CL63 short shifts on full throttle 1-2 upshift

[juicee63]

[quote=fixinbones;3791642] Originally Posted by alx true when you have traction. you maximize tq to the ground and when you upshift the rpms drop back in the sweet spot. no question. what i am trying to say is that in sports mode if you have traction, the car will upshift at redline. if there is no traction and abs is pulsing the rear brakes on non-lsd car and tq mgmt is actively retarding timing and throttle control - the car will elect to shortshift as "forecast" is that this unproductive behavior will continue for the rest of 1st gear. as mentioned before it is important to note that the driver might or might not be aware of this intervention as the yellow triangle might or might not flash depending on many things. what you are doing by "teaching" the car to shift at redline in first gear when there is limited traction is "skewing" the adaptive algorith I understand your explanation, but during short shifts its not like the tires are breaking loose that much there is minimal wheel spin. You would think that a hi perf amg car's computer would be able to realize the difference between slight wheel spin which is not hampering acceleration and continue to accelerate the car in the current gear under WOT They are way too conservative. Turn tc off man, drive that car hard and you will be much quicker than other CL 63's. ALX is correct but he has no solution, training the upshift was my solution and it works. Algorythm's aside, the cars performance will speak louder than any post in this thread. Just be safe, and practice launching the car in a way that maximizes a contact patch.

To remove this ad, register today or login if you already are registered!

[alx]

Originally Posted by fixinbones

I understand your explanation, but during short shifts its not like the tires are breaking loose that much there is minimal wheel spin. You would think that a hi perf amg car's computer would be able to realize the difference between slight wheel spin which is not hampering acceleration and continue to accelerate the car in the current gear under WOT

"slight wheel spin" is a result of the tc braking actively the wheel that is about to spin on the open diff to transfer torque to the other wheel... unfortunately, braking and spark retard is counterproductive to acceleration. so yes- little to no wheelspin but the net net is slower acceleration and tc upshifting to maximize traction.

juicee63 is correct in that if you are really good- you _might_ be able to outshine the tc in a strictly controlled environment, but this does not hold true for 99.99% of the drivers which will produce faster 0-60 if in sports mode, tc off and gradually floor the pedal and let the residual tc kick in and upshift early to 2nd gear if on less than vht-prepped surface.

i will give you an extreme example - imagine black ice - both cars are on summer tires and are racing from a dig to 60mph... essentially no traction - one car shifts 1-2 at redline, the other shifts at 4000 rpms... which one you think will get to 60 faster? hint: it is not a coincidence that most "winter" modes start off cars in 2nd gear even from a stand still

higher wheel speed = more flexibility in controlling torque on open diff via the brakes...

alex

[sysacchi]

I accept with information:The headers as all our other Mercedes Benz headers will bolt to your factory exhaust with no modifications. This means no cutting, no welding, no modifications or changes to emissions and no check engine light. For those that do not have a CL 55 or S55, the headers will also fit the CL500 and S500.

[benz_addict]

I have the same problem in my 55. If in manual or in S mode in 1, it will upshift early if it detects any little wheel spin during acceleration.

ATK, teach me how to launch you former 55 owner!

[ATKM5]

Originally Posted by benz_addict

I have the same problem in my 55. If in manual or in S mode in 1, it will upshift early if it detects any little wheel spin during acceleration.

ATK, teach me how to launch you former 55 owner!

Will do my best! I should be in Sauga tomorrow... I'll give you a call!

[ieb]

I'm up to 22000 miles on my CL63 030. Nothing beats a fresh set of tires to give a good launch. As benz addict says the tc will get in the way if there is any wheel spin.

The Continentals are only good for about 5000 miles before they start to loose it. I have a set of Pirelli 240 snows going on next week and I'll report on those.

[juicee63]

Tires are mission critical wider the better in thy rear.

[fixinbones]

Originally Posted by ieb

I'm up to 22000 miles on my CL63 030. Nothing beats a fresh set of tires to give a good launch. As benz addict says the tc will get in the way if there is any wheel spin.

The Continentals are only good for about 5000 miles before they start to loose it. I have a set of Pirelli 240 snows going on next week and I'll report on those.

What rims are you putting the pirellis on? im looking for a good winter tire to put on an extra set of 20" wheels that I have/

[ieb]

"What rims are you putting the pirellis on? im looking for a good winter tire to put on an extra set of 20" wheels that I have"

AMG 030 20". As far as I can tell the Pirelli 240's are the only ones available this year. I'll report back later this week after they are mounted.

[fixinbones]

Originally Posted by ieb

"What rims are you putting the pirellis on? im looking for a good winter tire to put on an extra set of 20" wheels that I have"

AMG 030 20". As far as I can tell the Pirelli 240's are the only ones available this year. I'll report back later this week after they are mounted.

Yeah, I noticed that. The 240 sotto zeros are the only ones in exact sizes for the 20" wheels. Whats with the price!!! They are more expensive than high performance summer tires? I may wind up going with them as well.

[ieb]

I paid for the 255's $409 installed and the 275's $419 at Town Fair Tire, a chain that may have a store near you. My MB dealer quoted $640.

You may have a problem finding these tires. The 275's are in VERY short supply.

[ieb]

The Pirelli’s are very grippy but of course the weather has not changed so won’t be able to see how they perform for awhile.

There is a huge difference when launching with new tires even at cold temperatures. Like many have said above if the tc detects any spin it will take over and the car starts to hop around and rapidly change gears. With new tires that doesn’t happen and the car holds first gear much longer with very smooth performance.

[fixinbones]

Originally Posted by ieb

I paid for the 255's $409 installed and the 275's $419 at Town Fair Tire, a chain that may have a store near you. My MB dealer quoted $640.

You may have a problem finding these tires. The 275's are in VERY short supply.

I dont see a 275 size 240 sotto zero on the tire rack website. Only 255 and 265. The 275 definitely exists?

[ieb]

yes, they do exist.

[fixinbones]

Originally Posted by ieb

yes, they do exist.

Did you consider an all season high performance tire instead of the hi perf winter tire? (ie pirelli Pzero nero M & S) I guess I would use an all season hi perf tire if I didnt have two sets of rims. I live in LI so I think your snow fall might be a bit more than ours.