SMB Chevy Emissions

[Guest jwelch]

I'm still in the battle against emissions and wondering if anyone has some ideas to help.

 

I've made some changes to the engine and emissions have improved but can't quiet get there. Here are the specs. on my engine.

 

77Z SMB350/4bolt/10.5:1 compression/mild cam 218in/224ex @ .050" (COMP# 12-238-2)/Holley 4D (900cfm) Analog Pro-Jection/HEI ignition/Performer Intake/Block Hugger Headers/Single Exhaust with cat.

 

Since I live in AZ. the car doesn't need a cat. or air system for this year. But I use a cat. to pass (at least in the past, even with a bigger cam)

 

I'm failing Hydro-Carbons (HC) @ load (reading is 4.31% and the standard is 1.50%)

 

I'm failing Carbon-Monoxide (CO) @ idle (reading is 485 PPM and the standard is 250PPM)

 

I think that I'm running too rich so I have leaned out the projection slightly and moved the timing from 10BTDC to 17BTDC. I haven't taken it back for another test yet because the retesting is starting to get expenisive. Does anyone think the changes I've made will get me thru?

Any input is greatly appreciated.

 

 

BTW: I spent $600 2 years ago to have the cat added and carb re-jetted to pass with a larger cam. (I will never waste money on that again)

[labrat]

There is a gasoline additive called RxP that i have successfully used in the past to help pass the sniffer test in dallas county. I think it's a fuel oxygenator of some sort. I think it guarantees on the bottle that you will pass if used according to the directions. With that high of compression, i figured you would fail for Nox. Is there a clause in the emmisions laws in your area that if it would cause excessive financial hardship to smog the car, you pass by default? I know a lot of friends have scraped by using this loophole. Spend 3-4k on a motor build up, then get it to pass smog because it would cost more than 500.00 to make it legal. Just a few thoughts, it's late here...