How much can you bore a 2.5L to???

[01325iSil]

How much can you bore a 2.5L to???

I was thinking a 2.8L or 3.0L. Is that possible. What about a stroke also? I have a 2001 325i with 40,000 and think its time for some motor work some i figure i bore it out and make the block stronger with a stronger crankshaft and titanium rods and pistons and cams ect.... not real crazy but safe but with alot of power. But im just curious of what i can bore and/or stroke my 2.5L to. thanks.

[david05111]

How much can you bore a 2.5L to???

I was thinking a 2.8L or 3.0L. Is that possible. What about a stroke also? I have a 2001 325i with 40,000 and think its time for some motor work some i figure i bore it out and make the block stronger with a stronger crankshaft and titanium rods and pistons and cams ect.... not real crazy but safe but with alot of power. But im just curious of what i can bore and/or stroke my 2.5L to. thanks.

It would probably just be easier to swap in a 3.0 rather than go through all that...

I'm really not sure about any of that stuff so I'll let someone else have a crack at it...

[TonyluvSilvia]

....stronger crankshaft and titanium rods and pistons and cams ect.... not real crazy but safe but with alot of power..

:rofl: what's wrong with the forged aluminum variety? After all the parts, labor, and materials, it probably makes more economic sense to swap in the S54 while achieving more power.

[bmw_chuzo]

I personally think a 3.0L swap would be more economic and easy :)

[01325iSil]

But my motor has only 40,000 on it and i really dont need to go as big as a 3.0 if that i would just put an M3 motor in it but i dont want to so im just looking to bore it out a little and just what needs to be stronger for some power looking between 400 and 500whp. What can do to make it bigger then a 2.5L. Let me know. Thanks for the imput.

3.0 swap, doesnt that mean i need a to change the tranny to.???

[e46hoodrich]

i think hamann makes a 3.2 liter engine. :dunno: for sure. but i knows its bigger than the 3.0 liter. 3.2 liter + supercharger + nitrous. sounds like a monster to me.

[CGRIZZ516]

But my motor has only 40,000 on it and i really dont need to go as big as a 3.0 if that i would just put an M3 motor in it but i dont want to so im just looking to bore it out a little and just what needs to be stronger for some power looking between 400 and 500whp. What can do to make it bigger then a 2.5L. Let me know. Thanks for the imput.

3.0 swap, doesnt that mean i need a to change the tranny to.???

400-500rwhp with a 325i is a little far fetched. I dunno, just put a supercharger on it but you won't go near 400rwhp. I think you need to rethink what you're trying to achieve. a bored out 2.5 to 2.8l is still goin to need lots of work and monetary investment given your power goal.

[kerisabe]

i think hamann makes a 3.2 liter engine. :dunno: for sure. but i knows its bigger than the 3.0 liter. 3.2 liter + supercharger + nitrous. sounds like a monster to me.

I think Hamann makes 3.3

[Activ3]

3.0 swap, you can keep your tranny, intake manifold, and exhaust.

[pei330ci]

To the original poster:

The M54 engines all share the same cylinder bore, and thus piston sizing. The difference in displacement between the 2.5L and 3.0L engine is the crank's stroke. The difference in output is 20+ Lb/ft of torque at the wheels, which will easily be felt.

The 2.5 and 3.0 engines have different intake manifolds.

For the money, you'll get more from a supercharger kit than an engine swap.

[2K5 325i]

You're forgetting about your VANOS. With your variable valve timing with different size cylinders, you will certainly break your sh!t real good if you don't alert the computer so it can compensate for it. I have no idea what method you would need to use to tune your ECU such- but if I had to guess- it wouldn't be pretty. :dunno:

-Chris

[rushman]

I wouldnt even bother swapping motors. I'd just supercharge it or sell my 2.5 and buy a 2.8 if thats what you want. Can't for the life of me see why you would devalue your car, go through shitloads of work just for the sake of 300cc.

