Performance Chips and Tuners

PLEASE COPY ONLY IF YOU GIVE CREDIT.  THANKS.

So - you've got a newer vehicle and you'd like to tune it.  Unfortunately, when you looked under the hood there was no carburetor to adjust and swap jets in, and there was no distributor to turn.  To make things worse, you don't even see any spark plugs or spark plug wires.  Don't panic.  The spark plugs are still there at the top of each cylinder, and they still do the same thing.  Instead of the car's electrical power going through a coil, then a distributor, and then to each spark plug - the car's computer tells each spark plug when to fire.  In most cases, there is an individual coil over each plug, and the computer sends a signal to the coil, telling it when to fire the spark plug.  The distributor is not needed because the computer knows the exact position of the crankshaft and therefore each piston because it is hooked up to a crankshaft position sensor.  The carburetor hasn't been needed for years since fuel injection came out, but you knew that.  "That's all great," you're saying, "now how do I tune it?"  This is the tough part.  In some vehicles, there are a few things to try, like relocating the Intake Air Temperature (IAT) sensor, installing a timing adjuster or a fuel pressure regulator.  In many cases, they work very well, but these things are just means of fooling the vehicle's computer.

A modern vehicle computer controls everything from fuel delivery and timing to rev and speed limits, shift points, and a number of things most people have never even heard of.  It does this by receiving a whole bunch of inputs, referencing some tables, and then changing output values.  Inputs are taken from such things as the IAT sensor, the crankshaft position sensor, the throttle position sensor, the Mass Air Flow (MAF) sensor, the Manifold Absolute Pressure (MAP) sensor, and a few others.  Through these sensors, the computer knows exactly what the environment is like and what the engine is doing.  The main outputs are fuel delivery (injector duty cycle - how long the injector remains open vs. closed) and spark delivery (timing.)  For every rpm, throttle position, and load (as determined with the help of the MAP or MAF sensor,) there is a table filled with fuel delivery and timing values.  Actually, there are too many rpm, throttle position, and load values, so the programmer writes tables for every 250 rpm (for example) and the computer interpolates the rest of the tabled values.

Therefore, in order to properly tune a modern vehicle, the tables stored within the computer must be changed.  This can be done by getting a new computer, re-flashing the computer, or adding a chip to the computer.  The chip stores all of the tables itself, and they override the tables stored in the computer.  The computer can be re-flashed by sending it to someone that has that capability, or by using a hand-held tuner.  The tuner stores one or more programs (or tunes, which are simply groups of tables.)  Some hand-held tuners also have the capability to change some of the values in the tables stored within the computer with the push of a few buttons, i.e. adding 5% more fuel or timing throughout the entire rpm, load, and throttle position range.  Many can take new tunes from your home computer.

If you have a heavily modified vehicle, getting a new tune for the computer is a necessity.  If your vehicle is stock or only slightly modified, the advantages of a new tune may not be worth while.  Many vehicles come very well tuned from the factory, and many stock computers (and the tunes within them) are capable of adequately handling some performance modifications.  If I don't think that you will benefit from a new tune, I will tell you up front.  There is no need to spend $400 - $500 for only a couple of hp.

BRISTOL  DYNO  carries Superchips Custom Tuning (SCT.)  SCT offers multiple-program chips, hand-held tuners, and dataloggers for Ford vehicles.  We can burn the chips and create and modify the tunes in-house while you're on the dyno.  Check the SCT website by clicking on the banner below or click on the brochure icons for detailed information.  Click here for pricing, then call me at 860 282-2248 or e-mail me to order a part or to make a tuning appointment.

For vehicles other than Ford, other methods must be used.  There are countless other systems to tune fuel-injected vehicles, including chips, flashers, "piggy-back" systems, and "stand-alone" engine management systems.  Victor Research sells, installs, and tunes some of these systems, contact them to get some more information.