Introduction

The 4 cylinder engines are found in the following,

M40B16: 1990-1993 316Ti
M43B16: 1994-1998 316Ti
M40B18: 1990-1993 318i
M43B18: 1994-1998 318i
M42B18: 1992-1995 318is
M44B19: 1996-1998 318is

Summary

The M4x engines are the least favorable in the E36 chassis. With poor performance in factory form and lack of aftermarket support, performance modifications are scarce, expensive and provide minimal gains. The best bang-for-buck upgrade would be to swap in a M50B25/TU or M52B28. However, if you insist on modifying the mighty 4 banger, here are a couple of ideas.

Intake

The biggest gain in performance for this platform comes with the biggest cost - ITBs (individual throttle bodies).
Racehead Engineering and Dbilas Dynamics are the go-to options for ITB kits. Racehead Engineering is a local Australian company out of Sydney, so support local and Rama will help you with any questions you may have. Gains are 12wkw+ seen on the M44B19 on the stock ECU tune, more can be found with a custom dyno tune.

Camshafts

Performance camshafts should be considered if ITBs are already installed. Mild performance cams around the 276/276deg can be used with the stock valve-train, anything bigger will require at least upgraded valve-springs and race cams in the 300deg range will require solid lifters.

Forced Induction

In progress! Come back soon!

Introduction

The 6 cylinder engines are found in the following,

M50B20: 1990-1991 320i
M50B25NV: 1990-1991 325i
M50B20TU: 1992-1994 320i
M50B25TU: 1992-1994 325i
M52B25 1995-1999 323i
M52B28: 1995-1999 328i

Summary

The M5x engines found in the E34/E36/E38 are one of the most popularly modified BMW engines ever. With decent performance in N/A guise and limitless potential under forced induction, the M50 and M52 is a great platform for any build. The 2 liter M50B20 should be avoided as it only produces a little more power than the M44B19 with a huge weight disadvantage. M50B25/TU tuning is done by replacing a physical EPROM chip inside the DME, M52 tuning is done by flashing the DME via OBD/20pin.

All M50 engines have cast iron blocks, while M52 came in both aluminium and cast iron variants. All M52s found in the US have iron blocks - apart from M52s in the Z3. European (and the rest of the world) have aluminium blocks.

Vanos vs Non Vanos, M50 vs M52

The M50 has 2 versions, one with Vanos and one without. M50 indicates non vanos, while M50TU (Technical Update) indicates single Vanos. All M52s came with Vanos, M52TU is a different engine entirely with double Vanos.
Vanos is BMW’s version of variable cam timing and shifts the phase angle of the intake camshaft. Single Vanos indicates Vanos only on the intake side while double Vanos indicates Vanos on both the intake and exhaust cam.

Key Differences between M50 and M50TU

Double Valve Springs (M50NV)
Hotter Intake Camshaft (M50NV)
7mm Valve Stems (M50NV) vs 6mm (M50TU/M52)
35mm Valve Lifters (M50NV/M50TU) vs 33mm (M52)
Stronger Connecting Rods (M50NV)
135mm Con-rods (M50NV/M52) vs 140mm Rods (M50TU)
Iron Block (M50/M50TU) vs Aluminium Block (M52)

Generally speaking the M50NV has more desirable hardware however lacks the Vanos unit. However, Vanos is crucial as it greatly increases torque under 4200RPM and is extremely beneficial for day-to-day driving and turbo spool. Deleting or limiting Vanos would be only be suitable if high lift and duration camshafts are installed - to avoid piston to valve contact when the Vanos is fully advanced.

Intake

The most common intake upgrade for M52B25 and M52B28 is to install the intake manifold from the M50B25 or M50B25TU. The 2.5L variants of the M50 have a much larger intake manifold which increases peak power and extends the torque band. Without a tune there is a small dip in low/mid-range torque, however with a tune the dip is removed and strong gains are made up top. The intake manifold swap is relatively straight forward and is widely documented online.

