Bimmer32

If M5 4.4 liter can churn out 560 HP, then how come MB 5.5 with 18.9 psi can only churn out 550HP? Both are DI engines. How much boost is the M5 running? Certainly a displacement different of a liter should make a lot more potential output. Afterall, a 2012 CLS63 has been cocked by C/D mag. at 3.8 seconds to 60 mph and 12.0 seconds to quarter mile. These two car weight nearly the same. Either MB is underrating their outputs or BMW is overboosting their engines, or both.

Any engine experts could enlighten me, please?

m630

the S63tu (new M5/M6 engine)is rated at 22 psi, cant speak to why the MB is rated as it is, but the better question is, how can Porsche get 620hp out of just 3.6l! Those are the stats for the new GT2 and serve as the benchmark for turbo technology, imho....

Bimmer32

How much boost can these engines take to have reliability like the NAs? Or is it that the owner of a overboosted SOL not long after the warranty runs out? I'm leery of today's market where things are made to just last until the warranty runs out. :thumbsdown:

m630

this has been a heavily debated subject, i dont think there is any way that a turbo engine can last as long as a NA, all other things equal. There will be many problems encountered when the new Ms come out with their all turbo engines and people try to mod them. Overboost will be problem to some I suspect, and they will surely be SOL even if they have a warranty if its shown that a remap was done and can be pointed to as a contributor to the "meltdown". It will be interesting to see if the Ms suffer some of the same issues that the 3er turbos suffered on hot track days and becoming limp...Cooling is the biggest issue of course, and though bmw are great engine builders, their forte is not turbo tech like it may be to Porsche, so I have many concerns about the early models and how this all works out. Im no fan to any turbos, btw, but that leaves few choices if one wants to stay with the roundel as they've all but abandonded NA

SilberGrauE60

I think Porsche uses variable geometry vanes in the GT2 turbos. That, and Porsche engineers are geniuses!

Bimmer32

Well, the Nissan dudes are not far behind.

Isaiah_Charles

+1

Moopai

BMW is not new to developing turbo engines, they had turbo engines since the 60s in the 80s on many models including the 6 & 7 series. I'm sure they know what they are doing and they took the heating problems into consideration!

Not sure if you've seen this article, take a read according to BMW this is the best M5 engine EVER!

http://f10.5post.com/forums/showthread.php?t=588858

As to turbo engines lasting, in 1987 I bought Volvo 740 Turbo (4 cylinder), I drove that car pretty hard most of the time and end up putting 350k/km before I retired the car and even then, I did not retire it because of engine problems, I had a transmission problem and did not want to rebuild. I bet if it was not for the transmission I would've drove that car to 500k/km.

My two cents!

m630

Well Im sure we did not expect BMW to say that the new engine was WORSE than the outgoing model, now would we???

As a matter of fact, the 6er and 7er never had turbos in the past at any time for petrol engines, so not sure where you were going. But, if the point was, BMW has used turbo in the past, yes surely that is true, they were leaders in the 60s and 70s, but then they stopped, developed the M formula of high revving - naturally aspired engines, and have built them soley as their performance engines for the past 30+ years. They have not made the investments into developing high performance turbo engines until the past 3-5 years max. They have no business coming to market with a complete shift in philosophy without proving to themselves they can meet their own standards, let alone those of its core customers. They are NOT Porsche and cant compete with the P cars in this realm. Porsche has been in the market for more than 30 years developing performance turbos, so I have alot more faith and trust in their ability vs BMW.