Dual fed fuel rail idea.

[turbo2086]

Mods are up to date. My next mods, are an fmic kit, evo iii 16g, cyclone manifold ( I know how to make it properly function), mild cams, and the "high flow fuel delivery mod." Found here:

http://www.stevetek.com/R-FuelSys.html

I just want to do bolt ons for my car. That's my goal. No tuning, no fuel control, none of that. I want to work with the stock ecu, and it's stock map only.

There are a few restrictions in the stock fuel line. I'm planning on replacing the whole fuel line system. I know the further most injector from the feed tends to have the least pressure. I was thinking of customizing my fuel rail, and further down the rail adding another feed. Thinking it would help keep the same pressure across all four injectors. What are your thoughts?

 

[FORMONTOYA]

Sounds like a lot of work to fix something that is not broken at the level you're looking to run. The restriction is really at the fuel filter to rail feed banjo bolt, that's what you need to concentrate on in the fuel line for now.

And that EVO 16G is going to need some type of fuel upgrade and management system if you're going to get any real use out of it.

But "stick with it" and let us know what your results are.

 

[gixrman]

I know the further most injector from the feed tends to have the least pressure. I was thinking of customizing my fuel rail, and further down the rail adding another feed. Thinking it would help keep the same pressure across all four injectors. What are your thoughts?

I understand your theory, but if you look at our setup the last injector is at the AFPR and is where I sourced my fuel pressure gauge. So by seting your base fuel pressure you are insuring that the last injector is getting the proper pressure and the first is getting the highest. I have two gauges, one at the end of the fuel rail before the AFPR(were I set my base at idial) and one inside the car that reads off of the AFPR to make sure i'm not losing pressure under boost.

 

[turbo2086]

Sounds like a lot of work to fix something that is not broken at the level you're looking to run. The restriction is really at the fuel filter to rail feed banjo bolt, that's what you need to concentrate on in the fuel line for now.

And that EVO 16G is going to need some type of fuel upgrade and management system if you're going to get any real use out of it.

But "stick with it" and let us know what your results are.

Thanks for the input. I know that I will need to get a fuel mods, to get the full use out of that turbo. I was planning on running around 13-14psi. I just want more top end power. I feel as if the 14b doesn't deliver from 5500 to 7000rpm. I'm not knocking either. My buddy is an idiot, and his first mod was a bigger turbo, the evo iii. However, even still without a boost controller (still using stock bcs setup, so factory boost.) I felt as he gained much more top end. That's my reasoning, maybe it's just me!

I understand your theory, but if you look at our setup the last injector is at the AFPR and is where I sourced my fuel pressure gauge. So by seting your base fuel pressure you are insuring that the last injector is getting the proper pressure and the first is getting the highest. I have two gauges, one at the end of the fuel rail before the AFPR(were I set my base at idial) and one inside the car that reads off of the AFPR to make sure i'm not losing pressure under boost.

Good point. I want to get an even air/fuel ratio across all four cylinders. From the article I read it seems that the first two cylinders are rich, one stoich, and the other lean. Increasing fuel flow to keep the last cylinder from running lean, will cause the other two to run extremely rich, and rob power.

 

[delta448]

Good point. I want to get an even air/fuel ratio across all four cylinders. From the article I read it seems that the first two cylinders are rich, one stoich, and the other lean. Increasing fuel flow to keep the last cylinder from running lean, will cause the other two to run extremely rich, and rob power.

As you stated in the quote, an AFPR won't completely solve this problem (even if you use really high fuel pressure). I think you may have a pretty legit idea here on fixing it. But I'm thinking that maybe just boring out your fuel rail and replacing the fuel supply line with some bigger diameter braided hose could work the same way though.

I think the most important thing is that you have to be able to replace the used volume of fuel very quickly after an injector fires in order to stabilize the fuel pressure across the rail. Increasing the speed of the fuel replacement will minimize the effects of uneven fuel distribution by bringing the pressures across the rail closer together.

The stevetek mod is cheap and effective. I don't know first hand but I have read that it can produce better results on the stock pump than just swapping to a 190lph with stock lines.

