quick question phunk. i noticed a difference in how the cjm kit and aam kit run the lines for the fuel rails. is there a benifit to running them how they are run on the cjm kit vs. the aam kit. also what benefit is there to teeing off the sending line to both rails and the teeing back into the regulator? thanks.

 

You would “T” (we actually use a “Y” which is better) the pressure lines before the rails and then join them back after the rails to help promote equal pressure to all injectors. As you know, you can refer to this as running the rails in parallel. If you run all the injectors in-line, then you are at a greater risk of pressure drop from the entry to the rails and the exit, as every injector will take some fuel as it passes by on the way to the other end of the rail. Think of each injector as a little pressure leak. By having the system loop around as a parallel, it helps promote equality as the pressure can transfer back and forth and reduces the amount of “leaks” that are in-line. It also reduces the risk of unequal pressure drop by only having 3 injectors inline at each bank, rather then running 6 inline crossing both banks.

Running a system in parallel also allows you to maintain this equality of pressure udner circumstances where you are not running a massive bore fuel rail. If you have all the space in the world, it is all for the better to run a fuel rail with massive interior real estate. However, we have limited space on the VQ35, especially with the taller aftermarket injectors that most people are using. This means that we cannot super-size the fuel rail interior bore. The parallel systems ability to transfer back and forth at either end of the rail is like dual feeding the rail on both sides to further promote equality.

Basically the positive effects are pretty compounding.

Under no circumstances you would ever want uneven distribution of fuel to each injector! This would cause unintentional individual cylinder tuning effects that could be catastrophic to your pistons.

People often do not stress enough on equal cylinder tuning when it comes to fuel system layout or intake manifold designs. In some ways they could be looked at as partially similar as they share some traits into what could cause uneven fluid/air pressure transfer into the cylinders. But either way, unconscious inequality in your fuel systems ability to provide each injector with the same supply of gasoline is, of course, risky.

Note that you will see some supra guys, who have 6 injectors inline on a single rail, will feed their fuel rail on both ends and then put the outlet in the middle. This is accomplishing the same thing as running 2 rails parallel.

 

CJM is an awesome system. I have had no issues raising or lowering the pressure as far as I have wanted to, and I have wideband 02 sensors on both sides and they run almost identical.

 

Maybe I missed it, but didn't see a response to the difference in how the lines were run TO the fuel rails. Also, phunk, I have some PE 510cc injectors with the collars for the stock rails. How do they fit in your rails, with or without the collars?

 

AAM uses a "T" shaped union.

CJM uses a "Y" shaped union.

CJM

 

Ok, got it, that is a change, they (AAM) used to use a Y.

 

I was not sure which AAM system he was referring to. The standard AAM system connects to the stock hardpipe where it ends, which some may find advantage to for ease of install or the ability to return to stock. Our system uses a compression style adapter, where we have you actually CUT the stock hardline down under the passenger footwell and attach this adapter. This was our preferred method for doing the feed line on our stage 1 kit due to our preferences for routing. To go back to stock and remove our fuel system would require you to replace the hardpipe overall (not expensive, but a PITA), or run a cheap fuel injection rated hose to the stock rails (a little ghetto).

AAM also has another system now that runs the stock rails in parellel for those who do not need as much flow as their other system or ours. (Pretty cool idea actually, for those who it would suffice for)

As for your injectors - I cannot really comment since I havent seen them. However - stock injectors fit right into our rail using the factory plastic rail spacers and our bolts. If the PE injector w/ collar fits into the factory OEM rails in terms of O-Ring sizing and height, etc, then it will be compatable.

 

Ok, much clearer. Thank you phunk. Now get back to work on that intake manifold. j/k

 

Finished it monnnnnnnths ago. Just never put it on a boosted car to see what its about

 

charles, what is the pic in your avatar?

 

charles,

someone could convert back to stock by putting another compression fitting on the part of the factory hard line that was revmoved and them use a short section of line with -AN fittings to mate the 2 pieces of hardline back together.

 

I can be there in a few hours more or less. Let's find out.

 

good point. The 2 compression adapters could be mated with a solid AN union so that no hose is even required.

 

we have to make a quick adjustment to the prototype sheet metal plenum top next time we fire up the TIG welder. Having the CNC - we hardly ever have to use it anymore. However I can already think of a reason that we need to use it in the next week or two - so im sure we will take care of it then, and then maybe we will face the other way and toss it like a bouquet.

 

So running lines in parallel does not become a necessity until you reach extreme power level situations where your fuel pump is struggling to keep up with the fuel demands of the vehicle. Fast's Gm LSx and Ford modular fuel systems don't run their lines in parallel and that's for 1000hp fuel systems. As long as you have the pump to keep up with fuel demand running lines in parallel is unecessary. I'm just trying to understand why you wouldn't run the rails inline with each other. but i guess it makes sense if you're planning on using a walbro for potential 500+ horse. It's a nice option to keep things more reliable when you start running our of pump.

 

Yes, you pretty much got it there.

However, those cars usually run a larger bore fuel rail as well, which also reduces their need for it. If you got a massive weldon pump, and a full -10 feed line going to huge bore rails, you probably dont need a parallel setup

we like to try and do everything pretty top notch within reasonable expense.

 

The CJM system is very complete and well thought out and I probably would have purchased it but it wasn't out at the time...

The AAM system that shipped to me also came with the 'Y' shaped union - maybe they made a change...?

 

i didnt want to start a new thread just to show this, but i am so happy with how it turned out i wanted to post it somewhere. Brandon (the more important half of CJM) made an electrode for the EDM last night, so we can finally complete the final step in the fuel rail production that we havent been doing.

some of you might have wondered why there was a flat spot on the back of each rail... the missing link:

(they should easily make more HP now)




Previously the only set to wear the markings were the ones that were put on the K&N time attack car... actually I think we did 3 sets while it was setup..



hmm, rare - most likely significant collectors value there. Those were done by the CNC, which is still cool, but the EDM is cooler because it can create sharper corners and that neat texture

 

I'm a new CJM owner.

 

thanks! should anything ever arrise, feel free to contact us.

your car must be a blast to drive and i bet the engine looks great. if you have a thread where i can read about your project, post it up!