Stock N54 vs. PPK1 - Here's some actual acceleration data...

[wjk_glynn]

Last October I got a PPK1 for a good deal ($500 for parts and installation).

Rather than do before-and-after dyno testing as many have done, I’ve tried to capture actual acceleration differences between the stock N54 setup, and then with PPK1 installed.

The acceleration runs were all rolling starts in a single gear from low in the rev-range to near the rev-limit:

• No standing starts as I don’t trust my ability to have consistent launch repeatability
• No hard/speed shifting for reasons of mechanical sympathy

The quick summary is:



When I had the PPK1 installed I noticed a modest bump in grunt, but nothing huge. Others have reported driveability improvements, but I never really noticed any issues when stock.

From the results above, it seems gains don't begin to emerge until about 2,500 to 3,000 rpm, through BMW says the full increased torque is available from 1,500 rpm.

Speaking of which, BMW claims the following performance improvements with N54/N55 PPK:

• 0-60 mph: 0.2 sec
• 50-75 mph: 0.5 sec

The 0.5 sec improvement I observed from 70-100 mph is roughly in line with BMW’s claims. I also list some instrumented road test results of the N54 135i and N55 135is. Excluding the 70 mph time of the 135is from Car and Driver, you broadly see the same gains (give or take).

So I think it’s fair to say that the PPK1 “does what it says on the tin…”


TEST METHOD

I don’t have access to sophisticated timing equipment (e.g. RaceLogic VBOX). My crude technique was to point a GoPro camera (720p, 30 fps) at my P3 Gauge and measure time using timestamps in the resulting video clips.



I wouldn’t trust the absolute measurements from that method, but I think it’s sufficient for relative measurements of the before-and-after runs.

The attached PDF has the "raw" data. I only used data from runs with DTC set to OFF in the results above.

Karl.

PS: I'm fortunate enough to have intermittent access to a private expanse of smooth concrete where the tests could be done safely. Here's the test procedure/notes in a bit more detail:

Maintenance items up to date

• Fresh/clean air filter and sparkplugs
• Correct suspension alignment (e.g. excessive toe will cause higher rolling resistance)
• Adjust the cold tire pressures of the stock RE050A tires to factory recommended specs (i.e. 36-psi)
• Etc.

Get the car to its curb weight

• Remove extraneous items from the car (e.g. dump the dead body in the trunk…)
• Check that all fluids are topped up (e.g. engine oil, coolant, windshield washer fluid)
• Fill the gas tank (Chevron 91-octane used on these runs)

Recommendations regarding a location to perform the runs

• Do not perform on public roads, obey all posted speed-limits and other road signs
• The location should be PRIVATE and have RESTRICED-ACCESS, to ensure the safety of participants and bystanders
• It should have excellent sightlines
• The location should be straight and flat, at least a ½ to 1 mile in length for safe acceleration and braking zones
• It should have a smooth surface with good traction (i.e. tarmac or concrete), no excessive bumps or dips
• Runs should be made in both directions and averaged to cancel out effects such as gradient or head/tail winds

Measure time-to-speed of the runs

• Adjust the cold tire pressures of the stock RE050A tires to 36-psi
• Set a P3Cars to display speed, which is the raw uncorrected speed from the Vehicle Speed Sensor (VSS)
• Record the runs using a GoPro 2 Camera set to 720p, 30 fps, wide view, spot metering on
• Import video from the runs into a software package that can show timestamps of individual frames (e.g. Apple iMovie or Windows Live Movie Maker)
• Record the frame timestamp as the P3Cars display begins to transition to each speed of interest (e.g. for 30 mph, the frame when the display starts to transition from 29 mph to 30 mph)
• Calculate the time-to-speed results from the timestamps (a spreadsheet is easiest)

Performing a run

• Set the traction control and HVAC to the desired settings
• Start recording the P3Car gauge speed output using the GoPro camera
• Start rolling forward at 600-700 rpm (approx. 6 mph in 2nd, or 9 mph in 3rd) - the speed should be stable for a few seconds
• Then floor the accelerator and run all the way to the rev-limit (approx 70 mph in 2nd, or 105 mph in 3rd)
• Repeat the runs a number of times in both directions to cancel out effects such as gradient or head/tail winds

[foghat]

Great post. That is a pretty significant bump in the 20-100 time.

[Suds]

Well written, very methodical and a good post.
Go have a beer, cheers!

[wjk_glynn]

Originally Posted by Suds

...Go have a beer, cheers!

There's a margarita in my hand, and burgers on the grill

Karl.