spark plug types

[kevywevy]

so i recently found out that spark plugs have heat ratings?
i haven't been getting very good gas milage in my 97 LGT so i replace the plugs a while ago with no noticable difference in gas milage. but it seems that at start up when cold the idle surges a little bit. i did recently get a CEL saying my cat was going out (most likely O2 censor) and i've just ordered a new one. so im hoping its just that.

but anyways, can anybody tell me if the plugs i ordered: NGK #7994 (stock#) IFR5E11 (part#). Iridium Platinum (Extreme Long life Plug) are the correct heat rating?

oh and my wires are looking pretty ratty. any input on a good replacement set?

thanks guys!
KEVIN

[decke48]

im guessing they cold plugs irdiums usally are. the only plugs that would be the correct heat are OEM plugs. aftermarket plugs usally never have the exact correct heat rating as the OEMs do.

[Airgne]

the colder the plug runs the more power you will have out of your motor. i know when i was running 6s in my turbod car it was good, and them when i went to 7s holy crap was there a diff in power. i think in the states the heat rating of plugs are backwards.

[kevywevy]

so im fine to run these plugs?

[decke48]

according to ngk there rated 5. they should run fine.

[Airgne]

when was the last time you did a good tune up? i know when i changes my o2 sensor my mpg went up about 3 mile to the gallon. at cold start is it rough? it might be the comp just trying to figure out how much fuel to dump in and the right a/f mix. restet the comp. unplug it when you get home and let it stay unpluged over night. that is how most comps are reset. the taking it off for 10 to 15 min isnt a full reset. do that and see what it is like in the morning. you might just need to do a good tune up on it. look under the DIY section on the forum and do the msd setup. it works.

[kevywevy]

i've had the car for almost a year now. besides the plugs (and wires soon) and a k&n filter, i haven't really done anything. im running synthetic motor oils and will probably be changing out the front the rear diffs.

i wouldn't say its a rough idle at start, its just like a slow surge, but never comes close to dying.

sounds good. i'll wait till i get my o2 sensor and then do the reset.

[Airgne]

for oil if you can afford it i would go with amsoil. its one year change or 12,000miles. this stuff is awsome. i have been using it since 2002.

[decke48]

^ i hate that 15000 mile oil stuff.. filters dont last that long. unless you drop the filter every 3000 and drop in a quart. your ok. what your using for a synthectic oil

[Airgne]

thast why amsoil maked there own filters to go with there oil.

[Huffer]

I think the idea would be that a good quality oil would reduce overall wear and chemical breakdown - and therefore the oil filter wouldn't get quite so "dirty".

Back ontopic to SPARKPLUGS - I just use the factory items. They're NGKs and cheap as chips from Summit Racing or any NGK supplier.

[Sarra]

Depends on the engine you have. Use Iridium if you have a 2.5 DOHC motor, having them last longer is a huge bonus, and they're the OEM stock. On the SOHC motors, I'd use regular copper NGK's.

Colder plugs will SUCK on a non-turbo motor.

The 'heat' rating of a plug is directly related to the gap. A larger gap has more resistance, so more power is required to create the spark, which makes the spark hotter. A thinner gap means less resistance, and then, less heat. Stock NA motors use a gap of 0.044 IIRC.

[jey]

oh and my wires are looking pretty ratty. any input on a good replacement set?


OEM.

[kevywevy]

for oil if you can afford it i would go with amsoil. its one year change or 12,000miles. this stuff is awsome. i have been using it since 2002.

yup im running amsoil 5w30. :smile:

and i have the DOHC.

thanks for all the input guys! i just hope the o2 sensor comes soon.

[Airgne]

did you get the amsoil filter as well? i run it in all my gearboxes.