rondocap

I would really like to know exactly what is happening in terms of the power delivery/timing of the NA 55 engines in the older cars. (Like the W210 E55, W220 NA S55, etc)

Here's what I am talking about. I have an S55, and for all I can tell it is very healthy and typically runs very strong.

If I accelerate fully, with the kick down, up to about 30mph and below, I get a really strong push back in the seat, and the car's engine seems to go into an "overdrive" mode and really take off. The strongest range seems to be about 5mph-29mph or so to feel this after the car is already moving. How can this be explained? Is it the pulley engaging? Or what?

Similarly, If I accelerate from starting from around 31mph, and even if I start at around 50mph, the car does not seem to go into that "overdrive" mode. It still accelerates quickly, but it's much smoother and I do not get that push back into the seat. What explains this?

And lastly, starting at around 54mph, and each speed up to 65mph, it happens again - I get that really strong push back into my seat and the car's pulley seems to engage or something like that, the noise is louder and more aggresive - similar to the 30mph pull but at a higher speed. If I kick down 66mph or higher, it does what it did 31mph-53mph or so - still accelerates rapidly but I don't get that "kick" and it is much smoother.

I hope you guys can shine some light on this - is it the pulley engaging, or perhaps the power band, something. I know that you can't expect the same power in every speed/RPM, so I am curious exactly what is going on here.

joeljp

Sounds just like how my C32 used to be, pre Sprintbooster. Now, I get that push in the seat regularly and readily but it doesn't run anywhere as smooth as the normally aspirated V8 in my CLK55. IMHO, it's to do with the supercharger or that darn torque converter.

elijah

Thats what I was thinking exactly, torque converter but I am no expert just my 02

betrezra

Kickdown to 1st can only happen at a lower speed...... you're prob going too fast to get the full kickdown. it's all has to do with what gear you shift down too.

MTLdude

Reset the tranny? Tranny will adapt to your driving style.

Johnpidge

Gearbox/torque convertor is the culprit - use the tiptronic if you want to get more pick up at certain speeds - sprint booster may help

benz_addict

Not sure what you mean by pulley engaging your 55 motor is a NA motor meaning there is no supercharger therefore no electromagnetic clutch to engage. Your power band seems to be at it's peak around 4-6k RPMs that's where the motor is producing the most ponies. So whatever the speed is make sure your around that powerband by manually shifting down, if your below your certain peak powerband RPM then it will take longer to accelerate.