SL55/63/65/R230 AMG: SL63 VS SL65
You complain about the 5 speed auto in the 65...but have you ever driven one? I drive one (CL65) every day and I have never felt that I needed another gear. When you have as much torque as the 65 produces, it makes a 7 speed transmission superfluous. Now a higher reving..less torque endowed engine (relatively speaking), like the 6.2 V8, necessitates a gearbox that can provide greater torque multiplication in lower gears. The 65s don't need that....
Tom

SL63, the auto box is ancient, but is ok with a car with lots of torque.
For instance I had a XKR with 380 bhp and a newer XKR with 410 bhp both
with auto boxes but the 380 had 5 speed and the 410 6 speed. The 380 5 speed was better, I guess they got the gearing better, the 6 speed never seemed to be in the right gear. A very big improvement on the mct box over
auto box is it's ability to recognize throttle input and put you in exactly the right gear to get the best from your engine, the auto box is a bit of a lottery
when you kick down as to what gear it will select, and also it doesn't brake the car on change down like the mct box, it's quite exceptional!

What your comparison fails to take into account is the Veyron's ability to go 250+mph. That top speed capability necessitates more than 5 (let alone 3) gears if you want robust acceleration all the way along. A stock SL65 will top out at 155mph due to its speed governor. An AMG "delimited" SL65 will be allowed to run to 186mph. A tuned SL65 may be completely delimited and may hit the wall at somewhere around 209mph. Maybe a 6th gear would help with acceleration above 155mph. However, I will stand by my previous statement (and reasoning), that I have never felt the need for additional gears, but maybe that is because I haven't exceeded 155mph. A 7 speed would have been "nice", but not really necessary.
Tom
Tom
My 1989 V12 Jaguar has a 3 speed box. It will pull away it top and go to
a terrorizing 150 mph.
Although not necessary it would surely improve the performance of a SL65
by it's faster change and ability to select gears better.

If it could take the torque of course.
My 1989 V12 Jaguar has a 3 speed box. It will pull away it top and go to
a terrorizing 150 mph.
Although not necessary it would surely improve the performance of a SL65
by it's faster change and ability to select gears better.

If it could take the torque of course.
Look at this website where I plugged in the relative ratios of the SL63 and SL65.
http://www.fatboyraceworks.com/gears...raph&Compare=1
You will notice that they don't have a slot for the .73 7th gear ratio. To me if the 6th gear has a theoretical top speed of 229mph (obviously assuming no friction)...then the 7th gear is purely an over drive gear for fuel economy. Then again, the SL63's 6th gear looks like an over drive gear as well. I just don't see the utility in two over drive gears..

Tom
Look at this website where I plugged in the relative ratios of the SL63 and SL65.
http://www.fatboyraceworks.com/gears...raph&Compare=1
You will notice that they don't have a slot for the .73 7th gear ratio. To me if the 6th gear has a theoretical top speed of 229mph (obviously assuming no friction)...then the 7th gear is purely an over drive gear for fuel economy. Then again, the SL63's 6th gear looks like an over drive gear as well. I just don't see the utility in two over drive gears..

