[sysop]

Can anyone tell me whether the 325 shares the same lightweight (magnesium parts etc) construction as the 330? BMW makes great play of the lightweight 330 with its high-revving capabilities, but says little about the 325.

[David325Australia]

as far as i am aware and have been told, yes, the 2.5 litre 325 is the same with a smaller capacity.

now the 325 cars destined for the USA, are in fact the very 3 litre engine bmw advertise with what you mention. it is a detuned
330.

hope this helps you.

[David325Australia]

sorry sysop,
my car has the 7000rpm limit as well and i can tell you that it truly begs to be revved but has such strong torque low down (my old bmws never had adequate low down torque) that i find building up speed easy even in a high gear.

now if i really want to zoom......the 325 can really zoom, no problem. the 330 is just a little bit quicker.

[E90Fleet]

Yes, all N52 engines use the magnesium and aluminium parts to reduce their weight

[romeo26]

hey david you should try a e30 325e or no letter they have a 2.8 letter and about 165tq but only 127hp, my 325 no letter can almost beat any thing off the line but speed wise its slow going to 60 but shines after 80!!

[David325Australia]

Originally Posted by romeo26

hey david you should try a e30 325e or no letter they have a 2.8 letter and about 165tq but only 127hp, my 325 no letter can almost beat any thing off the line but speed wise its slow going to 60 but shines after 80!!

an eta machine. Nice one romeo. 2 door?

[CA330i]

same engine, the 325 is just detuned...

[E90Fleet]

Originally Posted by CA330i

same engine, the 325 is just detuned...

Only in USA

[loihisteve]

From my research, I've concluded there are two primary differences between the U.S.-spec. 325i and 330i N52 engines: 1.) the camshaft profiles (the lift, duration and overlap all appear to be "slightly greater" for the 330i), and 2.) the intake manifolds (single-stage for the 325i, vs. a more advanced three-stage design for the 330i).

Both engines do utilize the same lightweight "special" metals and very complex production process.

I don't believe the exhaust system is significantly different between the two cars ... and, I do believe the cylinder head valves are probably the exact same size for both engines (I base this on the fact that the perf.-difference between the two is not significant, and could easily be accomplished with slight changes to the cam, intake and exhaust systems).

And I personally wouldn't label the 325i N52 as "de-tuned" ... IMO, it's simply less optimized for "higher-RPM" performance than the 330i N52.

And specifically, the higher valve-duration of the 330i N52 camshaft is what contributes most to the increased low-end torque ... the higher valve-lift & overlap is what contributes most to the higher-end HP boost ... I say the three-stage manifold is more advanced because it allows air & fuel to be funneled into either low-range, mid-range or high-range "sections" of the manifold, each of which is optimized for a particular RPM range.

Anyway, this is just my opinion.

[E90Fleet]

Originally Posted by loihisteve

From my research, I've concluded there are two primary differences between the U.S.-spec. 325i and 330i N52 engines: 1.) the camshaft profiles (the lift, duration and overlap all appear to be "slightly greater" for the 330i), and 2.) the intake manifolds (single-stage for the 325i, vs. a more advanced three-stage design for the 330i).

Both engines do utilize the same lightweight "special" metals and very complex production process.

I don't believe the exhaust system is significantly different between the two cars ... and, I do believe the cylinder head valves are probably the exact same size for both engines (I base this on the fact that the perf.-difference between the two is not significant, and could easily be accomplished with slight changes to the cam, intake and exhaust systems).

And I personally wouldn't label the 325i N52 as "de-tuned" ... IMO, it's simply less optimized for "higher-RPM" performance than the 330i N52.

And specifically, the higher valve-duration of the 330i N52 camshaft is what contributes most to the increased low-end torque ... the higher valve-lift & overlap is what contributes most to the higher-end HP boost ... I say the three-stage manifold is more advanced because it allows air & fuel to be funneled into either low-range, mid-range or high-range "sections" of the manifold, each of which is optimized for a particular RPM range.

Anyway, this is just my opinion.

Remember these engines have Valvetronic and VANOS, so the ECU can change the valve duration and lift like feels to, its got nothing much to do with the cam anymore.

The USA 325i and 330i is the exact same engine from top to bottom ( excluding intake path )

[loihisteve]

Yes, the cam-"profile" is controlled electronically ... thats what I was referring to ... and, I stand by my statement that the 325i-version has a Single-Stage Intake Manifold (vs. the three-stage in the 330i-version).

Also, for all, here is one of the better articles on the production process of the N52 engine ... go to the paragraph that beings with: "Start with the engine ...":

http://www.autoweek.com/article.cms?articleId=101850

[E90Fleet]

Originally Posted by loihisteve

... and, I stand by my statement that the 325i-version has a Single-Stage Intake Manifold (vs. the three-stage in the 330i-version).

Thats what I said, they are identical except for the intake

[cannonspike22]

Originally Posted by E90Fleet

Thats what I said, they are identical except for the intake

now is it possible to change the single stage intake on the 325 to the three stage intake on 330

[E90Fleet]

Originally Posted by cannonspike22

now is it possible to change the single stage intake on the 325 to the three stage intake on 330

You would need some way to control it and the wiring for it

[loihisteve]

oops, my mistake ... I was rushed posting my response while concurrently working on my picks before the NFL games start here in the States.