530i/xi N52 Engine
09-30-2009, 06:47 AM
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I found this description on the web for the N52 engine while I was looking for details about this engine. I though it might be a good read since I was curious what is the difference in this engine besides the 255 hp @ 6600 rpm, 220 lb-ft. torque @ 2750 rpm.
BMW?s new generation of 6-cylinder engines is designated N52.Compared to its illustrious predecessor, the M54 engine family, the N52 achieves notable progress on all fronts:
? Greater power, 255 vs. 225 hp for the 530i, 215 vs. 184 hp for the 525i. In the case of the 530i, this amounts to an impressive 85 hp per liter.
? Greater torque, 220 lb-ft. vs. 214 in the 530i, 185 lb-ft. vs. 175 in the 525i; and even stronger torque delivery across the broad range of engine speeds.
? Higher revving ability. The new engine?s redline is 7000 rpm, vs. 6500 for the predecessor.
? Fuel efficiency. Though not every model and version is up, there are some impressive gains in EPA mileage ratings: 525i with manual transmission up 1 mpg city/2 mpg highway, with automatic up 2 mpg city/1 mpg highway, 530i automatic up 2 mpg city.
? Reduced weight ? 22 lb. less. Had BMW engineers evolved the existing engine to meet their goals, it would have instead added about 30 lb.
? More compact ? because there is just one external drive belt vs. the previous two, overall engine length is about an inch less.
Here are some details of how this dramatic progress has been achieved ? over an engine that was already outstanding in all these respects.
Valvetronic variable valve lift. This patented innovation, already enhancing the performance and fuel efficiency of BMW?s V-8 and V-12 engines, now appears in a BMW 6-cylinder engine as well ? and in evolved form. Valvetronic varies valve lift to a far greater degree than other variable-lift systems ? so much, in fact, that it replaces the traditional engine throttle. Engine breathing is controlled entirely by the valves themselves.
The Valvetronic mechanism acts on the intake valves, imposing an additional control element between the camshaft lobe and rocker arm for each cylinder, called an intermediate follower. Upon contact by the lobe, this follower actuates a finger-type rocker arm and, in turn, the valve. The follower?s pivot point is positioned by an eccentric shaft, rotated by a servo motor in response to the driver?s accelerator-pedal movements; this varies the valve lift. The system?s advantages include:
? Greater efficiency. As a throttle closes, it poses a restriction to incoming air. Valvetronic eliminates this restriction, reducing ?pumping losses.?
? More spontaneous engine response ? again, because there is no conventional throttle.
? More power, because maximum valve lift can be higher than it could be with fixed valve lift.
? A ?fatter? torque curve. Not only does the engine produce more torque; the torque peak occurs at a lower speed, 2750 rpm vs. the previous 3500.
Compared to the 1st-generation Valvetronic system of BMW?s V-8s and V-12s, that of the N52 engine has evolved in several ways:
? Higher maximum engine speed, by making Valvetronic reciprocating parts more rigid.
? Maximum valve lift increased, contributing to the increase in power output.
? Greater maximum valve acceleration. Less time is spent opening and closing the valves; thus they are effectively open longer, further reducing pumping losses.
? Phasing of intake valves. A given cylinder?s two intake valves now open at different rates, resulting in a more targeted, asymmetric distribution of the fuel/air mixture that enhances fuel economy under low-load driving conditions.
Additional developments contribute to the new engines? performance:
? Combustion chambers have been refined.
? BMW?s VANOS variable valve timing has also evolved; the range over which it varies intake-valve timing has been increased by 10 degrees.
? 3-stage induction system (530i engine only). BMW 6-cylinders have long had a 2-stage system, with one intake-path length for lower rpm, the other for higher rpm. By providing an additional ?middle? stage, this system further optimizes torque and power delivery.
? Higher fuel-injection pressure, increased from 3.5 to 5 bar (50.8 to 72.5 lb/sq in.), improves the injection spray, reducing emissions from a cold engine.
? All-new engine electronics to optimize engine behavior and performance under all operating conditions.
Unique new magnesium/aluminum composite engine construction
Recent BMW 4-wheel vehicles (i.e. not motorcycles) have utilized three types of engine construction, all with aluminum cylinder heads:
? Regular-production 6-cylinder engines (3, 5, Z4, X3 and X5 Series) ? aluminum block with cast-iron cylinder liners.
? V-8 and V-12 engines, new V-10 (5, 7 and X5 Series, M5) ? aluminum block with integrally cast silicon-impregnated aluminum cylinder surfaces.
