I've been reading up on the 'FSM, trying to figure out all the inputs that correlate to the functions of the emissions devices on a stock '90 TII. It seems it would be damn near impossible to have an aftermarket EMS have total control of the necessary emissions devices.

With this said, I figure it might be possible to run a stand alone and the stock ECU together to be able to have all the emissions devices working and also have all the benefits of a stand alone. The questions is... How? Has anyone done this before with the sole purpose of retaining all emissions functions?

In the end, I may not even pass smog, but I think it's a worthwhile challenge to have a +350rwhp car with all emissions intact and working as they do from the factory.

People will suggest going with just a piggyback such as the Greddy E-Manage or the SAFC, but I find those devices crude after messing with the Microtech in my old car. As for the aftermarket computer of choice, I'm planning on going with the Autronic SM2. I've been messing with the SM2 software and looking up info and specs, and it seems like a VERY capable computer.

 

373rwhp @ 12psi and passes VA emissions tests with the standalone EMS:
http://www.cris.com/~Asam/20B.html

 

I guess I forgot to mention the part about sticking with an S5 13bt in a S5 TII.

 

Which means that you have 1/3 less emissions to worry about.

 

True, but how would this all wire up? Inputs/outputs, etc.?

 

It's mostly in the tuning. I don't think you need any of the emissions devices other than the cat. The cat may limit the boost, and tuning for emissions will be more difficult with a ported engine. I suggest that you contact an EMS guru (EMS brand doesn't matter) in your area and see what kind of power he thinks is possible from an emissions-legal engine. I realize that most people on this forum like the idea that they can do everything themselves via bolt-on mail order performance parts, but a good tuner is really what you need IMO.

 

Well, I realize passing the sniffer test may not be too hard as tuning can get me a long ways around this. However, the whole goal of this project was not just to pass the sniffer.

My goal for this project was if I was put into a situation where I would have to pop my hood for authorities or a smog technician, I could open the hood with full confidence that they would not find one stray emission device missing from under the hood. Passing the sniffer part of a smog test is only secondary to what I'd like to acheive by doing this.