How much power can my stock lines and rails support if I am using a set of 60lb injectors? I am trying to decide if its worth running lines for ~600awhp (or about 650rwhp on a dynojet). I have a stock motor so I don't want to turn the power up anymore than that.

To elaborate, my fuel system would consist of a stock 996 Turbo pump in the tank, a Bosch 044 Pump in line, and a set of 60lb injectors (with a standard 3.8bar FPR (though I have a 5bar also I could install)).

If I ran a fuel system I would use a -8an feed from the stock intank fuel pump to the 044 pump, then -6an to the stock rails modified with a -6an fitting.

Thank you all in advance for some quick replys.

 

You will have no problem with with the stock fuel rails.we use the stock fuel rails runing 85lb injectors.

 

What do you feel is the limit on the stock fuel lines?

 

A lot depends on what setup you have.you can run 800hp with the stock fuel rails depending on what injectors and pump you're using.But a lot depends on the set-up.

 

Your asking some tuner to give you his R&D- I doubt any will. Todd K pushes 620 rwhp pn stock lines wiht 2 pumps in series with 60 lbs injectors...
The other question is what fuel pressure will one be running?

 

You've got a point, but we'll see how mine turns out. I think I will be doing lines just in case.

I will be using the stock 3.8bar Regulator. I've heard bad things about using a 5bar on aftermarket fuel injectors. Thats just what I hear, and I'm going to play it safe just in case.

 

Todd recommended upgrading the fuel lines for my set up which puts down around 640.

 

I noticed that on some kits Todd runs 4.2 bar of fuel pressure and on some 5 bar....

 

I can't imagine 1.2 bar (17.4 psi) more pressure causing issues with any modern fuel injector. Chris, call me if you need a source for injectors. You will be glad if you do.

 

Apparently, the bigger injectors don't like the 5 bar. They can get stuck closed. Of course, this may be related to a specific injector type.

 

Interesting, but so far the only information here is "I've heard" and "apparently." We should try to figure this out. It is important info and should be shared. Rumor helps nobody. What is the rest of the story (or stories)?

 

As an engineer i would like to add my comment about fuel injectors and fuel pressure...imagine some stock injectors running on a stock fuel pressure regulator...The response time of the injector in order to fully open from closed when needed is lets say 2msec.Now lets replace the fuel pressure regulator with a 5bar.the response time now is greatly raised...about 50%...This is because the coil of the injector sees more resistance from the raised fuel pressure...so if we focus on fuel sprayed from close to fully open injectors,the stock fuel pressure regulator is better...On the other hand ,when injectors are fully open,the fuel injected is more as there is higher fuel pressure...As a conclusion higher fuel pressure regulators are needed and are efficient when duty cycle of injectors are about 100%.if it is lower,first raise the duty cycle and last the fuel pressure...

 

skandalis447- thanks for the description. There is a rubber air manifold line going to the FPR which regulates its pressure. Under high boost, max fuel pressure is achieved (whether 3.8 or 5bar). Under vacuum, zero manifold pressure, or low boost it is under that level. So according to your explanation all is good. Nothing in your description predicts fuel injector failure, thank goodness.

The statement that needs proving/debunking is that bigger injectors at 5bar get "stuck closed" or have other failure issues. Where is this information coming from??? Is it true, or misinformation?

Raising the fuel pressure is a common trick to get more fuel from an injector. Adjustable rising rate FPRs have been successfully used for many years. They are not the most accurate way to control fuel but they can certainly be used to keep the A/F rich under high boost conditions. They don't cause failures that I am aware of, but please educate me if I am uninformed.

Powell, Porsha...cough up your sources!

 

I have a about 60 psi I believe... 4 to 4.2 bars...
just so you guys know...

 

higher fuel pressure does not necessary means failure of injectors...however an injector in order to open must override fuel pressure so the results are obvious...more pressure,more resistance to open,more stress to injector,shorter life of injector,slower opening of the injectorthis is the cheapest way to add fuel...if mark has only 4bar to produce that hp,imagine the work done to his fuel system...
If cost is not essential,you should install a bigger pump and bigger injectors and fine tune your software on a dyno...otherwise raise the fuel pressure...