I see a lot of threads on cam selection and how it pertains to power, gas mileage, and driveability, but what about passing emissions? How many of you are running an aftermarket cam in a state with emissions testing? How big can you typically go and pass the sniff test with a good dyno tune?

02 Sierraz71_5.3, you're from NC, what's your thoughts on it?

 

Overlap is a bad thing if youve got to pass a sniffer, in NC OBD 2 vehicles are plug and play. If it passes all readiness codes but 1, no SE lights and visual your good too go.

I think the way around the sniffer if you had to go to lengths is to put it in open loop and command about 15:1-16:1 at idle then you can get around any sniffer problems if its looking for unspent fuel, this would create more hydocarbons though not sure which a sniffer actually looks at or if its looking for just a stoich afr.

hhhmmmm

 

This got me thinking, called a buddy he related the sniffer is mainly looking for hydrocarbons and 02 content looks at several things not just one. I believe those additives that help you pass inspection just oxygenate the fuel alot.

 

So holding all other variables constant a cam with a wider LSA (such as a 114) would be more apt to pass the OBD2 test? A Vinci 062 cam would be a plug and play with my programmer but the more research I do, the better the old man cam looks for my simple goals.

Thanks.

 

Sniffer also looks at NO levels. Not sure how leaning out the mixture affects that, but I doubt you could pass commanding a leaner AFR...

 

I like the old man cam I was looking at it before I got my LPE gt2-5,
anyone got the cam card?

 

'Should' be pretty close...

OMC: 214.220.115+2



This cam probably looks good in lobe area but, the VEs get a bit funky from the radically different lobe profiles. Maybe it works quite well tho. It's a very interesting design. I'd much rather have it on a 110-112 LSA.

 

Im at work I dont have the cam card in front of me but the valve events look very different. The old man cam seems to have more DCR than mine I think my LPE closes the exhaust around 52 ABDC and it has more overlap.

 

I'm confused... What VEs do you recall the OMC having? These are probably not the exact lobes. The intake lobe I took is a SBC lobe and the exhaust is X-E, low lift LS1 lobe. Also, what was the ICL? Was it 4* advance? I thought Thunder sent it off at 2* for a 113* ICL.

 

I'll post up my card when I get home