Hi Guy's

This is what I received from AMG about my complaints on turbo lag and transmission



Explanation from the AMG Manager:
When we deliver these cars as new, they are intentionally benign in their performance as they learn and adapt to the driver…much the same the AMG engine needs to be broken in for 1000 miles before you really start hammering on it…

Second, the ‘C’ mode stands for ‘Controlled Efficiency’ and as such its design is use a little fuel as possible with slower throttle engagement, more driver input required on the throttle to force a kick down, the transmission automatically shifts to a higher gear as soon as it can to achieve better econ.

However in the ‘S’ mode (for Sport), the focus is all performance so everything in the above is opposite to provide performance.

The DCT is technically a manual transmission that is run by a computer, that also has to ‘break in’ as it uses two wet clutches…meaning so it will also adapt to the driver’s behavior but also is a bit benign when new…also as it is a manual transmission, from a stop it has to slip the clutch just like if you were driving a conventional manual you would have to do the same…so if you take your foot off the brake and then just hammer the gas, it will take it a second to calculate how quickly can it drop the clutch to not spin the tires nor stall the engine…

Basically I would tell the customer all of the above…tell them that this is a brand new car that has to be broken in, and that it will adapt and this process is going to take about 1000 miles…this is why we do this process ahead of time before we hand these cars to the press and magazines or put them on the track at the AMG Driving Academy…

Lastly the term ‘turbo lag’ is so incorrectly used because these cars do not have turbo lag…that is a term that was prevalent in the 80’s-90’s when engines used to have turbos that only came on boost at certain RPMs…our turbos run all the time and have positive boost basically off idle…as such we have max torque at 2,250 rpm all the way to 5,000 rpm…this would not be possible with a turbo that ‘lagged’…what he is feeling has nothing to do with the turbo, it is all of the above as the throttle is run by a computer and the gas pedal is nothing more than an electrical dial…

 

Are you satisfied with his response?

 

NO, but i'll keep on trying until they come out with and program update
so if your not happy as to how your CLA 45 is running then please contact AMG, this is to all 45 members because the more people complain the faster they will come up with a fix....

 

I find with our GLA 45 that I need to depress the accelerator quite a bit and then back off immediately. It seems to take an inordinate amount of pedal to get any kind of motivation and by the time you do, it takes off! A little more linear pedal would be better. We are 600+ miles into our break-in period.

 

I actually agree that the car doesn't have turbo lag...or, more precisely, I don't believe turbo lag is the 45's biggest problem. The 45's biggest problems are:

1. Its DCT; which sucks; and
2. Its throttle; which sucks.

The DCT is extremely slow to change gears whether in Sport or Manual mode. While shifts are admittedly quicker in Sport and Manual modes than in Comfort, there is still a noticeable delay between the time that I flick the paddle to upshift or downshift (in Sport and Manual) and the time the DCT actually changes gears. It's almost as though the tranny thinks to itself, "Oh, he just asked me to changed a gear. I'm on it!" and then 'bam' there's the shift.

It is unlike even the DCT in the SLS which does a fantastic job of anticipating gear changes and downshifts noticeably to ensure the car stays in the power zone. I never felt the need to drive the SLS in manual mode, whereas I constantly feel the need to drive the 45 in manual mode because I often find that I don't like what the DCT is doing in Sport.

I've also found that the DCT likes to shift early in Sport regardless of the level of throttle input. I've hit the throttle aggressively off the line only to watch the DCT upshift at around 3K from 1st into 2nd and then again into 3rd gear rather than holding onto 1st until much closer to redline.

Oh, and don't even get me started on the abrupt fuel shutoff as you approach redline in Manual. I understand the safety nanny but it kicks in early and since the DCT takes so long to shift, it's easy to shift (when you actually want it to shift) only to have the DCT hang onto the gear long enough for you to hit the fuel shutoff demarcation point. What a PITA.

Similarly, the throttle is unlike any other car I've ever driven. From a stop you have to dip deep into the pedal before the car actually moves. If you've never driven one before it is very disconcerting the first time you do. It makes you wonder whether something is wrong that might cause the car to abruptly lurch forward or backward. I've noticed a throttle delay in other Mercs I've driven (including the current E63 and CLS63) but it is particularly bad in the 45.

I love my 45 but it is not without its issues...and these two, in particular, are notably annoying.

-Eric

 

Hi:
you are correct, I did not explain my self very well, I was more complaining about the DCT than the turbo it self
Yes the DCT sucks. my main concern is that it takes to long to down shift as your coming to a stop or slowing down, for example if I slow down to lets say between 5 to 1 MPH it stays in second and does not shift in to first unless I come to a complete stop or I manually shift it my self, and it doesn't matter if I am in C or S it reacts the same. this is what I am trying to get AMG to understand.

