Thread: Spark plug suggestions?

Originally Posted by projectGTP

i have a 97 gtp and i have the 3.4 pulley, 180 thermo, colder plugs(im guessing), resonator delete, and soon to have the u bend and high flow cat. i just blew out my trans and am currently rebuilding it. since i pulled the motor i started to disassemble everthing to paint it. everything was clean but there was alot of sludge build up. anyways, the car ran like **** when i had it out in the summer. when i removed the plugs they were very dark and my dad said it was running too rich. the plugs were bosch platinum i believe. is there any plugs that anybody recommends i should run?

Your best bet is probably 104's (regular copper). Our cars don't like platinum very much. The copper's will have to be replaced often but, $1 a plug im not complaining

Originally Posted by projectGTP

i have a 97 gtp and i have the 3.4 pulley, 180 thermo, colder plugs(im guessing), resonator delete, and soon to have the u bend and high flow cat. i just blew out my trans and am currently rebuilding it. since i pulled the motor i started to disassemble everthing to paint it. everything was clean but there was alot of sludge build up. anyways, the car ran like **** when i had it out in the summer. when i removed the plugs they were very dark and my dad said it was running too rich. the plugs were bosch platinum i believe. is there any plugs that anybody recommends i should run?

al 104's! the car was prob running like crap because you have a 3.4 on with stock manifolds & stock down pipe.

Originally Posted by 05SS45

al 104's! the car was prob running like crap because you have a 3.4 on with stock manifolds & stock down pipe.

X2...you could probably HEAR it knock

Originally Posted by projectGTP

and thats how i bought the car. i just got it in december. im new to grand prixs

i would def get a plog & down pipe w/tune for that pulley asap!

Bigger gap is better as long as you have the ignition system to put enough voltage behind it. If you coils are in good shape and you have low resistance wires, you'll see the same power with greater efficiency (MPG) with the stock size gap than going to a smaller gap.

104's .035 gap

That seems a little small. For a 3.4" setup, I don't see why you're running anything less than a 0.050 gap.
Try something like 0.052 or 0.055, and if you don't see spark blowout then consider increasing the gap up to as far as 0.060.
Like people have said, you'll see better efficiency with a bigger gap as you will get a bigger, longer spark and therefore more complete combustion.
Just keep an eye on misfires at WOT if you increase the gap size over 0.055.

Also-
x2 on the plog/3" dp idea. Don't blow up your motor by running a pulley that's too small for your mod list.
-Riggs.

Originally Posted by BiggRiggs

Like people have said, you'll see better efficiency with a bigger gap as you will get a bigger, longer spark and therefore more complete combustion.
Just keep an eye on misfires at WOT if you increase the gap size over 0.055

I have a feeling that after I finish the top swap and start tweaking it, I'll see some benefit to having the huge PRJ wires on what size gap I can run.

Originally Posted by projectGTP

well what if my car is running perfectly fine wit the pulley?

Have you had it scanned? If not, then you don't know. There's no way to tell if you have knock without a scanner that can look for it while you're driving.

Originally Posted by projectGTP

i heard that every grand prix is different and some have KR when others with the same mods dont. and i dont think the dp is all that restrictive. just the cat

As long as it isn't clogged up, the cat isn't really restrictive. The DP is horrible as far as how tight it gets (not even talking about the u-bend). The front manifold is worse. You increased the boost on the engine without giving it a way to move the air out, and I bet you have tons of knock for it.

Porting the front manifold doesn't really help since you can't port the part that's the tightest. The rear doesn't really need porting. Get a Plog.