GT/C192/R192: Upgrading a GT 55 to a GT 63
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You might want to watch this video before saying that. Even with the tune it wasn't close at all. The 63 is definitely under rated in power. https://www.youtube.com/watch?v=sCxgtuQQy-8&t=290s
The 55 has better lower end torque which is why it’s able to jump ahead at the start of both races. Thats how Mercedes makes thier cars. On a street the 55 is actually a bit more torquey and quicker than the 63 especially with a tune.
you don’t notice the difference unless going too a track like such. Also considering how close the roll race was I wouldn’t say it “wasn’t close”
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Actually just got my 55 back from Renntech and definitely worth the money. The 55 had plenty of power before but I felt the responsiveness was lacking a bit and the Renntech tune fixed that and the extra power certainly was nice. I initially drove the 63 and 55 and think the 55 plus the tune is quicker (and certainly for the price). Also noticed a bit more burbles in sport+ mode when letting off the gas at speed.
I read on another thread here from another member that the way AMG builds thier cars are so that the 63 can really thrive on open roads at 150+kmph range. Below that on shorter pulls and regular city driving the 55 and lower models actually feel quicker and more responsive due to them being built for that.
if you put the time and money into it you can most certainly get the 55 to well above 63 levels although I wouldn’t recommend anything past stage 1 for avoiding warranty issues. But a stage 1 on the 55 is more than enough if you’re not going to track it.
Last edited by AMGeneticzo; Jun 20, 2025 at 01:15 PM.
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I am shooting for high 800s low 900s with my 63. Sounds like it shouldn't take too much to get it there. I knew when i was buying it that was the plan. Wasnt anticipating how slow the aftermarket parts were going to be. Been waiting 8 months for an aggressive carbon aero package. Finally was able to place my order the day after they called me saying parts were ready. Looking forward to the end product. I usually get my car done a month or so after purchase. This has been a lesson in patience for me which i needed..lol
800-900 is absurdly fast, any goal of what output you’re trying to reach or just shooting for the stars
Last edited by AMGeneticzo; Jun 20, 2025 at 12:57 PM.
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You might want to watch this video before saying that. Even with the tune it wasn't close at all. The 63 is definitely under rated in power. https://www.youtube.com/watch?v=sCxgtuQQy-8&t=290s
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Could be just the differences noted above and was just going off the old seat dyno and didn’t actually measure it, only going off actual driving feel. I asked how they were getting crazy numbers from the 63 tune if it really was the same engine and seemed to be more about the available parameters they could modify with the 55 vs the 63. 63 with those tune numbers is crazy and that might have swayed my decision if that was available at the time!
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OK so for starters both the 55 and 63 use the exact same M177 4L twin turbo engine, this includes the same bore, same stroke, same displacement and same compression ratio. This is all confirmed on MBusas website. As superswiss said there maybe be a difference in forged veruss non forged or cast but thats not a architectural change that is a bolt on and also still just pure speculation. If anything the facts point towards the pistons being forged on the 55.
Number 2 an article and press release linked below from MBusas website confirms the vast similarities between the 55 and 63 engines including BOTH HAVING the twin scroll turbos, his experience as stated stems from the M177 variant in the c63 model. Remind you this is a GT were talking about not a c-class, completely different worlds here.. So the idea that the GT55 uses or may use single scroll turbos like the old C63 is flat out wrong. That reference point doesn’t apply, this is a flagship top tier AMG GT not a c-class with older hardware..
The only thing id say i cant argue is his claim about a simple piggyback tune not turning the 55 into a 63 which is somewhat correct, but it gets it fairly close for just a piggyback. Put a real ecu tune and some minor cooling upgrades and youre there. Both engines share the same mechanical dna and makeup. Its the same engine same platform tuned differently with minor upgrades to allow for sustained abuse and higher tolerance as implied by Mercedes benz themselves. I still stand firmly by my 90% same to 10% different stance and the facts from mercedes benz themselves undeniably backs it up.
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Number 2 an article and press release linked below from MBusas website confirms the vast similarities between the 55 and 63 engines including BOTH HAVING the twin scroll turbos, his experience as stated stems from the M177 variant in the c63 model. Remind you this is a GT were talking about not a c-class, completely different worlds here.. So the idea that the GT55 uses or may use single scroll turbos like the old C63 is flat out wrong. That reference point doesn’t apply, this is a flagship top tier AMG GT not a c-class with older hardware..
The only thing id say i cant argue is his claim about a simple piggyback tune not turning the 55 into a 63 which is somewhat correct, but it gets it fairly close for just a piggyback. Put a real ecu tune and some minor cooling upgrades and youre there. Both engines share the same mechanical dna and makeup. Its the same engine same platform tuned differently with minor upgrades to allow for sustained abuse and higher tolerance as implied by Mercedes benz themselves. I still stand firmly by my 90% same to 10% different stance and the facts from mercedes benz themselves undeniably backs it up.
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Could be just the differences noted above and was just going off the old seat dyno and didn’t actually measure it, only going off actual driving feel. I asked how they were getting crazy numbers from the 63 tune if it really was the same engine and seemed to be more about the available parameters they could modify with the 55 vs the 63. 63 with those tune numbers is crazy and that might have swayed my decision if that was available at the time!
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There seems to be a lot of misinformation on here. If the 55 and the 63 were so similar the performance wouldn't be so different. The 55 isn't close to the 63. As I stated earlier working with a tuner they can only get so much out of the 55. The 63 is a completely different story. If these were the same logic would say once both were tuned to max output the both should be the same hp. They aren't even close. People aren't paying the premium for the 63 if there was only the tune difference.
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There seems to be a lot of misinformation on here. If the 55 and the 63 were so similar the performance wouldn't be so different. The 55 isn't close to the 63. As I stated earlier working with a tuner they can only get so much out of the 55. The 63 is a completely different story. If these were the same logic would say once both were tuned to max output the both should be the same hp. They aren't even close. People aren't paying the premium for the 63 if there was only the tune difference.
I still stand by my thoughts that the 63 is extremely poorly priced but there are deals to be had no doubt.
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There seems to be a lot of misinformation on here. If the 55 and the 63 were so similar the performance wouldn't be so different. The 55 isn't close to the 63. As I stated earlier working with a tuner they can only get so much out of the 55. The 63 is a completely different story. If these were the same logic would say once both were tuned to max output the both should be the same hp. They aren't even close. People aren't paying the premium for the 63 if there was only the tune difference.
As shown in the video above, a properly tuned 55 making 579hp is still understandably reeled in by a stock 63 likely putting down as you said earlier closer to 630hp. That doesn’t contradict the argument, it supports it. The 55 can absolutely match or exceed stock 63 numbers with a solid tune. That’s the whole debate whether the $30K+ premium for a 63 is worth it, given how closely related they are mechanically.
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Where’s the misinformation? The only misinfo I’ve seen is the claim that the 55 and 63 don’t share nearly 90% of the same engine components when they do. Both use the same M177 engine block, same twin-scroll turbos, same compression ratio, and most core internals apart from what was being said. Nobody’s saying the 55 makes more power than the 63 or can out tune it because that’s definitley not the case. Higher baseline power almost always equals higher tuned ceiling. The point is that the 55 and 63 share almost the exact same mechanical platform, apart from things like cooling ECU tunin and possibly forged components in the 63. Even Mercedes has confirmed this.
As shown in the video above, a properly tuned 55 making 579hp is still understandably reeled in by a stock 63 likely putting down as you said earlier closer to 630hp. That doesn’t contradict the argument, it supports it. The 55 can absolutely match or exceed stock 63 numbers with a solid tune. That’s the whole debate whether the $30K+ premium for a 63 is worth it, given how closely related they are mechanically.
As shown in the video above, a properly tuned 55 making 579hp is still understandably reeled in by a stock 63 likely putting down as you said earlier closer to 630hp. That doesn’t contradict the argument, it supports it. The 55 can absolutely match or exceed stock 63 numbers with a solid tune. That’s the whole debate whether the $30K+ premium for a 63 is worth it, given how closely related they are mechanically.
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There must be a few upgrades to the 63 that we are missing. The 63 is running a larger turbo i know that one. If a tuner tunes the absolute most hp out of the 55 then does the exact same to the 63 according to some post here their hp should be the same. They are not, they are quite aways apart. So something is causing it, cams, intake I honestly don't know. Logic tells us that if they were just different by their factory tunes then installing a max tune to both would prove that by both showing the same output which they don't. This tells a story just don't know what it is.
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Once they start producing actual ECU tunes for the 55 it will no doubt hit 63 power with a simple tune.
