SnazzyLabs

Hi everyone,

New to the forums. Was planning to get a 2014 W204 C300, but after seeing the W205, I can't help myself. Planning to buy the car tomorrow. That said, I'll be opting in for the C300 2.0L Turbo. Drove the car today and it had decent pep (at least, on par with the 328i); however, I'm interested in the tunes on the market.

I've read a fair bit about the BMS plug-and-play tuner ($379) and people seem to be relatively happy with dynos showing 20-30HP increase with 91 octane fuel—nothing crazy—but a nice improvement for a couple hundred bucks. Some are even getting into the high-290s/low-300s with E85 fuel, but I'm mostly concerned about day-to-day practical tunes.

OE Tuning has been offering a ECU flash that is significantly more than the BMS ($795) and throws out the "Tuned Peak HP" at 306HP. I've seen OE talk about the tune on MBWorld, but I've yet to come across someone that has actually claimed to have done the tune (let alone post dynos). I know a lot of people rave about OE Tuning but the fact that Kleemann nor Renntech have done tunes for the C300 W205 makes me skeptical that OE Tuning has got any advantage over BMS.

To those that have tuned or considered tuning the C300: What tune did you go for? Was it worth it? What practical day-to-day performance benfits have you noticed? What issues have arisen since the tune?

Would love to centralize people's thoughts in a less outdated, less convoluted thread.

Plutoe

They are a FW of money!!

Shadwell

Care to expand on this?

Tartan43

Been driving my new 2016 C300 4MATIC for a week now after turning in a 2014 E350 4MATIC – a night and day driving experience. Wife is driving a 2014 c300 4MATIC with the detuned M276 so I have a couple recent reference points. In absolute terms the 4cyl isn’t as smooth or sounds as refined as the V6s, but not enough for me to care - the 2016 is an amazing car. Also, we live in Denver where these V6 engines are robbed of their power more notably than the turbo charged engines. So the lighter W205 is very comparable power wise even before any mods.

All week I’ve been researching available ECU tunes for the M274. Kleemann does offers a K-Box with 40HP gain for $1495 (odd that the car has been out for two years, but Kleemann can’t find the time to update their website with the C300 spec or dyno stats). Then there’s the OE Tuning ECU software map with 65HP gain for $795 and the promise the same day reprogramming and return shipping. That’s just over $12 per 1HP as compared to over $37 per 1HP gained with Kleemann.

And then it happened; I received an email this afternoon from Rocco at OE Tuning telling me about their 20% Memorial Day weekend sale! Same 306HP tune for $636 (below $10 per 1HP) – I pulled the trigger. I’m traveling in a week so then will be the perfect time to ship the ECU. I'm happy to provide an update once the ECU is back in the car.

Str8Down

I want a tune also. Aren't you concerned with modifying the ecu map for warranty purposes? I really want a piggyback for that reason alone.

Dkinsley

Talk to your dealer. Mine does Renntech tune for you. I went with PP Performance on C400 and they didn't have a problem with it.

SnazzyLabs

Keep us updated! Looking to pull the trigger on the BMS, but if you notice some serious improvements with the OE, I will do that. It's weird Kleemann hasn't updated their site yet. You'd think they'd get more prospecting buyers if the engine were listed.

Who? Ken Garff?

Tartan43

From everything I’ve read, piggyback tuners won't improve the horsepower and torque gains across the full engine range as much as a custom ECU map. Both BMS and Kleemann appear to intercept signals from sensors before those get to the factory ECU and modify the signals by that “tricking” the ECU to compensate for a perceived condition (lean mixture, rich air, etc.) Seems like the piggyback is continuously fighting the factory ECU.

As to the warranty, it comes down to individual priorities; I would take the extra 25HP over the ease of knowing the warranty is unaffected. My rationale - the ECU flash is undetectable unless a Mercedes decides to do a “forensic” search of the ECU map as compared to the factory copy. In Practice the only time the dealership would put the ECU on diagnostic computer is to update the ECU for a recall or installation of an upgraded part, which requires an ECU update. In my mind, the bigger risk is the dealer reflashing the ECU back to factory settings as part of a recall or update campaign. In that case, back to the tuner I go (who promises to restore the tune I purchased).

Tartan43

I will. However on paper OE Tuning looks to have approx 48 more HP over BMS. I'm not sure how I would quantify "serious improvements". The w205 is already faster then the wife's w204 off the line to 60mph (in Denver). The only other objective measure would be a dyno. I'll search for one around town, but it will need to accommodate the 4MATIC.

