I recently purchased a Dinantronics N26 tune for my 2014' 328 xDrive and this is my review of it.
I'll go over why I care about getting an engine tune to begin with, what are some of the different options available that I looked at, a relative performance comparison and my subjective opinion of Dinantronics after having it installed.
I suggest grabbing a cup of coffee if you're interested in reading it - there is a sizable chunk of text incoming.
1. Overview - I need more power... or do I?
I think it's fair to say that the definition of the 'best' engine tuning kit depends on what you hope to get out of it. Is it for street use? Racetrack? Drag strip? Do you plan to mod other parts of the drive train? Are you concerned with reliability, or maybe you just want peak performance? Is warranty & convenience of dealer maintenance a factor? How about being emission legal? You'll probably want to keep these in mind, as what I think is great for me might not at all be the best (or even good enough) for you.
In my case I was looking for 335-like performance with as little hassle (warranty, service issues etc.) as possible. I plan to keep the car for 7-8 years so I care about long-term reliability, and generally speaking I am willing to pay a premium for a quality product that matches the rest of the car.
I did not buy the 335 because when I did the drive test I did not find the 328 to be lacking, and 240HP seemed more than enough for a family car. However, after a few months of regular driving I came to regret that choice. The car seemed oddly underpowered and unresponsive at lower RPMs, and while Sport mode and revving the engine fixed that, it just didn't not feel all that great during daily use. The engine was adequate, certainly, but somehow not at the same level as the rest of the car. That is my reason for looking into tuning.
As it happens, the same week that I had scheduled to install the Dinantronics I took the car to service for squeaking door trims. I also told the SA that the car felt a little sluggish. I fully expected to get the standard 'there's nothing wrong with it' response.
Surprisingly, that was not the case. When I got the car back they said they duplicated the issue and it was fixed with a software update from BMW. I could not get any other details about what that update was about.
The car drove so much better after that fix. The throttle was immediately responsive and the car would pull forward on the lightest pedal tap. Before the fix there was this 0.5-1 second lag, where I could mash the throttle almost entirely and then quickly release it, and nothing would happen. No RPM change, no gear change. That is no longer the case now, every tap of the throttle has an immediate result.
I initially suspected that the dealer might have left my car in some power-limited transport mode to begin with, given the huge difference in perceived power and responsiveness after that update. However, I've heard that other people recently received a similar fix, so that's probably not the case.
That software fix effectively resolved the issue I had with the power delivery in my 328, but at that point I figured I might as well still try the tuning box and return it if I didn't feel it was worth the expense. I strongly suspected I couldn't be bother with it anymore though.
2. Tuning kit options
There is no shortage of choice, as long as you don't want an ECU tune (without drilling into the ECU, thank you very much).
There are three categories of piggyback tuning kits that I looked at; below are my notes on them.
1. BMS Stage 1 and JB4
Advantages:
- Low cost
- Simple install (Stage 1)
- Flexible, programmable platform (JB4)
- CANbus connection for JB4
- Good technical support (from what I can tell)
Disadvantages:
- Very low enclosure and harness quality
- Not waterproof or dust-proof
- Direct wire tapping required for CANbus
- Illegal in CA
- No drivetrain warranty
These are the low cost leaders - $380 and $530 respectively. It doesn't look like you can get more HP per dollar anywhere else. JB4 in particular provides a lot of flexibility as it connects to the CANbus and can read & clear engine codes.
The enclosure and harness quality is very poor. The product has the appearance of a school project made out of RadioShack clearance parts (are those re-purposed LPT and VGA ports?). There are multiple instances on this forum where people had issues with CELs and rough engine behavior from crumbling connectors, shorts, condensation or water ingress on the electronics. The BMS installation manual recommends using a zip-tied bag to protect against water, so you can get an idea of what you're getting into.
I can not speak for the quality of the algorithms on the software side, but the consideration they put into hardware is certainly not confidence inspiring.
