Hello,

I just purchased a 2006 SL65 with 25K miles on it.

I also own a 2008 CLS63.

I haven't had time to take the SL65 to the track yet, but it I *DO* have a G-tech, so I took both cars out and ran them with the G-tech.

On the G-tech, the 2008 CLS63 ran 12.99@117.8 mph. The ET is accurate, as that is the ET that this particular car tends to run at the dragstrip, but the MPH is way too generous, as the fastest that it has run at the dragstrip is 109mph.

On the G-tech, the 2006 SL65 ran 12.53@122.5 mph. I haven't taken it to the dragstrip yet.

I believe the SL65 should be running much faster than that. I need help figuring out what is wrong with it.

I used to have a 2004 E55 that ran very well, then gradually it started running much slower. Eventually I had the intercooler pump replaced and it started running like a monster again. I am hoping that the same thing is what is happening to the SL65....

Has the SL65 been prone to intercooler pump failure with other users on this board?

 

I don't like to use GTECH times to establish whether or not an SL is running properly, but the MPH does not seem to indicate a big problem with the 65. 65s do have water pump failures just like the 55s.

My suggestion would be to either take it to a dyno shop that has had other 65s dyno there, or hit the drag strip.

Do not judge your SL's performance on ET, base it on 1/4 MPH.

-m

 

Hi, my CL65 2004 ran a little slow when I first had it, then there was a recall
to change the cats. It was far crisper and the power stayed right up to 6k after.Apparently they can de-laminate causing a slight blockage.
Good luck fixing her

 

have seen pump for low pressure cooling circuits go out on the v12s

 

I am not judging it by the ET. The Gtech read the mph of my CLS63 at 117.8. It has NEVER run that fast at the track. The fastest it had ever run at the track is 109 mph, so the Gtech is reading about 8 mph too fast. Since the SL65 ran 122 on the Gtech, it probably really only ran 114 mph in real life. 114 mph is a little slow for a SL65.

 

Your CLS should not be running 109mph at the drag strip.

I know GTECH reads too high, which is why I said I don't like to diagnose things using GTECH #s. I don't think you should be too concerned yet with those numbers, hit the drag strip and see what it really runs. You may also have something up with your CLS if it only traps 109 at best...

-m

 

the splits you ran sound very realistic insofar as the difference between the two cars.

The stock SL 65 is about 5-7 mph faster than the CLS 63 stock , your result is reasonable.

 

in so many words.

gtech is good for relative comparison, but dont take it at face value. speaking of relative - your delta between the sl and cls is just right.

dyno or track to get better idea

alex

 

I will take it to the track this Friday.

If the delta between the SL and CLS is about right, then that makes me feel better.

Thanks....

 

I agree. The BEST I've ever been able to run in the CLS63 is 12.97 @ 109 mph with a 2.19 60FT.

Not sure why it's slow......at least there is no intercooler pump to worry about....... My 2004 E55 was faster.....12.7 @ 112mph.

 

Honestly, the G-tech is not really reliable (I own one) unless you have set it up correctly. If you look at the instructions they suggest that you run it simultaneously at the 1/4 mile track and adjust the "pitch" accordingly. The suspension and weight transfer of the CLS63 and SL65 are probably different. That may be what is skewing the "performance" of each...as the accelerometer is measuring the g-force generated inside the car. I would imagine a more loosely sprung suspension...with less weight up front and allowing greater weight to transfer aft...would show much better acceleration figures with this device. I would invest in a vbox/pbox (which I did) as the GPS based data logging doesn't need to be tweaked for accuracy.

Tom

 

Well, I took the SL65 to the track tonight. 1st run: 1.99 sixty foot. 11.81@122.5 mph.

I guess it's working just fine after all.......

:-)