Spark Plug Replacement??

**LuckyBambu** · 02-08-2010

So I've taken the plunge and started modding my GTP.

Went out and bought a 180° thermostat today, and am slowly working my way down the list of pre-mod "stuff to do." Hopefully at the end of the week I'll do a coolant flush and get rid of the Dexcool crap. I have a couple leaky bits to find and fix, as well, and am debating replacing the LIM gasket even though the motor is only ~15k old.

Spark plugs are on my list of things to replace before I get much further. I'd like to replace them with colder plugs (TR55 or 104), but I figured I'd ask if this is alright on an otherwise stock motor. I do run 92 octane in my car at all times, if that makes any difference.

Also, what should the spark gap be on the plugs?

**windycitygtp** · 02-08-2010

both are to cold a plug for a basic stock setup u need al605's or 606 also read this http://www.grandprixforums.net/f81/s...car-17482.html study this.

**LuckyBambu** · 02-08-2010

Originally Posted by windycitygtp

both are to cold a plug for a basic stock setup u need al605's or 606 also read this http://www.grandprixforums.net/f81/s...car-17482.html study this.

Thanks for your speedy response.

Is it worth it to get the platinum plugs, or should I just stick with the copper?

**matt5112** · 02-08-2010

copper

**almighty** · 02-08-2010

I did 104's in my stock set up, expecting to run a small pully and few other things, but bad time and cold weather have slowed me down and i have yet to do any other major mods, now the car runs rich and has a horrible idle, hoping when i drop pully size and tune it will fix the issue but until then i will just have to deal with it.

**windycitygtp** · 02-08-2010

Also what mods do you plan on doing.

**matt5112** · 02-08-2010

This is not "run the plugs you're going to need 3 months from now."

This is "run the plugs you need, when you need them."

**LuckyBambu** · 02-08-2010

Originally Posted by windycitygtp

Also what mods do you plan on doing.

CAI/Fenderwell, headers, PCM, pulley drop. I have actually been referring to the thread you pointed me at. I was thinking about porting the throttle body and supercharger case, as well.

I have the money to do cam/rockers/intercooler/methanol, but I don't really want to go quite so far yet. Also I need to replace some bits and bobs on the car (and there are some I want to replace... headlights, redo the interior in LEDs, etc), so I need some leftover.

**Bio248** · 02-08-2010

dont do the thermostat or plugs until you drop a pulley.

start with headers and the other small mods and then get a tune on the car. see how you like it. see if you want more. if you want more, drop to a 3.5 or 3.4 and tune again. if you still want more, then look into valvetrain stuff (cam or rockers).

**matt5112** · 02-08-2010

Originally Posted by Bio248

dont do the thermostat or plugs until you drop a pulley.

This times infinity.

**LuckyBambu** · 02-08-2010

Originally Posted by matt5112

This times infinity.

Out of curiosity, what would running a cooler tstat on a stock do?

**matt5112** · 02-08-2010

take away fuel economy, not sure what else.

**Bio248** · 02-08-2010

technically you should never need a lower temperature thermostat on a car youre driving on the street. it does allow the car to run cooler, essentially helping with detonation. however, its really not necessary.

**LuckyBambu** · 02-08-2010

Originally Posted by matt5112

take away fuel economy, not sure what else.

?? Because the pump runs more often?

Originally Posted by Bio248

technically you should never need a lower temperature thermostat on a car youre driving on the street. it does allow the car to run cooler, essentially helping with detonation. however, its really not necessary.

Thanks