kevster30
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M Series Engine SpecBy chanklI believed we discussed the specs of the M50/M50TU/M52/M52TU/M54 before but the 3 series forum has been pruned so all those info was lost. I just spent a bit of time reviewing the TIS (again) and compiled the following specifications information on the M5x engines. The number in hp are U.S number which typically is 1 or 2 hp less than what the other part of the world uses. I try to stay close to the CKD model so some specific model like E46 325Ci or E38 or E53 are not listed. Well, let see how long can these spec info survived in this forum.The M50 engine was first introduced in 1990 in the E34 525i replacing the M20 engine. In 1993, the M50TU replaced the M50 engine in the E35 525i and E36 325i. In this spec, the maximum torque arrive at a lower rpm compared to the M50 engine.M50B20 110KW/6000rpm, 190Nm/4700rpmM50B20TU 110Kw/5900rpm, 190Nm/4200rpmM50B25 141KW(188hp)/5900rpm, 245Nm(181lb.ft)/4700rpmM50B25TU 141KW(188hp)/5900rpm, 245Nm(181lb.ft)/4200rpm (E36)M50B25TU 141KW(189hp)/5900rpm, 250Nm(184lb.ft)/4200rpm (E34)The TU stands for Technical Update, which offer a new Engine Conrol System (DME 3.3.1) and the introduction of Variable Camshaft Control (through VANOS) which gave improved torque curve, lower fuel emissions, better idle quality, and lower fuel consumption as compared to the M50 engine.M52B20 110KW/5900rpm, 190Nm/4200rpmM52B25 125KW/5500rpm, 245Nm/3950rpmM52B28 142KW(190hp)/5300rpm, 280Nm(207lb.ft)/3950rpmThe M52B28 engine was available on the E36 328i and E39 528i in CKD form. The earlier batch of M52 engine incorporate a cast iron cylinder block while the later batch was make of alunimium silicone alloy. (I found out recently that the earlier batch of 328i use the same cylinder head as the M50TU. The different is in the number of holes for cooling has increased. There are other differences in the cam design and hydraulic lifters but I wouldn't go into details. Now I know why we don't hear M52 engine overheat that often). Engine control is via the Siemens MS41.1 system.When the E46 was launch in 1999, the M52TU engine was introduced in E46 323i, E46 328i and the E39 528i. The major changes in this Technical Update is the redesigned crankcase, modified pistons, Double VANOS for the camshaft drive, and Siemens MS42 DME syste. Later the E39 523i was introduced with the M52B25TU engine.M52B25TU 126KW(170hp)/5500rpm, 245NM(181lb-ft)/3500rpmM52B28TU 144KW(193hp)/5500rpm, 280Nm(206lb-ft)/3500rpmIn 2000/2001, the M54 engine replaced the M52B2xTU engine. These are available in the E46 320i, 325i and 330i, E39 525i and E39 530i. Interesting to note is that the E36/7 Z3 2.5 and Z3 3.0 also uses the M54 engine!M54B22 125KW(170hp)/?, 245Nm(181lb-ft)/?M54B25 141Kw(189hp)/6000rpm, 244Nm(180lb.ft)/3500-4750rpmM54B30 170KW(228hp)/5900rpm, 298Nm(220lb.ft)/3500-4750rpmNoticed the range of rpm for the torque. I remember 3er mentioned something on the infinite variable camshaft control. I have yet to dig up more on that.The development objectives of the M54 engine were to reduce emission and fuel consumption levels while maintaining power and performance compared to the M52TU six cylinder engines. In the M54B30 engine, the changes include shorter skirt pistons, forged crankshaft, higher lift camshaft, shorter ram tubes intake manifold, slightly large injection valves. On the M54B25 engine, most of the features in the M52 engine were carried over. New on the M54 engine is the use of Siemens MS43.0 engine management system which is an electronic throttle control system adopted from the ME7.2 system on the M62 engne.It is tough going through all the spec! The version I had don't have a complete picture yet. Anyone want to do some home work on the M4x or M6x series engine spec?I'll try to dig out more on the transmission unit next time
