Stock Fuel System Limits....questions answered!

[Weasy2k]

Stock Fuel System Limits
What your going to get out of this: What the stock limits are and some directions to take on what to upgrade first.

Well this is by far the most common asked question asked and i figured if mr2controls primer isn't enough ill write down a cliffs notes version here for all to see.

As most of us know the stock CT26 will not go beyond what the fuel system can handle, but upgrade to a turbo that can produce 4X+ the flow the ct26 can do you are looking for trouble, heck even the CT20b can run you into the red zone of your fuel system.

I myself always go by the rule of 75-80% MAX duty cycle of your injectors and within about 80% of your pumps max flow. This is to keep temps down and your reliability up which most people want!

Fuel Pumps:

The fuel pump on the turbos has been tested to flow enough fuel for about 25psi of boost with 100% duty cycle which should NEVER be done...never max out a solenoid like that it will fail
With 550cc injectors you are looking at a max boost of roughly 19-20psi which is barly enough to take on the likes of most aftermarket turbo kits.

The N/A fuel pumps are barley capable of handling stock ct26 boost levels and is not recommended to be used for those who are thinking of a NA to Turbo swap.

I have heard of people using inline pumps and those end up working well...but the lift pump aka the stock fuel pump has to be running or else fuel starvation will occur and
I recommend getting a walbro 255lph fuel pump and be done with it....can flow more then enough fuel (tested with 850cc injectors with no loss)and runs for around 99-129usd.

Fuel Rail:

Here is also another big thing to look at when pushing those power levels.
The stock rail has been tested by Wolfkatz and he has come to the conclusion that the fuel rail handles the 440cc injectors fine but when you put the 550cc injectors in there you have an approx 6psi drop across the rail...which...really sucks, because the injectors will flow less with less pressure and thus your first cyls are getting enough fuel while the last couple are getting less which means a leaner mixture...not good at all.

Wolfkatz recommends no more then 10psi with 550cc injectors in the stock fuel rail, and by GOD don't run 850cc injectors...!!

There are upgrades out there like the Wolfkatz side feed and top feed rails, both of which can support huge power numbers no problem.

Fuel Injectors:

The stock 440cc injectors are MAXED out at approx 275whp and should be avoided!! Pushing those things to go over 80% duty cycle will cause them to overheat and fail which in turn bye bye engine.

Most people goto 550cc injectors with upgraded side feed rail (or 850cc injectors from blitz). The 550cc recommended max is 340whp...330whp ish to be on the safe side.

Once again stick to a higher flowing fuel pump and rail when you upgrade these!

OK so what do I need fuel system wise to go 290+ whp?

Well first off the fuel pump has to be upgraded...well its strongly recommended

Second get at LEAST 550cc injectors with a higher flowing side feed fuel rail so there is no risk of detonation due to pressure drop from the stock rail.
Or you can go with the top feed fuel rail and get top feed fuel injectors which are easier to find and much cheaper!

Lastly you will need a way to assist the stock ecu in handling the larger injectors. Lots of people recommend EMS's but i say stick with a piggyback until you start hitting 350+ HP levels or as soon as you change the internal design of the engine (higher/lower compression, port and polish head etc).
"Piggyback" and "Standalone" systems will be brought up in another thread ill be making soon.

Well that ends this thread...of course like most things that will be here this is all up for discussion and questions....did i F*ck up somewhere above? let me know!

Thanks to Wolfkatz for doing all the studying and research for everyone!

Its now 2am....mission accomplished....and I'm out