m60 cam timing improvement

[iamsam]

If this really works, then the next logical question is: Can you do this to an M60B44 hybrid, and how much power might it end up with, providing the factory ecu can be tuned accordingly?

[senorcarey]

It was my understanding that all of the new timing blocks take this into consideration? In for info...
I also believe that this was the timing that Alpina used and BMW changed over to later.

And wow, 300whp? Was this with a retune on the stock DME or a stand alone?

[nrubenstein]

Before/After dynos please. :)

[JGood]

Interesting info I stumbled across:

http://www.bimmerboard.com/forums/posts/775197

Attempt this upgrade entirely at your own risk. If you adjust the cams the wrong way the pistons will smash the valves.

Below is my own experience, yours may be totally different.

The cam setup in the M60B30/40 are fairly complex to set, and you need prior knowlege of how everything works as well as the ability to fabricate an acceptable degree wheel for this particular setup. (I printed one of the internet and glued it to cardboard backing)

To cut a very long story short, I just did quite a bit of research into camshaft timing, and the effects it can have. I then proceded to "experiment" with the 540, trying out different combinations of inlet Vs. Exhaust camshaft timing.

The M60B40 has fairly agressive cam timimg with quite long durations (valve opening times) and 28 degrees of overlap between the exhaust and inlet, and it is optimised for mid range power. The intake is fairly advanced and the exhaust retarded compared to the later M62B44 and M62B44TU engines. A lot of overlap improves midrange due to scavenging but reduces both idle quality and high rpm power.

I decided to sacrifice a bit of midrange for improved quality idle and low end torque and topend rev power by retarding the intake 14 (crank) degrees and advancing the exhaust 6 (crank degrees)

The result was really awsome , the midrange power dropped very little, the lumpy idle improved to perfection and it revs to the redline very willingly now, producing heaps more power from 4000rpm.

I still cannot beleive the improvement in behavior of the engine with the modified cam timing. This was the best thing I have ever done to this car. It is now much more refined. I think BMW were a litte over enthusiastic when they did this design, giving it too much overlap and emphasis on mid range power as opposed to driveability.

There is no question the low end and topend power improved significantly through this change, and interestingly the valve timing is now almost identical to the M62B44TU engine with a longer exhaust duration

M60B40 Standard timing

IO/IC 14 BTDC / 52 ABDC
EO/EC 48 BBDC / 14 ATDC

Inlet, Exhaust Overlap is 28.00 degrees

Intake Duration 246.00 degrees.

Exhaust Duration 242.00 degrees.

Inlet Cam Centerline 109.00 degrees ATDC.

Exhaust cam Centerline 107.00 degrees BTDC

__________________________________________________ _________

M60B40 modified cam timing

NOW IO/IC 0 BTDC / 66 ABDC
NOW EO/EC 54 BBDC / 8 ATDC

Inlet, Exhaust Overlap is 9.00 degrees

Intake Duration 246.00 degrees.

Exhaust Duration 242.00 degrees.

Inlet Cam Centerline 122.00 degrees ATDC.

Exhaust cam Centerline 113.00 degrees BTDC

The reason I brought this up is because there is a guy overseas with an m60b40 e30 putting out 297whp after doing the timing upgrade and a retune, on an otherwise stock m60b40. His trap speed in the 1/4 mile is 5+mph faster then mine, which is pretty significant. I may attempt this over the winter, figured I'd share in case anyone else is interested.