HEy guys I have Ngk Iridium plugs on my 2000 mustang gt. Well mechanic was talking to me today and told I should swap those out to the stock motorcrafts. The plugs are fairly new. Any recommendations or tips? Its not blown or supercharged. Its got full bolts ons and diablo tune with some spark advance but no pinging or detonation. If I should change them to motorcraft why would this be better? THanks

 

NO need to change the plugs you have unless they are bad, though I would of gone with the much cheaper TR55's then those over hyped Iridium plugs, but they work so do not throw money out the window.

 

I got the motorcraft spark plugs for free from a friend so they are just sitting in the garage but my iridium plugs are fairly new nothing wrong with them.

 

keep em... no reason to change.

 

spark plugs are spark plugs special ones won't help any

 

Well I knew they wont help just wondering about the temp ranges if it mattered any someone told me ngks are cooler in temperature.

 

Cooler sparks are for nitrous and boost figure out what your oem sparks are and get them or keep the ones you have if they are the right temp I'm not sure what that temp is though

 

If you got stock equivalent plugs, then they are neither hotter or colder. Now, it is true that the temperature ranges associated w/ Japanese plugs are usually cooler than the American counterparts (due in part over °F and °C) but the difference is so small and since the range is still right, it's negligible.

 

ok so pretty much those NGK wouldn't cause my car to run any different...? They are still new and I just don't want to go through the trouble of taking them out if it won't make any difference that I am running ngk instead of motorcraft.

 

you should be at or around a .53-.55 gap....am i right or wrong guys? I cant remember from the old gt...

 

I only run NGK plugs and your car will be fine with those in there. Just save the other plugs for when you need to change plugs again and you get a free plug change.

 

Alright thanks spike and everyone else got exactly what I needed to know.

 

what about for a supercharged, high boost, cobra?...not to steal the thread, but figured why post another, plus everyone already subscribed can get a N/A and supercharged point of view.

 

i know 1-2 ranges colder, but what gap and brand?

 

NGK TR6 plugs are what you would want for your basic cobra up till you are over 550rwhp then you might want to swap to a 2 step colder plug.

 

what about the gap? thanks for the above info though!

 

find out who tuned the car...they probably put in the widest gap before spark blow out. majority of blown cars i seen usually wear a gap of .035. If the car breaks up under load in the upper rpms close the gap a lil bit.

everyone runs TR6's which is 1 step cold. i run NGK BR7EF's which are 2 steps cold and they are gapped to .035 and i change them every 2 oil changes, i beat on the car quite often.

 

so the gap is partially determined by the tune? So when i get a new dyno tune let him know what i have them gapped to and he can adapt it to the gap?

 

the person who tunes the car usually knows what works best for them i dont tune cars so i dont know what the gap does to a tune. i was just suggesting a typical gap for a supercharged app. i just know that if a gap is too wide you will get blow out and your car will have mulitple miss fires in teh upper rpms...its like the car is running out of gas. i know this because my plugs were fouled from my mom driving the car with a horrible exhaust leak. i cleaned them up while i waited for new ones to be shipped to me and the gaps opened up to .047 on the right bank and .040 on the left bank. yeah, my car wasnt taken care of while i didnt drive it for 18 months.

 

ok thank you...ill replace them AT the tuners shop...then i can get his tuning knowledge in the gap too. thanks for the help.

 

You shouldnt change plugs when the engine is hot.

 

so you suggest going with a 35 gap and just letting him now thats what i gapped them at?

 

The gap isn't determined by the tune, it's determined by cylinder pressures. Also, don't change the plugs while your engine is hot, it's bad for the Aluminum threads in the head. Instead, run a cap on the safe side (not sure what a good gap is F/I) and call it a day. You are not going to gain a lot by running the ideal gap. However, if you want those extra ponies, just index your plugs instead.

 

From what I have in my manuals it says .050" for 03-04 Cobra, but that's stock and thats a really big gap. I would run them at .040" gap or even .035" gap. On my lowly sprayed 2v I run them at .035" gap. No spark blow out at 380rwhp here.

 

thats what i was averaging in different posts i've read. .33-.35....thanks for the help guys.