Accelerating through the turn
 

Hey everyone, got a c250 sedan a few weeks ago and I noticed it's hard to accelerate thru the turn in this car. It feels like the car almost bogs down and then picks up speed. I don't think it's the turbo that's causing the lag. This happens when driven either in E or S mode. Any of you had the same observation? is it the TCU or some other safety feature of the car?

Honestly it's kind of annoying and don't recall if the 350 I drove had the same issue. Don't know if I need to adjust my driving style :nix:

Your feedback is appreciated. Thanks!

When the wheels starts slipping, the ECU retards my engine pretty much puts my C230 in the middle of traffic for everyone to hit.

I will take my 2010 with the manual and the ESP off button any day just so I don't have to deal with that.

Yah I tried with the ESP off and didn't notice much if any difference. Also I don't think there's too much power through the turn otherwise wouldn't I see like the ESP light come on or something right?

Donning my instructor's helmet.....

What do you mean "through the turn?" A 90 deg intersection turn or a higher speed corner of some sort?

My first thought is that the trans needs to be in a lower gear. Trans mode is irrelevant.

Ahh good question. For clarification I'm referring to the intersection. Yes it feels the trans should be in a lower gear because I am pretty sure I saw the rpms drop to 1k.

Like I said.....love my manual.

I'm assuming there is no boost gauge so you really don't know whether the turbo is spooled up but I don't think it is. Try selecting 2nd gear before you start the turn so as to keep the revs in a range where boost is developed and get on the throttle sooner.

Has a torque curve for this engine been posted somewhere?

I don't think so. Maybe in the Renntech C250 thread. I'm not sure though.

Nope no boost gauge. I have tried the turn in second gear but now don't recall how it felt. I think it was better but I just want to drive the car and I don't think this behavior is normal.

I think a vendor is working on a tune for this model and has posted the stock dyno. Terry from BMS???

Well, I had NO problems in my c300 4matic, but perhaps because it was AWD. But I don't really know how fast you can accelerate on a 90 degree turn, I thought this had to do more with highway ramps?

I have yet to really "get on" my C250 - especially since I got it there has been snow/ice and its a RWD. But I will try to see what you are talking about.

And at what speed are you talking about? Perhaps its the ESP getting involved because you are at the outer limit of losing traction? If you dare, you can try it in Dyno mode (Full ESP off) and see if the issue persists. But I would do this on a simulated turn, with no other cars around. Preferably somewhere blocked off like an abandoned road, etc.

Who has the keys to get into Dyno Mode? Haven't heard of this one yet. I almost always drive with the ESP light triangle on my dash. It's just way more fun.

You access it in the "Service Menu" in the speedometer cluster. I can't recall from memory right now, but it is something like holing the accept call button and the "ok" button on the steering wheel (pressing them down at the same time) and holding them both for like 3 seconds until the menu pops up.

But definitely be careful as it completely shuts off most/if not all, safety features.

I'm really talking about taking the turn at normal speed. In this scenario a right hand turn. As I am approaching the intersection I slow down to a reasonable speed around 15, but I will pay more attention next time, and then gas out. Just feel like the car bogs down and then picks up. I have tried this in both ESP mode both on or off.

Thanks for trying it and providing feedback.

Not directly related, but I have the same symptom in my 300ce. I notice it only when I try and traverse a turn at speed. Its not wheel slippage, but simply that the engine loses power until the car is straight/level. Its such a weird thing, and doesn't happen all the time.

I find it happens much less severely when the gastank is full up. Have you been noticing this only when you are low on gas?

i hate this too. i always thought it was just the transmission not in the correct gear. so what i do now to avoid this problem is to slow down, then gas it before i even turned in and keep going.

Try not coming off the throttle as much when approaching the turn. The minute the throttle plate is closed on overun you strangle the turbo & it's revs drop.

I test drove the new 250 coupe a few weeks back and can confirm that it does have a touch of turbo lag. Nothing like the old 1980s Shelby/Dodge turbos or anything like that but maybe a second or so delay once back on the throttle.

You can treat an automatic two ways, either sit back and just let it do everything for you (ie: my mother), or you can learn how to work it to meet your needs.

My 1st suggestion, especially since it's a turbo, is use manual mode when you don't want to drive like Mom.

My second suggestion is, in auto mode, learn how to anticipate what you are going to do, and also experiment with punching the gas pedal to 1/4 pedal stroke, 1/2, etc, for different senarios. You may learn how to pop into a lower gear before the turn in question.

If it's like previous W204's, the TCM is adaptive, and if you drive around for max mpg's, or like Mom, it will learn to be lethargic, and you will start looking like my Mom.

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I had this similar problem with my 2010 C300 and I think it's somewhat improved in the 250, but it's still definitely there.

It's most noticeable when you are turning right in one of those right-turn lanes that separate and are curved. In those situations I usually let off the throttle and brake a little or none at all. Then when I step on the gas...nothing. Unless I pretty much floor the throttle.

Only solution I see is to hold the stick to the left(-) so it down shifts before turning and then hold it to the right(+) so it goes back to full auto after you're done.

Well it sounds like I need to change my driving style a bit to compensate for the car not being in optimum mode. I have never owned a car with a turbo before so didn't know if this was the characteristic of the turbo or this auto tranny.

I have driven a manual most of my life and just switched to auto, after becoming a family and owning sedans. Coming from a G35 I never had to compensate for it being an auto and driving style remained unchanged. Given the c250 has decent hp and torque I'm surprised to hear of this issue even from others.

Thanks everyone for all your feedback. Keep them coming, well except for the part of being looking like someone's mom. :smash:

Face it. You have a 3600 pound car powered by a little 4-cylinder and if the engine is at idle in a corner those horsepower and torque numbers are not there. You are going to have to compensate for the low rpm shortcomings by keeping the engine on-the-boil (very old expression) by keeping the revs up which does not mean staying on the throttle and riding the brakes.

Downshift.

It was an accurate, and a bit exagerated, warning to the general "you" about driving style. Don't take it personally.

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No worries bud I don't take things personally. Thanks for the feedback :y At least I wasn't downgraded to a grandma but I maybe getting close :)

Thanks bud i understand.