? M3 6-cylinder engine ? cast-iron cylinder block.
With the N52 engine, BMW introduces a unique and pioneering engine structure: magnesium/aluminum composite construction, the first in a contemporary automobile. Structurally, the all-new engine block consists of three major castings:
Bedplate (magnesium alloy ). This casting forms the lower portion of the block (crankcase), and is similar in concept to a construction element found in some racing engines ? as well as the 500-hp V-10 engine powering the new BMW M5.
Upper crankcase (magnesium alloy3). Joining the bedplate at the level of the crankshaft (main) bearings, this too is a weight-saving casting. Mounted onto the bedplate from above; combines with the bedplate to form the cylinder block?s outer shell. The result is an ultra-rigid, yet remarkably light engine structure.
Insert (aluminum alloy). Forms the cylinders and their coolant passages. Analogous to the entire blocks of BMW?s V-8, V-10 and V-12 engines, silicon particles are cast into this insert; a ?soft honing? machine removes just enough of the aluminum to leave the crystals as ultra-hard cylinder surfaces.
How it goes together. First, the aluminum insert is cast by conventional methods. Then, during a newly developed die-casting method, the magnesium upper shell shrinks onto the insert while cooling; structural rigidity and stability are ensured by interlocking ribs where the two castings meet.
In the next step, the upper crankcase, consisting of magnesium shell and aluminum insert, is mounted onto the magnesium bedplate from above. The sintered-steel main bearings? lower halves are in place in the bedplate, the upper halves in the upper crankcase. After the bedplate and upper crankcase have been bolted together, a liquid sealing compound is injected into a groove on the contact surface between the two components. Special aluminum bolts are used to attach parts, such as the engine mounting brackets, to the magnesium/aluminum castings.
As the ?conventional? part of this construction, the cylinder head is of aluminum; however, the head of an inline 6-cylinder engine must be cast with great precision because its length implies relatively large contraction during the cooling-down process after casting. The casting process used here is called ?lost-foam?; because all BMW gasoline engines since the 1960s have had aluminum heads, BMW?s experience in this regard is long and successful; BMW has used the lost-foam method for cylinder heads since 1997. This process, which employs a polystyrene ?dummy? of the head to form the mold into which the aluminum is poured, results in an extremely precise casting of this critical engine component.
Other weight-saving materials. Though the magnesium/aluminum composite crankcase construction is the most conspicuous example, other materials and production innovations also help pare weight from the N52 engine. One is the adoption of hollow camshafts, which save a remarkable 2.6 lb. Beginning as steel tubes, the camshafts are shaped in a hydroforming procedure, subjected from the inside to a water pressure of 4000 bar (58,000 lb./sq in.) against outer forms to achieve the cam profiles. All this takes place in a cold state ? nothing melts ? and as a final step the cams are polished to a finish quality of 1/1000 mm.
The engine?s camshaft cover is of weight-saving magnesium. The VANOS sprockets, via which the camshaft chain drives the two variable-valve-timing mechanisms, are newly of aluminum. And the chain camshaft drive ? a high-durability, low-maintenance feature of all current BMW engines ? has an aluminum chain tensioner that also saves weight. Instead of being a separate casting, the camshaft drive?s housing is integrally cast into the magnesium structure, eliminating a production step and sealing components. As one final weight-reducing element, the exhaust headers? flanges are formed from 2-mm-thick steel, significantly lighter than the 12-mm flanges used previously; for a secure seal of this steel to the aluminum head, graphite rings are employed.
Electric coolant pump. A conventional engine coolant (?water?) pump is driven by a belt, and always runs at a speed directly proportional to engine rpm. This innovative feature is electrically driven and electronically controlled according to the engine?s coolant and oil temperatures at any moment. Thus it runs only as much as needed, consuming a maximum of 200 watts vs. up to 2 kilowatts (10 times as much) for a conventional pump. This pump has further benefits:
? By requiring less power, it contributes to the engine?s increased power output.
? Faster engine warmup, because it doesn?t pump when the engine is cold.
? Provides coolant circulation for the climate control?s Heat-at-Rest feature. (With a conventional coolant pump, this needs a separate electric pump.)
? By eliminating an external drive belt, makes the engine shorter.
Variable-volume oil pump. Conventional oil pumps, too, deliver oil in direct proportion to engine speed. In order to supply the VANOS system (which employs oil pressure to vary valve timing) at all speeds and temperatures without excess capacity at high engine speeds, BMW engineers developed a new type of oil pump. By varying the output of its pump element according to engine oil pressure, the engineers achieved a pump that always delivers sufficient pressure to lubricate the engine and operate VANOS, yet never pumps more oil than is necessary. Thus it ?
