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Terry @ BMS Terry @ BMS is offline
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Default 328i BMS Stage1 vs. "BRAND X" Dyno Testing - 03-25-2015, 07:08 PM

Hey guys,

We've had customers emailing in asking about how our tunes compare with this brand or that brand, so we've decided to do a little in house testing just so we know where we stand. For this first comparison we wanted to see how our N20 Stage1 tune stacks up against other similar non-CANbus tunes.

To try to keep this comparison somewhat professional we're going to obscure the name of the tune we compared with and instead just refer to it as BRAND X.

Test vehicle: 2013 328i, automatic transmission, 100% stock, 38k miles, 93 octane fuel.


BMS Stage 1

This is the newer universal version of our Stage 1 system that has been shipping for the last six months or so.

This box has a 64mhz processor and four 10-bit DAC outputs, compared to the original system which was 8mhz with four 10-bit PWM outputs. Although technically superior there is no real change to the tuning end as the sample rate of both systems exceeds the rate of change of the sensors modified. The reason for the faster processor and true DAC was to make this board more universal. e.g. we're using the same Stage1 board for our new MINI & Mercedes applications. It also just so happens the faster processor is more readily available and less expensive.

In addition to a revised board the new universal Stage1 system features a new wiring harness which has been greatly simplified. It has TMAP & MAP connections only. Making for a cleaner and easier install. The Stage1 can datalog boost and adjust the boost profile using a DATA cable. This test was done on the default map 1 setting. For the 328i it runs a +4psi setting by default.


This is a tune that is fairly new to the market, although versions of this tune with a different sticker on the box have been sold in Europe and Asia for several years. The harness has 4 connections. TMAP, MAP, RPM, and MAF. The RPM & MAF signals are completely pass through meaning they are being sampled only and not modified. TMAP & MAP are modified. There is a dial on the back of the box which you can use to adjust the aggressiveness of the boost profile. The manufacturer suggests using a setting of 6 or 7. During testing we ran it at each position and found setting 7 performed the best for this particular application. The manufacturer claims it's running at 64mhz although inside the box the circuit board has been potted with epoxy so it's not possible to verify. Again given the scope of the tuning involved with these non-CANbus analog signal tunes they could run at 1mhz and it wouldn't make a difference.

Testing procedure:

I started with BRAND X which was installed a day prior to arriving at the dyno and did around 15-20 runs under various configurations and settings, the best of which are shown in the chart. Then I removed the tune and did several stock runs, the best of which is shown. Finally I installed the BMS Stage1, did 5-6 runs, the best of which are shown. For both BRAND X and Stage1 I also did a short video of one of the pulls.


As expected, the tuners performed almost identically. The BRAND X tune had more of a tendency to cause boost oscillations in this particular pneumatic wastegate vehicle, although I expect it would not be the case on EWG vehicles. Pneumatic wastegate cars especially older ones are more prone to boost oscillations at higher midrange TMAP attenuation values. The air/fuel ratio was also a bit leaner overall with BRAND X also due to the slightly higher midrange TMAP attenuation values. But basically regardless of the setting used it performed on par with the BMS Stage1 tune using it's default settings. There is only so much a tune can do without CANbus & direct wastegate control so I can't say I'm surprised by the result.

Just as a subjective note I found the Stage1 tune to be much smoother under low and partial throttle operation. BRAND X has clearly been set to give a bit of a "wow" factor when tapping the gas pedal. You get much of the boost gain at a very low pedal input. I didn't care for it at all. But, since the Stage1 is programmable with the USB cable, we'll probably add a similar map to the device just so customers can experience that if so inclined.

Up next we'll be doing a similar test on a 320i (184hp) model.

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