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Fuel: Parallel vs. Series

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Old Dec 6, 2012 | 10:45 AM
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Fuel: Parallel vs. Series

I'm getting ready to start building my fuel system and I've bought enough hose and fittings to run either a series OR parallel system.

I'm using bosch ev14 550/2000 with FFE rails.

Aeromotive 340 fuel pump

Aeromotive FPR

Power goals on my ball bearing TD61 with methanol injection will be around 400whp.

I'm just curious to see what others have done and why.
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Old Dec 6, 2012 | 11:06 AM
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That turbo will hit 400whp on pump easily. Water injection is always a great mod to have nonetheless. If you are limited to 91 octane, I can see the need.

The idea behind parallel configuration is to distribute equalized pressure across the system. So the primaries dont lower the pressure of the secondaries, they are given their own source. I personally never saw a need for parallel. The root would be large primaries and a barely adequate fuel pump. Pressure drops because the pump can't keep up. I am making 454whp on 720/2000 with the Stealth 340lph and have had zero fuel issues in a series configuration. I plan to hit 500 with the same setup.

In a big power setup, I can see the possibility of needing parallel fuel lines, but for most setups, it just isn't needed. This is my experience.
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Old Dec 6, 2012 | 11:10 AM
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Yea. I read in a thread that if I were to stay with a series setup, to just feed the secondaries first since they need more fuel anyway.
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Old Dec 6, 2012 | 11:18 AM
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That makes no sense. The injector duty cycle of all 4 injectors comprises the desired AFR. Yes, the secondaries supply more fuel, but only as much as the ECU is tuned for. I would not want to sacrifice any pressure loss to any injector.

To me, its all about adequate pump supply. The Stealth is a beast. It has been proven on 520whp. I would be more hesitant to move to the Walbro 400 before simply running 2 Stealths.
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Old Dec 6, 2012 | 11:20 AM
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Got it.

So running in series won't hurt my goals then, right?
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Old Dec 6, 2012 | 11:22 AM
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I'm running mine in parallel... So truthfully... is it an absolute necessity with your power goals and set up? ...probly not.. But if you have enough line and fittings to do it. Then I say do it for the sake of having that much better of a system..ya know?
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Old Dec 6, 2012 | 12:14 PM
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Originally Posted by JBF
Got it.

So running in series won't hurt my goals then, right?
It's fine. As Manny mentioned, if you want to do it definitely won't hurt, but it's far from a necessity for your setup.
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Old Dec 6, 2012 | 12:22 PM
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I think I'll save all the extra fittings for when I want more power later.
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Old Dec 6, 2012 | 12:39 PM
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Go parallel now and save the work later! I'm running parallel on my 20b! And I have had zero problems from it! Build it for 600! Run it at 400!!!
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Old Dec 8, 2012 | 08:46 AM
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Money and time spent on needless fuel system parts could be spent on something else.
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Old Dec 8, 2012 | 08:37 PM
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Originally Posted by arghx
Money and time spent on needless fuel system parts could be spent on something else.
Damn right.

You don't need all of that for 400
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Old Dec 8, 2012 | 08:43 PM
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My opinion...

I'd run two pumps, in the tank, and 5 no. 6 hardlines to the engine compartment. That gives you a supply and return for each pump and the charcoal line to keep the fumes down. They like the fuel and thats how I build em and have never had a problem. Others will likely say that is overkill, to each their own. I myself do not like two pumps on the same supply line, that is just my opinion. Also, I like two big DENSO's, and have never had a fuel supply issue, assuming injectors and everything else is up to par. I'm sticking with two in tank DENSO's and five no. 6 hardlines, because it works. Spare no expense!

Last edited by KD-93R1; Dec 8, 2012 at 08:48 PM. Reason: Add ons
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Old Dec 8, 2012 | 09:02 PM
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That's definitely overkill for my power goals.

If I decide to go for more power, I'll just do an LSx swap.
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Old Dec 8, 2012 | 09:10 PM
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Originally Posted by JBF
That's definitely overkill for my power goals.

If I decide to go for more power, I'll just do an LSx swap.
If I want more power I'll just swap in a 6 rotor tri-turbo (gtx42 x3)
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Old Dec 8, 2012 | 09:19 PM
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I'd think about it...

Originally Posted by JBF
That's definitely overkill for my power goals.

If I decide to go for more power, I'll just do an LSx swap.
I'd think about it man. 400HP is really not that shy of needing that fuel setup. I know money can be a big issue no doubt. Just sayin. Whatever you decide I hope it brings you many years of satisfaction.

