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mike100 · 09-20-2012

I have never deviated more than one heat range from 'stock' (if known) for any particular engine incl mild street supercharged applications.

The one time I got some free plugs that were 3 or 4 heat ranges colder that I threw into a tpi 305 camaro, it immediately failed to meet the max allowed hydrocarbons on the two speed idle emissions test that we used to use here. (I worked at a shop and we had the 4-gas bar-90 machine). It idled fine, ran fine, ...just ran dirty at idle loads.

if you don't run catalysts, I suppose it doesn't much matter.

09-20-2012	#2
mike100 Join Date: Feb 2011 Location: San Marcos CA Posts: 1,786	Re: tuning questiion I have never deviated more than one heat range from 'stock' (if known) for any particular engine incl mild street supercharged applications. The one time I got some free plugs that were 3 or 4 heat ranges colder that I threw into a tpi 305 camaro, it immediately failed to meet the max allowed hydrocarbons on the two speed idle emissions test that we used to use here. (I worked at a shop and we had the 4-gas bar-90 machine). It idled fine, ran fine, ...just ran dirty at idle loads. if you don't run catalysts, I suppose it doesn't much matter. Last edited by mike100; 09-20-2012 at 11:34 PM.