Spark Plugs for Boosted Motors???

M

Melmark93

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Vortech recommends NGK 4177 or Autolite 764 gapped down to .032.
A search of both Mark sites only turned up a good post by A-train several
years ago over on the Dark Side. It covered just motorcraft plugs:

AWSF-32PP & EE, stock plat. and coppers
AWSF-22C, 1 range colder copper
AWSF-12C, 2 range colder copper
AGSF-12EE, 2 range colder plat. /medium wire/full thread base(99-00 Lightnings)
AGSF-12FM1, 2 range colder iridium/fine wire/full thread(01-02 Lightnings)

Given that cooler plugs are less knock prone and a spark from a fine wire
electrode is harder to blow out under boost (see A-trains post), other than
cost, why not use the AGSF-12FM1s?
Who do you believe Ford or Vortech?
Jeremi, what have you used in your several Marks?
Mike, have you got to this point in your SC project?
Driller, Tommy, anyone, feel free to add your 2 cents

Mel C.
93 garnet/grey X2
Garage Queen w/ escort
 
Last edited:
Hi Mel, Aric has chosen NGK BR7EF Spark Plugs for my Mark. I did not ask him why he has chosen them, but I will ask. I am sure you have gone through both the street and race Vortech owner manuals already, but they recommend 1-2 heat ranges colder, and a gap in the .030 to .040 range, and do not use the OEM platinum tip plugs.

I have read that some plugs will have miss issues at idle, and others higher up the rpm range. Some have said that AR103's are the best all around plugs for 6psi and up all around without a miss. They are sidgapped to unshroud the center electrode and allow the spark kernel to ignite the charge mixture faster, and even with the colder plugs like the AR93 and AR94, you will not have the loading and miss problems that regular plugs exhibit.


Here is a list I found on the web from some Lightning owners...



MOTORCRAFT

PART# / HEAT RANGE
AWSF-32C / stock heat range - copper plug
AWSF-22C / 1 Heat range colder - copper plug
AWSFA-12C / 2 Hea range cooler - copper plug
AGSF-32C/ Recommended for FRPP heads(not sure on heat range)

NGK

PART# / HEAT RANGE
TR-55/ 3951/ Stock Heat Range
TR-6/ 4177/ 1 Step Colder
BP7EFS (PN - 3526) BR7EF (PN - 3346) two steps
R5724-8 (PN - 7317) two and a half steps
R5724-9 (PN - 7891) three steps
R5724-10 (PN - 7993) four steps

AUTOLITE

PART# / HEAT RANGE
764s / Stock
AR103 / 1 heat range cooler
AR94 / 2 heat range cooler
AR93 / 3 heat range cooler
AR92 / 4 heat range cooler

CHAMPION

PART# / HEAT RANGE
YS-59C / -3 or -4 below stock heat range

DENSO

PART# / HEAT RANGE
IT16 / stock heat
IT20 / -1 heat range
IT22 / -2 heat range
IT24 / -3 heat range
 
I think this article pretty much covers it... Spark Plugs 101.

There are newer technology plugs on the market now. The new Iridiums and Brisk plugs come to mind.

I run the AWSFA-12C / 2 Heat range cooler - copper plug in my N/A setup. Basically you want the coldest plug that will not foul under normal driving conditions. I think that holds true for N/A or boost. I started with the stock heat range Autolite plugs, moved to the one step colder Motorcraft plugs and finally the two step colder plugs and have no sign of fouling.

I'm not a fan of precious metal plugs but most with boost experience will run a fine wire center electrode(meaning silver or iridium) and a narrower gap than stock.

I personally feel a quality copper plug(i.e. Motorcraft or Autolite) of the proper heat range and gap will outperform any other when regularly changed, even under boost. You can also "Nitrous Prep" the standard construction spark plugs by filing back and rounding off the ground electrode to partially unshroud the center electrode.

That's my 2 cents. :D
 
I am running the same plugs as Driller gapped at .030" at 13lbs boost and no problems. At .032" + we were getting some blow out. Hope this helps.
 
I switched back and forth between Motorcraft 22c and Autolite 103s, gapped at .035. No real difference ever noted.

Use a cheaper plug and change it more often was the ticket for me over the years.
 
Autolite AR103's are the best, NGK TR6's are also very good and you can get them in copper or iridium. Never use a platinum plug with boost.
 
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