Anyone ever done this? Down tune with your fc specifically for smog purposes... like kill boost to reduce output. Thoughts?

 

There is no reason to tune for smog. If your emissions work correctly and the car is tuned correctly it should pass smog. Boost will not effect smog. In FD's the smog test should never exceed 2800rpm at very light throttle. If you can put a stock ECU in the car and run a known good stock cat and with all of the emissions devices and everything set correctly you should pass no problem.

EB Turbo

 

+1 if you hit boost during a smog test, something is wrong.

the stock ECU is in closed loop for the smog test

 

The thread on how to make the base map safer has some tips on how to temporarily lean out your map for smog purposes.

 

Thanks guys.... the advice is much appreciated.

Btw, and I posted this in wtb, but if any of you have a spare air pump and associated parts (the mount clamp, tubes connecting to cat, etc), I would love to buy it. I need the whole assembly basically.

 

The question is very sensible if you have a modified engine!

My non-seq engine with DP, high flow cat, large IC, and mild porting required a leaner map to pass Texas testing on a dyno. The first time it was tested, I logged it and slightly failed. Since TX allows one more test for free at the same station, I came back prepared.

I looked at the tests logs for which cells were used for the 2nd and 3rd gear runs.
Reduced fuel there, put in stock hotter plugs than my normal 350 hp required plugs,
went back and passed.

Every year the leaner map goes back in and if tests results vary, I adjust for it for the next year.

 

Chuck, do you install an airpump when you got for a test? I'm curious how TX standards (in terms of ppm concentration) compare to California standards.

 

My air pump was always attached and working not only for my non-seq but it is still there and working with my GT35R single turbo setup.

Low speed test maximums:
2nd gear 15 mph, HC(ppm) 136, CO %(.76), NOx(ppm) 1045

High speed test maximums:
3rd gear 25 mph, HC(ppm) 132, CO %(.73), NOx(ppm) 945

These are map locations that would not be used for real driving.

 

Are you using the ACV or plumbing the air directly to the cat?

 

No ACV as it does not fit with after market large injector rails.
I have an SS injection pipe welded into my mid-pipe just like my hi-flow cat has.
The air pump flows directly into the fittings on both pipes/cat.

 

Do you have air flowing upstream of the O2 as well?

EB Turbo

 

No as the stock way only worked with the ACV and into the exhaust port. All that is blocked off with a single turbo manifold. I do not run O2 FB thus no reason to engineer for it. It would also be difficult to figure and control the correct amount of air flow.

 

You will get nowhere if you are not pumping air upstream. Pumping air into the center of the cat only helps the cat lite off. You need to delute the exhaust into the cat. What kind of cat are you running?

EB Turbo

 

RP Bonez hiflow but only for yearly testing.

Mixing some E85 or adding straight ethanol helps with reducing HCs.