? Contributes to usable power, by requiring less power from the engine.
? Doesn?t require a bypass to divert excess flow, which can be up to 80%. This also avoids possible excess oil temperatures and oil foaming.
Oil/coolant heat exchanger. Another feature that speeds engine warmup; during this phase it transfers heat from the coolant to the oil circuit. Under conditions of high engine power and high oil temperatures, it performs the reverse, transferring heat from the oil circuit to the coolant to remove excess heat.
525i/xi and 530i/xi: the two engine versions
A distinctive engine version powers each set of 5 Series models. Instead of the traditional correlation of model designation to engine size, each is a 3.0-liter N52, but equipped and calibrated for different levels of performance:
? 525i/xi ? 215 hp @ 6250 rpm, 185 lb-ft. torque @ 2750 rpm
? 530i/xi ? 255 hp @ 6600 rpm, 220 lb-ft. torque @ 2750 rpm.
Significant differences between the 525i/xi and 530i/xi engines are as follows:
? Whereas the 530 engine has the 3-stage induction system, the 525 unit has a single-stage intake manifold.
? Engine software differs between the two models.
BMW?s new generation of 6-cylinder engines is designated N52.Compared to its illustrious predecessor, the M54 engine family, the N52 achieves notable progress on all fronts:
? Greater power, 255 vs. 225 hp for the 530i, 215 vs. 184 hp for the 525i. In the case of the 530i, this amounts to an impressive 85 hp per liter.
? Greater torque, 220 lb-ft. vs. 214 in the 530i, 185 lb-ft. vs. 175 in the 525i; and even stronger torque delivery across the broad range of engine speeds.
? Higher revving ability. The new engine?s redline is 7000 rpm, vs. 6500 for the predecessor.
? Fuel efficiency. Though not every model and version is up, there are some impressive gains in EPA mileage ratings: 525i with manual transmission up 1 mpg city/2 mpg highway, with automatic up 2 mpg city/1 mpg highway, 530i automatic up 2 mpg city.
? Reduced weight ? 22 lb. less. Had BMW engineers evolved the existing engine to meet their goals, it would have instead added about 30 lb.
? More compact ? because there is just one external drive belt vs. the previous two, overall engine length is about an inch less.
Here are some details of how this dramatic progress has been achieved ? over an engine that was already outstanding in all these respects.
Valvetronic variable valve lift. This patented innovation, already enhancing the performance and fuel efficiency of BMW?s V-8 and V-12 engines, now appears in a BMW 6-cylinder engine as well ? and in evolved form. Valvetronic varies valve lift to a far greater degree than other variable-lift systems ? so much, in fact, that it replaces the traditional engine throttle. Engine breathing is controlled entirely by the valves themselves.
The Valvetronic mechanism acts on the intake valves, imposing an additional control element between the camshaft lobe and rocker arm for each cylinder, called an intermediate follower. Upon contact by the lobe, this follower actuates a finger-type rocker arm and, in turn, the valve. The follower?s pivot point is positioned by an eccentric shaft, rotated by a servo motor in response to the driver?s accelerator-pedal movements; this varies the valve lift. The system?s advantages include:
? Greater efficiency. As a throttle closes, it poses a restriction to incoming air. Valvetronic eliminates this restriction, reducing ?pumping losses.?
? More spontaneous engine response ? again, because there is no conventional throttle.
? More power, because maximum valve lift can be higher than it could be with fixed valve lift.
? A ?fatter? torque curve. Not only does the engine produce more torque; the torque peak occurs at a lower speed, 2750 rpm vs. the previous 3500.
Compared to the 1st-generation Valvetronic system of BMW?s V-8s and V-12s, that of the N52 engine has evolved in several ways:
? Higher maximum engine speed, by making Valvetronic reciprocating parts more rigid.
? Maximum valve lift increased, contributing to the increase in power output.
? Greater maximum valve acceleration. Less time is spent opening and closing the valves; thus they are effectively open longer, further reducing pumping losses.
? Phasing of intake valves. A given cylinder?s two intake valves now open at different rates, resulting in a more targeted, asymmetric distribution of the fuel/air mixture that enhances fuel economy under low-load driving conditions.
Additional developments contribute to the new engines? performance:
? Combustion chambers have been refined.
