dual injectors?

Pimpin Dsmstyle · 04-15-2006

I was pondering the idea of running 2 banks of injectors on a project dsm. I'm not sure how it would work, but I want to see if a guy could figure out how to install / tune 2 rails with 4 injectors on each bank. I haven't had alot of time to research or anything so I figured I'd toss it here for quick, easy reponses before I go looking into it deeper. There could be something very obvious I'm not seeing. Perhaps just using 4 900cc injectors would be more efficient than 8 450s. That's what I want to discuss here. I also want to know if anyone has ever done this. I will post again with my arguement on this topic. Feel free to say whatever that is pertinent to this!

The goal is to get maximum daily driving efficiency while still being able to get a "stock like" MPG rating. I guess doing something different then most is always cool too.

Pimpin Dsmstyle · 04-15-2006

I'm anything but a tuning expert but the main idea was to have the capacity to run alot of fuel while still getting good gas mileage without the boost. I think having something like 4 1600 CC injectors would create horrible gas mileage even with no boost. I'd imagine in order to tune for high air flow, it would at least slightly hurt your everyday driving.

So the idea is that if you could somehow run just something simple like 450's on one bank, and when boost is introduced ( clearly where the tuning comes in) the second bank activates and essentially gives you 2x the fuel capacity as you had from the 4 450's.

Again, I have no idea how you could make 2 rails work - or how you could tune it in such a way as I described.

CVD · 04-15-2006

If your car can idle properly then its clear that the injectors can deliver as little fuel as is required. I ran 750cc injectors with no negative impact on gas mileage.
I'm sure its doable, but I really think that simplicity is the answer here.

Pimpin Dsmstyle · 04-15-2006

I'm talking about when you run massive injectors and you can't tune out the nasty idle problems. I've heard of a few cases where they were using large injectors and without boost, ran pretty shitty. I'd like to avoid this problem.

Yes I'm aware you can have different tunes on Link or SAFCii but I'm looking for a possible different solution / idea. I duno, it's just a thought I had :P

**Shane@DBPerformance** · 04-15-2006

You could run 8 injectors. You would want something like an AEM EMS or Haltech to control when the additional 4 injectors come online though. If you want to run 1600cc injectors, try getting an injector driver box. Our cars(and alot of other kinds) use a resistor box to allow the ECU to handle low impedance/peak and hold injectors without burning up. That is not how peak and hold injectors are actually designed to work. With an injector driver box and the resistor box removed, you can get more precise control over huge injectors by actually giving them a true higher voltage peak spike and a lower voltage hold.

If you are just trying to run 900cc injectors, then a working FPR system that actually lets the fuel pressure go down under vacuum might be enough to get the fuel under control with a DSMLink.

Pimpin Dsmstyle · 04-15-2006

Oh I'm sure 720's or something will be fine for my goals. I was just doing some thinking about later on down the road. Just wanted some input from you guys

TheBlizzard · 04-15-2006

Its definetly possible. I was going to buy a 94 with a 2.4 that had the stock 1G intake manifold that would support two sets of 450's. They drilled the bottom side of the runners and had another fuel rail installed. The secondaries would come on as the car needed more fuel under boost/load. From talking to the guy he said it made the car a dream to drive since it idled as if it was totally stock.

It took some massaging to get it right. If you have the time and the tools to manage them it would be cheap way to get the effect of bigger injectors at a fraction of the cost.

Pimpin Dsmstyle · 04-15-2006

Quote:

Originally Posted by TheBlizzard

Its definetly possible. I was going to buy a 94 with a 2.4 that had the stock 1G intake manifold that would support two sets of 450's. They drilled the bottom side of the runners and had another fuel rail installed. The secondaries would come on as the car needed more fuel under boost/load. From talking to the guy he said it made the car a dream to drive since it idled as if it was totally stock.

It took some massaging to get it right. If you have the time and the tools to manage them it would be cheap way to get the effect of bigger injectors at a fraction of the cost.

That's what I'm saying! However if it turned out well, I wouldn't mind transporting the idea into a nice sheet metal intake sometime in the "near" future." I think if a person could figure out how to activate the 2nd bank properly, it would make tuning easier and the extra 4 450's would cost like 40 bucks? For the capacity of 900 which are like 300 new?

EclipseGST · 04-15-2006

I run PTE 1600cc injectors with DSMLink and my MPG didnt change at all. Only when I am boosting is where it makes a difference, just like on any other car.

Pimpin Dsmstyle · 04-15-2006

unless for some reason ( like many experience) you can't control it from dumping excess fuel at low RPMS. I keep reading about problems like that. That is what got me to the thinking.

TheBlizzard · 04-15-2006

Like I said. Its been done before. It would take some planning and some fabrication but in the end I am sure it would be worth it. If you ever decided to take the injectors out, you could just fill the holes with nitrous bungs and spray it.

You would most likely need a stand alone ECU to run such a system though.

**Shane@DBPerformance** · 04-15-2006

Dual rail setups are nothing new. People used to have to run stuff like that before all these huge injectors became available.