I've never really had the luxury of sitting around and asking a bunch of questions while my car was being tuned (old Supra). Too many places to be, not enough time...

I'm quite familiar with what some of the parameters should be but I wanted to get a better understanding on how one would tune a car from start to finish. Not in grave detail but basically in a nutshell, what are some of the steps involved?? Of course we're talking F/I here.

 

www.howstuffworks.com has some good information on how an engine works. I'd check out their guide if you have a few minutes of reading time.

There are a lot of different things you look out for while tuning a car, but the main ones are obviously ignition timing and fuel mapping. Oh, and don't forget boost. Obviously, all of this stuff is going to look like rocket science if you don't have a firm grasp on every step of the combustion process.

 

OEM's spend hourless man hours and R&D dollars to perfectly tune the stock ECU. Essentially, you use a load based dyno or an engine dyno to properly map ignition and fuel across the entire load site area that the engine will see during operation. As BSP mentioned, an OEM car's ECU controls a vast number of functions, and there are correction tables and other checksums that allows the car to operate under all engine/load conditions. This is the reason that modern cars start up on the first try, regardless of ambient conditions, and they run smoothly and efficiently throughout the power band.

When you add FI to a car, you are picking up where the stock ECU left off....assuming you are using a typical piggyback style ECU, such the Emanage Ultimate, UTEC, or Unichip device, for instance.

The most import element is lambda, or A/F ratio across all the load sites...not just WOT. Second is ignition timing, which must also be optimized across all the load sites that the car would see under normal operation. Most tuners will start by dialing in AF ratios, and then read the trq curve to determine how to optimize ignition timing mapping. There are certain techniques people use, and these may vary from tuner to tuner. There are ways to maximize trq, for instance, or maximize top end power., for instance. There are ways to keep EGT's down at higher RPM, and minimize the chances of knock near the trq peak, where the chances of detonation are greatest.

 

Sharif, just a bit of **** kissin from me. Just wanted to say thanks for all your info that you post on this site. Ive learned a LOT from your post! Props to you!