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Over revving

3K views 13 replies 10 participants last post by  480hpSLK55 
#1 ·
Hello there!

Just finished the run in my new SLK, and I have experienced over revving ie, on some gears (when being drivin hard) the rev counter goes way past the rev limiter into the red zone (more than 7000 RPM) seems fine before and after though...

I had experienced this in the other SLK (R171) but put it down to being just another problem in a problematic car.

Anyone with any thoughts on this?
 
#4 ·
When I get to the red line, not sure at exactly what rev point because I am always watching the road, my power is cut back quite harshly, it feels to me like the fuel is cut, some sort of limiter definitely kicks in, the acceleration stops and I have to change gear. Its happened a few times in overtaking, and I see it as part of the process of getting to know the car, learning when I have to change up.

In my previous car, an Rx7, there was a loud and alarming beep when the rev limit was reached, beeps are not good to hear when pushing the car hard, but bloody annoying and shocking, feels like something has gone wrong. At least in the SLK it is not shocking at the limit.
 
#5 ·
Yes the limitor kicks in around the mid 6000 RPM mark, on most of my changes.. however once in a while it does not kick in and goes WAY over into the RED zone...

No idea why or if it is harsh to the engine.. and obviously not easy to replicate to the dealership! :(
 
#6 ·
SLK-SA - 4/27/2005 5:21 AM
...I have experienced over revving ie, on some gears (when being drivin hard) the rev counter goes way past the rev limiter into the red zone (more than 7000 RPM) seems fine before and after though...

I had experienced this in the other SLK (R171) but put it down to being just another problem in a problematic car.

Anyone with any thoughts on this?
You are of course referring to up shifts and not down shifts which can't be covered by a rev limiter.
 
#7 ·
Call me old fashioned, but if you are hitting the rev limiter or exceeding the maximum safe RPM then you are doing something wrong. The rev limiter is there to prevent catastrophic failure due to overspeed, not as a driver aid. It's lucky we have these electronic systems nowadays. 20 years ago, you would have already trashed the engine by the sound of it. It is possible to use all of the rev range without hitting the limiter. That's what the rev counter is for.
 
#9 ·
Doctor K - 4/27/2005 3:52 PM

I completely agree with Steve. The car is a gem, but has reasonable limitations. Start your shifts at 5000 rpms. The car revs VERY quickly...you have to watch it.
I notice on the videos of the SLK55 acceleration posted here, the auto seems to shift late, maybe at 6000 rpm or maybe later. Its not easy for me (yet) to hear when it hits that point because it starts wailing before then. Anyway, I was aiming for 6000.
 
#11 ·
Seems like you should be learning when to downshift first on your 6-speed before you downshift/upshift too aggressively. Too bad it's really hard to heel/toe on our cars because the gas pedal is so recessed. But I would recommend learning to/getting better at double-clutching before you do anything too crazy. I'd imagine that over-revving the engine once or twice is ok since it's a Mercedes engine, but is never good so don't get into a habit of it. I had a friend who blew out the engine on his K20A RSX Type-S when he downshifted from 5th to 2nd by mistake. So it's definitely possible.

These cars are definitely more fun to drive in the manual. Before I decided to get it in the manual, I drove the 7G and just hated it. It felt like I was driving a CLK500. You just get so much better control and such a better feel for the car when you're driving manual.
 
#12 ·
I have had manual on all my toy cars up until the SLK. Considered manual for it but had test driven the 7G and found it to be interesting enough.

I find that, so far, I drive the car less aggressively than I have done my manual ones. That's a good thing, because I'm crazy.
 
#13 ·
I agree with the post above. This my wifes car mainly and if I was buying I would get the 6 speed. But I am surprised how well i like the auto. The paddle shifter are a joke and MB should be sued for going to market with such a slow shifting POS. But put in D and let the trainy do its thing and it is the best shifting auto ever. Its the first auto I know of that actually beats the manual to 60MPH. You can not shift that fast and that accurate every time. It pulls hard to the redline and pops off the shifts like a bullet. I usually drive with big brother off and that allows for more aggresive shifts and down shifts. Im amazed at how the comp learns your driving style. They other day I was drive quickly with the comp of turn a corner and got on it. The tranny picked 2nd gear, the rear step out for a little tail out slide action that was just perfect. Brought a smile to my face for an auto.
My tranny did have the whole valve body assembly replaced with under 1000 miles on the car. I think the control module is still bad. Seams like you are still in gear pulling up to a stop. Feels like you forgot to push the clutch in on a manual. Time will tell. I like the auto, the 7 to 3rd highway downshift is awesum.
 
#14 ·
when i race off the lights my auto always goes to about 6400rpm, oh and some people were complaining when in manual mode using the paddles that they have lag when shifting gears, i think you should check with MB cause i have no lag at all when using the paddles, just fast acting shifts... i guess i just got a good tranny.. haha!![8D]
 
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