4VNA spark plugs

[96GTS]

What's the best plug for a N/A 2001 Cobra? Brand, P#, and what do I gap them at? Thanks.

Darren

[RandyStinchcomb]

Darren, in your case I would recommed either the Motorcraft AWSF-22C or the AWSFA-12C gapped at @ .045 to .048

Randy

[scothew]

Go with what Randy just said. I put the NGK equivilant in my car after his suggestion and its running DAMN good.

[96GTS]

Originally posted by RandyStinchcomb
Darren, in your case I would recommed either the Motorcraft AWSF-22C or the AWSFA-12C gapped at @ .045 to .048

Randy
What's the difference between the 12 and 22? How would I know which one would work better for me?

Darren

[scothew]

22 is one heat range colder than stock, 12 is 2 steps colder.

[RandyStinchcomb]

Originally posted by 96GTS
What's the difference between the 12 and 22? How would I know which one would work better for me?

Darren


Darren, trial & error. at @$16.00 a box, buy both ;)

[Brandon Alsept]

How many come in a box Randy? 8-16 what? I need to get a set of the 22Cs.

[RandyStinchcomb]

Brandon, Ford is still trying to figure out how many plugs come in a box? right now the AWSFA-12C come 10 to a box and the AWSF-22C are boxes of 4, you can buy 1 plug or as many as you like.

now my take on plug heat ranges and I've posted my thoughts on this before, so here goes: Ford puts a sparkplug in from the factory for "normal" driving and emission. now no one I know drives a Mustang "normal"? so I believe(my theory) is that Ford should have put in AWSF-22C in all the V8 Mustangs, based on that theory the AWSFA-12C are 1 step colder than what I think should be the "stock" heat range.

now on plug gap: again My thoughts. the gap of .054/.056 again is for "normal" driving(and emmission) wth cars that don't see 5K to 7K rpms, so a wide gap is ok. now I believe that a tighter gap(.045/.048) is better for a car thats seeing 5k to 7k rpms as this allows the coils more time to "load up" and less likley to miss-fire under load and high rpms.

[96GTS]

What does going to the colder plug (AWSFA-12C) gain you? I'm assuming 32 would be the stock heat range??

I know ZERO about this right now. Basically, oh wise one, tell me which one to buy:D I shift at 7K while racing and my car does see the occasional on ramp burst of the same. But I still need the perfect drivability...

Can you go "too cold" or is colder better?

12s or 22s?:dontknow:

Darren

[SCT Guy]

Spark plugs is one of my favorite subjects.

First off the material of the spark plug is very important. Platinum is bad, copper is good. The OEM's use platinum for two reasons. If the plug were to wear out in the emission warranty period then they have to replace them under warranty, this is money. Second, there are a few groups out there that track cost of ownership of vehicles. If you recommend spark plug replacement at a certain interval, then they include the cost of doing this in their ownership cost when they put them together. If some company, like Hyundi, offers a spark plug that only needs to be changed every 100k, and Ford says every 50k, then the cost of ownership is less for the Hyundi (I know I spelled it wrong but I"m an engineer, cut me some slack). This ownership cost gets read by people and OEM's. If you think it's not true, how many older people like me are there out there that remember when tie rod ends and ball joints had grease fittings? Now they don't, why? I bet Randy (the Ford parts guy) will tell you he has looked at greased vrs non greased tie rod ends and he thinks they look the same to him, and they are. Ford use to recommend to grease the fittings every oil change. This cost of grease and labor was reported in the cost of ownership study and in a year, Ford removed the grease fittings because GM had....

(now I know this last section is way off the topic of spark plugs, but it's kinda important).

So, copper is a much better conductor of electricity than platinmum, but it does wear out sooner. Use a copper plug and with an N/A replace them every 15-20k, 5-10k on a blown car. Get over it, going fast costs money. If you want your motor to run well all the time these things must be done.

Heat range is good one.

First off, due the huge difference in combustion chamber design, what works on a 4V may not work on a 2V and vice versa. The 4V chamber is very efficient and you can end up with too cold of a plug. For both blown and non blown applications for 4V's, I'd run a 22C plug. For an N/A car I'd gap them about .050" and a blown car in the .030"-.040" range depending on boost. You want to run the largest gap you can and not have spark issues. A larger gap gives a more intense spark.

On a 2V, I'd go with a 22C at .050" on an N/A car but I'd go with a 12C on a blown car with a smaller gap. The 2V chamber is not as efficient and you can help surpress some detonation by using the colder plug (the 4V chamber does not respond this way to a 12C).

Now, if someone was paying attention, they'd ask why an '03 Cobra uses a 12 heat range plug then. I'd ask, how many plugs and cats has Ford replace under warranty on those cars due to plugs fouling out....

[justin00stang]

I've pulled several sets of original platinum plugs out of 30-50k mile Fords. Many of them had a .060-.065 gap. Stock spec is .054. Now is that large of a gap an issue?...they 'say' these things last for 100k. I know sometimes the plat discs fall off, these ones just seemed to be worn.

[SCT Guy]

The larger the gap the better, as long as the engine does not start to misfire at higher RPM. The older folks here on the board will remember some GM engines in the 70's with recommended gaps of like .080", but those were like 4500 RPM motors.

Like I said, platinum is just bad...

[96GTS]

Sweet, thanks for the explanation, SCT Guy...

Darren

[scothew]

great info here! Thanks Randy and SCT Guy

[Joe Lynch]

By the way, the 12C plugs will not foul on the street, in an engine with a functional closed loop control (stock) system and seem to run fine with even a 0.032" gap. They are definitely not too cold in a 4v non power adder car on the street. My nitrous car runs all stock tune and likes the 12C heat range just fine on the street. I think the stock 32 heat range really is too hot for the 99 up DOHC engines.

I have to run the copper plugs with the narrow gap with the nitrous system, and I just leave the 12C plugs in during the week.

Joe