M52 manifold swap

[Rha]

You're right about the potential costs. However, as per my post, I'm planning on a complete new part - the aluminium part.
The operation of the mechanism will still be driven by the same electronics part of the TB, so no new programming will be required. All that changes in effect is the size of the aluminium side of the TB and that it will be able to bolt directly to the M54 manifold.
This together with my intention to replace the intake camshaft with one from the M54 3.0. it will bring the intake system up to par with the 3.0 intake system. The only difference will then be the overall 200cc smaller engine capacity - which equates to just 33.33333 cc per cylinder less than the 3.0 motor. I imagine the final improvement in HP will be as near as dammit to the 3.0 HP output.
There is only one final difference other than the 200cc - that is, the 3.0 has pistons with shorter sleeves which obviously reduces friction inside the cylinder, but changing pistons requires a complete engine strip down which really isn't worth the effort for 2 or 3 HP. I expect an overall gain should be in the region of 25 - 30 HP to around 220 'ish from the official spec of 193 HP for the TU 2.8. At 220 HP, it would be just 5 HP shy of the 3.0 OEM spec of 225 HP. Perhaps with a re-map / chip tune etc, it may make as much or even more. Certainly in the acceleration stakes it should out perform the 3.0 given that the 2.8 TU has a shorter stroke than the 3.0 and will rev up a little quicker. Once all the above is in place, I will look at the option of larger injectors to compensate the greater air intake, but the OEM injectors could be adequate given that a re-map / tune could be done so that the OEM injectors are opened fractionally longer than currently in the OEM DME programme.

Hear what your saying but seems to me your making extra work for yourself when the gains for just the manifold with OEM TB plus a live remap is getting within these numbers already, for the extra 5-7 bhp the big bore TB will give you might in some owners minds be worth it. It’s the torque figures and curve which will increase the most as I see it, so again they’re already there with the OEM TB on this conversion. Those extra 200cc that’s available on the 3.0 will be hard to better as the volume for air fuel available on the 3.0 is bigger and there’s an old old saying amongst the tuning fraternity that there’s no substitute for CC’s when your trying to make an engine go better. In this case I’d say good advice, after all BMW upped the CCs on both the 3.0 and the “M” when they already had the 2.8, must tell us something. If I had the funds when doing my 2.8 I would have bolted on a supercharger after upgrading the braking system, but after 11yrs with it I craved for something different and hoped one of my family would take on the 2.8 but alas my son went back to motorcycles. Your enthusiasm to get this engine up or beyond the 3.0 is bewildering to say the least but I do understand the love you have for the good old 2.8. If I never get another BMW I’ll be thankful that I’ve had 2.8tu and tried my hardest to make it better, loved this engine to bits untill someone gave me the opportunity to try a N52k e86 (coupe) then I fell in love all over again. Best of luck, will follow your progress and hope you get something out of it. Get on and do something with your ideas then you’ll have something in real terms to tell us. Good luck.

RHA,Roy.