cams and emissions

[sothpaw]

What characteristic(s) of a cam affect its emissions? I am about to make my final selection,
and the car with new heads+cam must still pass MD state emissions.

The cam:

Comp. cam #?
Dur @ .050: 212/224.
Lobe sep: 112 degrees
lift: 520intake/536 exhaust w/1.6 RRs
Advertised duration(.006"): 264/286

The 286 number bothers me a bit because the lobe intensity for most cams
I'd consider is something like 67/59 (LT4 Hotcam), and I compute this to be
a lobe intensity of 61/71. I am a novice here, but maybe I was not quoted
the right advertised duration.

 

[vader86]

That cam can pass emissions, its not radical. You will just need some tuning.

 

[sothpaw]

What parameter of cam makes it "radical" enough not to pass?
Duration @ 050 of 230/245?

 

[vader86]

What i usually look at is the duration at 050, but its really a combination of things.

Something like 230/230 probably wont pass emissions, Something like 220/220 could.

 

[Vettelt193]

which cam is that? I haven't seen that one before. That cam isn't too radical, and should easily pass emissions with proper tuning.

 

[WhalePirot]

My Comp passed

I have a Comp 230/236@.050, hydraulic roller in my 406. With a brand new CAT and a LOT of chip work, I passed California emissions. The car has a cool, lumpy idle, as all real cars should, while most 'tuners' claimed that my 'chipper' would never get the car to idle, much less pass SMOG.

The results for the new California test-->>
At 15mph (1256rpm): HC=35 CO=0.06 NO=18
At 25mph (2020rpm): HC=33 CO=0.29 NO= 9

The smogger claimed that the new factory CAT worked its butt off, but the result is MY interest.

The COMP grind number is CS XR282HR-10; PN:12-432-8

Enjoy yer project!


Mike

 

[oldace84]

I know of no cam that will pass emissions...just too much overlap....
but you can try...if you like tearing your engine down.....
I'd rather drive my vette....than pay the price the smog nazi's ask.....
tony