Tom
I like about the mct gearbox is it's proper manual mode, fast gear change and
the way it responds to throttle input, do you not think these attributes would
improve a SL65, even if it was still 5 or 6 speed?
The Best of Mercedes & AMG
I like about the mct gearbox is it's proper manual mode, fast gear change and
the way it responds to throttle input, do you not think these attributes would
improve a SL65, even if it was still 5 or 6 speed?
MB has had the G-tronic 7 speed for at least 4 years...and have developed the MCT. I am sure they have been testing with the V12TT. They obviously don't feel comfortable sending it out to market. This probably isn't because they can't make the transmission stout enough...but more likely the process to get the transmission strong enough to handle every day use is cost prohibitive. The 65 models are already over priced coming from the factory. Why incur additional costs in manufacturing when the car is still going to be discounted at the MB dealer to get it off the lot?
Tom
MB has had the G-tronic 7 speed for at least 4 years...and have developed the MCT. I am sure they have been testing with the V12TT. They obviously don't feel comfortable sending it out to market. This probably isn't because they can't make the transmission stout enough...but more likely the process to get the transmission strong enough to handle every day use is cost prohibitive. The 65 models are already over priced coming from the factory. Why incur additional costs in manufacturing when the car is still going to be discounted at the MB dealer to get it off the lot?
Tom
Instead of trying to produce a box to take the torque, would it not be better
to reduce the torque ( blasphemy ) to a level where a mct type gearbox
could be used. Bear in mind how much torque you are loosing to traction/wheelspin. By reducing it ( not to 63 level ) and introducing a new
box surely that would make up for the reduction of torque. The one thing
I hate about the auto box in my 600 is when you want to change down quite
often it doesn't, this is maybe because changing down would bring the revs to near the red line, yet the 63 box will change down where there's only 500 revs before the red line. This must have happen to you unless you always overide it with buttons, however the same will apply if your too near the red line. I love the feeling of torque, but I also love the feel of the gearbox, I still
think it's a triumph of technology.
believe me. I have had 12.5 116mph.
But it's not just about speed or torque, the 63 as a whole it's fantastic, looks,
g/box,roadholding, and that fantastic exhaust which you never seem to get tired of, apart from slightly more power what else is going for the SL65.
http://www.roadandtrack.com/article....rticle_id=7449
11.8 @ 121.6mph for a stock SL65
As for real drag strip times...a member here (Camdon) got 11.27 @ 123.5mph in an SL65 with the only modification being drag radials.
And then you have Lou Fishgold's RENNtech tuned SL65 that ran a 130+mph trap speed and also ran a 10.853s 1/4 mile.
I really don't think the 5 spd auto itself is holding those cars back. In fact in the 1/4 mile, both the SL65 and SL63 are in 4th gear crossing the traps. Yes the new MCT is faster shifter...but will it be as "bullet-proof" as the old reliable 5 speed???
Also, you really are displaying some questionable knowledge on the 63 engine. The C63 is DETUNED from the factory by 50hp. So of course the software upgrades unlock an enormous amount of power on the C63. The tuning on the SL/S/E/CLS will not see those type of gains because they have been already improved right from the factory. You may see a 10hp-15hp increase in those other platforms but nothing close to the C63 gains.
Tom
Last edited by TMC M5; Oct 5, 2009 at 03:25 PM.
http://www.roadandtrack.com/article....rticle_id=7449
11.8 @ 121.6mph for a stock SL65
As for real drag strip times...a member here (Camdon) got 11.27 @ 123.5mph in an SL65 with the only modification being drag radials.
And then you have Lou Fishgold's RENNtech tuned SL65 that ran a 130+mph trap speed and also ran a 10.853s 1/4 mile.
I really don't think the 5 spd auto itself is holding those cars back. In fact in the 1/4 mile, both the SL65 and SL63 are in 4th gear crossing the traps. Yes the new MCT is faster shifter...but will it be as "bullet-proof" as the old reliable 5 speed???
Also, you really are displaying some questionable knowledge on the 63 engine. The C63 is DETUNED from the factory by 50hp. So of course the software upgrades unlock an enormous amount of power on the C63. The tuning on the SL/S/E/CLS will not see those type of gains because they have been already improved right from the factory. You may see a 10hp-15hp increase in those other platforms but nothing close to the C63 gains.
Tom
I merely qouted some figures from another member and my own experiences.
For normal every day driving the new mct gearbox is far superior to the auto box. First it has a far faster change, secondly manual is proper manual, not just buttons which get overridden by the box, it's pointless having them.
Then there is the the way it reacts from throttle input, and lastly it's the way
it brakes the car. It seems that you and most other members are only interested in drag times when we are talking about a car that most members will never take to the track. Also the way the auto box memorises the way you drive and can have adverse effect, does not seem to be a problem in the mct box. It's time to hold up your hands and say the auto box is ancient, and
praise the mct box.
I merely qouted some figures from another member and my own experiences.
For normal every day driving the new mct gearbox is far superior to the auto box. First it has a far faster change, secondly manual is proper manual, not just buttons which get overridden by the box, it's pointless having them.
Then there is the the way it reacts from throttle input, and lastly it's the way
it brakes the car. It seems that you and most other members are only interested in drag times when we are talking about a car that most members will never take to the track. Also the way the auto box memorises the way you drive and can have adverse effect, does not seem to be a problem in the mct box. It's time to hold up your hands and say the auto box is ancient, and
praise the mct box.

