The time has come around when our cars are getting older, and now subject to emission' tests (at least here in Ontario, Canada). Unsuprisingly, the sniffer didn't like my longtube headers, aftermarket h-pipe (hi-flow cats), borla cat-back, C&L racer intake and tune.

Here in ontario, they do 2 tests, one for ~1 minute at idle, the other under load for 2 minutes at 40km/h, called the ASM2525 test.

On the idle test, they measure HC ppm (hydrocarbon parts per million i assume), and CO%. I passed both of those with a 94 HC ppm (limit 150) and .60 CO% (limit .70).

On the ASM test, they do the same measurements in addition to NO ppm. My results were as follows:

HC ppm = .94 (limit .52) = Fail
CO% = .38 (limit .29) = Fail
NO ppm = 348 (limit 385) = Pass

I was wondering if anyone had some insight as to ways that would improve the results to a passing grade. I tried a 2nd time after returning the computer to the stock calibration (figuring that would make it run leaner with my increased airflow), but my results got much much worse, and also caused me to fail the NO ppm by about 5 times the limit.

Obviously I'm not going to take off the headers, but would returning to the stock airbox and tune appropriate for that setup (still have both) likely help my case for the test?

 

Your high flow cats are definately hurting your numbers. If you have your stock mid pipe you might want to try changing that out for you test.

 

Unfortunately the stock mid-pipe wont work with long tube headers.

 

Oh ya i forgot about that. I would say about your only bet is to reset as much as you can to stock.

 

Get a cheap H-pipe and splice in 4 mini-cats. I was told that this would pass emissions in Ontario even with Hot Rod cams.