SnazzyLabs

Im in high altitude too (upper benches in Salt Lake City) so I'm a fan of the turbocharger. I'd love to see dyno results. The theoretical HP on the BMS is in the 300s, but practically, I think it's lower due to the relatively low octane fuel here in the U.S. My suspicion is that the OE is likely similar; however, I would be thrilled to see improvements over the BMS. Perhaps you're right about ECU flashes being more successful than piggyback stuff.

Dkinsley

Who? Ken Garff?[/QUOTE]

I live in Draper but purchase the car in Lindon. They haven't given me any
trouble with any of my mods. They offered to do the Renntech for me but I wasn't interested in the markup. Have you ever driven a C400 stock? If so I would be happy to let drive mine to see what PP Performance tune did for it.

Tartan43

I also read that BMS tune delivers around 300bhp, but the math doesn’t add up when reading the dyno results on their website.



Mercedes claims that a stock C300 4MATIC delivers a peak 241bhp. The “rule of thumb” is all wheel drive cars loose 20-25% of their quoted bhp figures as measured at the wheels due to friction etc. Using 25% loss, a stock C300 4MATIC should produce approximately 180.75whp on a dyno.

The BMS chart above confirms approx 25% loss, showing the stock c300 max power at 179.81whp. This is consistent with the fact that BMS apparently developed their tune using a 2015 C300 4MATIC (http://www.n54tech.com/forums/showthread.php?t=28003)

Here’s where the math doesn’t add up. Using the 25% loss rule, a 300bhp engine (~60bhp tune) should produce approx 225whp on the dyno. However the dyno chart shows the BMS Stage1 C300 max power at 196.33whp, which translates to approximately 262bhp (~21bhp tune).

I don’t do any of this for a living so please let me know what I’m doing wrong.

Tartan43

I love what the Renntech (63bhp increase) and PP Performance (67bhp increase) tunes do for the C400. Unfortunately Renntech doesn't appear to have a tune for the C300 and the PP Performance tune only adds 30bhp for $888. OE Tuning claims 65bhp for $636 (Memorial Day sale price).

In the end I'm just trying to get as much power increase as possible. Off to find a 4 wheel dyno for the "before" measurements...

Wkar275

If anyone dynos the OE tuning and it's near 60bhp I will purchase the tune asap

SnazzyLabs

Same here.

z8achoc18

I'm also interested in seeing how this tune does on the dyno.

Tartan43

A quick update; I found a performance parts shop with a four wheel "Dynojet" dynamometer - MAC Autosport. I'm trying to get the next available appointment, which at this rate is looking more like Monday. Once the stock ECU is baselined they will store the measurements for comparison to the ECU tune. Using the same dyno within a couple of days I'll try and keep as many variables as possible the same.

Tartan43

Did you loose any of the DYNAMIC SELECT features after the PP Performance tune? My understanding is the ECU tune changes not only throttle response and limiter, but also the shift points. So do "Sport+", "Sport" and "Comfort" modes feel different from each other or is it all just one map now?

Dkinsley

No, they feel significantly different. Spot+ is a blast and nothing like Sport+. The shift points are different. Yesterday I was playing around in Sports+ (with the radio off) and I could actually hear my turbo's whining.

Tartan43

Thanks, very nice! Hoping for a similar result...

SnazzyLabs

Received your ECU back, yet, Tartan43?

Tartan43

On the Bench at OE Tuning as we speak. Back in the car tomorrow afternoon. Dyno round 2 on Thursday afternoon. Detailed update on this thread by EOW.

LateC300

BMS tune did wonders for my car. Especially when connecting the 4th plug (the one that's quite annoying to get to), torque was pretty insane compared to stock. It really would throw you back in your seat during low-mid rpm pulls in any gear

Top end was about the same, butt dyno didnt notice much of a difference. But alas, I had to remove it to get some engine warranty work done to the car, so now it's just sitting in my garage . Too lazy to install it again

SoDakBenz

That is my concern, I will get it love the changes it makes to how the car drives and have to take it off for service then not want to mess with putting it back on. My car is a lease but has the wrist pin issue at cold temp so I'm debating if I should get that squared away first or say f-it since it's a lease.

LateC300

Honestly, taking off the factory ECU bracket and wiring is probably the hardest part now. I would definitely get any known issues taken care of first with your car.

I found a way of getting my hand and wrist angled perfectly to get that 4th plug in there when i was taking it off, so really it's just about the time it would take to get everything cleanly installed ("all-black" on this forum did a bang up job installing it for me and made it practically invisible), i dont think i could get it exactly the way he got it for me.

That being said, I'm really missing the power, boy was the car a hoot to drive. im so conflicted!