[pei330ci]

You're forgetting about your VANOS. With your variable valve timing with different size cylinders, you will certainly break your sh!t real good if you don't alert the computer so it can compensate for it. I have no idea what method you would need to use to tune your ECU such- but if I had to guess- it wouldn't be pretty. :dunno:

-Chris

That completely went over my head. Care to explain what you are talking about?

[2000_328CI]

i wouldn't touch this idea with a ten foot poll.... just sell the car and move up to an m if you want that much power

[Activ3]

I dont think you'd have to mess with the vanos...

When they stroke the M50s with S52 cranks up to 2.9L, I dont think they mess with the vanos system. As long as your firing at the same time which you should be, I dont think its a problem.

I was considering swapping an S52 crank into my motor to get the 3.0 displacement, along with an M50 manifold...

[Owtlaw333]

To the original poster:

The M54 engines all share the same cylinder bore, and thus piston sizing. The difference in displacement between the 2.5L and 3.0L engine is the crank's stroke. The difference in output is 20+ Lb/ft of torque at the wheels, which will easily be felt.

The 2.5 and 3.0 engines have different intake manifolds.

For the money, you'll get more from a supercharger kit than an engine swap.

So are you saying all that's needed to change the 2.5 to a 3.0 is a new crank, intake manifold and (I'm assuming) ECU update? What am I missing here?

[azzy989]

I think Hamann makes 3.3
yea its 3.3... i always wondered how much it would be to get that done :hmm:

[Activ3]

So are you saying all that's needed to change the 2.5 to a 3.0 is a new crank, intake manifold and (I'm assuming) ECU update? What am I missing here?
Pistons and rods for sure as well. If you keep the 2.5 pistons, you'll definately have more compression but I doubt it will work since the top of the piston will probably touch the top of the head...

[01325iSil]

So basically i can stroke my motor to a 3.3 that hamman makes or i can just change the crankshaft to a 3.0L and a new intake manifold. I can keep my exhaust and what about software. What do i use, 325 or 330 software. are the motors the same overall besides the bigger crankshaft?

The car is gonna have a custom turbo kit built for it because its what my father specializes in is custom turbo kits and will have prob nitrous and methonal. So im pretty sure i can reach my goal but i just want to know what to do to my block. so, i should buy a bigger crank and intake and (exhaust). Im not gonna sell my car, thats out the question but should i keep my pistons if not atleast get a stronger je piston or something. let me know.thanks everyone.

[pei330ci]

Pistons and rods for sure as well. If you keep the 2.5 pistons, you'll definately have more compression but I doubt it will work since the top of the piston will probably touch the top of the head...

Yeah....I probably should have used "stroke" instead of "the crank" when commenting. The pistons are not exactly the same between the Non-M E46 cars, but the cylinder bore is. The piston will crash into the cylinder head if you just change the crank. (Point and case, you'll get 1/3 of a revolution from the crank before this happens)

This thread is confusing enough...sorry.

If someone is really serious about building a bigger and better engine out of an M54 block, talk to Jim Rowe at Metric Mechanic. He's got some tricks...but they cost.

[Owtlaw333]

Yeah....I probably should have used "stroke" instead of "the crank" when commenting. The pistons are not exactly the same between the Non-M E46 cars, but the cylinder bore is. The piston will crash into the cylinder head if you just change the crank. (Point and case, you'll get 1/3 of a revolution from the crank before this happens)

This thread is confusing enough...sorry.

If someone is really serious about building a bigger and better engine out of an M54 block, talk to Jim Rowe at Metric Mechanic. He's got some tricks...but they cost.

Gotcha:thumbsup: I knew it sounded too easy at first, haha. Thanks for the info.

