2014 Mods - Diesel Power Tuning Module

[Tiato]

30 days until my track season starts and 90 days until I depart for my 48 day cross country jaunt. In both instances I will be towing a trailer. For track season a 900lb aluminum trailer with a 3600lb car. For the XC trip a 1050lb tear drop trailer.

In prep for those specific needs, I started researching functional upgrades that will make those tasks easier for the Interstate and more comfortable for the driver/passengers.

Easier for the interstate – power upgrade, transmission temp cooling strategies, chassis stability enhancements
Easier for the driver / passengers – chassis stability measures

What does that mean?
Power Upgrade – Renntech or Diesel Power software
Transmission – aux trans fluid cooler
Chassis Stability – suspension (shocks, anti-roll bar)

One big thing that I took away from racing cars was to make one change at a time so that if that one change it doesn’t provide you with the expected result you can undo it and so you can attribute any positive or negative data to that one change. I am using that mind set to initiate the non-electrical part of my development program for the Airstream.

I researched most of the power enhancement options for the 3.0L V6 diesel. Based on positive feedback and anecdotes garnished from various sprinter based sites, my first call was to Renntech. Unfortunately, they were not able to assist me as my Sprinter build date was past their development limit of their software. My chassis build date is 2/27/12. It appears that their software can only accommodate models up to 12/11. That was disappointing news but it is what it is.

I then called the sprinter store and asked for their feedback. They sell the European made 2 channel Diesel Power product which is an add on tuning module rather than an ECM re-flash. The Diesel Power Module is very German by design and quality. Interestingly, the plastic tubing that is used to protect the wire loom is made by the same company whose products my company sells stateside but for industrial purposes rather than automotive. The tubing is also OEM to BMW, Mercedes, AUDI and Ferarri

While the Renntech product claims some amazing power (188 -> 260+ HP) the diesel power solution is a lot more conservative but also manually adjustable in in 1.5% increments up to 25%. ( 0-37+ HP.) Diesel power achieves their gains by manipulating fuel rail pressure and turbo boost (up to a max of 2psi over stock). The idea is not to build max power but to increase useable torque. The module has 16 different power levels. I set mine 2 clicks from max, so 22%.

Now, I have read accounts that the Renntech product yields a blatantly obvious performance increase. The Diesel Power unit does yield benefits but is a lot more subtle in nature.

The install took less than 30 minutes. This afternoon I took my Sprinter for a 16 mile back road loop that featured level and undulating roads followed by some steep uphill climbs up the Sourland Mountain Range here in Central NJ.

From a sand still to road speed (0-45 mph) first gear felt unchanged up to about 2k RPM, then as my speed increased and the Sprinter started shifting through its gears I could feel a lot more midrange torque from 1800 RPM all the way to 3000RPM. I did a few standstill starts up hills and thoroughly enjoyed more torque in the aforementioned range. The Sprinter definitely powers up hills with more authority. On 0 – 45 mph accelerations on level roads the sprinter got up to speed much quicker. That easy going, I get there when I get there feeling was replaced with a brisker and authoritative response.The torque just builds and keeps building until you are way past the allowed speed limit. Good stuff.

I then replaced the stock Mercedes air filter with a high flow one from AFE, also bought from the sprinter store. The feel of that mod was not as noticeable but I sensed a bitty bit better throttle response and an increase in intake noise as well as blow off noise.

These two mods combined do yield a noticeable but subtle increase in power which feels very factory and is well worth the price that is 30% less than the Renntech product. Not having any other proven, conservative power upgrades available for my build date Sprinter I am very pleased.

Another benefit of having an overall lesser expenditure in engine management enhancements is that the difference between the Diesel Power product and Renntech paid for the air filter and rear shocks. J I love stretching mod bucks.

[73shark]

Any mpg changes or do you have enuf miles yet to determine?

What shocks and results?

[Tiato]

Only 16 miles so far, so only good to gauge power improvement. Need to run an extended trip to gauge any increase in economy.

Shocks will be the single adjustable Koni Reds. I know what to expect and will be curious if the shocks meet my expectations. Should be receiving those next week but install will have to wait 2 weeks due to an upcoming business trip.

[David M]

Wow, nice writeup Tiato! You'll have to put an AMG emblem on the rear of your Interstate soon 😜

[TerraYacht]

How about a posting, or link, to your travel schedule, so if you are at a local track we can come by an cheer you on? What is the track vehicle?

[Tiato]

David, perhaps a BMW Roundel.

Terra - Need to clarify. I used to travel to various tracks when I was racing in BMW Club Racing a few years ago. Nowadays the racing has been replaced with instructing and coaching 12-16 days a year at High Performance Driving Events with car clubs at Watkins Glen International.

The 45 day jaunt is more of a family adventure camping and driving west and back.

