Quote:
Originally Posted by tdizzle
Nice. The midrange torque is a beast. I honestly can't really tell much of an improvement above 6k rpm or 0-60 times but getting on it at 3k pushes you back in your seat for sure.
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According to the dyno's what you feel is what you should feel.
The N54 and N55 don't open up on the top end with a tune.
The biggest improvement is the mid range, and the improvement is huge.
On the dyno the torque curve changes nicely with a good swell in low to mid rpm torque.
There is a good improvement in HP, but the actual curve doesn't change.
You'll note that the curve shows a nice HP gain, but it follows the same path as the curve is not altered and HP drops at the same RPM as stock.
So once you feel the huge swell in torque the drop from around 5000 to 5500 blunts the actual HP increase that is there.
Still, for best accel don't upshift too quickly, let the HP do it's thing.
Shifting early around 5500 may put you back into the meat of the big torque wave, and it may feel stronger, you're losing out on the increased HP that continues to accelerate the car.
I would prefer a tune that elongates the torque curve and moves the upper RPM curve so that we have greater torque for a longer rpm.
Diesel like torque is great for that low rpm, low MPH WOW, but I like a better top end.
Maybe that's not achievable with these new BMW turbo engines, or maybe the tuners are doing this to show huge torque numbers that result in greater sales. I don't know, as I haven't yet seen a tune that moves the curve higher up the rev band.
The tunes for Audi's 3.0T in the S4 actually change the HP curve by really opening up the top end, but that is a V6 supercharged engine, so not truly comparable. But, it's tuning ability is also amazing as is the N20, N54, N55 just in a different way.