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performance up grades on the northstar in a 04 bonni gxp any ideas at all please!!!!!!!!!!!!!!

Not much out there. I guess the PCM can be cracked a bit but cant do much. some sort of FWI can be made im sure. uhhhhhhh....yeah not much lol.

Hey thanks that something.I do have a company close by that said he can do a tune which should bring out some power I just to get in there and do it.

intake, exhaust and tint..

now if only they made headers i seen a set of headers for a Grand Prix GXP once..900 something bucks

IIRC Doug Thorley's makes headers for the LS4, but they're not for the Northstar.

repinS just used the Corsa cat-back for the Caddy Deville on his 04 with just minor mods. Other than that you can fab up an intake and hope you find someone to tune it. I don't recommend Nitrous...

Amongst the Cadillac forums, the general consensus is that there is not much, if any, power to be made by altering the factory intake. Judging by the unmuffled snarl coming from the stock airbox, they might be right. Volant makes a CAI for the DeVille that MAY work on the Bonneville with some modification, but frankly I don't think it's worth the cost.

I may end up trying to fabricate a FWI that includes the stock intake. I don't like relocating the PCM and removing the airflow required to cool it - unless you guys have different ideas here. The Northstar engine bay gets REALLY hot, way hotter than any 3800 I've ever seen. Side effect of shoehorning a big engine and trans in...

edit: I think the PCM CAN be cracked and tuned - but nobody I know has done it yet. Again, I'm not sure if there is much to gain by tuning alone. 300 horsepower out of a naturally aspirated 4.6L V8 is pushing the envelope pretty far.

I bought my GXP knowing that there wasn't an aftermarket for the motor - and I'm not much of a modder, so I don't mind. The Corsa exhaust and PERHAPS the intake is about as far as I'll go.


Lastly, this isn't a mechanical issue - moving to Performance and Brainstorming.

rear mount turbo... FMU... MegaSquirt(?)

I've actually heard of rear mount turbos on the 99-04 STS. Not sure what they were running for engine managment though. MegaSquirt would be a TON of work, but very tweakable.

And just because your local guy THINKS he can tune it doesn't mean he actually can. This is a different animal.

That is so true he says he can but once in there can he make a diffrance.As for cai I talked to a guy from spectra when the good guys wr in Columbus Oh and he said to take pics from under the hood and pics of the intake system taken apart and show off the car take measurements.I don't have his web site handy but will post it when I have it in hand.

You need to type a bit clearer. That was actually painful to read.

Forget any CAI that is IN the engine bay. It won't help you nearly as much as a FWI. And even that won't net you very much by itself. You really have an un-moddable car.

My question is, didn't the deville motor have like 50 more horsepower then the gxp I thought it was just a tuning difference, is the deville 4.6 mechanically different as well?

IIRC the Deville is rated at 300, the GXP is rated at 275. Not sure the difference, probably exhaust and intake routing.

Read this:

http://www.automobilemag.com/reviews/se ... index.html


And then come to grips that everything about performance in that article is wrong in the worst way. The 3.8 supercharged is quicker, more moddable, and more reliable. The only advantage the GXP has besides looks is a beefier transmission.

The limited amount of things you can do to a Northstar simply aren't worth the money. I drove one, and wouldn't trade my 93 straight across for it (in terms of performance).

00Beast wrote:IIRC the Deville is rated at 300, the GXP is rated at 275. Not sure the difference, probably exhaust and intake routing.

The DeVille DHS, Seville SLS, and Bonneville GXP got the LD8 (VIN "Y") Northstar. Rated for 275hp, 300lb-ft. The DHS and SLS got the 3.11 gears, the GXP got the 3.71 FDR. The DeVille DTS and Seville STS got the L37 (VIN "9"). Rated for 300hp, 295lb-ft. All received the 3.71 gears.

Apparently, the ONLY difference between the two motors is the intake cam. The LD8 is tuned for more torque and response, the L37 for top end. And naturally, the factory tune will be different as well. I'm a believer that both variants of Northstar are closer than the 25hp gap that GM has them rated at. To me it seems more like a marketing thing.

It takes a different kind of car person to own and love a Northstar, and there aren't too many of us on this forum. Modding is not in our blood as much, and we are more of a 'connoisseur' when it comes to powertrain, if I were to describe it. In addition to going (reasonably fast), refinement, smoothness, and general behaviour count just as much as a 1/4 mile time or how fast you can top out at. Personally, I like cars that I can enjoy out of the box, and the GXP definitely serves that purpose well.

Either way, the car is no slouch - just expect it to remain more or less stock. I can run a 15 second-flat quarter mile without a single mod and a broken front trans mount. At higher speeds (50mph or higher), it can keep up (or even gain) on 3.4/3.6-pulley Series 2 3800's that have been tuned.

Jerry, I love how you've owned the car for like 6 months and are already a connoisseur, LOL.

Supercharge it.....DTS-V....

Also connoissuer my butt lol if you could add 50-75 more hp you would

00Beast wrote:Jerry, I love how you've owned the car for like 6 months and are already a connoisseur, LOL.

9

Didn't you notice I treated the 95 SSEi the same way? The GXP was just a step up.

And no, I wouldn't add 50-75hp. There's enough torque steer as it is. If I want to add 50-75hp I buy a G8 GT.

repinS wrote: And no, I wouldn't add 50-75hp. There's enough torque steer as it is. If I want to add 50-75hp I buy a G8 GT.

Truth! Make it a "proper" engine orientation and drive wheel layout with that additional horsepower.

LeSabre in Buffalo wrote:

repinS wrote: And no, I wouldn't add 50-75hp. There's enough torque steer as it is. If I want to add 50-75hp I buy a G8 GT.

Truth! Make it a "proper" engine orientation and drive wheel layout with that additional horsepower.

But those extra ponies would be very nice on the freeway.....Im done trying to drag a FWD car.