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Discussion Starter · #1 ·
As you can see from my dyno graph from DMS my car isn't doing what it should be..
Max of 407 PS at only 6200rpm which is 500rpm down on where peak power should be, and only 380ps at 6750rpm.
Should be around 421ps at 6750rpm as per the brochure. Has shell v-power in the tank, so not petrol...
Done a few quarter mile times best I got was 12.4 which is not right, should 12.1..
Booked in today at my local Mercedes garage and guess what, couldn't find anything wrong with it, no fault codes or old soft wear, Mercedes says haven't got the equipment to check power or logs. Told me to call Mercedes head office tomorrow.
The car is brand new in May of this year only done two thousand miles.
So any thoughts??

IMG-20210706-WA0001.jpg
 

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It should,doubt your average MB mechanic is going to sort that without a fault code to. Guide them
 

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They should be able to do basics like compression and check plugs, but your going to need it on a dyno again, was fuel definitely good?
 

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Discussion Starter · #8 ·
They should be able to do basics like compression and check plugs, but your going to need it on a dyno again, was fuel definitely good?
There is a place I can get it dyno where I live so will get it done again, Hopefully was only use shell v-power.
 

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As you can see from my dyno graph from DMS my car isn't doing what it should be..
Max of 407 PS at only 6200rpm which is 500rpm down on where peak power should be, and only 380ps at 6750rpm.
Should be around 421ps at 6750rpm as per the brochure. Has shell v-power in the tank, so not petrol...
Done a few quarter mile times best I got was 12.4 which is not right, should 12.1..
Booked in today at my local Mercedes garage and guess what, couldn't find anything wrong with it, no fault codes or old soft wear, Mercedes says haven't got the equipment to check power or logs. Told me to call Mercedes head office tomorrow.
The car is brand new in May of this year only done two thousand miles.
So any thoughts??

View attachment 8370
Just out of interest,what does it show if you get up the AMG performance engine data screen up?
I had a time when the power felt a little low and this showed up on screen,and couldn't get the claimed figures,but after a while it seemed to sort itself out.In my situation it was like it was stuck in the warm up phase which restricts full power.
8377
 

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Discussion Starter · #12 ·
Just out of interest,what does it show if you get up the AMG performance engine data screen up?
I had a time when the power felt a little low and this showed up on screen,and couldn't get the claimed figures,but after a while it seemed to sort itself out.In my situation it was like it was stuck in the warm up phase which restricts full power.
View attachment 8377
Not sure next time im out will have a look.

Thanks
 

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Do you live anywhere hilly. Otherwise you probably just need a few more miles under your wheels. Was it a hot day.
 

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Discussion Starter · #14 ·
Do you live anywhere hilly. Otherwise you probably just need a few more miles under your wheels. Was it a hot day.
Should still pull all the way to 6750rpm and not 6200rmp dont you think? Was only about 20 on the day it was on the dyno... Hilly??
 

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Should still pull all the way to 6750rpm and not 6200rmp dont you think? Was only about 20 on the day it was on the dyno... Hilly??
I was wondering if you lived anywhere at altitude.

I'd hang on a few more miles and see what happens before contacting MB again.
 

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2021 AMG A45 S Plus, Sun Yellow
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Just back from an extended blast around the Peak District. Best figures seen today on the AMG data screen were 424HP and 505Nm.

Car is stock with 2,200 miles.
 

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Just back from an extended blast around the Peak District. Best figures seen today on the AMD data screen were 424HP and 505Nm.

Car is stock with 2,200 miles.
They are the kind of numbers I see on a regular basis. It always hits 421hp with no difficulty. Quite close to 10K miles now.
 

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My guess would still be a poor batch of fuel
I think this is the most likely reason. I stick with Tescos 99, it's not a franchise which all Shell garages are likely to be.
 
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