In the past, I posted about not being able to pass Illinois state emissions, even with 4* base timing and 42 psi fp. My car ran exceptionally well, but still put out 1.54 GPM HC (I passed CO with only 6 GPM under a 15 GPM limit).

I finally bit the bullet, and had a Dynomax Superflow 3" cat hooked up (The best one, according to my friend at Car-X). I had removed my A.I.R. system, including smog pump, and had base timing set at 12* and fp set at 50 psi! I'm not even sure if my EGR works .

However, after running the crap out of my car to get the cat hot, and without any fuel additives I only puffed out a 0.28 GPM HC - well under the 0.80 limit. The best thing is, I have an eliminator pipe built, so when 2004 rolls around, all I have to do is bolt up the cat and take the sniffer.

Lessons learned (with my 1990 L98 SD)
1. No A.I.R. system necessary to pass.
2. Reasonable timing (6-12*) and fp (45-50) seem irrelevant.
3. Never underestimate the power of a good catalitic converter - I shed 1.3 GPM with tuning optimized for performance, not emissions.

Hope this is helpful
Kyle

 

So your brand new summit cat was to blame?

 

No...I was to blame for thinking I could get away with using a Summit (catco) cat. Those things might be okay for getting grandmas Tempest to pass, but you need a quality converter to pass a TPI thirgen (in IL).