At what point should the fuel system be touched?

[mar-spec]

This question may be vague so I'll try to make as much sense as I can. At what point would you start to benefit from a basic fuel system upgrade. Meaning, would adding a A/F controller ( like the uni-chip p&p kits ), along with injectors, fuel rail, and regulator, do any good with only an I/H/E upgrade. Or are those fuel upgrades best utilized while under F/I? I'm only considering this because a gear head friend of mine said it would be a good idea if I was serious about staying N/A (I may eventually have the motor built up a little).

[punk2m1d]

Good question. I'll be watching this thread.

[CadenceScion]

I wouldn't worry so much about changing the fuel system on a N/A. Stock injectors work really well as is. If you get into building up the engine, adding a S/C or Turbo, then I would consider upgrading the fuel system. If you tweak the fuel system in any manner, realize that you MPG is going to decrease and you may have an issue with running too rich/lean. Personally, I'd leave the fuel system as it is now, if you decide to build up your engine or add F/I then by all means add bigger injectors, fuel pump...etc.

A performance chip (Uni-Chip) isn't necessary and you really won't benefit from having it. Our engines run very efficiently as they are built and designed from TRD. The VVT-i learns on what we call a learning curve, it adjusts/learns based on how we drive and by what mods we add. In some cases adding computer chips for ex. causes more issues like check engine lights, running too rich/lean. The only option you may want to consider is having TRD reflash your ECM/ECU, but only if your going F/I or you could call Jet Performance and send your ECU/ECM out to have it reprogrammed.

[navylife59]

Cadence is right on the money. My only fuel mod beyond 550cc injectors is a Walbro 255lph in tank pump. I definitely noticed a smoother power curve at WOT going towards redline. The stock fuel pump gets limited when you increase to a larger injector than the 440cc ones that come with the TRD S/C. It does not have the volume. The size of your injectors, the rail pressure, and injector duty cycle determine you fuel capacity need. The size of the fuel line, the pressure regulator, and the fuel rail capacity can also affect this.

I am getting by just fine @ 15PSI on my TRD S/C and 550cc injectors. Oh, did I happen to mention that it is with only the OEM ECM (w/ TRD map) and no intercooling method? I went from 217WHP with my Greddy Ultimate boat anchor to an estimated 260-270WHP with just the stock computer and TRD map. Huh, go figure.

[ACE-tC]

I wouldn't worry so much about changing the fuel system on a N/A. Stock injectors work really well as is. If you get into building up the engine, adding a S/C or Turbo, then I would consider upgrading the fuel system. If you tweak the fuel system in any manner, realize that you MPG is going to decrease and you may have an issue with running too rich/lean. Personally, I'd leave the fuel system as it is now, if you decide to build up your engine or add F/I then by all means add bigger injectors, fuel pump...etc.

A performance chip (Uni-Chip) isn't necessary and you really won't benefit from having it. Our engines run very efficiently as they are built and designed from TRD. The VVT-i learns on what we call a learning curve, it adjusts/learns based on how we drive and by what mods we add. In some cases adding computer chips for ex. causes more issues like check engine lights, running too rich/lean. The only option you may want to consider is having TRD reflash your ECM/ECU, but only if your going F/I or you could call Jet Performance and send your ECU/ECM out to have it reprogrammed.

sorry guys im not use to the car talk what is an F/I? and what is the pupose of getting a fuel rail? i to was looking into getting a new pump (JDM) and adjustable regulator but someone said not to unless i had turbo.. that true?

[CadenceScion]

sorry guys im not use to the car talk what is an F/I? and what is the pupose of getting a fuel rail? i to was looking into getting a new pump (JDM) and adjustable regulator but someone said not to unless i had turbo.. that true?

F/I = Forced Induction
N/A = Naturally Aspirated
I/H/E = Intake, Header, Exhaust

Upgrading to a fuel rail is more for increasing fuel flow to the engine. This is not need on a N/A = Naturally Aspirated. This upgrade is more necessary on a F/I setup. To answer your question, this is true.