[Tiato]

Track vehicle is a 2008 BMW V8 M3 Sedan

[Jeff64]

Tiato,

Please let us know if you have any issues with your tuning module. I too bought and installed the same one on my Interstate. I like the performance also, however it has continuously been tripping the check engine light. I have been working with the guys at the Sprinter store trying different settings, first they said to use 9 then they said for a 2013 to use 5, still getting the light. Maybe a faulty unit not sure. I also discovered a torn gasket on the air intake hose where it mounts to the turbo so I need to repair that to rule it out as a possible cause. I would be very interested in your experience as you put some miles on.

Jeff

[Tiato]

Jeff, will do. Got a 140 mile drive planned for tomorrow. However I suspect the torn gasket is the cause of your CEL, especially if it's after the air meter in the air filter box. If it is, then the engine is getting unmetered air. Whenever engine tuning is changed, power is increased by leaning out the fuel mixture of engine. Engine can tolerate this within a specific range but at higher rpms will need more fuel. In your case it sounds like there is unaccounted air entering the system and causing a lean condition. That's why the Sprinter store is instructing you to turn down the tune

[Protagonist]

Originally Posted by Tiato

Whenever engine tuning is changed, power is increased by leaning out the fuel mixture of engine.

I was given to understand that the ideal air:fuel ratio for a diesel is 14.5:1, the so-called stoichiometric ratio, where the amount of oxygen in the intake air is exactly enough to burn all of the fuel, no more and no less. Operating at this ratio optimizes horsepower, minimizes emissions, and optimizes engine temperature as well.

So you're saying that a stock Mercedes turbo-diesel runs on the rich side of the stoichiometric ratio?

I have noticed that with my RennTech ECU tune, at 60mph (2200rpm) my fuel economy is way up from what it used to be even though I also have more power (the engine is operating closer to the stoichiometric ratio). But at 70mph (2800rpm), fuel economy is worse than before— though I still have the increased horsepower— so I'm guessing the mixture might be enriched at that rpm. Ah, the wonders of computer-controlled fuel injection!

[Tiato]

Pro, I think the Mercedes diesel runs just perfect. I'm sure it was tuned to achieve the best compromise between fuel efficiency, power and emissions.

It is when we deviate from the stock tuning via software that things get interesting. Leaner mixture, more power. but with suboptimal long term consequences. Thus as power is increased more fuel must be added to maintain the appropriate AFR's. Increase turbo pressure, more compressed air that can be burned. Lots of air, low fuel = lean. Have to add fuel to get the AFR's back in line.

You can mess with engine timing to have even another variable to have fun with.

As far as fuel efficiency at 70 mph, were you hitting the aerodynamic wall where more energy has to be spent to overcome air resistance. As sleek as our Sprinters look they still are aerodynamic bricks.

[Jeff64]

It sounds like Protag slipped in under the wire regarding the build date in order to get the Renn Tech tune. Did they happen to mention when they would be able to accomodate 2013 and 2014 models?

[Tiato]

No definite answer other than we're working on it. Seems Mercedes made software changes as a result of their add blue campaign that are proving tough to crack.

[Protagonist]

Originally Posted by Jeff64

It sounds like Protag slipped in under the wire regarding the build date in order to get the Renn Tech tune. Did they happen to mention when they would be able to accomodate 2013 and 2014 models?

Never even thought to ask.

[e93pvaz]

Originally Posted by Tiato

30 days until my track season starts and 90 days until I depart for my 48 day cross country jaunt. In both instances I will be towing a trailer. For track season a 900lb aluminum trailer with a 3600lb car. For the XC trip a 1050lb tear drop trailer.

In prep for those specific needs, I started researching functional upgrades that will make those tasks easier for the Interstate and more comfortable for the driver/passengers.

Easier for the interstate – power upgrade, transmission temp cooling strategies, chassis stability enhancements
Easier for the driver / passengers – chassis stability measures

What does that mean?
Power Upgrade – Renntech or Diesel Power software
Transmission – aux trans fluid cooler
Chassis Stability – suspension (shocks, anti-roll bar)

One big thing that I took away from racing cars was to make one change at a time so that if that one change it doesn’t provide you with the expected result you can undo it and so you can attribute any positive or negative data to that one change. I am using that mind set to initiate the non-electrical part of my development program for the Airstream.

I researched most of the power enhancement options for the 3.0L V6 diesel. Based on positive feedback and anecdotes garnished from various sprinter based sites, my first call was to Renntech. Unfortunately, they were not able to assist me as my Sprinter build date was past their development limit of their software. My chassis build date is 2/27/12. It appears that their software can only accommodate models up to 12/11. That was disappointing news but it is what it is.

I then called the sprinter store and asked for their feedback. They sell the European made 2 channel Diesel Power product which is an add on tuning module rather than an ECM re-flash. The Diesel Power Module is very German by design and quality. Interestingly, the plastic tubing that is used to protect the wire loom is made by the same company whose products my company sells stateside but for industrial purposes rather than automotive. The tubing is also OEM to BMW, Mercedes, AUDI and Ferarri

While the Renntech product claims some amazing power (188 -> 260+ HP) the diesel power solution is a lot more conservative but also manually adjustable in in 1.5% increments up to 25%. ( 0-37+ HP.) Diesel power achieves their gains by manipulating fuel rail pressure and turbo boost (up to a max of 2psi over stock). The idea is not to build max power but to increase useable torque. The module has 16 different power levels. I set mine 2 clicks from max, so 22%.

