Dual fuel rail?

[Morphius]

Let's say you're running a larger turbo needing larger injectors. You happen to have a few sets of injectors laying around with fuel rails off some stock DSM's.

Has anyone tried running a dual rail setup? Rather than go with a single set of expensive high flow injectors, why not port in a second set of 450's? Would wiring them in parallel to the stock set work?

I don't want to hear from anyone that will answer, "just buy a set of high flow injectors" or "that's dumb". I want to hear from anyone that has done this, seen it done, or could honestly see themselves pursuing this. I want to hear from the enthusiasts that want to think outside the box and entertain an idea that's NOT a bolt-on.

If you don't have something positive to say, don't post.

 

[Groomz]

It can definitely be done. The Honda boys have been doing it for a while. It will need some fabrication though. I would probably mount the second rail below the intake runners. Of course some injector bosses are going to be machined in there. In terms of controlling them, an AEM EMS would certainly do the trick. If not that, then running them together would be a rich combo ( fuel wise ). I think MSD or someone like that makes an extra fuel injector controller, but wiring it up would be alot of work. Good luck.

 

[Morphius]

Running rich?

Wouldn't the duty cycle be reduced if all 8 were on to adjust the A/F ratio?

What does the effeicency curve vs duty cycle look like on a typical injector?

How about putting in a switch for WOT conditions? Like you can for NOS? They would only be operational when you really needed them.

 

[MNGSX]

Go with AEM and none of that BS is required and you have 100x the flexibility in controlling them.

 

[Revolution]

Amazing how some ppl just think alike or better said like to admier what others have done.

I have personally seen in a few race cars that are pulling some serious # with dual fuel rails and injectors. Hypathetiaclly speaking if you were to get 8 550's and stack them parallel it would be the equivalent if not more than a set of 4 1000's .

It all really depends on how you do it.
Example I you have a sheet metal intake right ,,,,,ok remember how a nos system is setup? , you could tap into the runners like the nos system does but instead you have injectors.

Finding out a way of controling those four extra injector's on top of the original four would not be all that hard if you had a good stand alone.

All you would have to do is program the settings to your specific needs.

This has been proven to work , but very extream for a daily driver since all that fuel would never be needed on the street.

If building a race car would come to mind I would definitally use 8 680
fuel injectors , and add an msd to increase spark. well hope this answered your question .

 

[Morphius]

Originally posted by MNGSX
Go with AEM and none of that BS is required and you have 100x the flexibility in controlling them.

I realize that would be the easiest and quickest. However............. that's $1300 I don't want to spend right now. It's on the list of "to buy" but at the bottom.

Let's think budget minded. We're all tightwad DSMers and I'm a tightwad engineer. I'd rather engineer it than buy a set-up. (dam genes)

With all 8 running, would the computer reduce the duty cycle enough to keep it running OK at no or low boost levels? Any guesses on how rich it may run?

 

[DSM mechanix]

Originally posted by Morphius
With all 8 running, would the computer reduce the duty cycle enough to keep it running OK at no or low boost levels? Any guesses on how rich it may run?

I had read a while ago that this had already been done buy a buget dsmer. The result was less control, I dont belive the ECU did/will compensate.

Example: If I stick some 900cc (450 + 450 = 900) injectors in my car right now and left it up to the ECU to compensate, would it? Of course not, thats been proven many times already.

 

[Revolution]

well extreamly rich considering anything but a stand alone could manage 8 .

If you were to say flash or reprogram the ecu to handle an extra set of injectors and maybe just maybe get an afc to help out with the air flow readings, you might just be able to control them.

But then again the only person I know who has done it right and properly uses the haltech and thats marco passante owner of magnus motorsports.

 

[Morphius]

So, I'm trying to understand the difference between the stock ECU and the AEM ems setup........ how the fuel map is contructed.

I understand how the stand alone is setup to control 8 vs the stock ECU's 4. But how is the fuel map setup....... by duty cycle? Same for the stock ECU?

As many times as I've been around someone setting up a stand alone, I've not stopped to see what is being manipulated in the program.

