Thread: S55 vs. S65
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      12-14-2013, 08:49 PM   #20
Thurman Murch

Drives: M3
Join Date: Feb 2013
Location: Island in the sun

iTrader: (0)

I own both a tuned S65 and tuned N55...

The S65 is prone to conrod problems... Even Gintani pointed this out

Some limiting factors of the S55/F8X:
Increased Cd over E9XM (solvable)
Reduced air intake volume (solvable)
Lack of proper FMIC

Some positives:
Forged crankshaft
Closed crankcase
Direct intercooling/shorter path (water cooler congests air flow?)
Not that complex-easy to fit bigger turbos
Better turbo bearings and cooling

I think it shouldn't be a problem to increase boost and timing and CR... to what degree remains to be seen

I think it's easier to track the S65 because of the throttle dynamics - it's easier to modulate power... The N54T cars didn't have the right brakes and downforce to contain the power

The one thing I notice is the N55 has more power on top than top then bottom...but in comparing to my old N54T and S63 and merging all my thoughts... I think the F8X will fly up to 130mph not sure if it has the up top lungs of the S65 though but could be fixed with more air but this could be a taper of boost for the 155 limiter

Is there a way to modify the accelerator pedal to allow valvetronic to open faster?