LSX swap is NEVER an option for mines, not ever!
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Old Dec 8, 2012 | 09:21 PM
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My man...

Originally Posted by theasset
if i want more power i'll just swap in a 6 rotor tri-turbo (gtx42 x3)
I like your style!
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Old Dec 9, 2012 | 12:56 PM
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Originally Posted by campo
Go parallel now and save the work later! I'm running parallel on my 20b! And I have had zero problems from it! Build it for 600! Run it at 400!!!
Originally Posted by arghx
Money and time spent on needless fuel system parts could be spent on something else.
I'll be running a brand new (parallel) fuel delivery system for my current build, scrapping the stock lines in favor of something new and MUCH more robust. I think it's safe to say that my setup will be a bit overkill, but I'm operating on the thought of "better to have it and not need it, than need it and not have it".

That said, brand new lines, fittings, and a good filter came out to cost approx $475.

If anybody is interested I can direct them to my build thread on the "other" forum that has everything broken down in an itemized fashion with costs and part numbers from Summit.

Last edited by fendamonky; Dec 9, 2012 at 12:59 PM.
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Old Dec 13, 2012 | 04:24 PM
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Originally Posted by JBF
That's definitely overkill for my power goals.

If I decide to go for more power, I'll just do an LSx swap.
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Old Dec 13, 2012 | 09:43 PM
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^^
Lmfao
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Old Apr 23, 2014 | 10:46 PM
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Ok, i was actually going to run mine in series, but the new rails are -8an so will have to buy fittings anyway.

The diagram below is how I'm thinking of doing it instead of the traditional y-block in - y-block out arrangement.

I'm using t-blocks on both sides of the primary rail, for aesthetics more than anything and to keep down clutter

Everything connected to the rails is -8AN except the feed and return lines which will be -6AN to conventional 3/8 fuel hose/ bundy.

Any conceivable problems with this before i start ordering fittings? Thanks in advance.
Attached Thumbnails Fuel:  Parallel vs. Series-fuel-rails-006.jpg  
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Old Apr 25, 2014 | 07:57 PM
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Why not run the system in parallel?

I made my system parallel and the cost of the fittings and lines were not that much money.

Line was like $2-3/foot. te Y fitting was $13-14/piece, few extra fittings were $20-30.

Cost of the difference was maybe $50 more?


If people want, I can start sourcing parts for people to make a Parallel system and sell it as a kit. I am helping another one local in his system. I can start stocking parts and fuel lines and selling them to people if you want. Obviously I will do this for a small profit but it should still be cheaper than other "systems".

To take it a step further, I can also cut lines to length and install the ends on the lines and will obviously have to charge some for it. I can write install instructions and sell it as a kit. I could even buy a FPR/Gauge etc.
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Old Apr 25, 2014 | 09:31 PM
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It still is technically "parallel" , i probably could have labelled the sketch a bit better, with one feed and a return, i just thought it might be a bit neater in yhe engine bay like this. All the lines looping the rails together are -8an because my new rails are -8, so should have plenty of volume, going back down to -6 for the supply and return.
Re the parallel kits, im sure there is a market for it. I for one find listing all the stuff im going to needa fair head-****.

Got any pics of what you have in mind?
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Old Apr 25, 2014 | 10:12 PM
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Originally Posted by WANKfactor
It still is technically "parallel" , i probably could have labelled the sketch a bit better, with one feed and a return, i just thought it might be a bit neater in yhe engine bay like this. All the lines looping the rails together are -8an because my new rails are -8, so should have plenty of volume, going back down to -6 for the supply and return.
Re the parallel kits, im sure there is a market for it. I for one find listing all the stuff im going to needa fair head-****.

Got any pics of what you have in mind?
Yours is parallel and would work fine.
Attached Thumbnails Fuel:  Parallel vs. Series-new-fuel-setup.jpg  
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Old Apr 26, 2014 | 01:04 AM
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Ok, thanks for that mate. I might just wait till i get my engine back before ordering anything anyway just to make sure it will actually fit neatly. who knows, i might end up justgoing with the conventional y-block and twin return to both reg ports.
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Old Apr 27, 2014 | 04:05 PM
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I have mine wired in series. Could this be the reason my afrs lean a bit when my secondaries kick in? I can see in the log, when duty cycles drops(secondaries kick on) it spikes a couple of tenths of AFRs. I run 40psi base fuel pressure with ID1000pri and ID2000sec injectors fed by Aeromotive stealth pump. I've been wanting to sort that out, as im not sure if it is a tuning issue or not. I cannot currently log fuel press. im working on it.
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