boost are you intending? If you are going to stay in the 8 psi range, then you don't need to upgrade the fuse pump, but if you are going to go above about 12psi, then you will start to run into the limits of the stock pump.

abstractmethod · 02-26-2014, 01:56 AM

Quote:

Originally Posted by CTScott

In a perfect system one with a 1:1 regulator would be used. For most typical applications (up to about 8 psi) it isn't essential, and very few of the boosted Yaris owners go that route. With the stock fuel pump one is not required, but with an upgraded fuel pump you may find that the manufacturer says that one is required. With a closed system there are spikes in pressure (that can shorten a pump's life) when the injectors close. With a return system those spikes are significantly reduced, since the regulator is close to the valves (injectors).

So, the question is how much boost are you intending? If you are going to stay in the 8 psi range, then you don't need to upgrade the fuse pump, but if you are going to go above about 12psi, then you will start to run into the limits of the stock pump.

Thank you very much. love how simply you can explain both situations.

I'm in the process of pulling down the block, and forged pistons and rods will be installed, ideally looking at 12-15 PSI for a daily driver.

fnkngrv · 04-28-2014, 08:21 PM

Having a return style system will be crucial at that level of boost. Scott, GSD, and I determined that even with a modified stock pump the single line system will begin seeing issues at even just 9psi. This is with 1zz (240cc) injectors. You could do the lazy route and go with tC injectors (335cc) or the likes, but you will essentially being running pretty inefficient which will net you other problems or nowhere close to the potential you should see.

cali yaris · 04-28-2014, 09:37 PM

Quote:

This is with 1zz 9240cc) injectors.

Those are really big injectors.

fnkngrv · 04-28-2014, 09:40 PM

Quote:

Originally Posted by cali yaris

Those are really big injectors.

lmao....fixed!

02-25-2014, 03:22 AM	#1
abstractmethod Drives: Toyota Echo Join Date: Feb 2014 Location: Australia Posts: 23	Return fuel line. Any one running a return fuel line with an aftermarket fuel rail and fuel pressure reg or is it not important... Would love to hear every ones opinions. TIA

02-25-2014, 08:52 AM	#4
CTScott ULTIMATE View User's Garage Drives: 09 5dr LB, 2x 08 3dr LB Join Date: Oct 2008 Location: USA, CT Posts: 13,460	When upgrading the fuel system for forced induction systems, a return fuel system upgrade allows you to install a 1:1 fuel pressure regulator. That allows you to have the fuel pressure increase by 1 PSI for 1 PSI of boost (to compensate for the plenum pressure). For my supercharged Yaris, I modified a stock pressure regulator to increase the fuel system pressure to 6 PSI (which is the max boost for the S/C). I also increased one to 60 PSI for fnkngrv for his turbo setup. __________________

02-25-2014, 02:12 PM	#6
fnkngrv Mr. 155 and climbing View User's Garage Drives: Seriously Modded 07 Sedan Join Date: Jun 2006 Location: In The Hotbox Posts: 4,742	what is your goal here? __________________ Team Tiamat Racing on Facebook Youtube Channel: Team Tiamat Racing *Class record holder in Land Speed @ 154.5mph for 1.5 mile and 145.5mph in the mile in the F (2.016 to 3.014 L), G (1.524 to 2.015 L), and H (1.016 to 1.523 L) classes.*

04-28-2014, 08:21 PM	#10
fnkngrv Mr. 155 and climbing View User's Garage Drives: Seriously Modded 07 Sedan Join Date: Jun 2006 Location: In The Hotbox Posts: 4,742	Having a return style system will be crucial at that level of boost. Scott, GSD, and I determined that even with a modified stock pump the single line system will begin seeing issues at even just 9psi. This is with 1zz (240cc) injectors. You could do the lazy route and go with tC injectors (335cc) or the likes, but you will essentially being running pretty inefficient which will net you other problems or nowhere close to the potential you should see. __________________ Team Tiamat Racing on Facebook Youtube Channel: Team Tiamat Racing *Class record holder in Land Speed @ 154.5mph for 1.5 mile and 145.5mph in the mile in the F (2.016 to 3.014 L), G (1.524 to 2.015 L), and H (1.016 to 1.523 L) classes.* Last edited by fnkngrv; 04-28-2014 at 09:41 PM.

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02-25-2014, 08:35 AM	#2
dj92 Embracing Curves View User's Garage Drives: '14 Prius Executive Join Date: Aug 2013 Location: mid-western Germany Posts: 256	As the fuel is scarcely compressible, I see no advantage in moving the pressure regulation circuit from the tank to the engine.

02-25-2014, 08:49 AM	#3
abstractmethod Drives: Toyota Echo Join Date: Feb 2014 Location: Australia Posts: 23	Thanks for your reply. I'm more concerned about whether or not a return fuel line is necessary. If I don't have one will there be to much pressure in the fuel rail?

02-25-2014, 09:36 AM	#5
abstractmethod Drives: Toyota Echo Join Date: Feb 2014 Location: Australia Posts: 23	Thanks mate

02-25-2014, 06:41 PM	#7
abstractmethod Drives: Toyota Echo Join Date: Feb 2014 Location: Australia Posts: 23	My goal is to find out how necessary a return fuel line is for turbo application on a 1nz-fe..