 

[gixrman]

If you look at the inside of the fuel rail its about 5/8" in diameter roughly -8 size. Honestly I have never heard of anyone complaining about a lean or rich condition from one cylinder to the next. There are plenty of guys on here that put up some hugh #'s on the stock fuel rail. Its such a short distance I don't see it being a factor for what your building. Also from personel experience the e16g really comes on line at 20# of boost.

 

[black92_tsi_awd]

Why are you so against tuning and fuel control modification? You spending a ton of money ($1400+) and not optimizing it. Even a cheap MAF translator setup $200 used and you'd be able to tune in alot of HP.

 

[oldman]

Let's see, no fuel pump, injectors, fuel management, EVOIII @ 13-14 psi.

1. There is absolutely no need for you to worry about fuel lines or fuel rail.

2. At 13-14psi, well within the efficient range of a 14b, you might be quicker with a 14b due to quicker spool.

Sounds like you took the stevetec article a little too seriously at the level you're at, the article is a good read but it's for a little more way down the upgrade path. Take a break from the article and reset.

 

[turbo2086]

Why are you so against tuning and fuel control modification? You spending a ton of money ($1400+) and not optimizing it. Even a cheap MAF translator setup $200 used and you'd be able to tune in alot of HP.

I'm not against tuning. I just want to make all my power from the bolt ons first. That's all. I'm getting the parts cheap may I add. I'm performing mods that will benefit in it's stock form, and when I chose to further modify my vehicle. I find this very reasonable.

Let's see, no fuel pump, injectors, fuel management, EVOIII @ 13-14 psi.

1. There is absolutely no need for you to worry about fuel lines or fuel rail.

2. At 13-14psi, well within the efficient range of a 14b, you might be quicker with a 14b due to quicker spool.

Sounds like you took the stevetec article a little too seriously at the level you're at, the article is a good read but it's for a little more way down the upgrade path. Take a break from the article and reset.

Well, if you read the mods, I do have a Walbro 190. I'm running 16 psi with the 14b, 21psi race gas. As with a typical 14b you don't feel the power as much past 5500 rpm. I will be running lower psi on the evo iii, cause it flows more. Perhaps I'll run 15psi, I'll run as much psi as I can w/o knock, on a 5* degree base timing. Just saying 13-14 on safe measure. Also these levels are well within the efficiency range of the turbo, and the charge air would be much cooler then on a 14b.


Would you not agree with the fuel delivery mod will help out, on a stock, or upgraded fuel system? It would, that's why I'm doing it. Perhaps in the future I would love to upgrade injectors and get some sort of EMS. Right now money is tight, and I find that I can get more reliable power going this route. I'm going to start this in a few weeks. I'll keep everyone up to date.

I got the idea from the RX-7. My buddy just got a Turbo II motor from over seas, and it has fuel feeding in both lines of the fuel rail. Reading up on this, its to make sure each injector has equal pressure, each rotor has the damn near equal fuel ratio. Cause running lean in one rotor is hell of a lot risky then running lean in one of our cylinders. Thought hey, why not try it in our cars? Not worry about that one leaner cylinder, and robbing power from the others for being too rich. Thanks.

 

[slipstream808]

Well now, even though you have lofty goals and ambitions, they are very good. And yes, running lean in one cylinder is bad compared to the rest. This method will help fuel deliver better than stock, and the bigger you go (as far as injectors), the more this will help. If you are really motivated, you can get a standalone setup that alows individual cylinder tuning with an EGT for each cylinder and pressure transducers as well!!

I think your best bet for this in order to do a GOOD JOB would be to contact Fuel Injector Clinic or Magnus and ask them to help you as they make their own fuel rails. Tell them you want a -8AN fuel rail with -8AN fuel feeds on either side, and a -8AN hole in the center of the back of the rail (that faces the intake manifold for the fuel return/AFPR. It really wont be too hard at all. Just a headache running all those lines.

But oldman is right in that the need for this is FAR down the road from where you are. I personally would concentrate on the tuning aspects and fuel management first, as opposed to fuel delivery. But still, if your set on this, then I hope it works!!

 

[gixrman]

You could easly weld a bung in the center of the fuel rail and run a T-fitting off your feed line to feed both sides of the rail. But like I said i've never heard of a DSM suffering from fuel starvation this way only the Subi's!

