zxsaint

Depends where you're starting. The VQ35 in the nissan flagship sportscar is already tweaked up about 30hp from the advertised 260hp in the infinity, altima, etc. @ the factory.

Just speculating but I believe BMW would probably be less interested in narrowing the gap between the 330 and their flagship for performance, the M3. It's all about maximizing sales for each market. Therefore that would explain the room for tweaking it for more performance.

UF350Z

I agree with the theory of that but Nissan uses the same engine for those cars as opposed to BMW who uses a 3L for the 330 and the 3.2L for the M3...there is only a little difference in displacement but the engine's are designed completely different..ie the m3 has 6 individual throttle bodies one for each cylinder. interesting perspective though.

reen

I think the question has pretty much been answered.

Besides the "newness" factor, there's the fact that the 350Z's engine is already highly tuned from the factory. It has a great CAI, relatively efficient exhaust, etc.

Your standard 3-series BMW is detuned for comfort, fuel efficiency, noise & vibration reduction, etc. All of these things restrict power production to achieve the cushy, smooth, luxo BMW feel. If you don't care about that stuff (like tuners don't) than significant potential exists to open things up.

vegaseric

I would like to see an actual comparison of dynos of NA 330i and 350z cars; both with the same basic bolt-on mods. I have a hard time believing a 330 is producing 300 RWHP, much less 400 RWHP, with standard bolt ons.

Everyone here seems to understand the question, but the basic premise that the M54 engine is that much more receptive than the VG35 to bolt-ons is unfounded.

UF350Z

go to www.renn-sport.net find the contact section and email them about their Technik power kits for the e46 3series...ask them how much rwhp the Stage IV kit makes on a 330 and you'll have your answer...I think people are thinking that because BMWs are considered luxury cars that they can't be tuned...there is a turbo 330 making 400 rwhp ( http://www.atpturbo.com/root/monster...w_e46turbo.gif ) the BMW engine is a great engine and highly tunable...As to the claim of basic bolt-ons making these "rediculous" gains...Cams Headers Headwork are NOT bolt ons...they require disassembling of the engine not something you bolt on.

EDIT: i realized now i just wrote that headers weren't bolt on mods i don't consider them to be but yes they physicall do bolt onto the engine. Also I just found out the appropriate numbers for the NA BMW it's 315 crank hp...so i was wrong with that...if my math serves me correct that's about 250-260 wheel.

genieman17

Not to be a pain or anything, but adding volume to the combustion chamber will NOT give you more displacement. Displacement can only be changed by increasing the bore or the stroke of the engine. Increaseing the volume of the combustion chamber won't do anything except decrease your compression ratio.

Also you guys have to realize one thing. HP = RPM*TQ / 5252 for every point on the RPM range. Which means that the higher you go over 5252 rpm the more HP you will have holding TQ constant. If an e46 M3 has 333HP it is because the thing revs to 8000rpm. If you looked at the torque graph the 350 has more torqe. If you took some bolt-ons to make a 350 produce 333hp at the crank...their would be a big gap between the torque curve of the M3 versus the torque curve of the 350 (350 being much more). The thing with the m3 is that the engine costs a shitload more...so the internals can handle spinning faster. If you could get the VQ35 spinning up to 8grand...with headwork there would be no reason that it could not hit 400hp at the crank and maybe even at the wheels. Not saying that its possible to get the VQ up to 8grand...just dreaming

vegaseric

I never stated that the M54 couln't be tuned, just that there is no conclusive proof that it is more tunable than the VG35. I'm fully aware of the performance potential of BMW's offerings after owning a fire-breathing 318is for over ten years. Now that it has around 150K miles, I'm seriously considering an S50 conversion.

These numbers are a LOT more believable. Sounds as if with a bit of research, you've answered your own question.

reen

How do you figure? I'm not saying that this is a good way to increase displacement or that anybody does it. On the contrary -- screwing with your combustion chamber is a bad idea unless you really know what you're doing. I was just pointing out that porting your heads doesn't increase displacement.

However, bigger combustion chamber = more volume between piston and head = greater displacement.

Perhaps displacement is only conventionally measured as bore x stroke; I don't know. Actually, now that I think about it, the very word "displacement" implies a volumetric measurement of the region "displaced" by the movement of the piston.....or bore x stroke.

OK fine.

genieman17

Yea! increasing the combustion chamber increase the area of the compressed gas...meaning, it will decrease the compression ratio...

The one thing that messing with the heads does is increase flow, which at low rpms may hurt ur power but at higher rpms increases it, so if ur engine were say an s2000 motor, thats where you want it, cuz if you just increased the redline in a 350z without increasing the flow the hp would taper off and increasing the redline wouldn't do anythign except help you blow up the engine faster