GXP Performance

[DK2004GXP]

This is my first time on this site I have a 2004 Bonneville GXP I was wondering if any of you had performance upgrade ideas. It seems to me there is not much you can do to these northstars but that could just be my not knowing alot about them. Well any ideas will be great thanks.

[justdave]

Greetings DK. There is MUCH info on the www in general about modifying Northstar-related engines;
as there is about the common problems these engines have; which issues should be your very first things to get fixed BEFORE modifications (if, that is, you like to actually drive your car). Not to be a 'downer', but you will find that most folks will not reply to such general-tips questions such as yours; i.e. - they want you to prove you have done your OWN homework/searches, first.
Many Forum regulars are busy guys with familys and work and Bonneville responsibilities (drive, drive, drive it!). They will (eventually) offer real good advice, but they like to have 'newbies' prove themselves capable of some (what's-the-word?) initiative, first. [Even more, they like to see new members contribute to the common good, such as posting new information, or answering the questions of new members, or those just starting out in 'Forum-land'.]

[sethjamesrimrodt]

You can add a Volant cold air intake, it's made for a 2004 Cadillac Deville.
You can add a tune from madetuner.com
You can add a cat back exhaust made by Corsa for a 2004 Seville (slight modifications required)

But...
CAI=$300
Tune=$400
Cat back=$1,300

So for $2,000 you get MAYBE 20hp

[repinS]

The INTENSE FWI will work on the GXP with a little extra work and will be much cheaper than the Volant CAI. I bought the Grand Prix GXP LS4 kit ($99) and needed to source out a coupler that would let it attach to the GXP intake tube at the MAF sensor.

[MOTO]

How radical do you want to go? I'd start with research on how you are going to make your pcm compatible with the upgrades you plan on doing. If you simply plan on exhaust and intake duct modifications, pcm modification should not be necessary, but if you are planning on more major engine modifications you should keep the electronics in mind. It seems that EFI Live is a really popular tuning tool, but you'll have to take time to learn your way around it. I have never boosted a Northstar before, but i would imagine it would do ok as long as you don't push to hard. As far as natural aspiration goes, there are companies out there that will build custom engine parts for you, you just need to give them the specifications you want. For example: If you want a stout set of cams, there are a couple of companies that will grind the profiles to your order. Nitrous is another option, just don't get carried away with it and keep in mind you may be violating a state law for transporting it. Also think about the weaknesses of the dirvetrain and chassis when you get a plan together.

There is a list of part attached to this video that might help you. http://www.youtube.com/watch?v=CTwc8N-sjw4

[BigBonne]

Ok i have changed the oil using a K&N oil filter $ $11.04 @ farm and fleet. And it drank 7.5 quarts of oil (Pennzoil pla

Platinum) $5.49 x 8 quarts. It was da most costly oil change i ever did. I wanna know is this oil that great,overrated, or un appreciated? Also do yall/u suggest the K&N air filter n why? What difference does it make? & doed the non ethanol gas (even thougj it more costly run better (mpg) in the 05 GXP? Also what is the best fuel filter to use and its cost and where to Get it gone in Madison WI? & whats the best way to post to get a response? & Happy Holidays to u n yours ( Christmas & New Year).

Im new here n love n Big Bonneville except the gas n oil prices lol

[01bonneSC]

Well with the oil you should be able to go 7k miles between oil changes, expensive initially but you don't have to change to oil as much.

Also we need to keep your info in your own thread, so please continue there. It's keeps us from crossing info between other people's threads, keeps it tidy.

http://www.pontiacbonnevilleclub.com/fo ... 36797.html

[BigBonne]

Thanks man. I appreciate the advice/info

[pontiac83dave]

yes iam a new one.i know all about my 83 bonne broham.but i dont know about efi,computers,or anything newer than 86.yes am old skool.i got a 04gxp 7months ago.cant decide where to start.am getting ready to tune it up.have oil,filter,air filter,fuel filter,plugs. all acdelco parts and castrol highmileage oil.have 96,ooo miles.what else should i think about.do i have the right parts acdelco/castrol oil.are the msd coils worth it. what about cooler t-stat.and what about the chip.thanks for any feedback.

[00Beast]

I don't believe MSD makes coils for this particular application, and no they're not gonna be worth it.

There are no "chips", and only a few companies support the newer Northstar PCM, for the price of $400+. Honestly, you're best off leaving well enough alone...

[redzmonte]

I would also do a trans service. (fluid drain and filter replaced)

Not alot of stuff out there for the N* so things will be expencive... in this case the saying If you wanna play you gotta pay is the saying that comes to mind. the PCM reflash is pricy but ive allways been happy with the changes to the trans shift pressure and shift points... dont bother with a cooler stat unless the pcm is programmed for it. Start with the basics... Intake, exhaust, Tuned PCM.

[repinS]

Northstar/4T80-E combo does not have an easily replacable filter - you gotta tear the whole trans down to get at the internal filter. Instead, when you drop the pan, it has a screen that can be pulled off and cleaned.

I learnt this the hard way, and have a new Wix 4T80 filter sitting around doing nothing

[CMNTMXR57]

I made my own out of spare parts laying around from other CAI's I've had on other cars, and then buying whatever else I needed from Jegs/Summit, and ran it out through the hole behind the drivers headlight and turned down into that open area. I wasn't concerned about "pretty", just functionality. If you don't funnel it out from the engine compartment, on hot days you will get a lean code.

Fact of the matter is, there is NOT a lot of aftermarket support for this engine. You can use some stuff from STS's with slight modification as well as stuff from 3800 powered cars with modifications. I don't believe there is an aftermarket coil setup as this is a coil module pack all in one that when bolted down fits right over the plug. At least I have not seen any. And truth be told, the OEM coils are more than sufficient for firing a large gapped platinum plug, so running anything with softer metal and running the same gap or smaller, it'll have no problem.

Maintenance is just like any other vehicle. These aren't special, well maybe in the processes to perform the maintenance on them, yes. But they all take oil, Dexcool, transmission fluid, belts, air filters, etc. Do as you would any other car that you would maintain regularly and diligently. Agree though, the transmission is one item I'd keep close tabs on in this car. I watched mine religously.

Issues I had were coolant leaks (from freeze plugs on back of block), oil leaks from cam covers (the gaskets wear out, as well as the torque spec is only 7lb-ft I believe, which after a few heat cyclings, loosen right back up and leak again. I locktited mine and went 10ft/lbs and never had issue after that), and of course, the infamous GM quick connect transmission line seepage/leaks.