M50B25 vs M52B28....?

[E38Ross]

i noticed a while ago that both the later (TU) versions of these 2 engines produce pretty much the exact same power, despite the later M52 being 2.8 litres, and the earlier M50 being a smaller 2.5.

what's really the difference between the 2? the M52 has peak torque quite a lot lower down the rev range and produces peak power at a relatively low 5500rpm.

question is, is the later 2.8 noticeably better than the 2.5?

i'd be interested if there are any standard torque/power graphs hanging around for the 2 engines??

cheers

[steve_bmw]

in standard form there's not much in it, some say if you put the m50 manifold on the 2.8 it gains about 20hp but you trade off some low down power. I have done this conversion and wouldnt do it again as the gains are not noticable when you put the 2 cars side by side.

[disco!!!!]

^ this
the 328i has more torque than the 325i
the power levels will be more down to the 328i being restricted to meet german tax laws then they were first released
the did this by fitting the same inlet manifold as the 320i, if it wasnt for this it may have been sold with more power however this is the reason for the power gain when fitting the M50 inlet manifold

edit: spelling and more to add

Edited by disco!!!! on Friday 2nd December 21:07

[Frances The Mute]

steve_bmw said:

in standard form there's not much in it, some say if you put the m50 manifold on the 2.8 it gains about 20hp but you trade off some low down power. I have done this conversion and wouldnt do it again as the gains are not noticable when you put the 2 cars side by side.

You don't lose any 'low down power'. Torque starts to build around 250rpm later than the standard engine.

The gains are very distinct and are clearly noticeable. I've done it on two of my cars (one being a 728) and the breathlessness that the engine normally suffers after 4k is simply removed.

The M50 is a very revvy engine in comparison whilst the M52 relies on a very smooth and linear wave of torque to shift it along so they're quite different characters. Fact is that with the manifold mod, it helps liberate the M52's attack so it's more eager when revved. Adding an M20 flywheel will take things further agin for those who wish to do so.

[E38Ross]

Frances The Mute said:

steve_bmw said:

in standard form there's not much in it, some say if you put the m50 manifold on the 2.8 it gains about 20hp but you trade off some low down power. I have done this conversion and wouldnt do it again as the gains are not noticable when you put the 2 cars side by side.

You don't lose any 'low down power'. Torque starts to build around 250rpm later than the standard engine.

The gains are very distinct and are clearly noticeable. I've done it on two of my cars (one being a 728) and the breathlessness that the engine normally suffers after 4k is simply removed.

The M50 is a very revvy engine in comparison whilst the M52 relies on a very smooth and linear wave of torque to shift it along so they're quite different characters. Fact is that with the manifold mod, it helps liberate the M52's attack so it's more eager when revved. Adding an M20 flywheel will take things further agin for those who wish to do so.

i believe the intake mod can only be done with pre-double vanos M52's. if you want to do it with the double vanos cars you need the M54B30 intake....correct?

any idea of power gains from doing so and rough cost?

thanks chaps!

[Vixpy1]

I've got an M50 Vanos sitting here complete with ECU, Ancils, Gearbox, Clutch.,. everything..

Can I sell it?


Can I fk!

[Frances The Mute]

E38Ross said:

i believe the intake mod can only be done with pre-double vanos M52's. if you want to do it with the double vanos cars you need the M54B30 intake....correct?

any idea of power gains from doing so and rough cost?

thanks chaps!

Correct. I forgot that you mentioned the TU version. My bad.

[disco!!!!]

E38Ross said:

i believe the intake mod can only be done with pre-double vanos M52's. if you want to do it with the double vanos cars you need the M54B30 intake....correct?

any idea of power gains from doing so and rough cost?

thanks chaps!

yes
its only the single vanos M52 engines (not sure about the 320i though) that benefit the manifold swap
i dont think there is much to be had if anything from swapping the inlet on the later twin vanos 6 cylinders

[Mr Dave]

Frances The Mute said:

Adding an M20 flywheel will take things further agin for those who wish to do so.

