[FaRKle!]

I'm making this thread to put the data I've collected with the various tunes I've had out there. I'll update it as I compile the latest data.

Tunes I've had:
OE: 1yr, 2mo, 26,148mi
JR Stage 2:1yr, 2mo, 21,802mi
KermaTDI Stage 1: 3mo, 4,438mi
KermaTDI Stage 2: 6mo, 8,074mi (as of this post)

Fuel Economy
For fuel economy I'm only including "qualified" samples, meaning full tanks, typical driving (no track time), and diesel fuel (no bio or renewable diesel). For smaller populations I provide both with/without a longer road trip tanks since those are weighted more heavily.

OE: 35.09mpg, n=56
JR Stage 2: 33.81mpg, n=39
KermaTDI Stage 1: 35.06mpg, n=11, 34.09mpg, n=8 (no road trips)
KermaTDI Stage 2: 34.65mpg, n=14

DPF Regens
I use torque pro and monitor regens by looking at the commanded boost (typically goes negative during a regen at idle) and DPF EGTs. Unfortunately I didn't have this logging capability when I was still on the OE tune, and it wasn't until I started having CELs pop up with JR Stage 2 that I decided to start logging. I make a mental note of my mileage when a regen happens and then check to see that one is happening at the next expected interval. They've been very consistent.

OE: N/A
JR Stage 2: ~210mi
KermaTDI Stage 1: ~300mi
KermaTDI Stage 2: ~300mi

More to come...

[n00bkiller944]

Thanks for the data! I look forward to your additional updates!

[eugene89us]

I almost think the drop in fuel economy is related to users being more "heavy footed" after performance tunes. But Kerma's proximity may imply lack of statistical significance. From what I have read, it seems Kerma to be the most trouble free option compared to others. My biggest worry was about someone here reporting faster than normal Adblue usage after Kerma. FaRKle!, can you confirm if this is the case?

[FaRKle!]

Originally Posted by eugene89us

I almost think the drop in fuel economy is related to users being more "heavy footed" after performance tunes. But Kerma's proximity may imply lack of statistical significance. From what I have read, it seems Kerma to be the most trouble free option compared to others. My biggest worry was about someone here reporting faster than normal Adblue usage after Kerma. FaRKle!, can you confirm if this is the case?

So here's what I said the last time I talked about DEF useage with the KermaTDI tune:

Originally Posted by FaRKle!

The DEF system (passive plus active tanks) has a capacity of 18.1L. My DEF/1000mi light comes on when I'm at 3L remaining. When the first light came on after the Kerma tune I put in 12L (VW 10L jug + VW 2L bottle). My light came on again after about 5000mi. The next time I decided to completely top off the system to see how much it would take, and got 15L in there before things started spilling out. Thus my DEF consumption rate is ~400mi/L, or 6000mi before the DEF light comes on again.

It turns out my projections were darn close to reality! Two weeks ago my DEF light came on and I refilled it. The interval was 6,232mi from the last time I refilled it. My interval also included four track days, and a lot more NOX is produced at WOT.

When I was on JR's tune I was still under the BMW free maint plan, so my DEF was topped off every oil service (which was generally about every 8,000mi for me), so rate of consumption was less than KermaTDI's tunes.

That said... KermaTDI was very open with me about why that is, and while I won't disclose exactly why, what I will say is that they made design decisions which decreased fuel consumption at the expense of increased DEF consumption in order to maintain full emissions compliance.

[EricD735i]

I’ve been on my Kerma tune for about a month now and it’s been great. What’s Stage 2? I never had issues with DEF before, only topped off at oil changes. I keep it in mind since I had the oil changed right before I got the tune.

[swissarmyknife]

@FaRKle! +1 on the Stage 2 Kerma. Can you elaborate.

[FaRKle!]

Originally Posted by EricD735i

I’ve been on my Kerma tune for about a month now and it’s been great. What’s Stage 2? I never had issues with DEF before, only topped off at oil changes. I keep it in mind since I had the oil changed right before I got the tune.

Originally Posted by swissarmyknife

@FaRKle! +1 on the Stage 2 Kerma. Can you elaborate.

Sorry I missed this question earlier. Stage 2 is an accompanying transmission tune to deliver better power from the engine to the wheels/ground. It's not quite as smooth as stage 1 IMO, but definitely more efficient in power delivery to the ground. I noticed the most fuel economy gains in city driving with it.

[EricD735i]

Originally Posted by FaRKle!

Sorry I missed this question earlier. Stage 2 is an accompanying transmission tune to deliver better power from the engine to the wheels/ground. It's not quite as smooth as stage 1 IMO, but definitely more efficient in power delivery to the ground. I noticed the most fuel economy gains in city driving with it.

Interesting. One of the things I like about the Kerma tune is how smooth/linear the power delivery is compared to stock during day to day use. But when I floored it from a stop to merge into fast traffic the other day I was still surprised by the extra power.

[swissarmyknife]

Originally Posted by FaRKle!

Sorry I missed this question earlier. Stage 2 is an accompanying transmission tune to deliver better power from the engine to the wheels/ground. It's not quite as smooth as stage 1 IMO, but definitely more efficient in power delivery to the ground. I noticed the most fuel economy gains in city driving with it.

Ah, ok. Where is this advertised on Kerma's website? I am also interested. I am guessing the same programmer can be used for the transmission tune?

[FaRKle!]

Originally Posted by swissarmyknife

Ah, ok. Where is this advertised on Kerma's website? I am also interested. I am guessing the same programmer can be used for the transmission tune?

