tuning questiion - Page 3 - ZR-1 Net Registry Forums

XfireZ51 · 09-19-2012

Read this article on selecting the right heat range.

http://www.moparmusclemagazine.com/t...s/viewall.html

You start from there then move on to gap and timing.

Hib Halverson · 09-20-2012

That story doesn't say much at all about how to select a heat range but what's there, if anything, confirms what I said earlier about plugs.

But...if the plug originally developed for the engine was an AC 1 heat range, unless the engine is in a trailer queen...why is everyone running such hot plugs?

Do they know more than the engineers who spent years testing plugs?

I'll stick with my Denso 22 heat range.

But I will grant you, for engines which see a lot of starts without warm-ups, are running too rich at idle and part throttle or are using oil, the cold plug is a mistake.

scottfab · 09-20-2012

Quote:

Originally Posted by XfireZ51

Read this article on selecting the right heat range.

http://www.moparmusclemagazine.com/t...s/viewall.html

You start from there then move on to gap and timing.

Great post. Thanks !

XfireZ51 · 09-20-2012

Click in the pics of the various plugs. The one w high miles
but in good condition. Read the material there. It describes how to choose plug heat range using the coloring of the ground strap. This is really well known in performance circles. Nothing new actually. You don't pick heat range based on the color of the ceramic.

Hib Halverson · 09-20-2012

Well I haven't heard that much about using the color of the ground strap to select heat range.

But, heck, maybe I've not been in "performance circles".

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.

09-19-2012	#21
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,697	Re: tuning questiion Read this article on selecting the right heat range. http://www.moparmusclemagazine.com/t...s/viewall.html You start from there then move on to gap and timing. __________________ [SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX

09-20-2012	#22
Hib Halverson Join Date: Jun 2005 Location: CenCoast California Posts: 899	Re: tuning questiion That story doesn't say much at all about how to select a heat range but what's there, if anything, confirms what I said earlier about plugs. But...if the plug originally developed for the engine was an AC 1 heat range, unless the engine is in a trailer queen...why is everyone running such hot plugs? Do they know more than the engineers who spent years testing plugs? I'll stick with my Denso 22 heat range. But I will grant you, for engines which see a lot of starts without warm-ups, are running too rich at idle and part throttle or are using oil, the cold plug is a mistake. __________________ Hib Halverson Technical Writer former owner 95 VIN 0140 current owner 19 VIN 1878

09-20-2012	#24
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,697	Re: tuning questiion Click in the pics of the various plugs. The one w high miles but in good condition. Read the material there. It describes how to choose plug heat range using the coloring of the ground strap. This is really well known in performance circles. Nothing new actually. You don't pick heat range based on the color of the ceramic. __________________ [SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX

09-20-2012	#25
Hib Halverson Join Date: Jun 2005 Location: CenCoast California Posts: 899	Re: tuning questiion Well I haven't heard that much about using the color of the ground strap to select heat range. But, heck, maybe I've not been in "performance circles". __________________ Hib Halverson Technical Writer former owner 95 VIN 0140 current owner 19 VIN 1878

09-20-2012	#26
mike100 Join Date: Feb 2011 Location: San Marcos CA Posts: 1,802	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.