I havent heard anything of this? Does it make a big difference? I need a new clutch soon so would be tempted for the bant.

Would go well when I put my welded diff back in.

[disco!!!!]

Mr Dave said:

Frances The Mute said:

Adding an M20 flywheel will take things further agin for those who wish to do so.

I havent heard anything of this? Does it make a big difference? I need a new clutch soon so would be tempted for the bant.

Would go well when I put my welded diff back in.

its a way of getting rid of the dual mass flywheel on the M52 engines, i think you use the clutch basket and plate from the 328i but you need a release bearing from a E21 323i you would be best to have a search about to see if you can find a guide to get a definitive answer

[Frances The Mute]

The M20 fly would need a small portion machined off or you could use an M20 starter. Either way, the reduced weight will afford you a much more responsive throttle as well as less parasitic loss giving a small gain in headline power, too.

It livens up the M52 no end as it isn't as rev-happy as the M50.

[s m]

Frances The Mute said:

The M50 is a very revvy engine in comparison whilst the M52 relies on a very smooth and linear wave of torque to shift it along so they're quite different characters.

This is true - a friend has an early E36 325 - very different 'feel' to the engine on a later 328

[sparks_E39]

I have a November 1999 BMW 528, I read somewhere that the later 528's like mine were pushing out a tad over 200 bhp rather than 195ish in the 1995 528's to whenever they got the newer engine, is this correct?

[E38Ross]

sparks_E39 said:

I have a November 1999 BMW 528, I read somewhere that the later 528's like mine were pushing out a tad over 200 bhp rather than 195ish in the 1995 528's to whenever they got the newer engine, is this correct?

nope, quoted power output is the same, as is the torque figure i believe. the difference is that on the later versions with double vanos (as in yours....the same engine in my car) has a flatter torque curve. this means that, if you were to take the power output at every 500rpm from 1500rpm up (e.g. power at 1500rpm, 2000rpm, 2500rpm etc to 6500rpm) the overall number you'd get would be higher for the double vanos car.

the flatter torque curve makes it feel less peaker and gives it a slightly more linear power delivery; and marginally better economy too.

[e21Mark]

I have an e21 with an M52/2.8 conversion and recently fitted an M50 inlet and big bore throttle body. The difference before & after was considerable. Obviously I benefit from the lighter m20 flywheel too. I am put the car on a dyno on Thursday so will upload a scan of the results. I have also had the ECU remapped in order to make the most of the changes. In a car weighing a little over 1000kgs performance is lively.

[E38Ross]

e21Mark said:

I have an e21 with an M52/2.8 conversion and recently fitted an M50 inlet and big bore throttle body. The difference before & after was considerable. Obviously I benefit from the lighter m20 flywheel too. I am put the car on a dyno on Thursday so will upload a scan of the results. I have also had the ECU remapped in order to make the most of the changes. In a car weighing a little over 1000kgs performance is lively.

Hi mark,

how is it going? i hear my old E21 has found an enthusiastic member who has posted on the forums a few times....

i'm guessing your M52 is not the double vanos one? i don't think you can fit an M50 inlet to a double vanos M52....think you need to go M54 inlet.

also....car is a late E38 728i sport, so no manual boxes and flywheels to play around with. yes, i've gone TOTALLY the opposite direction to my E21 :lol:

i am enjoying doing to longer trips in the barge though....sublime comfort and refinement which is what i really wanted as 99% of my miles are motorway or around town so fancied something a little more relaxing.

[e21Mark]

Nothing wrong with a bit of comfort. I'm right in the middle of my mid-life crisis though so just pretend I can't feel a thing.

[e21Mark]

Inlet & generic map =

[Arturas2k12]

Hello How Did you fit m50b25 intake to m52b28 ? Did you need some extra parts?thank you