Burger Motorsports N26 tune
As an attempt to address the tip-in/throttle hesitation issue, and to add a little more liveliness to spirited little 4cyl engine, I decided to try out the Burger Motorsports (BMS) tune. The little unit comes with male and female adapters that are used to intercept (3) signals between the ECU and engine. The install took me about 45 minutes because the directions are written for the 328i N20 engine, and there are a few differences with our X1.
First of all, after disconnecting the battery in the trunk, the directions call for removing the engine cover and locating a solenoid on the passenger side of the engine. No need for this, as our car didn't have the solenoid, so leave the engine cover alone. This is also nice because the three sensors that you do intercept live in the driver's side of the car, so no need to route the BS wiring harness through the engine compartment. The next three steps involve locating the three sensors that are intercepted (green arrows in the pic), disconnecting them and connecting the male and female ends to the male and female ends of the appropriate wires in the harness, and then routing the wiring (dashed red in pic) through the weatherstripping and into the brake-booster compartment where the plastic unit is stashed (red box in pic). The install instructions offer more detailed pictures to make sure you locate the proper sensors, but as you can see, all three sensors lie in plain view, and installation is really just a matter of locating the sensors and disconnecting and reconnecting the the male and female ends.... ridiculously easy.
***A word of caution - leave the trunk hatch open during the install! The hatch release mechanism requires the battery to open! After dropping the back seats and crawling through to reconnect the battery I was ready for a test drive.
Driving impressions: the car started right up, no check engine lights, very smooth. I started out in D and was immediately disappointed that the throttle tip-in remained. However, the car did appear to pull harder with moderate throttle in D mode. Switching into DS however was a pleasant experience, as the throttle hesitation tip-in was about 50% eliminated. What was great though was the immediate burst of power with only semi-aggressive throttle depression - WOW! The car screams through the powerband and is really a kick in the pants! The butt-dyno feels like the 40-ish HP gains BMS advertises, which is a substantial bang for the buck. We live in a relatively quiet neighborhood and I didn't want to go rocketing too much around, but it was enough to leave me satisfied with the ~$400 investment. It would be nice though if the tip-in was also addressed in D mode, because in DS the shifts come at higher RPMs, which is not always great for everyday driving. Unless an update comes out, looks like I'll have to wait for BMW to address this issue.
I'll continue to post more as we drive the car more - it is really my wife's car, so probably won't get a chance to stretch it's new legs until next weekend.
Mineral Grey Metallic X1 s28i M-Sport
BurgerMotorSports Stage 1 tune