Passing emissions test

[Tom Sarno]

I tried to get through inspection and failed for NOX by a small amount. I plan on doing a complete tune up, but was wondering if a slightly hotter or slightly colder plug is better at getting the NOX down. I know hotter is gas milage and colder is performance so I am thinking hotter but want to be sure.

Thanks
Tom

[Joe L.]

Re: Passing emissions test

Tom------

I don't think that spark plugs are going to make any difference, at all, with respect to NOX emission levels. Some other part of your system must be defective. If the car is a 73+, I'd check for proper operation of the EGR valve. EGR is one of the big factors for NOX emissions control.

[Duke W.]

Re: Passing emissions test

Spark plug heat range is not an issue. Stateing the year and engine and whether it conforms to OE configuration and spec would help. Also, type of test and all test results.

Retarding the timing can reduce NOx. NOx is produced in the flame front at over 4000 deg. F. Retarding timing reduces peak flame temperature. It also increases EGT, which helps coverter efficiency.

Duke

[Donald Brunswick]

Re: Passing emissions test

If you are that close retard the timing a little and go back and re-test.

[Tom Sarno]

Re: Passing emissions test

Duke,

Thanks you and all the others for the reponses. I feel bad because this was not a Corvette question, but rather for the tow vehicle that I use for my Corvette. It is a freshly rebuilt '88 350 that has stockcompression and stock type/RV cam. The catylitic converter is still on the truck, but from the cat back is a complete 3" exhaust with 3" flowmaster 40's.

I turned to this board because I knew you or one of the other members would be able to steer me in the right direction.

PS. Do you have still have the list of vacumn advance part numbers with the ratings for them?

Thanks
Tom S

[Duke W.]

Re: Passing emissions test

Yes. E-mail me if you want it.

Duke

[Roy B.]

Re: Passing emissions test

There are all kinds of additives you can add to the gas to help clean the engine before going for a smog check.
I always run WATER down the Carb as I stated before to rid the engine of carbon once a year. Water has been used for years by mechanics in the OLD days . It works better and faster and will keep your engine clean and running smooth.
%99 of most people to day don't or will believe it and wont try OH well good luck