ardy6931

I have been driving an slk55 for about 6 months now...I love everything about it, especially the engine...however, we just got a 650 bmw and im starting to have doubts about the handling on the slk55. I really love the car though so I was thinking about maybe just trading the slk for another one in a different color and with the performance package.

When I drive the 650ci it really feels like your connected to the road and the car is an extension of yourself. I have been a benz guy since i was 16, have driven nothing but mercedes. So my question is what how does the performance package better the handling? How is it different? Any comments?

I want to keep the slk but i want great handling as well.

Beleriand

Call BRABUS and ask about their LSD (Limited Slip Differential). You may not need to get an entirely new car. Also, BRABUS offers two other engine mods - the B55 or a complete engine displacement to 6.0 liters, 450 bhp.

trompazo

The best thing to improve the handling on any car is to reduce unsprung weight and get better tires.

THe 030 adds heavier wheels which is counterinuititive.

Your handing will be much better if you got lightweight wheels and some adjustable coilovers such as the KW variant3s.

The 030 adds nothing to benefit performance. Revalved shocks and heavier wheels ain't going to do jack squat.

But the SLK is still much lighter than a 650ci. I can't see how that overweight car would handle better than a stock SLK55. Maybe it depends on what you define as handling.

Steering feel and lateral grip often have poor correllation.

ardy6931

I am not looking in performance increase, this car has plenty of hp and torque for me...I want it to handle like a bmw. Thats the only way to say it.

In the 650, even though its slower and heavier you can take turns at much higher speeds and never feel out of control. When you move the wheel just a tiny bit the car turns a tiny bit. For example when i turn my slk weel just a few mm the car doesn't turn, there is some give in the tightness of the steering wheel.

In the bmw, the damn car sticks to the road no matter what and it feels like ever movement on the wheel is mimicked perfectly by the car.

Yellow R1

As Tromp rightly said, "feel" is not performance. The SLK55, at .91g, has a higher lateral G number than every mass produced street BMW produced except the Z4 (which is at .92g). This includes the "Mighty M3" at .87g. Slalom numbers are pretty much the same story, only the new M6 posts a higher speed at 69.5mph vs the AMG's 68.3mph (which is the same as a Porsche Boxster & within .4 mph of the vaunted 911 GT2 & GT3 - hardly slouches when the road bends).

I know what you mean by road & steering "feel", but don't let it fool you. The SLK55 handles every bit as well as any BMW (see above). And as Tromp said, lower your unsprung weight & get a wider & softer compound tire. If you want to push further, get some thicker anti roll bars, lowering springs from Barbus or Kleemann, & presto - a firmer/more sporting ride awaits.

See ya,
-Matt

AMG&AMG

get Michelin PS2 and you will be ok.... I think you are using Pirelli ...

reallife

It is not worth the money for you to get the so-called 030 AMG performance package. I got it on my car but only for looks. It does have a stiffer suspension but I think the stock 55 is stiff enough. If you must upgrade for better handling, go with the Michelins and maybe lighter weight wheels. It all depends on what you want out of the car.... I am very happy with mine, just the way it is!

trompazo

What you are describing is steering feel. That is only one small component of the catchall "handling". There can be a significant difference in steering feel with tire selection.

You say the BMW sticks to the road no matter what. Does this mean that you and oversteering and understeering too much in the SLK? I would doubt it unless you are on a racetrack. You can get power-on oversteer quite easlily if you want to in the SLK, but thats because it has massive torque. If you are over or understeering while cornering on public roads in the SLK, I suggest you are driving too fast.

ardy6931

Guys thanks for all the input....maybe statistically you are all right and the slk handling in slalom numbers is just as good as any other car.....I think what I am referring to is the steering feel. I just like that with the bmw every movement I make translates into an action by the car.. Its precise...don't get me wrong I love my slk but I just wish it was as connected to the road.

Shinigami

Do you have the parameter steering option on the SLK?

This too changes the feel of the vehicle when turning the steering wheel... can be the reason why the feel is so different.

fredfromny

Ditto!

ardy6931

I didn't know tires would make such a difference through the steering wheel feel. What I am talking about is the tightness of the wheel....like if you turn it just a little bit you should feel the car move, have a connection to the road so to speak.

Any tire recommendations? ps2''s? what size?

drmiller100

I can't speak directly to your car, as I've never driven one.

However, there are some general things you might consider. Stiffer shocks, particularly compression on teh front of the car, can make the car feel a LOT sportier, and actually show up on times in autocross.

Try 10psi more in all tires. May very well cause weird tire wear for a long term solution, but can give you hints.

A little toe out increases steering feel.

