Someone told me that a higher compression ratio changes certain pollutants. Anyone have any idea? I'm keeping my cat and I have a year until I get reinspected, I'm going to get a new hi flo cat but I'm wondering if I even have any chance of passing.

I'm running about 10.7:1 CR and the Comp cam XE268h....

it's a pretty healthy cam, but nothing over the top....will it be close or should i start saving up my 100$

 

An higher compression ratio, in itself creates higher combustion temps which cause higher NOX production.

EGR lowers peak combustion temps therefore lowering NOX.

So the higher NOX of a high compression motor can be somewhat offset by a higher overlap camshaft which tends to have a built-in EGR effect at low engine speeds. But a rougher idle.

 

my cam has 14 degrees overlap, duel pattern. my buddy said to run regular and i might make it with a really good cat, my emissions is all gone cept for the cat

 

u will most likely have to pay one of the mechanics in the emissions place to lean out the engine while making a run; that is most likely the only way it will pass. what is the lift and duration of your cam?? also if you run a higher octane your emission results will be far better than a lower octane (higher octanes burn more efficently and thoroughly and at higher temps) = less smog