Exhaust

The exhaust manifold from European E36 S50 motors is a great improvement over the factory headers. There are essentially no aftermarket headers for suitable for RHD E36s, so the best upgrade would be the headers from the S50. For best results the exhaust ports should be ported to match the larger diameter of the M3 headers. The complete exhaust will fit as well however the midsection will not fit if you have an automatic gearbox, the piping hits the gearbox. You will also need to extend the O2 sensor wiring or buy longer O2 sensors as the bung on the exhaust is deeper down on the M3 midpipe. The M3 O2 sensors cannot be used with as it is not compatible with the ECU.

For the E36 323i specifically, the midpipe is a single pipe configuration, limiting flow. A good bolt-on upgrade is to install the header-back section from a 325i or 328i as they are twin pipe the whole way.

Camshafts

Luckily for all M5x owners there is a cheap and cost effective camshaft upgrade. The intake cam from the M54B30 (specifically the 3L variant) is a great camshaft upgrade for M5xB25/B28 engines. The only modification required is to take 4.5mm off the Vanos spline - the spline is easily removed and easy to machine. On a M52B28 with a M50B25 intake manifold and M54B30 intake cam, there is a 15kw and 18nm peak to peak gain at the wheels - tuning is essential! There is also a substantially wider power band! For those willing to take it another step, replacing the stock exhaust camshaft with the Intake camshaft from a M50NV motor will also show even more improvements. This will require custom timing blocks available for purchase/hire.

N/A Build Spec Sheet

Budget Build

• M50B25 Intake Manifold

• M54B30 Intake Camshaft

• M50B25NV Intake Camshaft on Exhaust Side

• VANOS Rebuild

Intermediate Build

• M54B30 Rotating Assembly

• M50NV Double Valve Springs + 6mm Retainers

• S50/S52 US Camshafts

• S50 Euro Exhaust Manifold + Exhaust Port Matching

• Lightweight Pulleys

• Tube Headers

Full Build

• 2.8L Crankshaft from M52B28 or M52B28TU

• Honda B18C 138mm Connecting Rods

• Balanced Rotating Assembly

• K20 Turbo Pistons

• S50 ITBs + Adapter

• VANOS Delete

• 280+ deg Camshafts

• Head Porting

• Solid Lifter Conversion (shims under bucket)

• 35mm INA Lightweight Lifters + Tray

• Oil Pump Nut Saftey Wired

Contact or message via Facebook for specifics.

Turbo Build Spec Sheet

Read the E36 Turbo Guide here.

Getrag 250G

The Getrag 250G is the most common 5 speed manual gearbox found in E36s. It is found in ALL models except from the 328i and M3. The offical BMW code name for this gearbox is S5D-250G. This gearbox is notoriously known for its low strength; 2nd gear syncros during hard shifting may explode. The more grip there is the more easier it is to break this gearbox. It is not recommended to be used with anything more powerful than a M52B25.

Gear Ratios

1st 4.23:1
2nd 2.52:1
3rd 1.66:1
4th 1.22:1
5th 1.0:1

ZF 320Z

The ZF S5-31 aka 310Z/320Z is found in the 328i and M3 3.0. The offical BMW code name for this gearbox is S5D-320Z. This gearbox is known for its ability to handle abuse and high power (800hp+). It is also found in E34 525i, E46 328i/330i, E39 528i/530i. While it is a strong gearbox, the 5th gear detent and reverse detent wears over time and may result in ‘leaning 5th’, where the shifter lever has no resistance while shifting into 5th. Overrun offers the detent rebuild service.

Gear Ratios

1st 4.21:1
2nd 2.49:1
3rd 1.67:1
4th 1.24:1
5th 1.0:1

Getrag 420G

The 6 speed Getrag 420G is found in the E36 M3 3.2 Evo. This gearbox is similar to its counterpart found in the E46 M3, albeit with small differences to the input shaft. The 420G is a solid gearbox capable of holding big power.

Gear Ratios

1st 4.227:1
2nd 2.528:1
3rd 1.669:1
4th 1.226:1
5th 1.0:1
6th 0.828:1

Intro

All E36 flywheels from the factory are heavy dual mass units weighing approximately 12kg. While good for absorbing drivetrain noise and vibration, it lacks response.

A common upgrade is to replace the factory dual-mass flywheel with a lighter single mass flywheel. Anything lighter than 7-8kg will be a little annoying for a daily driver as taking off will require more revving and clutch slipping due to having less inertia.