 

[Revolution]

well The way I remember what was told to me was that by simply reintergrating the amount of injectors used the stand alone would in turn show you a duty cycle. Could be wrong so I will ask asap.

The great thing about a stand alone is you can manipulate all the settings , but I always thought it would just be easier to run a programed fuel curve and duty cycle from a sports car that already had 8 injectors like a v12??

I once read that a japanese tuner reprogramed a v12 to the specs he wanted by using two flashed v6 ecu's.

So if he can do it then I guess learning how to control 8 injectors the realistic budget way can only be a matter of time away.

 

[nine5raptor]

"I once read that a japanese tuner reprogramed a v12 to the specs he wanted by using two flashed v6 ecu's."

check out last the last issue or 2 issues ago of Modified Mag. I believe it was a ferrari that was running 2 Nissan ecus. The guy was a nissan guru and went with what he understood.

 

[MNGSX]

With the AEM it is called staged injection.

At idle and part throttle the only injectors running are the first four.

As engine load increases it starts using the other set. If programmed right the transition is smooth as can be.

 

[blackgsxrcst]

what if you only got two additional injectors, say, injecting after the throttle body and controled by splicing off some of the other 4 clips for the injectors. then, for instance, if you had 550's and added 2 450's then do you guys think it would be possible to control this with an safc only? and to solve fuel pressure problems, you could hack a stock fuel rail and weld it back together for it to only hold two injectors. im under the impression that this would work well. and your thoughts are......................?

 

[MNGSX]

I'd just get bigger injectors and MAFT V2 long before I'd consider running an extra 2 injectors.

Running an extra four putting them just behind the oe ones is better than just two at the TB. The manifold is'nt designed to route a fuel air mixture from the TB to the cylinder just air. Yes it can do it but not well.

Seriously look into Rx7 and other injectors before you pursue this. If the goal is to save money larger low impedance injectors are found on some other cars that will work very well for very little money.

 

[blackgsxrcst]

this whole job would be done for free. a friend would be hooking me up with it. so, cost wouldnt be an issue. but you're right about the intake mani not properly suited for an injector to be right there. i dont know, this was just a thought. just something i was looking into.

 

[monotalonawd]

Like Morphius suggested at first, why not running them in parallel. Meaning injector #1 is controlling injector #5, injector #2 is controlling #6... I also had this idea in mind 'cause I'm a cheap bastard What I wanted to do is running my stock 450cc in stock location and a second fuel rail under the manifold with n/a 4g63 240cc injectors. It would be like having 690cc injectors for dirt cheap! I would then adjust my Maft to have the correct setting. The difficult part here is how to mount the second fuel rail on the manifold. As for the n/a injectors and fuel rail, they can be found cheaply on Ebay.

 

[kpt4321]

This would work. I personally won't try it because it's not worth the the fabrication and the time to save 200 bucks, but that's just me.

With changes to the ECU code, you definately could get 8 injectors to run fine. In fact, it wouldn't be that hard.

Then, just run them together (parallel or series, I'm not sure which would be better, I'll think about that later), so that two injectors fire when the stock ECU tells one to fire.

 

[TurboDSM90]

This is the only other thread I found discussing dual fuel rails.

So I will bring it back....



ho kay, so

The greddy emanage has the ability to run 2 additional high impedence injectors.(auxilary injector function)..I have been using this on a high impedence injector for xylene injection. I have reched the single injector limits. Getting frustrated with limits has become a P.I.T.A.


So I have that single injector rigged up as a whole separate fuel system. Little 1 gallon reservior, hobbs switch, fuel pump, fpr, line, injector. All run precisely by the emanage. It has worked awesome on 91 octane, and I am very happy with the results. I just want more


So, I am thinking about running 4 additional injectors, with the emanage' aux. injector function, yes it can do it. I just need to have some injector bungs made, and welded to the intake manifold, or better yet, buy an aftermarket intake manifold, and have the bungs welded on there. I am planning on a fuel cell in the trunk, external Fuel pump inline, to the fuel rail, 4 injectors, fuel pressure regulator, then a return line back to the fuel cell. I will most likely be running 850s in that rail, and the stock 450 in the stock position. 116 or a higher octane will be in the fuel cell at all times.

