Engine difference between X5 and X5M

[poloka]

Is there really any differences between the V8 engines other than turbo pressure?

[TahoeM3]

Yes. Boost is a big factor, but there are other differences. There have been a number of posts on this, but to summarize: the intake is completely different allowing improved airflow at the top end, different turbos (twin scroll and slightly larger on the M), different spark plugs and engine management, some exhaust differences, and likely different internals with lower mass (and a resulting lower compression ratio allowing higher boost).

[el_guru]

"different internals with lower mass (and a resulting lower compression ratio allowing higher boost)" .......???

As an Engineer of some 32 years this is a new 'concept' of the engines internal mass affecting compression ratio.??
Do you mean lower compression ratio pistons per chance.?

[TahoeM3]

Sorry, I thought it was self-explanatory that the lower compression ratio was from the pistons. The parenthetical comment was was supposed to add on to the features of different internals, not lower mass. Let me re-write it so that is easier for the engineers to understand...

Different internals FOR less rotational mass (and resulting lower compression ratio ((due to the pistons (((which are also lighter))), which allows higher boost to be used safely))). And the pistons are lighter. And different.

[poloka]

Thanks guys! I'm new to the forums. I'm just used to old fashion American muscle. The X5M is a new endeavor for me.

[DDP2011X5M]

Originally Posted by poloka

Thanks guys! I'm new to the forums. I'm just used to old fashion American muscle. The X5M is a new endeavor for me.

I had a Shelby GT500 convertible; 540 HP, but the X5M is in a totally different league