The stock setup consists of a dual-mass flywheel paired with a solid unsprung clutch disk.

228mm

The smaller clutch and flywheel is found in 316i - 325i. It is worthwhile to upgrade to a 240mm setup as there are much more aftermarket options. The 325i clutch is the strongest out of the bunch, however still lacks absolute clamping force.

240mm

The larger 240mm setup is found in the 328i and M3. The M3 clutch unfortunately is not compatible with the 328i flywheel.

A proven and recommended setup is the Pure PF 240mm single mass flywheel paired with a Sachs -765 pressure plate. For anything 450hp or under, an organic sprung center clutch disk will do the job. Opt for a 6 puck ceramic/metallic disk to hold upwards of 1000hp.

The larger 240mm flywheel and clutch is compatible with all manual gearboxes.

Small Case 168mm

There are two variants of the small case differential found in E36 Ti and E36. The E36 Ti differential has a different exterior casing compared to the E36 however the internals remain the same. The small case diff is found in the 316i to 320i. Some came with LSD centers if they were optioned. Not recommend under high grip/torque situations, the pinion gear may fail.

To swap a small case diff into a chassis with a medium case, simply swap the larger output flanges onto the small case diff.

Factory Diff Ratios

*Check the diff tag for the most accurate identification*

• 316Ti 1.9L

  • 3.23

• 318Ti

  • Auto 4.44

  • Manual 3.45

• 318i

  • Auto 4.44

  • M40 Manual 3.345

  • M43 Manual 3.38

• 318is

  • Auto 4.44

  • M42 Manual 3.45

  • M44 Manual 3.38

• 320i

  • 3.45

Medium Case 188mm

Medium case diffs are found in the 323i, 325i, 328i and M3. These differentials are generally strong and robust and do not easily fail. Some came with LSD centers if they were optioned - all M3s have LSDs. It is very hard to find a medium case diff with a ratio shorter than 3.15 in Australia as no factory E36 had one.

To convert 2.93 - 3.07 diffs into 3.15+ a spacer is required for the crown gear. This is because the center, whether it be open or LSD, has a thinner flange for the crown gear to bolt onto. Ratios 3.15 and shorter do not need this spacer.

The M3 differentials come with a different input flange with reservations for 6 bolts instead of 4. Luckily the input flange can be swapped with non-M flanges.

Factory Diff Ratios

• 323i

  • 2.93

• 325i

  • 3.15

• 328i

  • Auto 3.07

  • Manual 2.93

• M3 Euro

  • 3.15

Large Case 210mm

The 210mm large case differential is only found in the European M3 3.2 Evo. The large case diff is not easily interchangeable like the small and medium case. The large case differential requires a different subframe cradle with different mounting brackets.

The large case diff is very strong and rarely ever fail.

The factory clutch LSD unit comes with 2 clutches, an easy upgrade is to install another 2 for a total of 4 clutches. New clutches can be bought from Racing Diffs.

The factory ratio is 3.23.

Street

Here are some suggestions for a daily street driven car.

Shock Absorbers

• Bilstein B6

  • Slightly stiffer than factory M-Tech suspension, suitable for stock height.

• Bilstein B8

  • Same as the B6 in terms of damping but designed for lowering springs.

Springs

• Lowering springs are shorter and stiffer than OEM springs, require stiffer shocks for best results and fitment.

• Aim for spring rates below 6 KG/mm or 330 Lb/in.

Street + Track

Here are some suggestions for a street driven car that sees the track or twisties.

Coilovers

• Bilstein B16 PSS9/10

  • Damper adjustable and height adjustable

  • On the stiffer side

• KW V2

  • Damper adjustable and height adjustable

  • On the softer side

• Ohlins R&T

  • Damper adjustable and height adjustable

  • On the stiffer side

Camber Plates

Camber plates are essential for any sort of aggressive driving, there is not nearly enough negative camber with the factory strut tops. Tuner and Ground Control make quality camber plates - ‘Track/Race’ versions of any camber plate will introduce some NVH and slight knocking sounds.

Track Only

Coilovers

• Bilstein Clubsport

• KW Clubsport

• MCS

• Ohlins

Bracing

The E36 is an old chassis and lacks rigidity compared to modern day cars. The following are things you can do to improve strength and rigidity.

