SLK 55 gearbox question for potential purchaser
02-27-2006 | 08:56 PM
#26
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From: sac, calif.
'06 slk55
Originally Posted by Jesseliu
Can you be more specific?
Trompazo raised a good question regarding AutoX. Many times, you want to let the vehicle bounce off the Rev limiter instead of upshifting (ie next corner approaching). Therefore, 'M' mode sounds like the best fit. Well, not so. I placed the car in 'M' mode and drove off. I then upshifted to 2nd gear. I floored it to redline mimicking an AutoX course. I expected the car to remain in 2nd gear and to continously bounce off redline. Well, it did remain in 2nd gear, but the car hit redline, lunged forward as it cut engine speed and did not rev until I lifted my foot and reapplied the gas. So, it seems 'M' is more for fun than anything else. If you drove in 'M' mode while on the track, it would be detrimental to your time if you ever redline. Again, 'S' mode seems to be the best.
Last edited by dsb; 02-28-2006 at 12:39 AM.
02-27-2006 | 10:40 PM
#27
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AMG
Originally Posted by bloflin
To be clear, even in M mode, the auto WILL still downshift if needed. IT WILL NOT stay in a high gear and lug the engine if the speed is too slow.
For example, you are in M mode, at some speed, you put the gear in 4. Then you use the brakes and come to a stop. The gear is now in 1 as you drive off again. Then you need to shift up to 2, then 3, etc.
M mode allows you to hold the gear in a high rpm for as long as you want (even to the detriment of the engine).
Also M mode will always show you what gear you are in. That is as you slow, you see the number count down as the auto downshifts, even if you don't press and buttons. (note this is from memory, I'll have to verify when I drive home).
For example, you are in M mode, at some speed, you put the gear in 4. Then you use the brakes and come to a stop. The gear is now in 1 as you drive off again. Then you need to shift up to 2, then 3, etc.
M mode allows you to hold the gear in a high rpm for as long as you want (even to the detriment of the engine).
Also M mode will always show you what gear you are in. That is as you slow, you see the number count down as the auto downshifts, even if you don't press and buttons. (note this is from memory, I'll have to verify when I drive home).
In M mode , SLK 55 will never shift!
02-28-2006 | 12:37 AM
#28
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Joined: Mar 2005
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From: sac, calif.
'06 slk55
AMG&AMG,
Bloflin is exactly right. If you agree, cool. If not, you are incorrect.
The only questionable statement from Bloflin is "M mode allows you to hold the gear in a high rpm for as long as you want (even to the detriment of the engine)." This statement can be argued as I pointed out that it will NOT hold at redline.
Bloflin is exactly right. If you agree, cool. If not, you are incorrect.
The only questionable statement from Bloflin is "M mode allows you to hold the gear in a high rpm for as long as you want (even to the detriment of the engine)." This statement can be argued as I pointed out that it will NOT hold at redline.
03-02-2006 | 12:39 AM
#29
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Joined: Mar 2005
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From: sac, calif.
'06 slk55
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
I have to retract my statement! I tried it again tonight. I was totally wrong!
Sorry 'bout that. It does, in fact, hold at redline. Bloflin is exactly right.
I attribute my error to not keeping the gas pedal down long enough.
So, here is what the car does. If you keep the pedal floored while in 'M' mode, the vehicle will rev past redline to approx. 6750rpm at which point it will slow to 6500rpm and keep it pinned there. It does not 'bounce' like previous cars I've driven... know what I mean?
Trompazo, I guess you would probably like 'M' mode for an AutoX track. However, it would be a toss-up whether 'M' or 'S' mode is better. 'S' still upshifts perfectly at redline while 'M' mode has a delay between driver input and transmission change.
I have to retract my statement! I tried it again tonight. I was totally wrong!
Sorry 'bout that. It does, in fact, hold at redline. Bloflin is exactly right.
I attribute my error to not keeping the gas pedal down long enough.
So, here is what the car does. If you keep the pedal floored while in 'M' mode, the vehicle will rev past redline to approx. 6750rpm at which point it will slow to 6500rpm and keep it pinned there. It does not 'bounce' like previous cars I've driven... know what I mean?
Trompazo, I guess you would probably like 'M' mode for an AutoX track. However, it would be a toss-up whether 'M' or 'S' mode is better. 'S' still upshifts perfectly at redline while 'M' mode has a delay between driver input and transmission change.