It's not on their site because the installation is more complicated than the q-pro flasher and has to be done remotely by someone. You'll need to call and ask about it.

[swissarmyknife]

Originally Posted by FaRKle!

It's not on their site because the installation is more complicated than the q-pro flasher and has to be done remotely by someone. You'll need to call and ask about it.

Got it. Thank you.

[swissarmyknife]

FaRKle! do you happen to know if Torque or other obd2 apps are accurate enough to do 0-60 runs with. Would like to take some data before and after the tune.

The programmer should show up by Tuesday next week and then based on the turnaround from Kerma I could have the new tune ready by Wednesday or Thursday. I just don't want to spend another 500 bucks on a handheld device if an obd2 approach could at least get me comparable data, but that would all depend on the sample rate the obd2 can read.

[n00bkiller944]

I ended up getting Kerma's tune. When I called though they claimed they just have one tune, not stage one or two. How can I confirm which one I got?

Also - the newfound torque with the tune is nice

[FaRKle!]

Originally Posted by n00bkiller944

I ended up getting Kerma's tune. When I called though they claimed they just have one tune, not stage one or two. How can I confirm which one I got?

Also - the newfound torque with the tune is nice

You got Stage 1. Stage 2 requires an additional flashing session. Stage 1 is a bit smoother than stage 2.

[n00bkiller944]

Originally Posted by FaRKle!

You got Stage 1. Stage 2 requires an additional flashing session. Stage 1 is a bit smoother than stage 2.

Why wouldn't they sell me stage two off the bat? I even asked the person on the phone about it and they told me they dont have a stage two?

[FaRKle!]

Originally Posted by n00bkiller944

Why wouldn't they sell me stage two off the bat? I even asked the person on the phone about it and they told me they dont have a stage two?

The installation is more complicated than Stage 1, so they haven't been advertising it till they can come up with a better way that's more end-user friendly.

It seems to me like one of those things that you'd want to limit to people who are very familiar and comfortable with using tools like ESYS and ISTA.

[Enabled]

Originally Posted by n00bkiller944

Why wouldn't they sell me stage two off the bat? I even asked the person on the phone about it and they told me they dont have a stage two?

"Stage 2" goes along with a matched transmission flash.
The 'stage 1' or 'stage 2' (or whatever you'd want to call it) would make exactly the same power until this transmission flash is done.

This is because the transmission computer puts a hard limit on how much the engine computer is allowed to output.

[n00bkiller944]

Well crap, tell them I want to guinea pig lol

[ward00]

No need to be a pig. I can attest to that Stage 2 rocks!

[devnull]

Originally Posted by FaRKle!

That said... KermaTDI was very open with me about why that is, and while I won't disclose exactly why, what I will say is that they made design decisions which decreased fuel consumption at the expense of increased DEF consumption in order to maintain full emissions compliance.

Hi FaRKle! I'm pretty keen on getting the KermaTDI tune but haven't been able to find much information on the kind of compromises to the engine to achieve this level of performance. The only person that I managed to speak to at Kerma was a sales type and was exceeding unhelpful in giving any kind of technical insights.

Is there some resources that I could read up on how diesel engine performance is achieved? I unfortunately have a EE/CS background and not a MechE

[Enabled]

Originally Posted by devnull

Hi FaRKle! I'm pretty keen on getting the KermaTDI tune but haven't been able to find much information on the kind of compromises to the engine to achieve this level of performance. The only person that I managed to speak to at Kerma was a sales type and was exceeding unhelpful in giving any kind of technical insights.

Is there some resources that I could read up on how diesel engine performance is achieved? I unfortunately have a EE/CS background and not a MechE

It's so multifactorial. These are a few basic factors involved:

1. BMW themselves had a few different power levels from the same or similar hardware, with software being the only difference. Marketing, road taxation, etc. is all involved here.

2. Manufacturers have to design engine software to run an engine even when the owner is neglectful and forget to change an air filter, fuel filter, etc. They have to leave a very broad headroom for all these conditions. Tuning pushes this higher, but obviously it's not for the neglectful owner.

3. In general, diesel tuning is achieved by extra fuel (timed correctly) and air to match. Fuel can be increased "easily", and the North American 328d is equipped with a very nice Honeywell Garrett turbo that can stand a pretty good increase without compromises, to an owner that isn't neglectful. Contrary to popular belief, it's not the boost that creates the power.

[devnull]

Originally Posted by Enabled

It's so multifactorial. These are a few basic factors involved:

1. BMW themselves had a few different power levels from the same or similar hardware, with software being the only difference. Marketing, road taxation, etc. is all involved here.

That makes sense. IIRC the same engine is sold in Europe at different level of tunes and definitely emission taxation is an important parameter in deciding engine output.

Originally Posted by Enabled

2. Manufacturers have to design engine software to run an engine even when the owner is neglectful and forget to change an air filter, fuel filter, etc. They have to leave a very broad headroom for all these conditions. Tuning pushes this higher, but obviously it's not for the neglectful owner.

3. In general, diesel tuning is achieved by extra fuel (timed correctly) and air to match. Fuel can be increased "easily", and the North American 328d is equipped with a very nice Honeywell Garrett turbo that can stand a pretty good increase without compromises, to an owner that isn't neglectful. Contrary to popular belief, it's not the boost that creates the power.

So if I am understanding correctly the turbo's boost is increased to make up for the additional amount of fuel that's injected? And we are blessed with a stout turbo that can withstand the higher psi?

What about the fuel injector? I did read about premature failure of those... would a tune potentially increase the chance of incurring this expensive repair?