• Front/rear strut braces

• Front Subframe

  • With poly or solid engine mounts the front subframe may crack or bend. OEM Weld-in reinforcement plates are readily available.

• Rear Subframe

  • Aftermarket reinforcement plates should be avoided, BMW make their own reinforcement plates which came installed on M3s from factory. These plates are contoured to the chassis and require welding.

• Shock tower reinforcement plates

  • BMW sells circular plates that goes between the shock tower and the shock mount. Prevents mushrooming of the shock tower from stiff shocks.

• X-brace

  • Convertibles and M3s came with a x-brace underneath the front subframe. All E36s have provisions to mount the x-brace however require nutserting.

• Half Cage

  • Half cages may be legal for street driving depending on your state.

  • Required for motorsport events

Swaybars

Look for aftermarket options for sway bars as M3 sway bars are thinner and less stiffer than non-M. This is because the sway bar on M3s mounts on the shock body instead of the control arm.

Look for solid 27mm+ swaybars with poly bushings.

When purchasing new suspension, it is preferable to order M3 suspension as they have the tabs for the sway bar mount on the shock body. Additionally, adjustable or longer sway bar links would be required.

Steering Racks

The E36 is notorious for its slow steering response, this is due to the slow ratio of the factory steering racks.

Purple Tag Rack

Found in E46s the Purple Tag steering rack is a bolt-on upgrade for all E36s. The steering ratio is a linear 3.0 turns lock to lock - a substantial increase over the factory non linear 3.2 turns lock to lock. Stock E46 inner tie rods can be used with the original E36 outer tie rods.

Z3 Rack

Found in Z3s, the ‘silver tag’ rack is one of the fastest steering racks compatible with the E36 chassis. It has 2.7 turns lock to lock and also linear. These are quite hard to find and carry a price premium.

Brakes

E46 330i Front/E46 328i Rear

An affordable and straight forward bolt-on upgrade are the front calipers from an E46 330i and the rear from a E46 328i. The caliper, bracket and rotors must be swapped. The brake line threads are the same. You may need to bend the E36 dust shields inboard to fit the rotor.

Diameter: 325mm
Thickness: 25mm

Unfortunately the 330i rear calipers are not compatible due to the hand brake assembly. The easiest alternative is to use E46 328i rear calipers. Like the front, the caliper, bracket and rotors must be swapped. Brake line threads are the same, dust shields may need bending.

Diameter: 294mm
Thickness: 19mm

The E46 330i brakes are larger in diameter (however thinnger) than E36 M3 brakes and are much more affordable.

Engine Mounts

The recommended mounts are E46 M3 engine mounts. Anything stiffer such as poly mounts will introduce NVH inside the cabin. With 75A and stiffer poly mounts vibrations from the engine are transmitted inside the cabin. Poly/solid mounts are only recommended if your car only sees the track.

Gearbox Mounts

The recommended mounts are E46 M3 gearbox mounts. Like the engine mounts anything stiffer will introduce noticeable vibration and gear whine inside the cabin. Solid or poly gearbox mounts add more NVH than the equivalent engine mounts. Only consider poly/solid mounts if your car sees the track more than the street.

Shifter Mounts

There are two rubber mounts connected to the shifter carrier - one located on the top-rear of the gearbox and one located on the chassis. Both are recommended to be upgraded to poly to reduce shifter play. The biggest source for shifter play however is from the shifter joint located on the gearbox.

Front

Front Control Arm (FCAB/Lollypop)

The OEM rubber bushings should be replaced with poly bushings, these do not add any perceivable NVH and increases steering feel and directness. The front alignment will also stay consistent under heavy loads. For track focused cars monoball bushings are recommended.

Sway Bar Bushings

The stock E36 swaybars are undersized from factory and should be upgraded. As the bushings are based on sway bar thickness. Upgraded sway bars typically come with poly bushes - a no brainer to simply upgrade the sway bar instead of buying poly bushes alone.

Steering Linkage Coupler

There is a rubber coupler within the steering linkage between the steering rack and the steering wheel. Overtime the rubber becomes soft, this makes alignments a pain as a reliable center point cannot be found. On center feel is also missing with a worn coupler. The go to upgrade is to drill out the coupler and replace it with a solid piece.