AquaMetallic94LT1

I finally finished the cam swap in my 383 stroker last weekend and took the car in for emissions testing on Monday. First attempt netted:

CO 16 g/mi NOx 2.39 g/mi THC 1.29 g/mi FAILED THC (1.20 g/mi max)

2nd Attempt - (Drive car around block as recommended by attendent then got sent to different test bay)

CO 9.6 g/mi NOx 3.47 g/mi THC 1.03 g/mi FAILED NOx (3.00 g/mi max) but passed THC -

WTF

So I reduced the closed throttle spark advance and increase the idle 50 rpm. I also had an intermittent problem with the high res signal which went away after I used contact cleaner on the contacts to the ignition system.

Next result - (raining this time late in day so different attendent again)

CO 3.9 g/mi NOx 1.71 g/mi THC .27 g/mi PASSED

Thank god since the tags had expired at the beginning of this month.

Conclusion -

Raise idle to get rid of HCs. Cam with 230 intake 242 exhaust 112 LSA won't pass. CO and HC too high. New cam is 222 intake 230 exhaust 112 LSA.

Pollutants are measured in grams per mile so values will affected by rear gear changes. Higher numerical gears will increase emissions. An attendent actually controls the cars speed etc during the test so the results will vary depending upon how the attendent drives the car. Aggressive ones will probably increase CO and NOx emissions since they will be going into enrichment mode and getting up in rpm more. Others will increase the HC if they stay in the lower rpms in each gear range. Makes me wonder how accurate this testing really is.

CarAteMyMoney

That's a pretty nice setup, im surprised you were able to get it running efficient enough to pass the IM 240.. We have that test here and it knocks out alot of people