Quote:
Originally Posted by soapman72
So, would you say that the power increase is definitely noticeable? Any chance you've dynoed your X1 or measured 0-60 times?
I agree that the cost seems very reasonable, but only if there is a real improvement.....
Any down side? Drivability or fuel economy while cruising normally?
Thanks for your input. I really appreciate the feedback.
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Power increase is definitely noticeable when you give it gas. Boost is increased by up to 3 PSI from stock and comes on much quicker (you can even increase to 4 PSI if you have 93 octane gas and you get the USB cable).
When driving conservatively, I have not noticed any change in drive-ability or gas mileage. This is how the car should have come stock, but I'm sure BMW has the EPA and other things to worry about. I will say that the transmission programming in DS mode is not ideal for the tune as at times it will rev higher than necessary before shifting. I generally leave it in D and paddle shift when needed. Most of the time D is just fine as the increased torque pays dividends.
Performance is just barely below a stock N55 35i IMO (I'm coming from a stock N54 335i and I'm happy), but you need to rev a bit higher than you would on the I6 for comparable power. I judge this solely by butt dyno. When passing on the freeway I hit 100 MPH quite quickly (have to get around car pool lane slowpokes in a short interval). 5th gear seems to be the sweet spot when passing on the freeway (was 3rd or 4th on the N54 w/6AT).
I'm averaging ~24MPG combined, same as I did before adding the tune. I can average 32MPG on the highway if I keep it at 65MPH and don't pass, 30 MPG at 75MPH. City driving however I only get about 18.5 MPG. A lot of traffic lights around here.