ECU Tune on a GT C

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Nov 27, 2020 | 05:13 PM
  #1  
Who here has purchased an ECU tune for their GTC? If so may I ask a few questions?

First, I'm considering only a tune with no hardware modifications for the time being, since I'm still under warranty.

The first and main one, did you find the tune worth the money you spent? Was the change in HP and torque significant and easily noticeable?

Who did you purchase your tune from and were you satisfied with the tune and the customer service? (You can PM me if you don't want to make a public comment).

Did the tune affect the drivability of the car in any negative way? Does it get tail happy with the extra torque?

These black friday deals have me tempted but you can't return the tunes and so I want to be sure I know all I can.

Thank you.



Reply 0
Nov 27, 2020 | 10:45 PM
  #2  
I don't have a GTC (GTS) but there's been a lot of threads so you might not get any new responses.

On a GTC, you will pick up around ~75-85whp with just a tune. The car will be rated ~650hp with a tune. Just do it. No downsides IMO. Renntech, Eurocharged, Weistec, OETuning (plus more) are all reputable.
Reply 0
Nov 28, 2020 | 10:45 AM
  #3  
Quote: I don't have a GTC (GTS) but there's been a lot of threads so you might not get any new responses.

On a GTC, you will pick up around ~75-85whp with just a tune. The car will be rated ~650hp with a tune. Just do it. No downsides IMO. Renntech, Eurocharged, Weistec, OETuning (plus more) are all reputable.

Thanks! I'm still trying to sort out the search function here. I can search "tune" but it brings up every Merc made. I can select "search subscribed forums" but I can't figure out how to subscribe to a particular forum.

Any help?
Reply 0
Nov 28, 2020 | 11:45 AM
  #4  
Quote: Thanks! I'm still trying to sort out the search function here. I can search "tune" but it brings up every Merc made. I can select "search subscribed forums" but I can't figure out how to subscribe to a particular forum.

Any help?
To get that little extra out of the GTC, you want to make sure that the tuner uses a different map between the GT/GTS and the GTC/GTR - both the same motors but with slightly different parameters. There are a few tuners that do this so be sure to ask. You will also want an HHT; some its included and some its an optional extra. Given you are still under warranty, you want to be able to take the tune out during service calls.

per your question about search - type the search in first, and then once you have the results select 'advance' to narrow to the GT forum and other filters per their relevance:



Reply 3
Nov 28, 2020 | 12:00 PM
  #5  
Quote: To that get that little extra out of the GTC, you want to make sure that the tuner uses a different map between the GT/GTS and the GTC/GTR - both the same motors but with slightly different parameters. There are a few tuners that do this so be sure to ask. You will also want an HHT; some its included and some its an optional extra. Given you are still under warranty, you want to be able to take the tune out during service calls.

per your question about search - type the search in first, and then once you have the results select 'advance' to narrow to the GT forum and other filters per their relevance:




Thank you Skilly! This is extremely helpful.

FYI If I was west coast I'd be offering you some money and food to help me put a wing on my GTC. I have a Solarbeam Yellow and I think a CF wing would look awesome, but I'm not skilled enough to attempt that myself of flush enough to pay $12K to have a dealer do it. ;-)
Reply 1
Nov 28, 2020 | 12:37 PM
  #6  
Quote: Thank you Skilly! This is extremely helpful.

FYI If I was west coast I'd be offering you some money and food to help me put a wing on my GTC. I have a Solarbeam Yellow and I think a CF wing would look awesome, but I'm not skilled enough to attempt that myself of flush enough to pay $12K to have a dealer do it. ;-)
I can't imagine it's any more difficult than swapping wings on the GT/S (which was very straightforward). Skilly can shed light on this, but here's the video that I used. The only differences I could see being the covers for the hatch vs boot, and not needing to swap the motors anymore now that a forum user has created a plug in mod to circumvent the error code from not having the motor plugged in.

Reply 0
Nov 28, 2020 | 06:57 PM
  #7  
Quote: I can't imagine it's any more difficult than swapping wings on the GT/S (which was very straightforward). Skilly can shed light on this, but here's the video that I used. The only differences I could see being the covers for the hatch vs boot, and not needing to swap the motors anymore now that a forum user has created a plug in mod to circumvent the error code from not having the motor plugged in.

https://www.youtube.com/watch?v=4Zq_7OAxnX4
Its identical; just plan for wiring a brake light too that requires you to pre-wire in the base and fish the wire though the wing. It has an entry point at the left bracket (facing the rear of the car).

The easiest way to do it is to assemble everything and wire for the brake light on a bench. Add length on both ends and trim to size once you have it all put together. At the base I would leave at least 2' and trim back and I'd leave at least 1' on the spoiler side - it's easy to tuck in spoiler once you confirm its operating correctly. The brake light on the C Roadster isn't compatible but it's wired the same way at least so I just repurposed the connector.
Reply 0
Nov 28, 2020 | 07:13 PM
  #8  
Quote: Its identical; just plan for wiring a brake light too that requires you to pre-wire in the base and fish the wire though the wing. It has an entry point at the left bracket (facing the rear of the car).

