Spark Plugs....which Ones?

ive searched and searched. found guys that run denso's, autolite 103"s, ngk's,
34pp's, 654 pp's, DAMN!!!!!!!!!!!

ill be running a 5% pullied 90 motor with fresh wires, an extremely free flowing true dual exhaust(except for the manifolds-stock). car has a 75mm bbk tb with a heavily ported inlet, i also cleaned up the other inlet type thingie that bolts to the lower, ported the lower, cleaned up the intercooler tubes also. car also has a mac fenderwell kit and a 80 mm maf.

so, i just put plugs in the gtp, and i went with autolite 104"s because a lot of people on clubgp.com had good luck with them

they say that platinum/ iridium plugs have such a small electrode that it causes a hot spot on the plug that can lead to detonation/preignition

the 104's seem to do very well in the pontiac, but theyre also a lot easier to get to than on an SC, so i want to be damn sure i install the right plug at the right gap. dont get me wrong though i dont mind doing plugs every 10000 or so, so if a copper plug would do better for me in my SC like it did in the gtp,
id be tickled pink. thanks for any and all advice. also maybe if this thread does anygood it needs to go in faq because the spark plug faq is kinda sparse

The 34PPs with stock gap will work fine on your car. If money is no object and your looking to buy the best plug, I think Denso IT20s are the one to go with.

David

IMO: Copper plugs are the best thing to go with. I prefer Autolites(even in our GM engines ). Platinum is a very poor electrical conductor in comparison, it's used more for the fact that it's VERY hard and lasts for long mileage intervals. i.e. gm's 100,000 mile first tune up(not a believer)

on a boosted car the ignition has a hard enough job without having to try to push through platinum. On the other hand they do run cooler in most areas. There has been info printed though about boosted vehicles(N2O included) that says the tiny cores of platinum plugs can get excessively hot and cause detonation.

Platinum on the left/ copper on the right. pretty crappy pic though.....

which copper plug do i go with? hotter? colder? some part numbers would rock thanks

that these guys could do better to help you. I just run my stockers.

go with...

The Autolite 764's are a good choice. They work well in my SC and runs without problem.

Don

those a little colder than stock?????? if so what are the drawbacks, if any, to running a colder plug? and what do you have those gapped at? thanks

I run Denso IT 20's. They last a long time and do not blow out under high boost which my platinums were doing at 21psi.

The IT 20's are also a colder plug.

Nology makes silver electrode plugs which are suppossedly a better conductor then copper..But I know what works for me and the IT20's are great

I'm with David, go with the Motorcraft 34PP. But if they are hard to find, the Autolite 2544 is equal (and only $3.99ea at Advanced Auto). If you were heavily modified, then the colder Autolite 764's would be good. NGK & Denso iridiums are expensive and overkill in my opinion. However, I also understand the benefits of just regular copper plugs, but with the PITA effort needed to change them on our SC's I like the 60-100,000m life of the platinums.

LOL...........agreed! The prescribed operation for the passenger side plugs are to remove from the bottom!

RBH Racing said:

LOL...........agreed! The prescribed operation for the passenger side plugs are to remove from the bottom!

Click to expand...

I get all mine up top. You just have to take the intake tube off. That's the easy side.

The only plug I have to crawl under the car with is #4 cylinder.

well ive ripped all the a/c off the car and got rid of those stupid ~~~ heater hoses. im running regular hose without fittings for the throttle body, since the 75mm bbk doesnt have provisions for the hoses anyway. it looks SO much cleaner on the pass. side now i can see and change every plug from the top. i will be reinstalling air on the car, but the compressor was toast on this car, so i need to clean the condensor/evaporator/lines, and replace the compressor and the dryer. fun stuff, but i aint wasting good go fast money on a/c sorry

abny other input on this before i reassemble?