How come the system only comes with one o2 sensor? don't you need to go with two so that you will know what is going on on both sides of the engine?
My FAST system is on the way... where should i put the 1 o2 sensor?
thanks guys...

 

Our 3rd gen cars come with only one O2 sensor, its located on the drivers side exhaust collector. Partically speaking, you could run it on either side. If I were you, I would buy an extra brung with a plug, and test it on each side to check balance across the two banks.

Go with the 396 at first, get it running really good, then go with a twin turbo setup.

Good luck and come home safely.

 

Your 96 uses what is refered to as a sequential fire fuel injection strategy. This means that each cylinder fires the injector when it is needed to. This is determined by the PCM using the crank sensor and the signals from the Opti unit. In 1995 the PCM only used the opti signals. The earlier cars from 93 and back was what is refered to as a bank to bank system. This means that the injectors are fired as two groups of 4, twice with each crank revolution.

With the sequential strategy two sensors are needed to monitor both banks to insure proper AFR. With the bank to bank system only one sensor is needed because the PCM metered fuel the same to each bank. With the Sequential system the PCM metered fuel to each bank independantly and has the ability to change the fueling to each bank and individually to each cylinder.

You should place the sensor just after the collector and before the CAT if you are using one.

 

was going with the nak to bank system a good choice with fast?
The car is going to be a turbo 355 running no more the 18psi... do i NEED the sequential setup???

 

The 96+ cars do not use the crank position sensor for injectors or for timing anything else. They use the exact same high and low res signals from the Opti. Need no other info. The CKP is for misfire detection, no other use.

The use of batch or sequential fire does not determine the need for splitting the control of the engine into two banks. The batch fire 93's had separate O2 sensor for each bank, and controlled each bank individually. On the sequential setups, the closed loop pulse width adjustments for the bank apply to the full four cylinders in the bank, not to the individual cylinders. ARe you suggesting that the O2 sensor can somehow determine which of the 4 cylinders in the bank the exhaust gasses came from, so it can adjust that cylinder?

And, in closed loop system the sequential fire system suffers from the same control issues as the batch fire system. A misfire in one cylinder on the bank is read as a lean condition for the bank, and the resulting increase in pulse widths affects the 3 cylinders that are still firing, and causes them to run excessively rich.

 

thanks you injuneer.. your response has helped clear up and misconceptions about this system and i now have a better working knowledge of what is going on my car.
i appreciate it.
-Tony

 

The guys I know running a single O2 sensor in a dual exhaust car are pretty much forced to run it in one side or the other. But typically, these cars have been set up on a chassis dyno, where it is possible to switch the sensor around and determine if there is any imbalance from bank to bank. Once you do the intitial set up and verify both banks are balanced, you can trust putting the sensor in a single bank. The sensor can not be the only source of data. You have to inspect the plugs regularly on both banks. The "misfire" situation I mentioned above will become very obvious when you look at all 4 plugs.

I have a MoTeC M48Pro full sequential setup, but I run it open loop, no O2 sensor. That option was about $1,000 extra with the MoTeC. I do a chassis dyno check at the start of each season, and the plugs have to be read regularly to insure things are staying in balance. The M800 will handle dual wide-band closed loop operation, fully sequential, not to mention variable cam timing control, drive by wire throttle, and a bunch of other exotic features.

http://www.motec.com/products/ecu/control.htm#M800