Less caster helps sporty feel, but can actually hurt ultimate performance.

If money is not an issue, try a set of the Kumho autocross tires. Pretty impressive, and I would guess you would get safely over 1 G laterals.

hope this helps,
doug

AMG&AMG

same OEM sizes ..... PS2 Michelin

LETO

benz steerings do feel "bigger" and slightly "numb" when compared to BMW....AMG's are the stiffest steering you can find on a benz....the regular benzes tend to have a lot of give (you can almost jiggle the wheel while driving straight and not have the car move). While the BMW steering feedback makes for a fun driving experience when you are looking for it.....all the other BMWish ness (suspension etc).....make for a rubbish daily/ long distance ride.

Also note that you have a very heavy engine in your snout that can generate some understeer that will effect cornering, which can easily be corrected with all the power that this car has. All in all, this car counter balances well, lets the tail kick out in corners when you want it to and makes for a very good experience.

lennyr

I think the paramater steering programming makes a difference too. When I first got my '55 the steering was incredibly heavy. After my welcome service it got much lighter - still not "flickable," but a vast improvement.

chrisnason

I bought my slk55 amg with performance upgrade in January. I have always had BMW's, mostly M series and mostly sedans. I immediately put 235's on the front and 265's in the rear. I stuck with the Pirellis, although I had the
ps2's on my last BMW and did like them. The slk has gobs of power so you have to be careful about driving into corners. Come in fast, slow through corner and hit throttle as car straitens to avoid oversteer. Very long front on this car and lots of weight from V8. Once you get used to it, which does take awhile, you will understand. Much more like driving an older Ferrari GTB type then anything on the market these days.

ardy6931

What is paramater programming?

2QUIK4U

If you want better handling, just buy a PSS9. Probably the best and most verstatile suspension setup out there.

ardy6931

Now Im confused as to what i want. I don't know if its better handling that i am seeking now that I have heard so many different definitions for it. I think I am just amazed at how there is no steering numbness with the bmw. It makes you feel more in control.

Thanks for all the info guys, keep em coming....and whats paramter steering option?

lennyr

MB calls the variable power assist on the steering "Paramater Steering." It seems to be computer controlled and the software seems changeable. My car got much lighter feeling after its welcome service, which I assume came from reprogramming.

fredfromny

From wikipedia:
1 Factors that affect a car's handling
1.1 Driver
1.2 Familiarity
1.3 Weather
1.4 Road condition
1.5 Weight distribution
1.5.1 Center of gravity height
1.5.2 Roll angular inertia
1.5.3 Center of gravity forward or back
1.5.4 Yaw and pitch angular inertia (polar moment)
1.6 Suspension
1.7 Tyres and wheels
1.8 Track and wheelbase
1.9 Unsprung weight
1.10 Aerodynamics
1.11 Delivery of power to the wheels and brakes
1.12 Position and support for the driver
1.13 Steering
1.14 Suspension travel
1.15 Electronic stability control
1.16 Alignment of the wheels
1.17 Rigidity of the frame

Steering is only one factor in a cars handling. Every manufacturer has its strengths. MB's steering may be described by some as a bit vague, but for some thats what makes a Benz a Benz. Parameter steering makes it easier to park but may take away some driver feedback at higher speeds. An extreme example of this is found in electronic steering such as in the Passat.
IMO my frontwheel drive TT with a limited slip differential has a better steering feel than the SLK, but FWD has other limitations that are part of the handling equation.
The powertrain, supension and frame rigidity (amazing for a convertible) of the SLK blow away the competition. It's a matter of preference.

PS2's may or may not make you happy as they seem to be a cut above all other tires.

trompazo

To have better steering feel, the best thing would be to replace the steering rack bushings. OEM bushings are usually rubber and make for vague steering feel. Firmer Polyurethane bushings can have a massive impact on steering feel. They are usually less than $50, but I doubt anyone makes as for this application. Having bushings custom made may be possible.

J10B

thats GREAT when you have perfect roads.... wait till you have a crappy road and need to commute.... you will DESPISE BMW every second.
I'd rather a car that was fun 90% of the time and decent that other 10%
than a car that was great on perfect roads only.
See that FEEL... means you FEEL the road, including trammelling. Thats when the wheel will fly all over the place following the grooves in the road. When you have tto keep constant pressure on the wheel to keep it straight....

trompazo

The other reason BMWs have such good feel is lots of Positive caster. I don't know if the caster is adjustable on the SLK (doubt it), although it could be something could be increased of you wanted to do some custom fabrication.

However, although this will increase the feel, it will have essentially no other benefit. The car wan't have any more grip and won't be any faster through corners.