? BMW?s VANOS variable valve timing has also evolved; the range over which it varies intake-valve timing has been increased by 10 degrees.
? 3-stage induction system (530i engine only). BMW 6-cylinders have long had a 2-stage system, with one intake-path length for lower rpm, the other for higher rpm. By providing an additional ?middle? stage, this system further optimizes torque and power delivery.
? Higher fuel-injection pressure, increased from 3.5 to 5 bar (50.8 to 72.5 lb/sq in.), improves the injection spray, reducing emissions from a cold engine.
? All-new engine electronics to optimize engine behavior and performance under all operating conditions.
Unique new magnesium/aluminum composite engine construction
Recent BMW 4-wheel vehicles (i.e. not motorcycles) have utilized three types of engine construction, all with aluminum cylinder heads:
? Regular-production 6-cylinder engines (3, 5, Z4, X3 and X5 Series) ? aluminum block with cast-iron cylinder liners.
? V-8 and V-12 engines, new V-10 (5, 7 and X5 Series, M5) ? aluminum block with integrally cast silicon-impregnated aluminum cylinder surfaces.
? M3 6-cylinder engine ? cast-iron cylinder block.
With the N52 engine, BMW introduces a unique and pioneering engine structure: magnesium/aluminum composite construction, the first in a contemporary automobile. Structurally, the all-new engine block consists of three major castings:
Bedplate (magnesium alloy ). This casting forms the lower portion of the block (crankcase), and is similar in concept to a construction element found in some racing engines ? as well as the 500-hp V-10 engine powering the new BMW M5.
Upper crankcase (magnesium alloy3). Joining the bedplate at the level of the crankshaft (main) bearings, this too is a weight-saving casting. Mounted onto the bedplate from above; combines with the bedplate to form the cylinder block?s outer shell. The result is an ultra-rigid, yet remarkably light engine structure.
Insert (aluminum alloy). Forms the cylinders and their coolant passages. Analogous to the entire blocks of BMW?s V-8, V-10 and V-12 engines, silicon particles are cast into this insert; a ?soft honing? machine removes just enough of the aluminum to leave the crystals as ultra-hard cylinder surfaces.
How it goes together. First, the aluminum insert is cast by conventional methods. Then, during a newly developed die-casting method, the magnesium upper shell shrinks onto the insert while cooling; structural rigidity and stability are ensured by interlocking ribs where the two castings meet.
In the next step, the upper crankcase, consisting of magnesium shell and aluminum insert, is mounted onto the magnesium bedplate from above. The sintered-steel main bearings? lower halves are in place in the bedplate, the upper halves in the upper crankcase. After the bedplate and upper crankcase have been bolted together, a liquid sealing compound is injected into a groove on the contact surface between the two components. Special aluminum bolts are used to attach parts, such as the engine mounting brackets, to the magnesium/aluminum castings.
As the ?conventional? part of this construction, the cylinder head is of aluminum; however, the head of an inline 6-cylinder engine must be cast with great precision because its length implies relatively large contraction during the cooling-down process after casting. The casting process used here is called ?lost-foam?; because all BMW gasoline engines since the 1960s have had aluminum heads, BMW?s experience in this regard is long and successful; BMW has used the lost-foam method for cylinder heads since 1997. This process, which employs a polystyrene ?dummy? of the head to form the mold into which the aluminum is poured, results in an extremely precise casting of this critical engine component.
Other weight-saving materials. Though the magnesium/aluminum composite crankcase construction is the most conspicuous example, other materials and production innovations also help pare weight from the N52 engine. One is the adoption of hollow camshafts, which save a remarkable 2.6 lb. Beginning as steel tubes, the camshafts are shaped in a hydroforming procedure, subjected from the inside to a water pressure of 4000 bar (58,000 lb./sq in.) against outer forms to achieve the cam profiles. All this takes place in a cold state ? nothing melts ? and as a final step the cams are polished to a finish quality of 1/1000 mm.
The engine?s camshaft cover is of weight-saving magnesium. The VANOS sprockets, via which the camshaft chain drives the two variable-valve-timing mechanisms, are newly of aluminum. And the chain camshaft drive ? a high-durability, low-maintenance feature of all current BMW engines ? has an aluminum chain tensioner that also saves weight. Instead of being a separate casting, the camshaft drive?s housing is integrally cast into the magnesium structure, eliminating a production step and sealing components. As one final weight-reducing element, the exhaust headers? flanges are formed from 2-mm-thick steel, significantly lighter than the 12-mm flanges used previously; for a secure seal of this steel to the aluminum head, graphite rings are employed.
