Lorne Greene

I just bought a 2013 S550 with 48k on it last week. Fantastic car but the way it accelerates drives me crazy. There seems to be a delay for half a second at times between when I press the peddle and the car moving and at other times the car lurches forward. Is that just the way these cars are or is something wrong with mine?

Polar Bear

I am unsure of your knowledge of automobiles in general, but what you are describing sounds like what many people refer to as "turbo lag" and is a characteristic of a turbocharged vehicle. If the RPM of the engine is high when you press the accelerator (high meaning 2,500RPM or more) the "lag" as people call it should be nearly instantaneous. If the vehicle is in 7th gear at low RPM (1,300 or so) and you request to accelerate, the vehicle must downshift to create the additional RPM like any traditional engine does, and once the RPM has come up the engine has more airflow and generates more heat in the exhaust, which is what drives the turbochargers. The turbochargers then force more air back into the intake of the engine causing a sudden increase in performance that is fun if you are a spirited driver, but also allows you to drive a vehicle with 4.6L of engine displacement and benefit from the increased fuel economy of a smaller engine but at the same time deliver more HP and TQ especially than the 5.4L engine it replaced.

If what you are feeling is what I described above, that is indeed normal behavior for a turbocharged vehicle. To ensure maximum acceleration, downshift manually using the paddles on the back on the steering wheel, or change the driving mode from E to S, which will keep the engine at a higher RPM and have more power to deliver on demand (at the expense of slightly less fuel economy).

Lorne Greene

Thanks, I have been meaning to get back to you. I have owned and currently own a few turbo engines, I will admit that my two Fords (F150 EB and Lincoln MKZ) which both have turbos do not suffer from any lag at all. Now that I have had the car for six weeks I have become used to the accelerator pedal, I am a bit surprised at unrefined it is for a high-end German product but I now do not believe anything is wrong with the car, it was me.

Polar Bear

The Ecoboost engines utilize a different turbocharger configuration- a smaller one that spools up quickly, and a larger one for high RPM power.

The V8 has equal sizes turbochargers for each side of the engine, so they do not place them in series like the Ecoboost. It would be challenging to engineer a V8 with the same design.

Jason B

I can 100% fix this. I did it to my own car. The problem is the drive by wire in these cars. The Sprint Booster Fixes the delay in the gas pedal. Message me and I'll send you a video.

WHPH28

Just took a look at this on their website....interesting.

Jason B

Yep. I also kno the head guy of the company and can get for ya at a better deal. Let me know.

BOTUS

is this a turbo engine or did they leave the normally aspirated 5.5ltr 386 bhp one in there to the end on these.

either way there should be no discernible lag, however if you just came from a modern turbo diesel with a manual box you might think it wasn't responsive
the twin turbo one needs so little assistance from the turbos they can run quite small turbo chargers and so should respond rapidly and overall the engine should have a very wide and flexible power band and no lag
the 5.5 ltr normally aspirated one makes quite big power low down it's more top end that missing

a few things to think about - the 7g box pulls away in second gear unless you select sport where it then uses first (its far smoother and nearly as fast to pull away in second and you shouldn't notice lag)
if you never had an auto - they do take a month to get used to. Throttle response on a slush box is wooly and unresponsive, you learn to open the throttle far more and far earlier after acclimatisation
it should do 0 to 60 mph in less than 5.6 seconds so no there's not much lag !!!

the best thing is to drive another and see how that feels