Can someone explain to me..........

[pony]

The key differences between:

M52B25
M52TUB25
M54B25

especially in performance/power/torque/driveability/reliability/engine design/electronics
Are there really a massive difference between them all?
I know the M52/M52TUB version listed above produce 170bhp possibly for German tax reasons and the M54 listed above produces 192bhp and they all have roughly the same torque.

However, i am hoping someone with a more in-depth knowledge can explain the differences between these in the sections listed above.

Thanks very much.

[fixedwheelnut]

Something like this?
TU = Technical Update and can relate to subtle changes as manifold shape design ECU software etc you can see the M52TU torque comes in slightly lower rpm

Engine M52B25
Displacement 2.5 L (2494 cc/152 in³)
Power 123 kW (170 hp) @ 5500
Torque 245 N·m (181 ft·lb) @ 3950
Redline 6500
Year 1995

Engine M52TUB25
Displacement 2.5l (2494 cc/152 in³)
Power 123 kW (170 hp) @ 5500
Torque 245 N·m (181 ft·lb) @ 3500
Redline 6500
Year 1998

Engine M54B25
Displacement 2.5 L (2494 cc/152 in³)
Power 143 kW (192 hp) @ 6000 rpm
Torque 245 N·m (181 ft·lbf) @ 3500
Redline 6500
Year 2000

[B7]

M52TU is for technical update and meant it had double vanos I believe.

Corerect me if wrong but M52 is Iron block, M54 aluminium??

[bss325i]

M52TU is for technical update and meant it had double vanos I believe.

Corerect me if wrong but M52 is Iron block, M54 aluminium??

All M52's and 4's are aluminium block.

[cecotto479]

M50 iron block, M52/4 alloy?

[pony]

Something like this?
TU = Technical Update and can relate to subtle changes as manifold shape design ECU software etc you can see the M52TU torque comes in slightly lower rpm

Engine M52B25
Displacement 2.5 L (2494 cc/152 in³)
Power 123 kW (170 hp) @ 5500
Torque 245 N·m (181 ft·lb) @ 3950
Redline 6500
Year 1995

Engine M52TUB25
Displacement 2.5l (2494 cc/152 in³)
Power 123 kW (170 hp) @ 5500
Torque 245 N·m (181 ft·lb) @ 3500
Redline 6500
Year 1998

Engine M54B25
Displacement 2.5 L (2494 cc/152 in³)
Power 143 kW (192 hp) @ 6000 rpm
Torque 245 N·m (181 ft·lbf) @ 3500
Redline 6500
Year 2000

It is interesting to note that the M52/M52TU produce the same power but the M52TU with Double-VANOS produces the torque a little lower so it a little more flexible.

Is there such a big difference between M52/M52TU?

PS the redline figures are incorrect for M52TU as it is 6000rpm.

How hard is it to make a M52TU perform as well as the M54?
Whare are the main differences in cylinder head design between M52TU/M54?

M52 has VANOS
M52TU/M54 have Double-VANOS

[bss325i]

M52tu and M54 heads are the same, just different size valves and cams.

My M52tuB28 has a 6500rpm rev limit.

[Andyboy]

The M52TU 2.5 is rated at 170 bhp, but they do a bit more in reality. The TU and M54 heads were made a different way by basically compressing billions of small alloy balls together, whereas the older heads were cast.

US versions of the single Vanos M52 as used in the E36 and E39 up until late 1998 used iron blocks, and the crank position sensor was mounted at the back of the block - that's what that weird lug is for on alloy blocks under the starter, but for some reason Euro engines didn't use it - apart from 9/98 onwards 323i and 328i E36 Touring/Coupe/Convertibles. These engines, like the US ones, have a crank with a TDC trigger wheel on the rear most crank web. This was standardised on the TU.

All M52 engines benefit from a remap.

[pony]

M52tu and M54 heads are the same, just different size valves and cams.

My M52tuB28 has a 6500rpm rev limit.

Red line zone
Yes the M52TU I think can rev up to 6500rpm I think (i cant remember last time i did that) but strangely the red line zone commences
in a M52TU is at 6000 rpm
in a M54 is at 6250rpm last time i checked
What is the reason behind this?

A M54 head on M52TU block
So pretty much just putting a M54 head on a M52TUB25 block should be extremely close in characteristics to a M54B25 except the engine management ECU differences?

Revving characteristics/flywheel
I cannot speak for the M52/M54 as i have not driven them but a M52TU seems to "hang on" to its revs alot certaintly compared to a M20B25 is this simply down to the flywheel being alot bigger in the M52TU and it having a "dual-mass flywheel" whatever that is?

Smoothness comparison of M52TUB25 v M20B25
The M52TU certainly feels ALOT smoother than the M20 (in the Tech1) and given they are same configurations/virtually same capacities:
How much is that down to Double-VANOS?
How much is down to the electronics ECU?

It is funny that a M52TUB25/M20B25 both produce circa the same power and even funnier that a well sorted completely standard325i Sport (E30) could potentially see off a 323Ci Coupe though i do not know for sure? This intrigues me.