Yup, you are correct. FPR is only needed when you need to suppliment the fuel to a point at which the stock system cannot compensate anymore. Your stock fuel system will note the added flow into the engine (through the maf sensor) and enrich the fuel through the stock system, the exhaust mods only allow spent combution gasses to flow out of your motor more smoothly and with less restriction, which has noting to do with fuel pressure at all, rather, it has to do with backpressure. Less backpressure gives more HP because it allows your motor to "breate" easier, but too little backpressure will result in a loss of torque. Therefore, the only mod that relies on the fuel system to work is your Intake
, and that can be handled by the stock fuel system.
*for example, the Celica GTS comes from the factory equipped with 310cc "saturated" injectors, I've done the math, and figured out that these injectors can flow more fuel than the stock 2zz setup requires for optimum operation. If this paragraph sounds like greek to you, Check out the July 2003 issue of Import Tuner magazine, and read the article, "Injection Perfection" for more info.
If you go forced induction, or do some serious internal engine mods, a FPR can help raise fuel pressure at the fuel rail to compensate for a lean condition.
However, using an aftermarket FPR can help maximize the effect of an Intake
, header and exhaust combo, used in conjunction with a dyno & some form of fuel management (like an Apexi AFC, or their new SAFCII, which looks to be even better) you can tune your configuration on a dyno, eliminating lean & rich spots in the powerband. doing this, you can squeeze a few extra HP out of your existing mods.
Of course, there can be problems. Most of the newer engines you see these days can't accept an aftermarket FPR because of how the fuel system is set up from the factory (like the I-Vtec motors that lack a fuel return line), this has led manufacturers to find alternate ways to suppliment fuel delivery, either with new computers, injectors and fuel pumps. While I believe the GTS and GT fuel rails can accept an aftermarket FPR, odds are, it will have to be an imported part, as I know of no domestic source for an FPR for our cars, Try Blitz or XS engineering for a hookup on a FPR, if they don't have them, they probably know where to get one.
You WILL need access to a dyno to dial it in, or at least a G-TECH, and you will need to know how to dial it in. otherwise, it's just a lump of metal under the Hood
that takes up space and adds weight.
This is on my list of future mods, I'll do a write-up on the install when I get around to it.