I did not look into the performance data in any detail since I had no intention to hook-up such a low-grade harness to the ECU of a $55k+ car. I am an electrical engineer by trade so perhaps I am more harsh on this than other people might be.
Note that the product is not a rip-off. BMS is honest about what they sell, they do not mis-represent their tuning kits, and most importantly they pass the cost savings to you: no other tuning box comes close in price. It's up to you to decide if their product is what you want, and they back that up with an excellent 30-day return policy.
2. Active8, Racechip
Advantages
- Simple install
- Waterproof, dust-proof enclosure
- Automotive grade harness
- Programmable boost levels, high peak gains
Disadvantages
- More expensive
- No CANbus interface
- Illegal in CA
- No drivetrain warranty
These tuning boxes work similarly to the BMS Stage 1, but use high-grade enclosures, harnesses and connectors that are designed for automotive applications. They also advertise somewhat higher peak gains. Compared to BMS the cost doubles to approx. $700. There are many other manufacturers with similar products, but I think Active8 and Racechip are easier to purchase in US. Neither of them is emissions legal in CA.
Out of the two I have a slight preference for Active8, for two reasons.
First, Racechip is a generic tune that is sold for almost every brand of car out there, while Active8 is specific to BMW.
Second, the Active8 box pays more attention to detail. A custom mounting bracket is included, and a bridge cap is provided that can revert the car to stock settings without having to remove the wiring harness. Nice touches.
These boxes are good options if you are willing to take on the risk of covering any potential catastrophic engine issues out of your own pocket. BMW is likely to cop out on your warranty claim once they see that the engine was tuned (which is not unreasonable). The chance of that happening is likely quite small, but it is not zero even when running stock so that is something to consider.
3. Dinantronics
Advantages
- High quality harness and enclosure
- Clean installation (nearly invisible), connects directly to the ECU
- Stated focus on reliability and stock-like driving experience
- Drivetrain warranty that mirrors the BMW warranty
- Bluetooth connection for wireless connectivity and firmware updates
- Emissions legal in CA
- Excellent customer support
Disadvantages
- The most expensive option
- Not targeting the highest peak gains
- No CANbus connection
- Harder to uninstall
- The Bluetooth iPhone app not yet available to end-users
This is the most expensive option at $1500. It offers high end components, connectors, wiring and mounting. Unlike other tuning boxes the Dinantronics taps directly into the ECU connectors - a more flexible, but also more costly harness choice. Uniquely to Dinan, you get a full warranty that shadows BMW's OEM warranty, and the tuning box is certified emissions legal in all states including CA (N26 pending).
With Dinantronics you can take your car to the dealer as usual for maintenance or warranty work, without worrying about what they might or might not say about it. Dinan recommends going to a BMW+Dinan dealer if possible since they are familiar with Dinantronics cars, but any dealer is fine.
Dinan claims that they put a lot of effort into maintaining OEM-like drive-ability and reliability. To be fair, all tuners will tell you that their tuning is well engineered and quite safe. However, Dinan is the only tuner that publicly backs that talking up with a warranty, and in doing so has a direct financial interest in keeping your car running smoothly.
The Dinantronics box is Bluetooth capable, but Dinan hasn't released yet the smartphone app for changing maps and doing firmware upgrades - and no expected release date is available.
The Dinantronics harness does not currently tap into the CANbus. I heard from Dinan that they are doing development work related to CANbus connectivity, but if my understanding is correct their primary reason is code reading and trouble shooting rather than performance tuning, and it is unclear whether it will be a Dinantronics upgrade or a separate product (if it ever makes it to market at all).
Some people claimed that Dinantronics is only active after the engine has warmed up (JB4 does that, I believe). That is incorrect, Dinantronics is always active. The ECU, however, will natively use less boost when the engine is cold.
Note that any of the above tuning boxes, including Dinantronics, will void the BMW extended warranty for the engine and related components. If you have an extended warranty be prepared to either drive stock while the warranty is active, or take on the risk of out-of-pocket repairs.