If you want an efficient gear box - you have to go DSG or SMG or F1 whatever the moniker de jour is: friction losses are around 35 to 50% lower compared to a slush box - thats more power to the wheels, they also have better gear ratios; the M5 and M6 are excellent examples of how well that concept works.
Or why do you think AMG is using a DSG on the brand new SLS?
If you want an efficient gear box - you have to go DSG or SMG or F1 whatever the moniker de jour is: friction losses are around 35 to 50% lower compared to a slush box - thats more power to the wheels, they also have better gear ratios; the M5 and M6 are excellent examples of how well that concept works.
Or why do you think AMG is using a DSG on the brand new SLS?
As you said the MCT is an improvement over the auto, that's my point,
so well said.
I merely qouted some figures from another member and my own experiences.
For normal every day driving the new mct gearbox is far superior to the auto box. First it has a far faster change, secondly manual is proper manual, not just buttons which get overridden by the box, it's pointless having them.
Then there is the the way it reacts from throttle input, and lastly it's the way
it brakes the car. It seems that you and most other members are only interested in drag times when we are talking about a car that most members will never take to the track. Also the way the auto box memorises the way you drive and can have adverse effect, does not seem to be a problem in the mct box. It's time to hold up your hands and say the auto box is ancient, and
praise the mct box.


Tom
your quote " was I talking to you" you replied to Bi-Turbo, I was responding
to what you said to him.
This forum should not get personal, when you post you are talking to everyone that cares to read, you can reply about the content of that post,
that's what I done.
your quote " was I talking to you" you replied to Bi-Turbo, I was responding
to what you said to him.
This forum should not get personal, when you post you are talking to everyone that cares to read, you can reply about the content of that post,
that's what I done.


Now...re-read Bi-Turbo's posts. Why not lecture Bi-Turbo for bringing up 1/4 mile drag times and trap speeds??? I was merely responding to him and his flawed logic...not you and your flawed logic.
Tom
I merely qouted some figures from another member and my own experiences.
For normal every day driving the new mct gearbox is far superior to the auto box. First it has a far faster change, secondly manual is proper manual, not just buttons which get overridden by the box, it's pointless having them.
Then there is the the way it reacts from throttle input, and lastly it's the way
it brakes the car. It seems that you and most other members are only interested in drag times when we are talking about a car that most members will never take to the track. Also the way the auto box memorises the way you drive and can have adverse effect, does not seem to be a problem in the mct box. It's time to hold up your hands and say the auto box is ancient, and
praise the mct box.


Now...re-read Bi-Turbo's posts. Why not lecture Bi-Turbo for bringing up 1/4 mile drag times and trap speeds??? I was merely responding to him and his flawed logic...not you and your flawed logic.
Tom
encyclopedia and bow to your superior knowledge about cars, you are the teacher and we are at school, however you don't seem to be such a genius
when it comes to personalities. I often praise your comments, but I guess I am wasting my time trying to be nice. I love cars, and talking about them, I
don't sit in an ivory tower waiting to put members right about there inaccurate posts.
encyclopedia and bow to your superior knowledge about cars, you are the teacher and we are at school, however you don't seem to be such a genius
when it comes to personalities. I often praise your comments, but I guess I am wasting my time trying to be nice. I love cars, and talking about them, I
don't sit in an ivory tower waiting to put members right about there inaccurate posts.


I try to be patient....when my patience wears thin my "flawed personality" takes over....and get it straight...I sit on an ivory tower...and flush when I am done...

Tom








