M60/M62 tuning: An intake manifold upgrade

The factory has provided at least four different intake manifolds for both M60 and M62 engines. If you have studied anything about airflow, its obvious to select the manifold with the best possible velocity stacks for optimizing the engine performance. Velocity stacks – also called as trumpets or horns – can increase maximum airflow approx 2-4 %, but the benefit may be even higher in mid-range torque due to intake resonance. The science behind trumpets is their ability to smooth out incoming air, maximizing airflow to intake runners.

Source: Wikipedia, Velocity stack detail.gif, credit for user Motorhead.
Picture published under GNU Free Documentation License.

Disclaimer: tuning a naturally aspirated engine is as strong as its weakest link. Cams, valves, cylinder head, headers, collector – and most definitely “the hot air intake system” may be hindering down the power and torque in your build. Thus, the benefit of changing the manifold depends on both level and quality of modifications you have made for your car.

Different intake manifold versions:

M60B30 and M62B35 – These are with smaller runners, so we will forget these.

M60B40 model year 1992 – Large runners with the best velocity stacks

M62B44 Nonvanos – Large runners with minor bends at intake runners

B62B44 Vanos – Version with small runners, so we will forget these too

The best option: Ultra rare M60B40 model year 1992 manifold with proper velocity stacks for maximum air flow.
The second best option: M62B44 Nonvanos intake. Note the pipe in the middle for distributing blowby gasses more evenly to all cylinders. You can read more information about Crankcase ventilation design fault from the other blog article.

There are four hypothesis, why BMW quit developing 1992 version of the manifold so soon:

  1. Factory may have wanted the best possible features and grunt for intimidating the press, when the new M60 V8 engine was introduced.
  2. Guys at the department of finance wanted to cut some costs. We know how expensive these engines are to build. Take for example M60 timing gear with duplex chain. The level of design and robustness is closer to a tank.
  3. Velocity stacks are prone to get loose. Simply put – why bother, if you can cope without them, and avoid any warranty issues.
  4. E34 540i may have been too close in terms of performance to E34 M5. Please check the youtube video about the matter.

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