GLC43 best tune that can be installed and removed
 

I have a ‘18 and do not want to void warranty. I’d also like to have an even better driving experience. There are many threads on tuning but none specific to this topic. I know there’s a lot of knowledge on the forum so I’d like your help. Thanks!

Get a used ECU, clone it to your vin, load the tune on the clone, and enjoy the ride. Just make sure to swap before you take in for service. I've heard this does not guarantee the dealer can't discover if you ran a tune but makes it very difficult to detect.

If maintaining your warranty is important, I would not venture into the world of tuning. You may find a sympathetic dealer but you also may find your dealer not so friendly. If you do go for a tune, I am extremely happy with the handheld unit from AMR. Apart from the change in performance, it is possible to restore the factory tune at will.

If a company actually put out a flash tune product that dealers couldn't detect that company
would be rich.
I will just have to be patient.
My racing days are over.
Would love to see if there is actually anything out there.
I think from reading a piggyback is the least detectable but I am sure someone will say they are- LOL.

There’s a way
 

I asked my SA if they did tuning a few months back and he said no. Just did a search and they’re now doing them. Won’t void the warranty.

You have a few options. You could easily get a virgin ecu have it cloned and tuned and just swap ecus for a dealer visit.

We do also have a handheld that allows you to tune from home and also stores your stock file to flash whenever you like. While we have done tens of thousands of cars before without issue, if they want to send the ecu to Germany they could find traces. (Piggyback no different)

for the gentleman that said he tuned at the dealer and no worries, it really is a crap shoot. There are quite a few people that have done that (search the forums here) and found that they got black flagged.

Uh..... so your dealership will tune the car for you ? Did they put limits on the threshold of tune , i.e. they won't go beyond a mild bump in power ? Just trying to understand this, so they will take, for instance AMR's software, tune your car and then if it goes boom it WONT void the warranty ? Never heard of this before.

Dealer tune
 

The local Audi dealer here is an APR shop operating out of it. They say it won’t void the warranty. Calling MB now.

He’s pulling details but said 100hp 80lbft torque and it doesn’t void warranty. Calling me back with $ and exact specs. Is obd2 delivered which leads me to wonder whose they’re installing. They said no Dyno. MBof Chicago street tuning has limited details.

Make sure you get it in writing about their warranty. It will be a dealer thing to cover issues that result from the tune, not MB, if something happens. JB4 would probably be the least detectable tune, but even then, if you blow your engine, MB can find out and deny warranty coverage. Good luck.

4 dealers
 

After all the feedback - I called 4 MB dealers in the area. All of them offer tuning and all of them will return to factory settings if warranty work is needed. They said unless customer is a jerk, they don’t really care because they get paid for the work. Has anyone been denied warranty work because of a tune or is it urban legend?

With respect, that's great that they tell you that, but if it's not in writing you are at risk. They/you have no recourse if MB Corp happens to ask for the data logs of ECU and they find there was a tune on say, a blown up engine. MB will more than likely deny and your dealer will run for the hills. If your radio goes out, that wont be a problem. Yes warranty work has been denied because of tunes causing issues. Tune at your own risk.

If you want to go under radar then I advise you to look into a piggy back tunes as they are plug-n-play and can be removed at anytime especially going in for warranty work or maintenance.I had the Dinan Elite then the Sport, then switched to a Jb1 and now JB4. I am super happy with the BMS Jb4 and we have a pretty large Whatsapp group shared with the C43 guys. The group is pretty lively and they share a wealth of information on tweaking and get the most out of the JB4. Not many people in the group have a GLC43 and the few guys that do have ran a 0-60 in 4.0-4.2 and quarter mile in 12.0-12.2. This is pretty good considering MB rated the GLC43 0-60 4.7 and quarter mile at 12.9-13.0. The only mod is JB4 and we don't have launch control. I am waiting for my intakes and downpipes to be installed and I will do some 0-60 and quarter mile runs to see where I stand, as I should be faster than those guys as I have more power mods. Nothing is truly undetectable; however, a lot of guys in our group have gone to service or got warranty work done and removed the JB4 before going to the dealer. Not one single issue has been reported about the jb4. .

There are other piggy backs like RaceChip GTS, Dinan, and a few others. I am not sponsoring JB4 but, I do like the implementation and ease of removal with out having to plug up ODB2 devices to keep flashing to stock when needed.

Dame how has the lowering module been working out?
Is it always at static height and aligned at that height ?
Also do you find more rock chips on the car overall as a result ?
These run flats stick to any loose debris and just throw everything back up onto the car.
I was riding with the windows down with my hand out the window and kept getting pelted by rocks.
I am dreading what this thing is going to look like in 5 years.
Either way thanks for the JB4 piggyback info and it kind of re-affirmed my original thought
that most are detectable but the piggy's have a tendency to raise less eyebrows.

