theformula

I have an MSD6AL and an MSD tech told me to go with the coldest spark plugs available.

I went out and bought AC DELCOS coldest available (3 levels colder than stock I believe)

Will I actually hurt performance and idle?
Did I go too cold?

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'92 Formula
305 TPI 5speed
1LE package
Mods: SLP headers,SLP catback,SLP air foil,ported plenum,Crane AFPR (42psi),MSD6AL,homemade cold air,K&Ns,3:73s,JET fan switch, Macewen white face gauges...ZZ9 cam (i still have to install it )

JakeJr

I hate to fight with MSD, but that advice is contrary to everything I've ever read, heard or experienced about selecting the 'right' heat range.

"The coldest plug available", they aren't going to last long if you follow that advice.

Jake



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1986 Corvette Coupe, 415 CID, Edelbrock 6073s, ZZ9

TomP

Are you sure MSD didn't mean "as cold as possible".. meaning, "as cold as you can go without your motor running poorly"? Usually heat range changes are made by going one up or one down; and by reading the plugs... a big jump like that doesn't sound like it would help.


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!

theformula

Hey guys I yanked a plug out to check it before I went and did anything else. It was a tanish color meaning everything is ok. So I went and returned the cold ones and got stock AC delco 45-TSs.

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92 Formula
305 TPI 5speed
1LE package
Mods: SLP headers,SLP catback,SLP air foil,ported plenum,K&N, Crane AFPR (47psi),MSD6AL, MSD wires, AC DELCO cap/rotor/plugs, Bosch O2sensor, 3:73s,JET fan switch, Macewen white face gauges, Intellitronix Digital Gauges

Stell1579

i do alot of town driving and some highway and i got regular r45s everytime i check a plug they look good as new

-Stell

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1988 IROC 305TPI MINT!!
Mods= Accell SuperCoil, MSD 6A, Ported Plenum, No MAF Screans , K & N, 160 Thermostat+ Temp Switch, Relocated MAT, Cold Air

MSD tech

theformula,

Like TomP said not the coldest plug available but as cold as possible with out fouling. If this is an normally aspirated application this is not as critical. If this is a blown or nitrous application it is recommended you go with a colder plug. The reason is to prevent pre-ignition that is caused by a plug that actually becomes to hot and ignites fuel in the cylinder as it comes in. This creates a very advanced situation and detonation.

Thanks,

Joe