Run fuel rails in parallel or series?
05-20-2008, 01:55 PM
#12
I see your point, the internal volume of those Edelbrock rails is so large that it is like having the injectors plugged into a pressurized fuel tank instead of a fuel line, how could one way be better than the other? My thoughts exactly, at first. Then I started thinking that there has to be a loss in the second rail due to the fittings and line, like one of BlackGMC's points in his post. Even if the loss might be small, that idea was stuck in my head and I went parallel.
05-20-2008, 02:35 PM
#14
I guess I am the odd man out here. I will be running my fuel rails in series with the FPR at the end of the 2nd rail. I will be using FAST components (rails and injectors). With the FPR at the end of this series I am confident that the FP will remain constant enough to give an uninterrupted flow and pressure to the injectors (with a dual pump set-up).
The more bends and lines, the more pressure drop you will experience through the lines (slower recovery), even though you may have the pumps to push it and the appropriate FPR. I just do not want to deal with the extra fittings really, just another chance for a leak.
The more bends and lines, the more pressure drop you will experience through the lines (slower recovery), even though you may have the pumps to push it and the appropriate FPR. I just do not want to deal with the extra fittings really, just another chance for a leak.
05-20-2008, 03:31 PM
#15
If you look at a stock system and how much hp you can get out of it series should support all but the most radical setup. (parish) If you think about it the regulator can't release pressure untill it hits the preset figure. The drop will be so minute it won't matter, especially if running larger than stock or double fuel pump.IMO.
05-20-2008, 04:32 PM
#16
There are actually four ways you can connect depending on which regulator you are using. Pre-regulated series/parallel or post-regulated series/parallel. In a pre-regulated system (pressure is regulated prior to entering the fuel rails) you definitely would not want to run it in series as you would have a substantial pressure drop between the first and last injectors. Even in parallel, you will see a pretty good drop in pressure between the first and fourth injector. In a post-regulated setup (pressure is regulated after it passes thru the rails) there is not as much of a pressure differential between each injector as the entire rail should see approximately the same pressure. As BlackGMC stated, you will have a pressure drop at each injector but will not be as pronounced with a post vs pre regulated system. With that said a parallel or series post-regulated system should be more than adequate for the majority of us here however, Aeromotive recommends a post regulated parallel setup with their A1000 components. When I eventually ditch my stock regulator for an aftermarket adjustable one, I will probably install a series setup simply due to space restrictions around the KB so that I may have access to the reg for adjustably yet still be a clean looking install.
05-20-2008, 04:52 PM
#17
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"if" the first injectors in the rail see the most flow, that would be cool, make the rear of the rail the inlet, the front the outlet, in parallel. Then you may be compensating for the lean rear cylinders by flowing slightly more fuel to them.......
05-20-2008, 04:58 PM
#18
This is exactly what I am doing. Fuel enters the rear of the rails, travels to the front, through the regulator, then back to the tank. Post regulated parallel...should give me the best possible flow according to everyone in this thread. Thanks everyone, this is some great info!
05-20-2008, 08:17 PM
#19
Here is the fuel system I have been working on for the TrailBlazer SS. I have the following setup and will be installing it soon with some other work I am doing.
*12 inches of -6 hard line off the tank
*-6 Y block with fitting for fuel pressure gauge
*3 feet of -6 braided stainless to each fuel rail individually
*fuel rails with -6 rear feed
*12 inches of -6 hard line off the tank
*-6 Y block with fitting for fuel pressure gauge
*3 feet of -6 braided stainless to each fuel rail individually
*fuel rails with -6 rear feed
Last edited by leftcoast32; 05-20-2008 at 08:47 PM.
05-20-2008, 09:20 PM
#20
on tech i seen a thread where it didnt make much difference. run in back of passenger rail go to front crossover then down the driverside with regulator in rear. this way you are going with angle of injectors for fuel and its been proven to work over 1k rwhp without issues. no reason to make things more complicated then they have to be not to mention little more expensive then need to be