The easiest way to do it is to assemble everything and wire for the brake light on a bench. Add length on both ends and trim to size once you have it all put together. At the base I would leave at least 2' and trim back and I'd leave at least 1' on the spoiler side - it's easy to tuck in spoiler once you confirm its operating correctly. The brake light on the C Roadster isn't compatible but it's wired the same way at least so I just repurposed the connector.
I agree this looks straightforward, and I'm 90% confident I could pull it off, but that 10% is daunting. For one, this video is a coupe and I have a roadster so I'm not sure about differences. I can see me dropping a bolt and listening to it rattle as long as I own the car. The solution for water intrusion, the gasket and plugging the drain hole, looks a little wonky to me. water would still pool outside that gasket and I'm not sure it would remain watertight over time. I also wonder about matching SBY color on the base, I guess a body shop can manage that.

Skilly, how long would you say it would take you to do the swap, now that you have done it one time?
Reply 0

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Nov 28, 2020 | 07:20 PM
  #9  
Quote: I agree this looks straightforward, and I'm 90% confident I could pull it off, but that 10% is daunting. For one, this video is a coupe and I have a roadster so I'm not sure about differences. I can see me dropping a bolt and listening to it rattle as long as I own the car. The solution for water intrusion, the gasket and plugging the drain hole, looks a little wonky to me. water would still pool outside that gasket and I'm not sure it would remain watertight over time. I also wonder about matching SBY color on the base, I guess a body shop can manage that.

Skilly, how long would you say it would take you to do the swap, now that you have done it one time?
I would say the roadster might be easier. Aside from the brake light it takes about 2 min to pull the trunk liner - easier than the coupe decklid in its size alone.

From removal of current wing to assembling the parts, testing the brake and installing the new parts and putting the trunk liner back on its max 2hrs. on a scale of 1 to 10, with 10 being the most difficult, this is about a 2. The challenge and most time consuming aspect of this is searching and confirming all part numbers from MB. That's why you see 'kits' on Ebay for about $1,000 mark up - its not easy to reverse engineer the parts required. Aside from that, this is a VERY easy job to do.

You literally pull the trunk liner and everything is there for you to start removing - no special tools and really easy engineering (nothing is overdone or complicated!).
Reply 0
Nov 28, 2020 | 08:41 PM
  #10  
Quote: To get that little extra out of the GTC, you want to make sure that the tuner uses a different map between the GT/GTS and the GTC/GTR - both the same motors but with slightly different parameters.
The GT/GTS is not the same motor as the GTC/GTC. The GTC/GTR use physically larger turbos (I think with higher boost pressure), lighter flywheels, and different transmission gearing (I think 1st and 7th gears are shorter).
Reply 1
Nov 28, 2020 | 11:54 PM
  #11  
Quote: The GT/GTS is not the same motor as the GTC/GTC. The GTC/GTR use physically larger turbos (I think with higher boost pressure), lighter flywheels, and different transmission gearing (I think 1st and 7th gears are shorter).
I used the wrong word "parameters" - they are all built with M178 motors and I think for the GTC/GTR screws are different on the turbos and the compression ratio is different in the motor (so you can run higher boost). In any case, you can get more from them with a tune specific to their makeup rather than assuming that all of the GTs are the same.

Not sure about the flywheel and gearing. It would be great to see one of the tuners catalog the differences.
Reply 0
Nov 29, 2020 | 09:26 AM
  #12  
Quote: Its identical; just plan for wiring a brake light too that requires you to pre-wire in the base and fish the wire though the wing. It has an entry point at the left bracket (facing the rear of the car).

The easiest way to do it is to assemble everything and wire for the brake light on a bench. Add length on both ends and trim to size once you have it all put together. At the base I would leave at least 2' and trim back and I'd leave at least 1' on the spoiler side - it's easy to tuck in spoiler once you confirm its operating correctly. The brake light on the C Roadster isn't compatible but it's wired the same way at least so I just repurposed the connector.
Quote: I would say the roadster might be easier. Aside from the brake light it takes about 2 min to pull the trunk liner - easier than the couple decklid in its size alone.

From removal of current wing to assembling the parts, testing the brake and installing the new parts and putting the trunk liner back on its max 2hrs. on a scale of 1 to 10, with 10 being the most difficult, this is about a 2. The challenge and most time consuming aspect of this is searching and confirming all part numbers from MB. That's why you see 'kits' on Ebay for about $1,000 mark up - its not easy to reverse engineer the parts required. Aside from that, this is a VERY easy job to do.

