Another X5M test that shows BMW really sandbagged the hp rating.

[onfireX5]

Logged the Mass Airflow of a 50i and my X5M. Typically we see 9.50 to 10.0 horsepower per Lb of Mass Airflow on the dyno for V8 TT engines....especially LSx builds.

50i maxed at 44.8 lbs/minute x 9.50 = 425.6 hp. Close to the 445 BMW rating.

X5M maxed at 68.6 lbs/minute X 9.50 = 651.7 hp. Sandbag city vs the 567 rating. No wonder the M outruns the Porsche Cayenne and Mercedes GLE even though they are "rated" higher.

Looked at the Dinan HP graphs attached below and they are very close to our Mass Airflow calcs. M's are bad dudes.

[sbash]

So this is not a dyno reading, but instead a measurement of inflow that along with fuel/air ratio estimates the HP and torque or is this done in conjunction with a dyno?

If with a dyno, what was the rear wheel HP/TQ figures or short of that, what percent of loss was figured for drivetrain in order to establish the crank HP?

Thanks!

[onfireX5]

The 9.5 to 10 lbs/min was developed from 100's of hours with Supercharged and Turbocharged v8's on different chassis dyno's.

The Above charts are from Dinan. They are calculated engine HP numbers in the charts based on a roughly 12.5% factor off their Dyna Pack chassis dyno. Even their numbers tie back to our airflow numbers for engine hp. For example, their peak "engine HP" for a stock X5m shows 647 engine hp. That means their chassis dyno peaked around 566rwhp. A DynoJet might show around 530rwhp. Mustang will be lower...all use different factors...

[onfireX5]

Here's a DynoJet rear wheel dyno of a stock X5m that IND posted a while back.

[jcfay]

Goddang, this car's a monster...

[sbash]

Thanks OnFire