Meeting CT Emission Standards

[ByronRACE]

Originally Posted by Don

Byron:

Appears the cam is a Crower, not more than a 280 duration and 526 lift , only data available. Within the range for tuning as mentioned earlier to meet the 1.20 CO and 220 HC ?

280 at .050? The industry standard is to measure duration starting at .050" lift. Assuming that's the duration number given, that's a pretty big cam. 526 lift, however seems to suggest it's probably not a .050" number.

So, I'll say it depends.... if it's 280 at .050, I'd say chances are NOT good...that's a pretty racey cam and would have rough idle/cruise characteristics. If it's 280 at .020, that's about a 240 duration cam at .050...and you'll most likely pass assuming the lobe center and overlap is somewhat normal/typical for a cam of that type.

So, I go back to my qualitiative statements about idle lope and rpm to determine how lumpy the cam is.

Here's a table of typical cam types...you can sort-of get a feel for duration and lift numbers as well as seperation by looking at what's been done in the past. Your cam PROBABLY doesn't deviate too far from one of these.

[Don]

Byron

Thanks for your time, information and patience regarding the cam data and tuning to meet the emission specs. My technical knowledge on cam specs and the relationship of the numbers = none.

I asked Don Scott, owner of CR II that built the 351W engine back in 1998 or 1999 for the first owner, I am the 2nd owner, if he could provide additional details. At that time Don was a dealer for CR and assembled the entire Cobra as well as building the engine.

Cam Specs for 351W

CT has had a history of lowering the emission specs for older engines, what night happen after 2007 is an unknown.