You literally pull the trunk liner and everything is there for you to start removing - no special tools and really easy engineering (nothing is overdone or complicated!).
One thing for sure then is I don't ever want to tackle a 5 LOL. I can see that taking the motor swap out of the equation makes things much easier. I don't suppose you can purchase the base pre painted from Merc can you?

Thanks Skilly.
Reply 0
Nov 29, 2020 | 09:33 AM
  #13  
Quote: Not sure about the flywheel and gearing. It would be great to see one of the tuners catalog the differences.
Car & Driver mentioned this in one of their reviews of the GTC.
Reply 0
Nov 29, 2020 | 04:52 PM
  #14  
Quote: One thing for sure then is I don't ever want to tackle a 5 LOL. I can see that taking the motor swap out of the equation makes things much easier. I don't suppose you can purchase the base pre painted from Merc can you?

Thanks Skilly.
you *may* be able to - Xentry has a lot of options with the base. That said, unless you plan to relocate the reverse light to the base as the GTR Roadster config is you will need to do some bodywork on it to cover the hole anyway.
Reply 0
Dec 2, 2020 | 09:30 PM
  #15  
I bought a tune. Will report back.
Reply 0
Dec 8, 2020 | 04:34 PM
  #16  
Preliminary report on tune. I bought a Stage 1 from Eurocharged.

Communication with the company was excellent. I had some hiccups with getting the PC and software to play nicely with each other, but that was cleared up with phone support.

There are a couple instances where the website is not exactly accurate, regarding performances gains and installation procedures, and it would behoove them to get that straight just to aid with customer confidence.

The tune itself is simply remarkable. Gobs and gobs of extra torque. With cold tires I broke traction in 4th gear. Starts, idles, and runs very smoothly. Right now it seems on the verge of too much, but once I relearn how to drive the car with all this extra power I may not feel that way. Switching from the tune back to factory takes about 4 minutes so it's easy to switch back an forth.

Why maybe too much? Only because the car will now spin in 4 gears (straight line, at least when cold) and you can't really use more power than you can get to the ground unless you are on a track or at "go straight to jail" speeds. ;-)

But so far it's damn fun to mash it.



Reply 5
Dec 8, 2020 | 05:20 PM
  #17  
now just add a pedalbox and you'll be complete!
Reply 0
Dec 8, 2020 | 05:33 PM
  #18  
Depending on where you live and how you use your car, the R888r tires will solve your traction problems. You just have to be extra careful in standing water and careful in cold weather until the tires have a few minutes to warm up.
Reply 0
Dec 8, 2020 | 05:55 PM
  #19  
Quote: now just add a pedalbox and you'll be complete!
I ordered an EVM today. I'll have to look at the pedal box.

And then...the spoiler. ;-)
Reply 0
Dec 8, 2020 | 05:57 PM
  #20  
Quote: Depending on where you live and how you use your car, the R888r tires will solve your traction problems. You just have to be extra careful in standing water and careful in cold weather until the tires have a few minutes to warm up.
I'm definitely going to chew up the stock rears long before the fronts, so I'll need to look at those when the fronts go too. Thanks for the advice! It's like being on wet pavement all the time now.
Reply 0
Dec 8, 2020 | 05:59 PM
  #21  
On second thought, how bad an idea would it be to mix and match fronts and rears? Factory on the front and R888r's on the rear?
Reply 0
Dec 8, 2020 | 09:39 PM
  #22  
Quote: On second thought, how bad an idea would it be to mix and match fronts and rears? Factory on the front and R888r's on the rear?
It's not optimal if you drive like you're on a race track/live in the canyons. It's fine if you drive like a reasonable person and just want more straight line traction.
Reply 0
Dec 9, 2020 | 01:51 AM
  #23  
Hi, Have any information about Kleeman in Denmark? Have time the second week in Jan 2021 for an upgrade of hardware and software. Have seen curves that it will be 740-750 HP.
Reply 0
Dec 9, 2020 | 07:30 AM
  #24  
What are the actual HP and Torque gains from a Stage 1 from Eurochargee? Their website says stock HP is 465, which is clearly wrong for the GTC. Not a great first impression when their quoted HP is off by about 100! Not to mention the turbos and trans gearing in the GTC/GTR is different than the GT/GTS. Odd they would get this wrong.
Reply 0
Dec 9, 2020 | 08:24 AM
  #25  
Quote: What are the actual HP and Torque gains from a Stage 1 from Eurochargee? Their website says stock HP is 465, which is clearly wrong for the GTC. Not a great first impression when their quoted HP is off by about 100! Not to mention the turbos and trans gearing in the GTC/GTR is different than the GT/GTS. Odd they would get this wrong.

Can you screenshot where you pulled that number from? Because their website is accurate.




https://www.eurocharged.com/product/mercedes-amg-gt-c/
Reply 1
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