Only dilema I am faced with is fuel cut on the stock injectors, and a very odd way to tune. I might have to cap the air flow at 1555hz or so and tune by rpm and knock with the additional injectors. Very very sketchy because, if something goes wrong, BOOM!

You guys get what Im saying? Its 2 in the morning here, and Im about to crash out...good night...
p

 

[monotalonawd]

That's exactly the kind of thing I want to do! But I'm sure some dumb "tooners" will quickly flame you for doing things differently. ...like asking you why not put those 850's in the stock location, or why not put race gas in the stock tank when you need it!

So basicly, you want to run stock boost (or near) with the 450's and when the unexpected Camaro or Mustang stops next to you at the lights, switch on the 850's and crank up the boost for an easy win!

What kind of fuel pump do you use in your 1 gallon tank? Did you have corrosion problems by running 100% xylene through 1 injector and the fuel pump?

 

[Tallen]

I really doubt the time and effort, as well as upfront cost, would be worth it.

 

[aves911]

Yeah, I don't mean to be a 'dumb tooner' but I just don't understand the benefit of spending MORE money to have your car reach its full potential only SOMETIMES.

I understand the appeal of having the super magic +100 horsepower switch, thats the reason NOS, ZEX, NX, etc do any business, but still on our cars you would be better off using the 850's in the stock spot, having a mean pump gas tune, and then MAYBE if you still wanted, have a separate tank for 116. That type of dual fuel setup has been discussed before.

 

[Bostedquest]

With the AEM it is called staged injection.

At idle and part throttle the only injectors running are the first four.

As engine load increases it starts using the other set. If programmed right the transition is smooth as can be.

And to be really honest AEM is not the only one that could do it.
If one wanted to they could try out MegaSquirt. It is rated to be used to control up to 16 injectors and is fully programable. And only 270 bucks...

But yes one would need and external controller for the 2nd set. Just do not get in the mind set that AEM, or Hawk and the like are the only options.

 

[logic]

Erich Moraga runs a dual-rail setup. Here's his write-up with pictures:

http://eclipse.erichmoraga.com/Fuel/

 

[Maglin]

Well I've ready that in Japan it's very common to see dual rail set-up running smaller injectors. Smaller injectors allow for better fuel spary at low demands and thus better efficiency as the fuel is able to be atomized more efficently. Runing in parallel with a EPROM ECU is attainable but you would want to run a new injector controller as the power demands for the additional injectors will eventually blow the injector drivers insdie the ECU. This is very common in the GM-ECU world where people try to run the 7747 with duel TB's and end up blowing up a very good ECU cause of the extra power required to run the other set of injectors.

Their are some controllers out their that are made by enthusiest like us that basicly just take the stock signal and send it to 2 injectors. And of course it also has it's own power supply for the additional power load. Then you can just set the ECU to compensate for larger injectors. ie... 2 sets of 450's would be like 900's... You would have to tweak of course... But now your injectors will have a very very small window at idle to open and you might run into idle problems. That is where a stand alone can be handy as you are only using one set for cruise and part throttle and both sets for accel enrichment and WOT runs.

I'm thinking if you really want to see the benifits of running a duel rail set-up a stand alone would definitly be a great thing to have and going with a set of EVO VIII injectors for your primary's as they have a more efficient design would be the way to go... I think you would end up with a very streetable set-up.

 

[TurboDSM90]

Erich Moraga runs a dual-rail setup. Here's his write-up with pictures:

http://eclipse.erichmoraga.com/Fuel/

Beautiful find Logic!!

Exactly what I had in mind!



As far as the pump gas tune...I am in california where we get 91(which I doubt it even comes close to that) thats my excuse and im stickin to it.

I already have the injector driver (E-manage) only other cost is gonna be an intake manifold (will be needed anyway), real external fuel pump, some welding of the injector bungs and nuts for the rail to bolt onto, and some SS braided fuel line.

I'll git er done, don't hate, motivate....