3. Expected performance gains
As I said above, I didn't spend much time evaluating BMS as it was clearly not the product I was looking for. Comparing Active8 and Dinantronics, are the Dinantronics warranty, emissions legality and the Dinan company pedigree worth 2x the cost of Active8? As with anything involving cost and benefit the answer is highly subjective. In my case the answer is yes, assuming the performance gains are noticeable and significantly increase my enjoyment of driving the car.
The subjective experience is the make or break test, but numbers are important too. Some people on this forum say that Dinantronics offers far less performance than Active8 or Racechip. Dinan offers dyno data on their website, and from what I've seen nobody claims that their published data is inaccurate. However, the major fault that some find with it is that Dinan posts crank numbers - which is what manufacturers use, but not what you actually measure on a regular dyno. The Dinan dyno setup is actually said to be one of the more accurate and repeatable in the business (they apparently need that accuracy when squeezing 1 HP at a time from racing engines).
The ideal case for a numbers comparison would be to have a car on a dyno, with both Dinantronics and Active8 and compare them against stock performance. As far as I can tell that ideal has not yet been turned into reality by any of the forum users - and I have no inclination to spend time doing that either.
So, I did an armchair experiment to approximate the results. I took the Active8 dyno data from the ActiveAutowerke website and scaled their N20 baseline to match the Dinan N20 baseline (the scaling factor, or "drive train loss" as people call it, ended up being 18% on average - but depends on the RPM). I then used the exact same scaling factors to map the Active8 tuned performance.
Take the results with an appropriately sized grain of salt. Both baselines are N20 engines, but they are not from the same car and so any manufacturing variations, if present, will add some shift to the data.
The N20 Dinan tune is running 93 octane. The Active8 does not specify the octane or mapping, but looking at the amount of boost (5psi+) is it probably running the most aggressive map 9. For comparison I also added the stock 335i dyno from Dinan, since it is presumably measured on the same dyno as the N20.
These are the resulting HP and Torque curves (crank):
Attachment 1168707Attachment 1168708
The N20 Dinantronics matches the 335i performance across the RPM range. There is an odd dip in the 335i curve at 4500-5000 RPM - I have no idea why, perhaps Dinan_Engineering can comment.
The estimated Active8 peak performance is just about the same as that of Dinantronics and the 335i, but Active8 puts out more power and torque at lower RPMs (25lbs-ft and 13HP more at 3000 RPM).
We can also try to estimate the PSI boost for Dinan based on the known Active8 boost and their relative performance levels:
Attachment 1168711
The Active8 boost increase is on average +5 PSI , and is effectively constant across the RPM band. The estimated Dinantronics PSI boost varies between +3 and +5 PSI, on average being +4 PSI. You can see that their approach is very different; Active8 tries to push the boost to 21PSI across all RPMs, whereas Dinantronics has a gradual increase that only pushes 21PSI of boost at high RPMs when gunning for peak power.
On paper, this looks pretty good for both Active8 and Dinantronics, with about the same peak performance. The estimated Active8 performance is significantly higher at low and mid RPMs, although I'd be a little worried about how you ease into that dollop of torque @ 3000 RPM.
So, at least based on manufacturer data, I see no reason to categorize Dinantronics as low performance. Active8 has more area under the curve, at the expense of a driving experience that is probably quite different from stock. Dinantronics has a similar peak performance, but has a very OEM torque curve that matches the N55.
There is one more set of data that I think is relevant.
I have an N26 engine, rather than N20. As it turns out, this really matters for performance. N26 has higher density CATs that rob the engine of a lot of performance at 5500RPM+: it makes 26HP less than N20, stock. The tuned N26 can barely exceed the stock N20 at 6000RPM+. The end result is that the Dinantronics N20 has 30HP more than the Dinantronics N26, and the tuned N26 engine can not quite match the N55 at the top end.
