So I was curious how the new f10 did as far as putting down power on a dyno and from the few dynos out there it looks really solid putting down 370ish hp at the wheels which puts it above its 400 engine hp or at the very least definetly no lower than that.

An m3 puts down around 350 which is spot on for a 15 percent drivetrain loss of 414hp.

The 550i e60 however rated at 360 at the engine puts out consistently 280ish horsepower on many dyno's out there. A 15 percent loss should put it closer to 305hp at the wheels.

The other evidence is the 545 dynos very similar to the 550 and from peoples experiences and 0-60 runs, teh 545 is the same as the 550.

My guess is that bmw overrated the 550 a bit to sell cars and probably slightly underrated the 545.

None of these are x-drive or have anything that would change the drive train loss. All the ones I saw were auto's as well.

Nothing bad about the 550 but just notice it dynos the lowest of all modern bmws in regards to how much engine hp its supposedly putting out?

I think its putting out closer to 340hp which would make sense if 280 is at the wheels

So the F10 550engine is very underrated? oooo so who needs the F10 M5 then? LoL

Hey, I just bought a 2008 BMW 550i earlier this week.

I have been researching BMW motors for a long while over the years, in my opinion, I'll spare you the rationale, is that that 545i has approximately 340HP, it was underrated to begin with. The 550i actually has 360HP, thats an SAE certified number I believe, they didn't bother underrating the engine again because the twin turbo 6 cylinder was released. The 8 cylinder needed to be differentiated in power from that engine.

The N54 engine found in the 535i actually has approximately 320HP and 330 FTLBS of torque if you ever wondered, not the 300/300 advertised. The new N55 motor has approximately 317HP and 335 FTLBS.

All great motors IMO! :thumbsup:

Seemingly with that entire paragraph you ignored my point which is if it truly has 360hp there is NO way it should be dynoing with 280-290hp at the wheels. It should be closer to 305-310 at the wheels. You can say dynos are all different and inaccurate but if you look at every other modern bmw engine-n54, s65, s85, the new TT v8-non-m etc. All completely dyno at numbers consistent with a 15 percent drivetrain loss. The 550e60 is the only one that dyno's much lower. Almost 20-25 percent loss from engine to wheels v. 15 for every other bmw.

It doesnt really matter as it was the top model car and not like you could choose between a 545 v. a 550 new so they are not competitors but I am thinking the 550 was not putting out as much as bmw initially thought but in order to keep it at a 8k premium over the 535 it had to overrate it to 360

Well, I guess we can use a real world comparison to determine the horsepower figures. The 550i can accelerate to 60mph in 5.0 seconds on average in magazine tests (Motor Trend did it in 4.8 seconds). The 535i can accelerate to 60 mph in 5.2 seconds. Considering the 550i weights about 200lbs more than the 535i, and has 40 horsepower more (360 vs 320 like I suggested earlier), the 40 HP difference and additional 200lbs in weight would result in a 0.2 second difference in acceleration.

But to answer your question, ALL of BMWs turbocharged motors are underrated. :thumbsup:

Oops, the engine in the X5M and X6M are not underrated. lol

What is your deal? What do you not get about the 550i putting out less than what is supposed to be put out by the typical 15percent drivetrain loss which every other bmw follows (including the NA bimmers such as n52 and s65 and s85 engines)

This is not a personal opinion but rather facts about the dyno numbers it lays down. Compariing 0-60 times is a complete farse because gearing is an enormous factor in that and 2 cars have totally different gearing for their respective engines.

If you need it more simpl-how do you explain the 550 putting down 280ish HP on a dyno? if it has 360 engine hp

haha, ok, I thought you were looking for someone to rationalize the numbers out for you. I mean, also theres a group of people out there that believe the 08 and after 550i's have more power than the 06 and 07s. Explain that also? I have no idea just trying to make sense of things here.

By the way, the gearing is exactly the same on both the manual and automatic transmissions in the 535/550i: 4.06/2.40/1.58/1.19/1.00/0.87 for the manual, 4.17/2.34/1.52/1.14/0.87/0.69 for the automatics, they should be comparable, no?

Difference is most likely due to the type of dyno used, settings..etc..

Case in point, an M5 with 500hp crank hp dynos around 380-390whp on most Dyno Dynamics but will put up around 420whp on Dynojets.