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New 2020 C43 Owner - Question about slow acceleration
Hi All, (Sorry for the long post)
I recently bought C43 and couldn't be happier. I might sound stupid, but the PE was the main deciding factor in getting this over M340i or S5. BMW dealer offered me better discounts on an 2021 M340i and I still decided to get C43. I have never owned Mercedes before and so far happy with my car.
I understand my C43 is not as fast as M340i, but I thought the acceleration for C43 was around 4.5-4.7 seconds. I recently completed my break-in period and tried some runs using the Dragy tool. The numbers I got were constantly in the range of 5.5-5.8 seconds. One time I was lucky enough to get to 5.3 seconds but the remaining runs I am consistently clocking at 5.6 or above. I have posted screenshot of my dragy results.
What am I doing wrong? I even tried brake boost (one foot on the brake and one foot on the accelerator) and launched at 2k and 2.5k rpm. During brake boost, I lose traction control (even though T/C was on) and sometimes my numbers are around 5.3-5.4 seconds. I even pressed accelerator beyond the click (max to the floor). I feel like I am going fast but the numbers are not that fast.
My current front tire pressure is at 44-46 psi and would that be the problem? I asked the dealer about this during my test drive and he said its nothing to bother. I constantly check my boost gauge and see that it is in the max level during the acceleration. Also during the acceleration I see 300-330 in the hp gauge. Sometimes I see 381 but most of the time I only see up to 330 hp in the hp gauge.
I am hoping to get some insights from my fellow C43 owners. Is this normal or should I be taking my car to the dealership?
What's your quarter mile time? If you are under 13 or high 12 in stock car, that's reasonable.
As for your tires, are you loosing traction with traction control off? Do you have 5 people in the car with trunk full of stuff? The max psi is for who hauls people and things. I suggest you go minimum high 30s instead of max. Check the sticker on gas door.
You can also go low low psi like on drag radials to rule out the tires being the cuprit. But I would imagine TC kicking in and slowing you down, psi set that high.
Last edited by stockbmw; Nov 11, 2020 at 11:17 AM.
What's your quarter mile time? If you are under 13 or high 12 in stock car, that's reasonable.
As for your tires, are you loosing traction with traction control off? Do you have 5 people in the car with trunk full of stuff? The max psi is for who hauls people and things. I suggest you go minimum high 30s instead of max. Check the sticker on gas door.
You can also go low low psi like on drag radials to rule out the tires being the cuprit. But I would imagine TC kicking in and slowing you down, psi set that high.
I am not sure why my car had 46 psi on front tires. The dealer said it was normal.
My quarter mile was 13.88 @ 94.76 mph which is way slower than what I expected.
I had rear wheel spin with T/C on when I tried to brake boost since C43 does not have launch control feature. II have seen people get 4.5 without brake boosting.
I was the only guy in the car and fuel tank was half empty when I tried dragy runs.
I went to another dealership and they are going to deflate the front tires to 38. Hopefully that makes a difference.
To get the best results you should shut traction control completely off and have the driving mode set to “Individual” with suspension set to Comfort and all other settings being the same as Sport+. Additionally, and assuming you have summer tires, your tires in 50 degree weather are not going to grip as was well as they would in warmer weather unless sufficiently warmed up first.
There is definitely something going on with your car. That time is not normal at all. You're practically at the same elevation I am and the temperature seems perfect as well. I am assuming that you properly warm the car and make sure that you're using 91 octane gas (in USA). Without braking boosting in my stock car, which is also a 2020 C43, I am getting 4.5-4.7 just slamming on the gas pedal from a stop. My rear tires are 32 PSI and front tires 34 PSI.
I have seen people on here having issues with boost and such. If you have the vehicle data with hp, torque and boost up, does it look like you're hitting max for all those?
There is definitely something going on with your car. That time is not normal at all. You're practically at the same elevation I am and the temperature seems perfect as well. I am assuming that you properly warm the car and make sure that you're using 91 octane gas (in USA). Without braking boosting in my stock car, which is also a 2020 C43, I am getting 4.5-4.7 just slamming on the gas pedal from a stop. My rear tires are 32 PSI and front tires 34 PSI.
I have seen people on here having issues with boost and such. If you have the vehicle data with hp, torque and boost up, does it look like you're hitting max for all those?