Attachment 1168709Attachment 1168710
That means the N26 can be noticeably slower in tests that benefit from a wide peak power band at high RPMs, like the 0-60 time. It would have been nice to know that when I bought the car.
You can fix the N26 power drop by changing the OEM CATs to something less restrictive. Although it is probably not enforced much, note that it is illegal to do so in CA.
4. Subjective review
I got the Dinantronics professionally installed by a Dinan dealer, although I think you can do the install yourself should you choose to (there is a PDF with instructions available on the Dinan website).
The additional power is instantly noticeable. There is much more 'pull' that you can feel in the driver's seat. This is perhaps most noticeable at higher speeds. In stock form at 70mph or more the car would accelerate relatively well, but you had to look at the speedometer to know it. With the Dinantronics, you feel it. It just pulls. Trying that out for feel I inadvertently ended up at speeds that I'd rather not quote here - suffice to say that never happened stock.
When coming back from the dealer I took a highway entry ramp at aggressive throttle and for the first time ever in this car I saw the traction control kicking in (I have an xDrive).
There are two things that instantly jumped out to me with the tune.
One is that in stock form the engine seemed eager to jump to revving high and make noise under load, but you would not feel all that much pull out of that commotion. With Dinantronics, the opposite is true. There is less revving, and more noticeable acceleration.
Second, there is a sense of having an excess of instantly available power throughout the RPM band - more so than what is needed. It is hard to describe, but it feels great. It drives like stock, but more powerful.
I am very much surprised at how much nicer the car is to drive because of that extra power. You look at the numbers and you'd think that a 15-20% boost in power would be something that translate into at best 15-20% better driving experience. Subjectively it exceeds that though.
The Sport mode goes from fun to even more fun, Comfort has more pull and is a little more 'nervous' than stock (which can be good or bad, depending on what you want out of it), and EcoPro is now actually usable. In stock form EcoPro is the death of all passion - it kills any resemblance of acceleration. With Dinantronics I enjoy EcoPro more than I enjoyed stock Comfort - and I get the added bonus of sail mode. I did not use EcoPro at all before, but now I use it for city traffic. In my case the average city MPG improved by a fair bit (from 19 to 24). I certainly did not expect to use EcoPro more after getting an engine performance tune, but there you go - such are the surprises of life.
I noticed that engine is a little louder than stock, and the engine note is maybe a touch harsher. If you haven't heard a '14+ 328, it sounds nothing like the N20 of previous years - it has a very smooth, low growl with an almost 'exotic' feel to it. I'm wondering if ActiveSound is slightly out of tune with the engine now, given the different rates of acceleration with Dinantronics. Or maybe I'm just imagining it - it's certainly subtle.
The engine temperature seems to be a little higher since installing the Dinantronics.
As far as measurable performance, I did only one set of tests: 0-60mph measured with the M Laptimer iDrive app. Flat road, one run in each direction (to make sure there is no slope), gas tank ~75% full with 91 octane, OEM all-season Pirelli tires. I had about 50lbs worth of other stuff in the back. Outside temperature 48F, sea level. Sport+ mode, automatic shifting using Launch Control (first time I ever used it).
The result was 5.1s on both runs. I suspect you can do 5.0 with less gas in the tank and no extra stuff in the trunk. I do not know what the numbers are running stock.
Edit: I did one more run, same as above but with the car low on gas. The measured time was a slightly faster 5.0s.
The 335 xDrive is quoted to do 4.8s 0-60. My car does not quite reach that - so I suspect I'm seeing the downside of the missing 30HP in the N26 vs N20 (the car was shifting at ~6400RPM during the run).
After two days of driving I went back to the dealer and asked them to switch the Dinantronics off so I can compare again with stock performance. I drove a lot that day, and really tried to convince myself that stock performance is just fine and that I can skip the expense of the Dinantronics. I failed, and Dinan is laughing all the way to the bank.