[Activ3]

Yeah....I probably should have used "stroke" instead of "the crank" when commenting. The pistons are not exactly the same between the Non-M E46 cars, but the cylinder bore is. The piston will crash into the cylinder head if you just change the crank. (Point and case, you'll get 1/3 of a revolution from the crank before this happens)

This thread is confusing enough...sorry.

If someone is really serious about building a bigger and better engine out of an M54 block, talk to Jim Rowe at Metric Mechanic. He's got some tricks...but they cost.



yeah I think the difference in stroke between the 2.5 and 3.0 is 14.6mm...

The 3.0 crank is the same crank used in the S52, with the 89.6mm stroke. I'm wondering if I could use this crank in my 2.8 without having to change pistons and rods, so my compression would be a bit higher. If not, I suppose I could get away with a thicker head gasket, and maybe 11:1 compression or so.

[01325iSil]

If i got a 3.0 block itself and did a swap, can i stroke it to a 3.3. What from my car will fit on a 3.0L. The exhaust and everything is going to be custom so no big deal but do i need 330 ecu, intake manifold and more. I know u guys know best. thanks for the help. keep the info coming.

[01325iSil]

Yeah....I probably should have used "stroke" instead of "the crank" when commenting. The pistons are not exactly the same between the Non-M E46 cars, but the cylinder bore is. The piston will crash into the cylinder head if you just change the crank. (Point and case, you'll get 1/3 of a revolution from the crank before this happens)

This thread is confusing enough...sorry.

If someone is really serious about building a bigger and better engine out of an M54 block, talk to Jim Rowe at Metric Mechanic. He's got some tricks...but they cost.

thanks that helped a little confusion.

[Titan 3]

The 3.0 crank is forged as well. Your current 2.5 is cast.

You have a very lofty goal in mind. I currently:4ngie: have a stock bottom end in mine w/ an asa blower @8lbs of boost..... and I'm making in the 300hp neighborhood. It's no 500hp but the car is a blast to drive..... You will be in need of a VERY large check book to make your goal a reality...... But with that said, good luck.

-M

[bernstem]

Stroking the 325 to 3.0 Liters isn't a big deal. As has been said, you need the 330 crank, rod, pistons and maybe a few miscellaneous parts. With the upgrade you also get forged parts instead of the cast from the 325. I would be leery of putting 400+HP through an engine with cast rods, etc - if you can even get that much power.

If you are also looking at boring out the block, you have several other issues to consider. How much cylinder wall will be left? Will there be enough space for your head gasket to hold the boost you will need to run to get to 400+HP?

IMHO, If you are looking for 400-500HP, you are aren't going to get there with stock compresison and boost limited to 10psi or so. You might as well get aftermarket forged crank, rods and pistons and run 8.5 or so compression ratio with the same bore you have now and increase your stroke for more displacement.

[01325iSil]

Stroking the 325 to 3.0 Liters isn't a big deal. As has been said, you need the 330 crank, rod, pistons and maybe a few miscellaneous parts. With the upgrade you also get forged parts instead of the cast from the 325. I would be leery of putting 400+HP through an engine with cast rods, etc - if you can even get that much power.

If you are also looking at boring out the block, you have several other issues to consider. How much cylinder wall will be left? Will there be enough space for your head gasket to hold the boost you will need to run to get to 400+HP?

IMHO, If you are looking for 400-500HP, you are aren't going to get there with stock compresison and boost limited to 10psi or so. You might as well get aftermarket forged crank, rods and pistons and run 8.5 or so compression ratio with the same bore you have now and increase your stroke for more displacement.

Thats what ive been thinking, of getting a forged 3.0 crank, titanium rods and some forged pistons, stock compression ratio, just aftermarket for strength. Thats pretty much it for the bottom end. Then ect... cams and stuff and then a turbo kit. I think ill be able to hit somewhere between 400 and 500whp. thanks all.

[Activ3]

For the price you pay for the 330 internals and installation, you might as well just buy an M54 block...

Or if you want to go really big hp, buy an complete S52 swap :eeps: