G63DCC

The sound isn't really any different, but the thrust is remarkably different...it's really the torque off of the line that is most noticeable after the upgrade. You really need to keep both hands on the wheel when you press the pedal all the way because you can actually chirp tires (you won't lose traction but to hold a straight line you will want all hands on deck, so to speak). It's exhilarating to say the least.

I won't knock the G55 at all, I loved mine. It was plenty fast and fun. My most favorite feature of the 63 is the interior. I've been driving G's for ten years, so the new cabin to me is a major plus!

drew138

How has fuel consumption changed post ECU upgrade? Although I don't think you had the car stock very long.

G63DCC

Not sure, but I do tend to currently average 15mpg on the highway, running in sport mode...I did the mod almost immediately after the initial break-in, at approx 1100 miles.

junc45

How are the ecu upgrades working out now that its been a couple of months? I just happened to look at Renntech's website and it appears they have dialed down the boost a bit. Now the ecu upgrade gets you 630hp and 620 tq which is still significant but the older upgrades look like they were claiming 669 hp and 734tq. Wonder if there have been issues.

G63DCC

No issues here...

junc45

Great to hear.

GiovanniD'aloja

Do you loose the warranty when you do the ECU upgrade?

twist-a-grip

I talked with Renntech about this today. Their explanation for this decrease was not that they dialed down the boost or they had issues with the tune, but rather the G63 and some of the other 4WD/AWDs with the 5.5 aren't putting down the power like the 2WD cars, therefore they reduced the published gains. Most of us realize that you'll lose power when it travels to 4 wheels instead of just 2, but the numbers they publish are at the crank, so why wouldn't they show the same numbers (669 and 734) for all 5.5 AMG equipped cars, if they were all really the same tune?

Probably gonna pull the trigger on this, but have another week or two until I crack 1000mi, so I was hoping to hear some more first impressions and more long-term experiences to push me over the edge.

G55K

I have Kleemann's ECu upgrade and down pipes. I have before and after dyno sheets that I can post when I get back in town if you're interested. The power difference is huge. I have about 5000 miles on the tune so far and it's been flawless.

plastique999

Where in SoCal can I get the Renntech ECU upgrade installed?

jyupitt

Im debating on this upgrade, the explanation that I heard from them directly is that it's the fuel quality, apparently majority of the pump quality in the US is not as good as they liked, therefore the tune needs to accommodate the lower quality and therefore published gain was reduced.


I would like to hear from owners whose had this tune for a long period of time, is it really worth it once the novelty wears off. I can certain appreciate the gain as I've always modded my cars, from giac/novitec to cobb, however I wonder if the ROI is there for a vehicle this heavy, as I don't plan to go drag race any one and the acceleration in its current state is impressive.

drew138

Bumping old thread. Curious any long term feedback / reviews on the G63 ECU tune. Seems there were two confirmed installs on this thread.. Any others?

frenchy206

I recently did the Kleemann ecu upgrade on my 2014 G63. It's less expensive than the Renntech upgrade and has more HP & Torq. Kleemann claims 690hp and 710torq.

The upgrade made a huge difference. Throttle response was so much better and the power is incredible.

Daily drivability has not been adversely effected. Everything is normal until you flex your big toe.

Kleemann was able to do the flash and send the ecu back, same day.