 

Eric, you have an SLS!?!?!? :O get your *** over to Mercedescla.org and post some pictures!! Haha or maybe they're already on here?

I couldn't agree more with you regarding the delay when flicking the paddle and the actual shift. The shifts themselves are very quick and I have no complaints there, but the tuning of the DCT that causes that delay is horrid. Like you said, it can be easy for you to accidentally shift too late and experience a slight interruption to the power delivery.

I must be honest though, although some people absolutely hate the throttle I haven't found it too bad myself. I guess I may be a little more tolerant than many, but I've learned the pedal well enough that it's second nature now. I have zero issues starting the car moving smoothly without any lurching whatsoever, and never have to question what the car is going to do when I use the gas pedal.

 

I wonder if the gear change issue, in manual at least, has been improved on the 2015s. My gla45 shifts quickly, nothing weird about it except when punching it there is a little driveline knock to go along with the exhaust bang as you come into the next gear, almost as if it has shifted too quickly.

The throttle from takeoff is wacked. You can see the tach rise as you apply throttle then dip for no reason and then take off. I think the car has acclimated somewhat to my driving as it is not as bad a thousand miles in and of course i learned too to the point i dont notice now. As far as the torque, sadly it needs the tune.

 

Hmm interesting, maybe there was a software change for the GLA45's. I'll ask my dealer when I'm in next week to get my winter tires mounted whether or not there's an update that can be applied to the CLA45's.

The tacho doesn't rise and dip for 'no reason' though. If you've ever driven a manual transmission, think about starting off from a full stop. The point where the tach rises a little bit and then drops is essentially the exact same process where you would be giving the car a little bit of gas and then easing off on the clutch. But in this case, the car is controlling that initial clutch engagement. It's not like a standard automatic with a torque converter that can basically start moving right from idle because there are no clutches.

 

there's updates, but getting the dealer to do it is another story.
been their done that.

 

Hate to resurrect an old thread, but the throttle response is so lame, just wondering if anything is been done about this? Either from Mercedes or aftermarket? I asked at my dealer and got the doe in the headlights look.

 

My thought is, the DCT is slower than DSG. My old Golf R had faster response on changing gear and faster clutch engage with minimal throttle. MCT needs holding the throttle to let the clutch engaged then accelerate, the clutch engagement time may be same or slower then release the manual clutch.

 

It's a lot safer for the car to shift into 1st once its at a complete stop. Every performance dual clutch car I've owned has done the same thing. It's probably a safety thing to preserve the clutches and protect them and keep them wear-free longer. As for turbo lag, this car doesn't have any. Try driving a car with a huge upgraded turbo. You hit the gas and the car doesn't go anywhere until 4k or 5k rpm and then all of a sudden VROOM. The turbo in the CLA is a smaller sized turbo. There shouldn't be any lag. If you want acceleration improvements, I recommend getting an ECU tune. My car was tuned at Alpha Performance in Chicago. I put the pedal down and the car takes off like a rocket. My 0-60 is 3.5 seconds, super car territory.

 

I'd get a tune, but don't want to void warranty. I've read some threads on piggy back tunes, can anyone chime in on those? Brands, experience, results, recommendations?

If that proves to be a dead end, anyone know a good tuner in Metro Detroit area?

THANKS!

 

[QUOTE=swiss028;7027345]I'd get a tune, but don't want to void warranty. I've read some threads on piggy back tunes, can anyone chime in on those? Brands, experience, results, recommendations?

If that proves to be a dead end, anyone know a good tuner in Metro Detroit area?

THANKS![/QUOTE

go pick up a second ecu and get it tuned.

 

This is an ancient thread and, respectfully, the question has since been asked and answered countless times.

Yes, there are plug and play throttle boxes that will mostly eliminate the wonkiness of the CLA's throttle response. Products like a Pedal Commander or Rebellion's TRS shouldn't have any real impact on warranty. They're simple to install and, for what it's worth, a piggyback tune won't eliminate the spongy throttle. It will only give you more power when it finally kicks in, which is to say, at higher RPMs.

-Eric

 

Getting a full dyno tune fixed my issues with the pedal delay. I got my tune at Alpha Performance in Chicago. Was worth the money, as it netted me more power than any of the other tuners I've tried and was also considerably smoother throughout the gears.

 

Going to find an ECU an send it to then, after we talk.

 

How much was your tune? Any mods? And what gains did you see?

Please and thank you!

 

try the TCU from Rebellion, i just installed mine and it helped.

 

HI ,
can you post any dyno graphs if you tested it?
Thanks,
C

 

My MY15 experienced the transmission noise and slip problem.
Interesting, you have to give a little enough throttle to tell the TCU to release the clutch, if too much throttle the clutch will slip.
And I feel the transmission noise from P to R occur by the input shaft, From P to D mine got no problem. Only occur when cold start. Every time when cold start, I shift the N first, then shift to R, no noise, but fo it slow.