noXor

I am wondering if anyone can shed some light on this for me. I got my car dyno'd the other day to see the difference in power from the stock map to the Velos tune map. My car put out 355RWHP and 320RWTQ with the stock map on the dyno dynamics dyno I was on. This seemed fairly low to me as my Evo I had before put out 260AWHP stock when it was listed at 291bhp. I am in Calgary, Alberta and it is about a 3600ft elevation. Would the elevation have a bigger effect on a NA engine as compared to a turbocharged engine? My friend had his 2012 GTR dyno'd there too and it put out 480AWHP stock when it is listed at 530bhp.

Is this common to have a C63 w/ PP to dyno way lower than it is listed at? My car is listed at 481hp and 443tq so it saw a 126HP (26% loss) and a 123TQ (28% loss).

If anyone can shed some light on this that would be great.

GeorgeSmooth

It's normal to loose power the higher up you go. At 5600ft where I am the 63 averages 300-310whp.
Most modern turbo car compensate for barometric loss so the make decent power at altitude.

rage2

In Calgary here too. For NA cars, we lose ~19% power and torque across the board due to the thinner air. For turbo cars (with big enough turbos that limit boost on absolute pressure), you won't lose much power at peak, but will lose torque and power on the low end as it takes more revs to spool. My CBS makes 415hp at the flywheel here (rated 517hp), while my CLS550 V8 TT puts out the full rated 400hp here, and both cars are close in a straight line. I'll need to be at sea level to have my BS kill the CLS.

With respect to the dyno, most shops will run a correction to show what your car would make at sea level. If your C63 is putting out 355whp, the dyno operator didn't apply the correction value. For reference, assuming you dyno'd on a perfect reference weather day, your car put out an equivalent of 422whp at sea level.

miguex

indeed for NA engines for high altitude losing power between 10% to 20%. Every dyno shows different numbers what you need is to run a dyno with linked rolls (no Christmas lights on the dash). For ecu tuning you need a custom tune that matches the altitude and Density of air. After tuning a na engine with lightly mods such intake and free flow exhaust, the ecu needs at least 4-7 fuel tanks to adapt the maximum performance unlike for turbo engine that adapts quickly cuz of boost turbo mapping (losing about 1% to 4% of power in altitude like Calgary).
a BMW 335i modded can kill to a C63 easily on a drag in Calgary.

if you use this calculator: http://www.dragtimes.com/da-density-...e=Calculate+DA you will understand better.

charliekay

Elevation, Humidity and more affect the dyno reading.

To give you an example by how much, I have based your 355whp reading on the current temp in Calgary.

Using:

Elevation of 3600ft
Temp of 18 deg. Celcius
Altimeter of 29.94Hg
Humidity of 74%

You get relative horsepower of 87.6% which means you 355whp converts to ~405whp.

All done using this calc - http://wahiduddin.net/calc/calc_hp.htm

The calculator miguex posted the link to on dragtimes helps work out the 1/4 time and ET based on the same weather variables.

khmergod

Houston is awesome for NA engines. ~40ft above sea level@~1700 DA. Only weakness it's warm/hot most of the year.