 

[Malero5]

I run 750 cc injectos, walboro pump 255, aeromotive afpr, dsm link, big FMIC, HKS SSQV BOV, hks 264 cams, slightly higher compresion, 1mm oversized valves, 3 inch exhaust, and an MBC at 18lbs of boost on a 14b.


The turbo pulls decently til 7800 but you can feel a slight drop in top end around 6500. i put down a lotus elise, 2005 mustang gt, 2 honda s200's, lexus is 400, 93-95 BMW 740I. Lol the list is bigger......but im just saying i put down some quick cars with a 14b. Here in the next few weeks im putting in an ported evo mani, ported evo o2 housing, and a really ported evo III.

Just gotta mod right. Please upgrade you fuel system and get some management if your gonna run anyhting bigger then the 14b. I got 92 % injector duty cycle at 16 lbs of boost with my mods on the 14b. After the new injectors the car was so much faster and i ran 18 lbs of boost without knock up to 7800.

 

[awdtalontsi1992]

I thought I would throw my .02 in on this question. The dual feed idea sounds like it would be ok for a high hp car. On a mostly stock car I think it would be overkill. I think your reasoning is correct because the three injectors in front of the number one cylinder are going to be first in line to get the fuel that is being replaced. If they are sucking up the fuel before it can be replaced, the last injector could be starved. The dual feed idea would go a long way to solve this.

Getting back to the reason for the number 1 cylinder going lean in our cars........from what I have read it seems to be more of a intake manifold flow issue than fuel. If you look at most SMIM they are tapered to address this problem. The stock manifold isn't tapered that I have ever seen. These differences in flow could be a source of the slight lean condition.

 

[KeltonDSMer]

Why would the runner furthest from the throttle body see more airflow? The #1 cylinder is on the driver's side.

 

[4SFED4]

Its pointless to upgrade the entire stock fuel line with #6 SS fuel line. The inside diameter of the factory line is slightly larger than the #6.

However you will gain from upgrading the filter along with the line past that point to eliminate the banjo fitting and the piss hole fuel rail fitting. The same tube nut and sleeve assembly will fit the line right before the filter. You will save a few bucks only needing 3ft of SS hose than 20.

I would also tap the FPR side to #8 and upgrade to an aftermarket fuel pressure regulator.

With a Walboro 255 intank the above mods will supply a little over 500HP flywheel.

If upgrading to #8 its best to sump the tank or go fuel cell with an external pump.
I went fuel cell, but if I had it to do over again I would sump the stock tank.

 

[perley03]

The best way I can see doing it is like this.

You must be logged in to view this image or video.

Sorry about the bad Paint drawing, i suck at Paint. Let me use Autocad and it will come out 1000 times better.....
Using two return lines to a AFPR and an inlet directly in the center of the fuel rail would optimize fuel pressure across all injectors. This is how i made my friends fuel rail on his neon. They came stock with the fuel line in the center, making it hard to put a return line on, so i fabbed up two return lines heading to an AFPR and back into the tank. Works wonders. I can post pics of you want, it will be a few days before i can get them on here though because i gotta take pics of the rail.

 

[NewB2dsm]

Why do you think you need more fuel? At your levels you dont need it, its a waste of time and money. Save up for that fmic and injectors with some fuel controll. What you are doing really serves nothing, other than HEY look what i did. I just see it as pointless, Im just now going to replace all of my fuel lines and its just beacuse i dont want to change my fuel filter b/c that bango fitting sucks to change.

My opinion is to wait, save your money and do things that will actually help.

Also, the dual feed idea, high hp supras do it, and have the return line in the middle of the rail. BUt this is on dual pump setups as well, so each pump feeds a side of the rail.

 

[turbo2086]

K guys thanks for the replies. Like I said, just an idea. I'm probably going to pursuit it, cause I'm just curious. For what I've looked at, and pieced together in my head, don't see it costing all too much. It's not that I'm against tuning, or fuel upgrades. It's just I want to do everything outside of that done first, then make sure everything is running right , then finally down the road, get the injectors, and fuel management.