The N* makes less power, but it is smaller. He said it has more horsepower per liter. That'* not necessarily everyone'* reason for having a smaller, weaker engine, but it works.

Most DOHC engines, unless they are pretty bad, should have more horsepower per liter because they achieve peak horsepower really high up in the RPM range, and pushrod engines shouldn't aspire to spin so fast so often. The snarl of a large, powerful pushrod engine is my thing. Personally speaking.

The LD8 is nice, but it really just is a Cadillac engine. It'* extremely luxury oriented and is often expensive to maintain. For modding, you ought to go with a cheaper and simpler pushrod engine unless you have an awesome budget. If you do have the means, please mod away and then post lots of pics.

That is about the only reason I did get a bonneville gxp. In addition to hearing more bad than good about the n*'*, the market for upgrades get really expensive, althought the market for ls4 upgrades is not the best either. In my opinion, my car is ballsy enought with the intake and the flowmasters. I might get the bug again later but I literally spanked a srt-8 two days after I got it on a closed track, so I cant complain!

I'd actually argue that the LD8 is cheaper to maintain than an L67 or an L36.

I'm not trying to change your mind, so I hope I don't come off as such, but there are very, very many misconceptions and misunderstandings about the Northstar engines, in addition to there being many very big changes in them over the years. The Northstar in a 2005 Bonneville is not the same Northstar that was sold in 1994. You have to consider the Northstar'* production span was from 1991 to 2010. As previously mentioned, head stud length and thread are two very big differences that eliminate the worry for head gasket leaks. In addition, other mechanics on this board have noted in the past that one of the greatest problems with Northstar engines is that they need to be revved and driven hard on occasion. Old people will drive them soft for extended periods of time, allowing carbon to build up, causing premature piston ring wear, causing it to burn oil, causing engine death. Carbon buildup can be attributed to a very wide array of problems that a car can have, and when you consider who typically buys cars equipped with these engines, you start to understand why some of them have a bad reputation. Do a search for "Italian Tuneup." We have members here with 160k+ miles on their Bonne GXP'* and fewer problems than your typical 3800.

However, I will admit if I had to buy a car that I wanted to modify, the Bonneville GXP would not be that car. Your car is so much easier to upgrade and get more power out of, whereas to everyone'* knowledge, its impossible or impractical to get more power out of the Bonneville GXP with the exception of nitrous. That'* why I have an L67 powered car as well. If you're planning on modifying your car, I would love to see what you can do with it. I've seen some pretty awesome things done with that car.

Also, if you could, I would love to hear some videos of your car with the flowmasters. Those cars sound downright badasss with louder mufflers.

Nice looking ride! yeahh the LS4 motors don't have the best options when it comes to performance upgrades bcuz people who have the SS monte'* with the same motor have the same problem. But have fun with it!

That'* a sharp looking car, and one of few non-Bonnevilles that I'd love to get my hands on. You'd better enjoy it.

Again, we are going off topic but I see it as educational purposes...

Agreed (How many intake gaskets have caused blown motors)

???

Waiting......

Exactly..

Aside from the Alternator, and Starter... haha ever changed a Starter on a LD8... (You don't want to)

The bonnevillle GXP on the 1/4 mile might not be the fasted thing out there... Don't forget She'* a fat Chick like 4400 Pounds fat... But on a long stretch of road... Look the &^%$ out.. Personally I have seen 240++ kms per hour enough to know what its like.. (Have you???)


While the Ls4 might have a little more on takeoff.. I haven't had a GP GXP beat me yet... its not all about the car its 99.999% driver


...

Show me a LS4 with more then 6psi of boost documented (Not Just words) Betcha it was more then worrying about the PCM,,,

You know the LD8 is good to turn 8000 all day long right ??
Try that in a LS4 with no mods haha oppps there goes well, better hope you got a big piggy bank lol.

I will however own all the BIG V8 GXP'* likely by this time next yer.. guess what ones in order I'll drive...

My Bonne the G8 and then the GP.


IMPO I find the styling of the Bonneville 100% nicer then the GP, I mean all that sets it apart are those Non Functional fender vents... At lease in 04 the GXP was a breed of its own..

the GP GXP lacks personality, but did gain a boat load of plastic..

With that said its still a good car, its a matter of preference..

100,000.00 VS 4000

Hold on... dont go knocking on his new ride.. I agree the Bonneville GXP is a better looking car but.. unfortunatly i would pick the GP over the Bonneville due to the engines. And the Gp comes with paddle shifters!

There is a lot of confusion here. There'* no way to compare the two engines properly. We can quote numbers and talk about boost and spinning into the thousands of RPMs all day long, but it'* not empirical.

If we absolutely have to compare for ~3-4 pages the LS4 in this new GP with the LD8, we should look to keep it objective. Saying things like the LD8 hasn't blown from intake gasket failure is an anecdotal blame. My friend'* 2001 Olds Aurora has blown head gaskets (on its 3.5L Shortstar), but that'* also anecdotal. Without statistics, empirical evidence, and objective observation, we can't really conclude anything.

I'm very glad that Silver Slayer has an LS4, and it'* fantastic that the LD8 can spin at 8K RPM. Since neither Slayer nor Stealth have turbochargers, there'* not much of a reason to say that either engine is better because of its performance under boost. Besides, spin as it may, the LD8 needs more than pure mechanical ability and a simple tune to get a turbo (i.e. a complicated tune). Here, the empirical observation is that the LS4 has a turbo kit, and we can objectively see the horsepower gains from its installation to conclude that a turbocharger is a reasonable upgrade with clear and sought-after gains. Then, we can look at the LD8 and simply keep looking at it. Perhaps add some NOS or so.

I will summarize the turbo thing briefly with that I'm sure the turbo kit upon its design was made for a low RPM power oriented pushrod V8 that doesn't spin up to 8K RPM.

On the intake gasket thing, that'* a logical fallacy. One engine'* fault which another engine doesn't have is absolutely no way to foresee which of the two will cost less to own and maintain. Honestly, I can assume that the roughly 30 MPG that I can get in a 3800 Bonneville will save enough money for me to use coolant instead of oil! No, that'* not empirical...

The 3800 has in one form or another been around since the 70s, while the N* is a fairly new engine. Both engine series have seen immense redesigns, even to the point that the Series II 3800 as it'* known in the US is not considered a true 3800 in Australia. What we're left with here is seeing that GM wanted its GP and Bonneville in GXP form to have V8s, and then we should observe the stock form characteristics of these two engines. Judging from that, we can better guess the intended use of each engine by its respective demographic. The N* is a Cadillac engine brought over to the most expensive Bonneville for aged people to buy. Giving oldies a crappy engine with frequent maintenance needs is a bad idea. The LD8 needs to be smooth, with less low end power so grandma doesn't spill her beans all over the place. On the other hand, the LS4 is made for the Grand Prix, which by its name only should be seen as a sporty car. I know "Bonneville" comes from the Salt Flats, but that'* since probably the 80s not been how quite a lot of Bonneville buyers have viewed it.

And the GP GXP has paddle shifters!

Ask me what I had planned for my 06 SS and then see if they have a problem getting mods. An LS series engine can take parts from another LS series engine, making modding very easy and cheap if you do it right.

Yeah, heads, cams, all stock from other LS engines may improve an LS4.