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      12-13-2013, 10:23 AM   #50
gee-m-w
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Quote:
Originally Posted by CanAutM3 View Post
I would add that 450-460 WITHOUT a tune is very likely .

As has been discussed multiple times in various other threads, the S55 at 431hp is most likely underated by 20-30hp, if not more. This has been demonstrated with most other FI BMW engines.

I am looking forward to see some real world data (acceleration runs/dynos) that will indicate the actual power that the S55 generates.
I agree with this 100%. My supercharged S4 is rated for 333 HP. Most tuners baseline it at around 310 at the wheels, implying 360 HP from the factory. A stage 1 tune with ECU removal gets you 420 HP and 390 ft/lb. It mostly plays with the valve timing angle and it is less aggressive with bleeding off boost at the top end.

The problem is the area under the curve doesn't change drastically. The tune is only useful from about 5200 RPM to 6800 RPM. Redline is 7000 but in practice it goes to 7200. It makes a big difference pulling down the front straight in 4th gear at 120 MPH. It only feels a little bit looser revving on the street.

I would get the Dinan tune but I don't expect it will be life changing. Just an enhancement like the completion package.
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