Renntech ECU 2019 G550 Upgrade
08-27-2020, 06:53 PM
#27
Junior Member
Thread Starter
Because I put on bigger tires (275/55R20 Pirelli AT) it has messed with my speedo a bit, combine that with the less fuel efficient tires and I can't tell if it is better. My friend claims his G63 improved about 10%
05-29-2023, 08:17 PM
#28
I wound up getting the Renntech tune for my 2020 G550. It has made a huge difference in power and speed. Sounds even better and the power at passing speeds is outstanding. I think I increased by 100HP. Gas mileage seems to have improved also (I have no idea how).
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jamgolf (06-24-2023)
05-30-2023, 10:08 AM
#29
I want to correct my old post as I did love my Renntech cars but in the end when I moved my cars warranties were both voided do to Renntech products installed on my cars. I have been a long time Renntech owner and have had 5 of them. Last two even had parts ordered directly through Renntech and were always serviced at MB Escondido with zero issue even for ck engine lights that weren't tune related. I would actually tell service writer dongle was in glovebox if needed. Never a issue.
MY 2015 S550 had every thing they sell bedsides downpipes which they don't show avail unless you ask. . It was badged, had wheels and exhaust so there was no hiding it. They denied my warranty because of the Renntech parts. After a long argument I paid the $5k invoice. Dealers would never put in writing Renntech parts voided warranty and I was caught in middle.
What bothered me is how Renntech handled it. It was just being blown off as you should have removed tune before service which was never explained to me.. My tune was removed back to stock by shear coincidence at time of service. MB was able to detect the ECU was modified which Renntech says they cant. MB also said my Renntech mufflers effected the car. MB was able to show me how it showed up on their handheld diagnostic tool. My dealer called closest MB dealer that was Renntech dealer and they explained they are no longer a Renntech dealer do to too many issues and that backed up my dealers claims to deny my warranty. Basically Renntech did nothing to assist me.
The worst part about it is the cats and pipes a $4k part needed to be replaced and Renntech never advised me the they sell theses pipe with modified cats that would have been cheaper and work better with the other Renntech parts.
I think Renntech makes killer parts that are well developed but they will void your warranty. Also they walk a very fine line of stating if their parts are approved or not. If you look at their new dealer network the majority of MB dealers are now removed. Do I think the Renntech parts caused the cat failure? I don't know but the tune was upgraded at about $1k for 93 gas several months earlier.
As per MB themselves ANY modifications will void warranty.
MY 2015 S550 had every thing they sell bedsides downpipes which they don't show avail unless you ask. . It was badged, had wheels and exhaust so there was no hiding it. They denied my warranty because of the Renntech parts. After a long argument I paid the $5k invoice. Dealers would never put in writing Renntech parts voided warranty and I was caught in middle.
What bothered me is how Renntech handled it. It was just being blown off as you should have removed tune before service which was never explained to me.. My tune was removed back to stock by shear coincidence at time of service. MB was able to detect the ECU was modified which Renntech says they cant. MB also said my Renntech mufflers effected the car. MB was able to show me how it showed up on their handheld diagnostic tool. My dealer called closest MB dealer that was Renntech dealer and they explained they are no longer a Renntech dealer do to too many issues and that backed up my dealers claims to deny my warranty. Basically Renntech did nothing to assist me.
The worst part about it is the cats and pipes a $4k part needed to be replaced and Renntech never advised me the they sell theses pipe with modified cats that would have been cheaper and work better with the other Renntech parts.
I think Renntech makes killer parts that are well developed but they will void your warranty. Also they walk a very fine line of stating if their parts are approved or not. If you look at their new dealer network the majority of MB dealers are now removed. Do I think the Renntech parts caused the cat failure? I don't know but the tune was upgraded at about $1k for 93 gas several months earlier.
As per MB themselves ANY modifications will void warranty.
09-20-2023, 02:22 PM
#30
UPDATE: I got the RennTech tune. Added 100+ HP. Am in Cali with 91 - it still is amazing. I reccomend. The power output is awesome and the speed off the line crazy. Mostly I use the power when merging / passing...or and when off roading!