Hey affalterthought - The lowering module has held up very well. I got an alignment done as I noticed my rear camber was look pretty bad. No issues since I got the alignment, tires are wearing even, ride is still comfortable and I haven't adjusted the settings since. Rock chips are unavoidable and I learned my lesson. I should have got expel wrap for the front of the GLC when I bought it. I may get paint correction before the summer hits and I will probably expel the front of my truck. 5 years, lol I already had my windshield replaced. A dump truck didn't have it's load covered and was slinging rocks all over the highway. I stayed in the far left lane but couldn't avoid other cars running over the rocks and sending them my way. I also got a nice nick on my door right under the mirror. Insurance wouldn't fix that :(

Let me know if you, or any of the guys are looking into the JB4. I am in a WhatsApp group and I can invite you. I did Service A and B and did some warranty work and I have removed the Jb4 each time. My dealer is mod friendly so after I install my downpipes, I am not going to be removing and reinstalling my JB4 anymore as I will just leave it on. It's out of site anyway, you would have to really be snooping around in my engine bay to find the device though my dealer doesn't care.

Have had mine since October 18 and just turned 5k on it- LOL (no Service warnings yet) . Yeah I am strongly thinking paint correction and Expel. Curious, on the JB4 is it totally customizable or are there preset tunes you choose from ? What are the gains ?? I am no mechanic by any stretch so how easy is it to set this JB4 up ?

Knock on wood, I bought my GLC in April of 2017 and no major paint defects except that rock chip under the mirror and a minor scratch from my umbrella. I was trying to hold it up to put my son in the truck during a very bad storm and wind blew the umbrella out of my hand and metal point on top of the umbrella hit my quarter panel. Left a nice scratch about the size of a dime. It doesn't bother me now, but I was annoyed for about a year. lol

JB4 is preloaded with map 1, 2, 5, 6, and 7. Map 6 can be adjusted for peak boost and BMS is currently working on fuel stuff. The guys in the Whatsapp group are constantly trying to perfect map 6. The best of the c43 guys are running 0-60 3.4 secs and quarters miles of 11.4 121mph+. So it's definitely making power but how much?, it varies from car. On my end, my bro has an audi s5 and I run over him all day and he has a stage 1 apr tune (it's not even close). JB4 also has phone app so you can change settings on the fly, I run map 2 daily or when I feel the need for speed I add a little race gas and run map 5. If I am out with the wife, and I get a little tipsy, I have her drive and set her to map0 (no tune). The guys in the group are very helpful and will check your logs, provide suggestions and even show you how to install the jb4. Took me 5 mins to install mine, because I wanted to zip tie everything to make it look OEM as possible.

Cool thanks man. Appreciate the knowledge.

Not to threadjack, but Xpel worth every penny, especially on a black car. Have on front bumper, hood and side mirrors. Also, have ceramic on whole car, but honestly not impressed with it.

If I tune, it will probably be with JB4, so good insights here for the GLC. I'm fighting the itch, though, to dump the 43 for the 63. Car addiction stinks. :)

I seriously don't think about the 63 at all. I got my 43 for $25k+ less than a 63. The 63 will always have the bragging rights because of the honking V8. I can live with that.

Renntech The hand held tuner can be installed and then removed at will. Just make sure you have a tender handy during install. I have a few tuners no issues what so ever. I would say those who do have fuel issues/maintaining proper octane.

Thanks, didn't realize they had the HHT for the 43 now. Oh boy, decisions, decisions...

If you want to play it safe then Renntech is probably the best choice since they provide the HHT. Other vendors will provide you with the HHT but you have to return it once you tune. Another option is to go on Ali Express and buy the Mercedes Star Diagnosis System (SDS)tool. Then you can just flash the Renntech, Eurocharge or AMR tune yourself. The only problem with the HHT devices is that if MB really wanted to do a deep scan search, we have found that with using the MB SDS tool, there's a section that shows Flash Counter. This flash counter let's MB know how many times the ECU has been flashed. I doubt MB will be digging that far but if something ever happened where you had to get like an engine replaced or transmission or something major, it can be detected . Now, not saying that the JB4 is not detectable, but I rather not be flashing the ECU imho. If you don't care about that then the ODB2 tunes are great.

Our handheld is sent to be kept by the end user. It stores the stock and tuned files to apply at will

also, you won’t be able to apply our tune via star FYI. Most of the tuners files are encrypted for the devices we use.

Thanks for the insight, DameMD, much appreciated. I'm all over the place right now with what to do with my 43...keep & tune, sell, get GLC63, something else... :D