Electric coolant pump. A conventional engine coolant (?water?) pump is driven by a belt, and always runs at a speed directly proportional to engine rpm. This innovative feature is electrically driven and electronically controlled according to the engine?s coolant and oil temperatures at any moment. Thus it runs only as much as needed, consuming a maximum of 200 watts vs. up to 2 kilowatts (10 times as much) for a conventional pump. This pump has further benefits:
? By requiring less power, it contributes to the engine?s increased power output.
? Faster engine warmup, because it doesn?t pump when the engine is cold.
? Provides coolant circulation for the climate control?s Heat-at-Rest feature. (With a conventional coolant pump, this needs a separate electric pump.)
? By eliminating an external drive belt, makes the engine shorter.
Variable-volume oil pump. Conventional oil pumps, too, deliver oil in direct proportion to engine speed. In order to supply the VANOS system (which employs oil pressure to vary valve timing) at all speeds and temperatures without excess capacity at high engine speeds, BMW engineers developed a new type of oil pump. By varying the output of its pump element according to engine oil pressure, the engineers achieved a pump that always delivers sufficient pressure to lubricate the engine and operate VANOS, yet never pumps more oil than is necessary. Thus it ?
? Contributes to usable power, by requiring less power from the engine.
? Doesn?t require a bypass to divert excess flow, which can be up to 80%. This also avoids possible excess oil temperatures and oil foaming.
Oil/coolant heat exchanger. Another feature that speeds engine warmup; during this phase it transfers heat from the coolant to the oil circuit. Under conditions of high engine power and high oil temperatures, it performs the reverse, transferring heat from the oil circuit to the coolant to remove excess heat.
525i/xi and 530i/xi: the two engine versions
A distinctive engine version powers each set of 5 Series models. Instead of the traditional correlation of model designation to engine size, each is a 3.0-liter N52, but equipped and calibrated for different levels of performance:
? 525i/xi ? 215 hp @ 6250 rpm, 185 lb-ft. torque @ 2750 rpm
? 530i/xi ? 255 hp @ 6600 rpm, 220 lb-ft. torque @ 2750 rpm.
Significant differences between the 525i/xi and 530i/xi engines are as follows:
? Whereas the 530 engine has the 3-stage induction system, the 525 unit has a single-stage intake manifold.
? Engine software differs between the two models.
09-30-2009, 06:59 AM
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Thank you for the thorough description. I find that the difference between the 525 and the 530 are minimal and one could probably spend a lot less money to make the extra 40 hp than the difference in dealer prices between the two engines.
09-30-2009, 08:58 AM
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Originally Posted by spiros' post='1021107' date='Sep 30 2009, 12:47 PM
Isn't the N52 the pre-facelift engine ?
09-30-2009, 09:51 AM
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Yeah, i thought the plain N52 designation -with the famouns lifter knocking- is the pre lci one. The only thing got me confused is the hp ratings on that article. Doesn't the 2.5 ltr n52 produces 185hp ?
09-30-2009, 10:33 AM
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Originally Posted by spiros' post='1021199' date='Sep 30 2009, 12:51 PM
Yeah, i thought the plain N52 designation -with the famouns lifter knocking- is the pre lci one. The only thing got me confused is the hp ratings on that article. Doesn't the 2.5 ltr n52 produces 185hp ?
10-01-2009, 07:42 AM
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Originally Posted by porsche911targa' post='1020972' date='Sep 30 2009, 10:59 AM
Thank you for the thorough description. I find that the difference between the 525 and the 530 are minimal and one could probably spend a lot less money to make the extra 40 hp than the difference in dealer prices between the two engines.
Probably so for horsepower, but you could never get the same torque vs rpm. A 19% difference in peak torque available. In addition, any changes you can do to make the extra 40 HP you can perform to increase 255 HP to 295HP for the 530 engine. This is just another perspective.
(2006-2007) 530i => 220 lb-ft @ 2400 RPM peak
(2006) 525i => 185 lb-ft @ 2750 RPM peak
10-01-2009, 07:47 AM
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Originally Posted by D33ZNUT5' post='1021257' date='Sep 30 2009, 07:33 PM
There is no 2.5l, it is the same 3.0l as the 530, just different software and intake.
. I'm in Europe i don't know if the 2.5ltr ones are not available in the US. The 523i and 525i are basically 2.5ltr, the difference is on the intake and software as you said. The 530 is a different 3ltr engine.
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