I have a 95 6 speed. What is the best engine managment for forced induction. Does the ems read boost pressure? Will it automatically adjust fuel for boost pressure? Details needed. Thanks in advance.

 

If you're talking about standalone systems, FAST XFI and Big Stuff 3 will both control an electronic boost controller and allow you to map specific boost levels. BigStuff3 has some more inputs which would be nice to have (including vehicle speed), and it's also capable of running multiple wideband O2 sensors so you can measure from each bank. Either of these are good systems depending on how radical you want to make the setup.

Ron

 

Most aftermarket EMSs are speed density. They work off a MAP sensor that reads both boost and vacuum, as long as you go with one over 1 bar. The 2 bar MAP sensors read up to around 15 psi of boost, and you get another 14-15 for each bar over that. They then determine the amount of fuel to add by the MAP sensor reading and the RPM. Some go off a pulse width table and need to be told to add more fuel, while many of the ones with what's known as a VE table automatically add more fuel based on the air density (boost and temperature).

Putting an aftermarket ECM on a car with an Optispark has a few unique challenges - the Optispark looks like someone tried to throw a Nissan 240SX distributor meant for a four banger on a V8 without changing the trigger pattern, and a lot of aftermarket ECMs have trouble with it. With many of then you would need a different trigger setup, like an MSD Flying Magnet or a missing tooth type wheel (A HEI distributor adaptation would also work as a trigger wheel; these are compatible with almost anything). A few systems out there do work with the Optispark sensors directly.

I thought I'd toss out some thoughts on different systems. I work for a company that sells Megasquirt and Spectre systems; I just wanted to let you know I'm not exactly neutral. But I do respect most of the other systems. Here's some commentary on some systems that could work for you, and some systems I don't like and why. I'll put them in alphabetical order. One rule to remember is that a system can't be better than its tuning; you'll want to tune it on a dyno to get the fuel and spark tables to match your engine's needs.

Accel DFI: A sound enough system, but they make you pay extra to unlock certain software features to tune it. I'm pretty sure this one requires a Flying Magnet type trigger wheel.

AEM: A fairly high-end system with a lot of features. Not sure if it requires a trigger wheel or not.

Big Stuff 3: Equipped with plenty of features and works with the Optispark sensors. Note that these guys are the ones who build ECUs for MSD as well.

Electromotive: A system with a distributorless ignition that requires adding a 60-2 Bosch style trigger wheel.

FAST XFI: Another system that works with the Optispark sensors.

Holley: The Commander system is a basic speed density system that could work with a Flying Magnet type trigger wheel. The Pro-Jection uses throttle position instead of a MAP sensor and is not appropriate for forced induction.

Mass-Flo: These are actually chipped OEM computers, usually (possibly always) based on a Ford EEC-IV.

Megasquirt: Currently, this would require a trigger wheel or HEI, too. It can work on this engine, but as different builders put different feature sets in them, be sure to talk things over with a dealer if you're buying one fully assembled.

Motec: One of the most feature loaded, and expensive, ECUs out there.

Spectre: A Megasquirt based ECU with a lot of features (and bling) added. Would require using a trigger wheel and a different IAC valve.