Pontiac Grand Prix Forums : Grandprix

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?

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 (Safely Modding Your 3800 Powered Car!!) study this.

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98 GTP wizair dhp pcm 180tstat ubend 20" merceli m2ssl rims magnaflow mufflers viper 5901 alarm dash-z projectors debadged ....mods on order yellow inlays tinted altezzas halo fogs hids 8000k ......gotta love tax time...

Thanks for your speedy response.

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

copper

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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.

Also what mods do you plan on doing.

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98 GTP wizair dhp pcm 180tstat ubend 20" merceli m2ssl rims magnaflow mufflers viper 5901 alarm dash-z projectors debadged ....mods on order yellow inlays tinted altezzas halo fogs hids 8000k ......gotta love tax time...

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."

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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.

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).

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98 XGT - sold
06 impreza 2.5i 5 speed - stock, slow, and awesome

This times infinity.

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

take away fuel economy, not sure what else.

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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.

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98 XGT - sold
06 impreza 2.5i 5 speed - stock, slow, and awesome

?? Because the pump runs more often?

Thanks

because the engine isnt running at its efficiency point, which the stock thermostat allows it to do.

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98 XGT - sold
06 impreza 2.5i 5 speed - stock, slow, and awesome