Easy Steps to improving performance of a stock FX50S without major modifications....... As mentioned above, if you want significant increase you'll need to look into superchargers or turbo's; costly. Personally I'd really love to the the Protean Drive hybrid technology hit the consumer market, it's a sleek, stealthy circular hub that fits behind your existing wheel; containing a 105HP electric motor, computer circuitry and sensors. Four units can be linked into the ECU of an AWD vehicle, and is instantly adaptable to the FX50's electronic driving dynamic, and safety programs. The questionable part is going to be the battery cell technology used, storage capacity, recharge technique, cubic size etc.
Pretty awesome... I might do a prothean post.
Remove the stock exhaust system! You have two primary options, only one I can comment on. You can go all the way with a full system, headers and all; but I suspect that you would need to be mindful of the sensors that are in place and aware that removing anything before the catalytic converters is 'frowned upon' with regards to your warranty. I personally left the cats in place, and then installed a custom system. The cats fix to flexi-joints, then 2.5" piping with a mandrel bent x-pipe. I'm using Varex mufflers, which have an electronic butterfly valve; so i can choose between straight through power or subtle silence.
It's a debatable subject, I believe that most after market cold air intakes are no more efficient than the factor design. Dropping in a set of K&N filters is always a good idea, if only for value.
I had my FX remapped and dyno'd. They made some significant changes which improved power, torque and efficiency. These cars run rich from the factory.
Jogging, swimming, removing the doughnut..... Anything you can shed. I went the other direction, making it heavier with sound deadening
--THE ACTUAL GAIN--
The claimed power of the factory V8 is 390HP, but by the time that power get's to the wheels it's actually closer to 240HP. All of the modifications I've done equates to a gain of around 40HP, which in my case in enough to counter the performance hit taken by adding all of my sound deadening material. End the end, it's all about you and what you want to do with your car. Dollar for dollar, going all out with the exhaust with a tune and some drop in filters is the extent of what you can do without forced induction.
Come and see my post for more info........
and stop by Infiniti Brisbane on Facebook.....