Ok I tried a search and found nothing... I am looking for info on modified rail pressure relief valves and aftermarket rails... any info or comments would be helpful.. thanks..

 

The relief mod is easy. Take the bango bolt out of the top of the relief. Once you have it out, run an 1/8" pipe tap on the inside of the bango bolt. It is already the right diameter for the tap (no drilling it out). Once you are done with that, clean it out very well. Install an 1/8" pipe plug into the bango bolt. Don't overly tighten it. You just want it fairly tight (you don't want to crack the bolt). After all of this is done, install the banjo bolt back into the relief.

 

chrleb1 do you happen to have any pictures of the process or know where some are?

 

is this safe?????


does it damage any thing

 

I would like maybe a pressure relief valve with higher holding pressure and to learn about modified or aftermarket fuel rails..

 

I have heard the GM guys talking about shimming the relief valve because the spring tends to weaken after blowing off too many times.


Is it possible and is there a need for this with our Cummins to be sure we are holding 25K+ PSI (provided we can build that much pressure depending on what fuel system we are running)

 

The GM one is different. Besides this much cheaper and easier than the GM fix. I don't have any pictures (cause i don't have a relief valve anymore). It's super easy though. You don't want to take off the whole relief valve, just the banjo bolt on the top of the return line. Like any normal banjo bolt, it is hollow in the center. That is where you want to tap your threads.

I've ran well over 27K through the rail. It never did any damage. I'm not saying you should run that much pressure though. Just saying that the rail will hold it no problem.

Aftermarket fuel rails won't do anything for a stock motor (even slightly modded). There are better places to spend your money. This is a great mod if not running a pressure box. It makes sure that the relief is not bleeding any fuel off. A long time ago, someone did some dyno testing. It showed a truck with a bad relief making about 20 or so less hp and it should have been. So they replaced or blocked the relief and it was back to normal. Pressure is a key element in the common rail motor.

 

I talked to a member on here about modded rails and he say his truck dynoed less than with the stock rail. sounds like a cheap mod I need to do to mine very soon

 

mine might be getting this bomb done this evening i have some extra banjo bolts from when i removed my stock fuel lines!!

another reason for my mom can ask me "what are you doing to your truck now?" lmao!!!

 

Modded rails don't work with a stock cp3. They barely work with a stage 2. They do work with dual cp3s though. Remember, you are trying to maximize pressure. If you have too large of a space to fill (i.e. modded rail or too much duration) and not a big enough cp3 or cp3s, you'll end up hurting your numbers.

 

In essence the plug is not allowing the valve to relieve the pressure???????

 

Yup. It is supposed to pop off somewhere around 25K or so. When it gets old, it starts popping off around 20K or lower.

 

they should have never did away with the ppump motors... should have used the ppump and 24valve together and made a sweet simple motor..

 

Yeah and no. You can street a 1,200 hp CR truck very easily. Streeting a 1,200 hp p-pump truck, not so easy.

The p-pump as it's advantages and disadvantages. No adjustable timing, no adjustable duration and other little things like that. The p-pump does have crazy amounts of fuel, RPMs, durability, and so on. It's a give and take.

 

Who's rail?

I have a modded rail with a single pump and ~150hp injectors. rail pressure was lowest at 17k and spiked to 28k with the PPE HOT, no pressure added.

Another truck at the same dyno with the same setup just different intake and exhaust from me dynoed 640hp on straight diesel....single pump, modded rail, single turbo.