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zr1don · 06-25-2011

The following got me through CA emissions, don't know if this will apply to the big cams, but this will help emissions on most engines:

Reduce stock spark tables 2 to 6 degrees (mine worked best for NOX at -4 deg)

Use thermal wrap on both the headers and CATS to get CATS hot (they remove more gases when hot).

Make sure fueling is at or very near stoichetric. If your computer is adjusting away from where you want to go, you can do closed loop or (my preference) reduce max min block learn cells to 1, both max and min block learn the same cell #. That lets the computer adjust up and down within that cell only.

If the engine is carboned at all use a cleaner like Seafoam to get the deposits out

Be sure the cooling system is keeping temps 200 to 210 deg F. Cooler or hotter will push regulated gases higher, they will be min at above temps.

If not using stock cats, use the biggest after market cat you can find (example: late 90's to early 2000's chevy big block pickups)

If I remember any additional relavent things, will post up again.

06-25-2011	#2
zr1don Join Date: Jan 2006 Location: Temecula, CA Posts: 88	Re: VA emissions tuning The following got me through CA emissions, don't know if this will apply to the big cams, but this will help emissions on most engines: Reduce stock spark tables 2 to 6 degrees (mine worked best for NOX at -4 deg) Use thermal wrap on both the headers and CATS to get CATS hot (they remove more gases when hot). Make sure fueling is at or very near stoichetric. If your computer is adjusting away from where you want to go, you can do closed loop or (my preference) reduce max min block learn cells to 1, both max and min block learn the same cell #. That lets the computer adjust up and down within that cell only. If the engine is carboned at all use a cleaner like Seafoam to get the deposits out Be sure the cooling system is keeping temps 200 to 210 deg F. Cooler or hotter will push regulated gases higher, they will be min at above temps. If not using stock cats, use the biggest after market cat you can find (example: late 90's to early 2000's chevy big block pickups) If I remember any additional relavent things, will post up again.