I have been trying to figure out what I should do for a fuel system on a boosted LS/VTEC with plans of 300-350 hp at the wheels. So far what I have come up with is: 550CC injectors, walbro 255 in-tank pump, new fuel rail, on-rail FPR (probably AEM unless I hear bad things about it), and of course the upgraded lines of correct size. I am planning on running a standalone with a GM 3bar MAP sensor. From what I understand this cancels out the need for the missing link piece, and also with a standalone I don't think I need an FMU.

If I have any of this incorrect or if anyone has a better way of doing all of this please let me know, just trying to get everything planned out before I buy everything.

 

wow im interested too, I have the exact same setup.

 

that set up sounds right.

no need for the fmu or missing link like you said.

just get a standalone of your chose and dyno tune it. you should be good to go...good luck

 

how necessary is it to upgrade the lines?

 

I was thinking the same thing. Is it even necessary?

 

There's mixed feelings about that, its never a bad idea. A very good idea around 350hp and a must above 450hp are my feelings on it.

 

so what lines do I exactly upgrade? The line from fuel filter to fuel rail?

 

From the fuel tank to the rail and the return line back. When upgrading the return line is one size smaller generally.


[Modified by Mr.Saturn, 10:30 PM 4/5/2003]


[Modified by Mr.Saturn, 11:12 PM 4/5/2003]

 

I doubt 550cc will support up to 400HP. 550cc running 1:1 fpr on a standalone reaching 350HP, hum... probably on the edge.

Why just upgrade the fuel line from the fuel filter to the fuel rail? what about the skinny fuel line underneath the car? What about the little skinny rubber tube that connect the 255lph fuel pump to top of the tank cover? Do it all or don't do it at all, waste of money if not done right. Oh, the stock fuel filter inlet/outlet is kinda small too and 350Hp will not require larger lines.

 

Stock lines are good till around 500whp. This is the main reason I plan on making over 400whp on pump gas, run 10's with slicks and just drive my car without that big hassle. To me a street car retians the factory lines. When you upgrade the fuel lines to aftermarket ones, you are begging for something to break or go wrong. Like evo hybrid said, if you dont upgrade all the lines you are wasting your time. Its expensive, time consuming and will make your car less reliable.

 

So you guys are saying that for 400whp OEM lines will not be sufficient??? I thought I saw some cars on here running 500whp+ on OEM lines.

 

Like I said, before its never a <U>bad</U> idea. If you want to upgrade the lines make sure you have the patience because its a pretty time consuming job.

I meant the from the tank to rail not the pump and didn't mention the fuel filter but definately would be upgraded with lines.


[Modified by Mr.Saturn, 11:13 PM 4/5/2003]

 

I was approaching 400whp on race gas stock block gsr with a 60-1. The lines were stock also. Run large injectors at least 900cc and walboro 255 lph intank pump and tune with a standalone. You dont need high fuel pressure if you run a large injector.

 

With 900CC injectors and stock fuel pressure I would think you would need an external pump to supply a higher volume without raising pressure.

 

I am at the edge of maxing out my 720cc right at 400HP. I just dunno about 550cc approaching 350HP on 1:1 fpr.

External fuel pump is definatly a good thing. I run Aeromotive external.
The little skinny rubber hose on top of the intank pump is really skinny, just a thought if you are going larger lines.


[Modified by [Evo]Hybrid, 7:22 AM 4/6/2003]

 

Pressure=Force/Area Volume=Area*Length

Your pushing pressure into the fuel rail, supplying the injectors with fuel. The pressure will stay constant unless you alter the pressure by a fpr. The volume of fuel to the fuel rail only matters when the fuel pump cannot supply enough pressure in the system. With stock fuel pressures, the injectors do not take enormous amounts of fuel even with large injectors. Volume should only be considered when the restrictions in the fuel lines (ie line size, fitting) provide significant resistance and dont allow for enough pressure. This usually happens when you need to raise fuel pressures so you dont go static in boost, or injectors are to small and you need to compensate by adding more fuel pressure.

 

Well said.

 

great info in here.

 

Ok so would I still be able to run 900cc injectors at lower engine speeds? The car is intended for street mainly on lower boost and turned up for weekends at the race track.

I did some math on it and I don't know how I got 550cc the first time, that would be good for like 350hp and even then at 70psi or so. What are the downsides to higher pressures other than faster wear on injectors? If replacing pretty much all fuel system components to accomadate the higher pressure would that be the only effect?

 

You can run even 1200cc injectors and still get stock idel and good dirvability, this is because your fuel pressure would be stock. This is also why I posted my first question just to get some more comments in here. Just like it was said before as long as your injectors are large enough you don't need to upgrade your lines if your fuel pressure will remain stock. I will be running a stock fpr with my 900cc injectors at about 400whp. Tunning - it's all in tunning.

 

You tune the injectors by pulse width by a standalone. You can have stock idle and drivability since you are altering the amount of time the injector opens. I get 30mpg with hondata, and most of the cars I tune get 25-30mpg as well.

 

So if I did up the fuel pressure but also upgraded lines, is that ok? What negative effects would that cause if any?

 

ttt

 

The only negative effect that you could experience would be idel problem for higher fuel pressue, but I am not 100% sure on this.

Rafal

 

If you did the lines and keep fuel pressure stock, you'll have a much easier time at regulating the fuel pressure when large amounts of fuel are being used. At high horsepower levels 600whp+ the fuel lines and fittings of the stock system will become somewhat of a restriction, or resistence to the overall flow. The whole fuel system is about flow, with large injectors the stock lines and fittings will flow enough. When you are increase the fuel pressure, and taxxing the large injectors the flow becomes more critical and you need to upgrade.