Now, I have read accounts that the Renntech product yields a blatantly obvious performance increase. The Diesel Power unit does yield benefits but is a lot more subtle in nature.

The install took less than 30 minutes. This afternoon I took my Sprinter for a 16 mile back road loop that featured level and undulating roads followed by some steep uphill climbs up the Sourland Mountain Range here in Central NJ.

From a sand still to road speed (0-45 mph) first gear felt unchanged up to about 2k RPM, then as my speed increased and the Sprinter started shifting through its gears I could feel a lot more midrange torque from 1800 RPM all the way to 3000RPM. I did a few standstill starts up hills and thoroughly enjoyed more torque in the aforementioned range. The Sprinter definitely powers up hills with more authority. On 0 – 45 mph accelerations on level roads the sprinter got up to speed much quicker. That easy going, I get there when I get there feeling was replaced with a brisker and authoritative response.The torque just builds and keeps building until you are way past the allowed speed limit. Good stuff.

I then replaced the stock Mercedes air filter with a high flow one from AFE, also bought from the sprinter store. The feel of that mod was not as noticeable but I sensed a bitty bit better throttle response and an increase in intake noise as well as blow off noise.

These two mods combined do yield a noticeable but subtle increase in power which feels very factory and is well worth the price that is 30% less than the Renntech product. Not having any other proven, conservative power upgrades available for my build date Sprinter I am very pleased.

Another benefit of having an overall lesser expenditure in engine management enhancements is that the difference between the Diesel Power product and Renntech paid for the air filter and rear shocks. J I love stretching mod bucks.

Great write up. Does this mod negate the MB engine warranty or adversely affect the warranty??

[Jeff64]

Tiato, I'm curious how things are working out with your tuning module. I have replaced the air intake gasket on my AI, cleared the code and still got another check engine light. I then installed the block/plug that is supposed to convert the tuning module back to factory settings. I then cleared the code once again and haven't seen the light yet but need to put on a few more miles to be sure, but at this point I'm rather sure that the unit is either not compatible with the 2013 Sprinter or I have a faulty unit. That is why I'm curious as to how you are getting along with yours. I like the module and am hoping they will send me another one and all will be well.

[Denis4x4]

Interesting thread...I have an SOB 2013 class B on an MB 3500 chassis and towed one of my Hot Rods to a tour last month in AZ and took my wife's Porsche to Albuququre last week to have both vehicles serviced. Worst mileage was 13.1 and best was 15.9. Trailer is an aluminum H&H 20' tilt bed with a tool box and winch. Based on my experience, I see no need for modifications to the engine/CPU. I might install some air bags under the rear end from a handling standpoint. The towing capacity is 5000 pounds with a 500 pound tongue weight.

Quite frankly, the M-B has exceeded my expectations as a tow rig.

[Tiato]

Originally Posted by Jeff64

Tiato, I'm curious how things are working out with your tuning module. I have replaced the air intake gasket on my AI, cleared the code and still got another check engine light. I then installed the block/plug that is supposed to convert the tuning module back to factory settings. I then cleared the code once again and haven't seen the light yet but need to put on a few more miles to be sure, but at this point I'm rather sure that the unit is either not compatible with the 2013 Sprinter or I have a faulty unit. That is why I'm curious as to how you are getting along with yours. I like the module and am hoping they will send me another one and all will be well.

Jeff, to be honest it has been hit or miss. When installed at 2 clicks from Max, it drove fine for a my test run of 16 miles, which included a few steep uphill runs.

When I went for a extended drive to bring my interstate to get serviced at colonial airstream, 3 miles from my home it threw a check engine light and went into limp mode. Pulled over, turned it off, powered back on and was ok. Check engine never turned off but I knew it would reset itself after several on / off cycles.

Another run was to pick up my new aluminum car trailer. 3 miles out, the Sprinter went into limp mode. Disconnected the module and installed the endplug. No problems rest of the drive.

Later I set the module to 9 clicks and went for a 7 mile drive and it felt ok. Modest power increase where expected. Check engine light remained on despite a dozen or so on / off start cycles in the driveway.

Since then I have not had time to investigate further as I was traveling for business.

How do you reset the check engine light?

[Protagonist]

Originally Posted by Tiato

How do you reset the check engine light?

You will need a good-quality OBDII reader that includes a reset feature. It plugs in near the under-dash fuse block. Before resetting the light, make a note of the error codes from the OBDII for reference.

Since my RennTech ECU tune isn't adjustable like the one you're using, I'm glad it's not giving me "check engine" lights. I've only put about 600 miles on it since getting the tune, but the engine has been very well-behaved in that distance.

[Tiato]

Pro, gotcha. Love my scangauge but wish it could reset codes.