Fuel Set up

[fiberedimage]

Hi Everyone!

I wanted to get some fuel system ideas and suggestions.

I'm going to list what I plan on using and how I think I want to install and route it all. Let me know what you think and please post picture. If possible not using photobucket What I have in my head makes sense but that doesnt mean its right.

Ok, lets start at the tank:

Ill be using a DW300c pump (should I hard wire it?) and sticking with the OEM fuel lines.
Connected to the OEM lines will be a Fuelab 818 fiberglass filter with -6 in/out ports.
Fuel will then pass through a COBB Fuel Pressure fitting and then this will be feeding a Perrin FPR configured using all 6 ports (2 feed/return on one side, 2 feed to rails and 2 return from rails)
The FPR will be feeding Perrin Equal Length rails and in the rails will be as set of ID1300's
From there, the return lines will be going back to the FPR ports and then to a COBB Flex Fuel kit/sensor and then back to the tank.

I need to do something with the evap system, dont care to use it if I dont have too so looking for suggestions on this as well.

Oh, and if someone can tell me what the stock size is on the OEM fuel line quick connects that would be awesome too. I thought they were 3/8 connections but I read somewhere else they are 5/16. Info on that would be great!

Thanks again everyone!

 

[fiberedimage]

For some reason my fuel filter made it in as an attached file...

 

[SudoSTI]

Pressure differential is moot and frankly I'm surprised anyone thinks it exists.

Here's why:

1. From the first injector to the last, the amount of fuel being used is less and less in steps. So from the beginning, you have less flow which lowers any potential for pressure drop. The largest demand on the fuel system is the line in the frame rail. Once it hits the first injector, the demand is less, which means flow rate is less, which means pressure drop is less.

2. The fuel system does not flow ONE flow rate through the whole system evenly.

3. The fuel pressure regulator is at the end. So if it sees a drop in fuel pressure at the last injector, it's going to bypass LESS fuel, which therefor keeps the pressure more balanced from beginning to end.


Lastly:
Nobody has ever had misfire issues from Series lines.
Many people have had misfire issues with Parallel lines.
Nobody has been able to prove any benefit with Parallel.
Many people have experienced uneven fueling from cylinder to cylinder with parallel.
The first year subaru implemented parallel rails, TONS of misfire issues. Just look up any 08+ STi.

Parallel fuel rails result in large differences in rail temperature and fuel temperature. Fuel temperature is a very important part of fueling (how important? 50C is over 6% fueling. 6% is a lot when we're concerned over 1 or 2% see the last article http://www.injectordynamics.com/NewsletterFeb2013.html). Someone mentioned that by going parallel you lower the speed of the fuel in the rail by half. This is true, in fact in extreme cases it's more than half. HOWEVER, that's not ideal. You want the highest velocity you can get away with without creating a back pressure and pressure drops. Higher velocity means you do a better job of balancing rail temps. Balanced rail temps means balanced fueling. Nice fat rails with a large quantity of fuel going through them would be nice too, but too big and fuel have such a slow fuel flow that you'd once again establish large changes in fuel temp from rail to rail.

So what you guys are doing is creating a problem while trying to prevent a problem that doesn't exist.

If you go series with injectors in the wrong order, you could have issues. However, our firing order is linear down the fuel rail. Subaru H4 is the only engine ever created to do this. The order of fuel feed should be opposite of engine firing order. This means that the fuel injectors are always firing towards the source of fuel. That means that you aren't going to get any lack of fuel from the load on the rail.

In V8's, I4, I6 etc, the firing order is not in a linear fashion down the rail and it is absolutely important and correct to go parallel with your fueling. Subaru isn't like any other engine out there.


Any lack of fuel is from a pump that is too small or from a rail system that is too small to handle the flow rate. It isn't from being series.

Taken from this post:
http://forums.nasioc.com/forums/showpost.php?p=40788677&postcount=34

Just some food for thought. Also what are your current mods? Stock fuel system (not including injectors or pump) should be good to 500whp.

 

[SudoSTI]

Not sure what's up with the font. [MENTION=1]IGOTASTi[/MENTION] can that be fixed?

 

[IGOTASTi]

Not sure what's up with the font. @IGOTASTi can that be fixed?

Fixed.

 

[Batmobile_Engage]

Great info, Sudo!

 

[HolyCrapItsFast]

Unfortunately, unless you are building your own fuel lines, it is not often feasible to have a series system because most of the pre-made kits are parallel by design. Do I like that? Nope! But then again it is easy enough to make your own custom lines and given a choice, then I prefer Series for many of the reasons you suggest.

As you already said... even in a parallel system the pressure at the injectors all remain the same and there is no drop because the whole system is regulated by the FPR which maintains a constant pressure from the inlet to the exit. If pressure is observed to drop anywhere in the system then you need another fuel pump bottom line.

