18 C63s Coupe not hitting anything above 430hp on gauge
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Newbie
Joined: Jun 2024
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2018 C63s Coupe
18 C63s Coupe not hitting anything above 430hp on gauge
Hi all,
Im having an issue with my car, under WOT my car seems to be only hitting about 430hp and torque at peak and dropping off to high 300s at higher rpm’s. No hard codes, I haven’t scanned the car yet but I was wondering if anyone else has experienced the same? The car is stage 2 with downpipes. It feels really good at times, however this past day it’s been feeling really sluggish and not as responsive to throttle. Will attach video for reference in comments.
Im having an issue with my car, under WOT my car seems to be only hitting about 430hp and torque at peak and dropping off to high 300s at higher rpm’s. No hard codes, I haven’t scanned the car yet but I was wondering if anyone else has experienced the same? The car is stage 2 with downpipes. It feels really good at times, however this past day it’s been feeling really sluggish and not as responsive to throttle. Will attach video for reference in comments.
Out Of Control!!
Joined: Nov 2018
Posts: 11,427
Likes: 5,336
From: San Francisco Bay Area
2019 C63CS
If you had filmed this in landscape mode like any normal video we could also see your boost gauge. Is it making full boost or not? A common cause of not making full power is limp mode. Stuck exhaust valves is a common source of limp mode. You won't get any warning if this happens, but if you scan the car it should give you a clue.
Thread Starter
Newbie
Joined: Jun 2024
Posts: 3
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2018 C63s Coupe
If you had filmed this in landscape mode like any normal video we could also see your boost gauge. Is it making full boost or not? A common cause of not making full power is limp mode. Stuck exhaust valves is a common source of limp mode. You won't get any warning if this happens, but if you scan the car it should give you a clue.
Member
Joined: May 2021
Posts: 89
Likes: 18
From: Brooklyn
2018 C43 Coupe
Hi all,
Im having an issue with my car, under WOT my car seems to be only hitting about 430hp and torque at peak and dropping off to high 300s at higher rpm’s. No hard codes, I haven’t scanned the car yet but I was wondering if anyone else has experienced the same? The car is stage 2 with downpipes. It feels really good at times, however this past day it’s been feeling really sluggish and not as responsive to throttle. Will attach video for reference in comments.
Im having an issue with my car, under WOT my car seems to be only hitting about 430hp and torque at peak and dropping off to high 300s at higher rpm’s. No hard codes, I haven’t scanned the car yet but I was wondering if anyone else has experienced the same? The car is stage 2 with downpipes. It feels really good at times, however this past day it’s been feeling really sluggish and not as responsive to throttle. Will attach video for reference in comments.
Potentially the valves in the exhaust could be stuck causing the car to lose power. It doesnt throw a code I believe but if you hook it up to a good diagnostic scanner(xentry) it will show if there was a fault in the exhaust flaps.
Out Of Control!!
Joined: Nov 2018
Posts: 11,427
Likes: 5,336
From: San Francisco Bay Area
2019 C63CS
Car does show full boost once it catches full traction, here’s another clip. I scanned the car and it gave me nothing relating to the exhaust valves. Audibly they also seem to be working fine. What are more symptoms that my exhaust flaps are stuck? Would I be able to hear it?
https://youtube.com/shorts/Yp-hxBYBE...GzqNi6W-F2EgeF
https://youtube.com/shorts/Yp-hxBYBE...GzqNi6W-F2EgeF
Junior Member
Joined: Dec 2017
Posts: 44
Likes: 4
Lexus IS
This!
Had the same issue. Exhaust flaps sealed shut and they had to replace under warranty. Almost replaced my whole exhaust system. (This is not the same as open valves button for louder noises)
What you're talking about is it feels like the engine is cutting timing and I bet you are getting fantastic gas mileage now. Feels like a neutered car. Took the dealership a while to figure out the problem but once they did it was an easy fix. Problem came back here and there but an engine restart usually cleared it right up after they replaced the exhaust flaps.