I did warm up the car and always use 91 octane gas. My tire pressure at the time was (Front - 46, Rear - 36). I went to Mercedes dealer to reduce the tire pressure to 38 and still see sluggish acceleration. During the acceleration (WOT), there is some lag before boost reaches max. Hp meter and tq meter reaches max as well but I don't see hp number beyond 330 and most of the times I see something between 275-330 (sometimes rarely I see 378-380 hp in the meter)
Originally Posted by C43HeartBoost
To get the best results you should shut traction control completely off and have the driving mode set to “Individual” with suspension set to Comfort and all other settings being the same as Sport+. Additionally, and assuming you have summer tires, your tires in 50 degree weather are not going to grip as was well as they would in warmer weather unless sufficiently warmed up first.
My spec sheet tells me I have All season tires (R02). I did drive around for an hour getting it warmed before running tests. We are getting closer to winter season here, any recommendations on which tire I should use for better acceleration?
If you're seeing between 275-330hp or torque when you're WOT most of the time, then this is definitely something wrong. I would bring it in to the dealership and tell them that. Every time I slam my foot down, I always hit max hp and torque after a second or so. Your car may be in what's called "limp mode" and this can happen due to several different things. I've seen posts from owners on here attributing this to boost leakage or even battery/alternator issues. I'm not expert myself on diagnosing issues but I can tell you that this is not how the C43 should perform.
By the way, I am sure you know this already but just to make sure we rule it out, are you depressing your gas pedal past the click-down?
If you're seeing between 275-330hp or torque when you're WOT most of the time, then this is definitely something wrong. I would bring it in to the dealership and tell them that. Every time I slam my foot down, I always hit max hp and torque after a second or so. Your car may be in what's called "limp mode" and this can happen due to several different things. I've seen posts from owners on here attributing this to boost leakage or even battery/alternator issues. I'm not expert myself on diagnosing issues but I can tell you that this is not how the C43 should perform.
By the way, I am sure you know this already but just to make sure we rule it out, are you depressing your gas pedal past the click-down?
Yes I go past the click-down and still experience lackluster acceleration. I am going to take it in for diagnosis. I hope the dealership can identify if it's boost leak and resolve it.
I did warm up the car and always use 91 octane gas. My tire pressure at the time was (Front - 46, Rear - 36). I went to Mercedes dealer to reduce the tire pressure to 38 and still see sluggish acceleration. During the acceleration (WOT), there is some lag before boost reaches max. Hp meter and tq meter reaches max as well but I don't see hp number beyond 330 and most of the times I see something between 275-330 (sometimes rarely I see 378-380 hp in the meter)
My spec sheet tells me I have All season tires (R02). I did drive around for an hour getting it warmed before running tests. We are getting closer to winter season here, any recommendations on which tire I should use for better acceleration?
I suggest you to check boost pressure transducer. Part# 010-153-13-28 This part has been proven some manufacturing defects from several 2019 or later model year C43. It will shut down or not provide enough boost sometimes.
Tried again and got better results. I reduced the tire pressure to 37/38 both front and rear. I turned traction control off completely and got following results when I brake boost off the line. If I don't brake boost and just mash the gas pedal I still get 5.2 seconds (only one time managed to get in 4.7 seconds)
With Brake boosting
Last edited by aradhakr84; Nov 16, 2020 at 07:46 AM.
I still think there's something not quite right right. Below are my 0-60 times from the Track Pace app in the car. 91 octane gas and car maybe warmed up for 10 mins.
I finally put her in Sport + after 2000km and floored it today. OMG the up shift was so lound, I almost sh*t my pant 😃. Full disclosure, my first performance car. As soon as I heard the upsift bang, I quickly step on the brakes and was rewarded with the exhaust bubble...WOW.
I still think there's something not quite right right. Below are my 0-60 times from the Track Pace app in the car. 91 octane gas and car maybe warmed up for 10 mins.
I still think there's something not quite right right. Below are my 0-60 times from the Track Pace app in the car. 91 octane gas and car maybe warmed up for 10 mins.
is it me or is that rain on your window indicating that the ground is wet?
is it me or is that rain on your window indicating that the ground is wet?
LOL! Yes, the rain started after the few runs I did. Nothing wrong with my car though - I was more showing OP that I'm getting 4.2 - 4.7 sec 0-60 times with little effort.
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