Just for the record I have no issues what so ever and my misfire counts actually went down with a parallel system. I feel that the issues with the 08 and higher is not the parallel vs series system but the delivery system at the head and the configuration of the FPR and dampers. The kits that they sell to resolve the stumble addresses this but everything after the head remains unaffected.

Pressure differential is moot and frankly I'm surprised anyone thinks it exists.

Here's why:

1. From the first injector to the last, the amount of fuel being used is less and less in steps. So from the beginning, you have less flow which lowers any potential for pressure drop. The largest demand on the fuel system is the line in the frame rail. Once it hits the first injector, the demand is less, which means flow rate is less, which means pressure drop is less.

2. The fuel system does not flow ONE flow rate through the whole system evenly.

3. The fuel pressure regulator is at the end. So if it sees a drop in fuel pressure at the last injector, it's going to bypass LESS fuel, which therefor keeps the pressure more balanced from beginning to end.


Lastly:
Nobody has ever had misfire issues from Series lines.
Many people have had misfire issues with Parallel lines.
Nobody has been able to prove any benefit with Parallel.
Many people have experienced uneven fueling from cylinder to cylinder with parallel.
The first year subaru implemented parallel rails, TONS of misfire issues. Just look up any 08+ STi.

Parallel fuel rails result in large differences in rail temperature and fuel temperature. Fuel temperature is a very important part of fueling (how important? 50C is over 6% fueling. 6% is a lot when we're concerned over 1 or 2% see the last article http://www.injectordynamics.com/NewsletterFeb2013.html). Someone mentioned that by going parallel you lower the speed of the fuel in the rail by half. This is true, in fact in extreme cases it's more than half. HOWEVER, that's not ideal. You want the highest velocity you can get away with without creating a back pressure and pressure drops. Higher velocity means you do a better job of balancing rail temps. Balanced rail temps means balanced fueling. Nice fat rails with a large quantity of fuel going through them would be nice too, but too big and fuel have such a slow fuel flow that you'd once again establish large changes in fuel temp from rail to rail.

So what you guys are doing is creating a problem while trying to prevent a problem that doesn't exist.

If you go series with injectors in the wrong order, you could have issues. However, our firing order is linear down the fuel rail. Subaru H4 is the only engine ever created to do this. The order of fuel feed should be opposite of engine firing order. This means that the fuel injectors are always firing towards the source of fuel. That means that you aren't going to get any lack of fuel from the load on the rail.

In V8's, I4, I6 etc, the firing order is not in a linear fashion down the rail and it is absolutely important and correct to go parallel with your fueling. Subaru isn't like any other engine out there.


Any lack of fuel is from a pump that is too small or from a rail system that is too small to handle the flow rate. It isn't from being series.

Taken from this post:
http://forums.nasioc.com/forums/showpost.php?p=40788677&postcount=34

Just some food for thought. Also what are your current mods? Stock fuel system (not including injectors or pump) should be good to 500whp.

 

[SudoSTI]

Also need to mention that was Dominic Acia formerly of Maxwell Power, then Turn In Concepts, and now the new Tier 1. Maxwell Power wouldn't even sell a parallel setup. Their custom fuel rail package was designed and sold in series.

 

[fiberedimage]

Hmmm, well shit!

I read that post and it makes sense. I guess I always thought that by using the stock set up I would starve one side. The last thing I want to do is cause a problem where there isn't one. If this post is accurate, and my numbers will hopefully be hovering around 500Hp, I guess I should rethink using the new equipment.

Right now the car is down, just wanting to make sure I don't limit myself with the regards of fuel. Right now I will be running a larger than normal 20g set up but eventually I see a rotated set up on the car. Ill be using an AIG closed deck block and I guess Im just trying to future proof the set up in regards to the fuel so I can eventually run the rotated set up I decide to go with and have the ability to meet the fuel demand with that as well.

Hrmmm, ok

 

[SudoSTI]

Well FWIW I am running a rotated Borg Warner S256 which is between a 30R and 35R in size and my fuel setup is Five-O Black Ops 1400cc injectors, a Walbro 460 fuel pump, and an Aeromotive FPR. Everything else is stock. And the FPR was just because I got a good deal on it. I'm still in the process of tuning though so we'll see if I run out of fuel at some point.

 

[SudoSTI]

Oh and I only run E85 so my fuel demand is higher.

 

[fiberedimage]

They only make one style of FPR right? I think I have the right information I need after reading some more stuff about it.

Thanks for the help on all this stuff!

 

[SudoSTI]

I'm using an A1000-6. I am also using a Tomei FPR adapter and any fittings are adapted to a 5/16" barb to accommodate the use of standard 5/16" fuel line just like stock. I haven't yet but I also plan on getting the same FueLab filter and fiberglass element being that I'm running E85 and don't want to eat through my stock fuel filter. I also deleted my evap system except for my charcoal canister which is just hanging out until I have time to pull it off. All my other stuff is deleted/disconnected though. You can check my journal for pics. If all the pics are terrible I can get some more specific ones tomorrow afternoon for you.