I found most of you guys put a lot of effort on increase the power and straight line performance, beside up grade of wheels and tyres: is there anyone done any other handling improvement on their C63?

 

KW V3 coilovers...they will transform the car and definitely improve the handling. Evosport rotors also help by reducing unsprung weight.

 

I tried to KW V3 on, there was a clearance problem with my 19" wheels.

 

Quaife LSD, Strut Tower Brace (MB Arts or Smerc), upgraded brake fluid if tracking

 

When improving the handling of a car, you need to focus on 3 primary areas (there are more, but this is a good rule of thumb for a general discussion).

1. Reduce Weight: You want to reduce unsprung weight as your first priority (wheels, rotors, tires, etc) as this will have a 4 to 1 impact (ie: saving 1lb on a wheel is like taking 4 lbs off of the chassis, thereby, saving 7lbs per rotor with evosport ones is like taking 112lbs off of the "sprung" chassis).

Methods to reduce unsprung weight:

• Lightweight Wheels
• Lighter Rotors
• Lighter Tires
• Lighter Suspension/Springs

Methods to reduce sprung weight:

• Lightweight body panels, the roof being the biggest improvement as it is farthest from the ground
• Lightweight seats
• Removing unused interior panels
• Etc. etc. etc.

2. Improve Mechanical Grip: While it is true that the lighter the car, the better it will grip generally, you want to maximize your mechanical grip as much as practical for a street car (ie: too stiff or low might be ideal for a RACE car, but miserable on the street)

• Suspension Improvement: get the best matched shock/spring you can, I recommend H&R coil-overs as I find them the absolute best compromise for this car. I know many recommend KW, but I have never been a fan, YMMV.
• Better Tires: going to a stickier tire, like a DOT-R will help tremendously
• Alignment: correctly adjusting the alignment specs to maximize grip (warning: this may cause premature tire wear)
• Stiffen the chassis: roll bars, cages, strut braces (non-hinged), etc.

2. Improve Aero Grip: Improving the downforce of the car will help, but only with medium to fast turns

• Front Splitter/Rear Wing that are balanced
• Reducing drag: not super practical on a street car, but things like the wing mirrors are not helping!

Let me know if there are any questions, hope this helps!

thanks
brad

 

^
Very nice explanation.

 

Brad, thanks for sharing the very organized and informative post above.

Lots of good ideas in there.

 

no problem guys! I run our race program, so these questions are in my wheelhouse! Happy to help with specific product recommendations as well (even if we don't make or sell a solution).

thanks
Brad

 

Brad, thanks for your input. I'm curious to know any more info. you can give me in regards to coilovers for the C63. I'll be replacing the stock suspension with coilovers in the spring but am on the fence on going with H&Rs and the KW V3s. I ran H&R street coilovers (only height adjustable) on my last 2 cars and have been VERY happy with both experiences and was fairly certain that they were gonna be on my C63 but I've noticed very few ppl running them and it seems like the KW V3s (albeit much more expensive) have been getting very good reviews from owners.

I don't NEED adjustable suspension really as I drive 95% in the city but I do go for spirited mountain runs in the summer and might hit up a road course once or twice a year. Having no experience with adjustable coilovers I'm inclined to go with the H&Rs again but having said that, I do feel the C63 could use some serious body control and it looks like the KW V3s will do the trick but at what cost to ride comfort? The one thing that I liked about the H&Rs is their relatively comfortable ride but I also felt that under high speed cornering, they do get a bit soft (based on my last 2 cars performance). I'm wondering if you can explain a bit further about your likes and dislikes between the two so I can make up my mind.

Thanks

 

I'd be interested in hearing Brad's opinion on this as well......

 

I've got the H&Rs on my C63, and it handles really well, with very little body roll. That being said, it still rides very nicely. Quite a goood balance in my view.

However, I'm not going to argue that they are any better or worse than KW V3s, because as far as I know, V3s are the best, entry-level coilover on the market.

 

Are you using the stock wheels?

 

Less Weight and more downforce are the 2 factors i think that will greatly improve handling.

 

Excellent explanation, thank you!

 

I use the stock 18s during the winter, and a custom set of 19s during the summer.

 

Before spending any money for new hardware, have the car custom alligned to your driving style. The one size fits all factory specs leave a lot on the table in order to please the masses.

 

Well I have VERY strong feelings on this. IMHO adjustable coil-overs for anything less than a full race/time-attack/auto-cross car is a waste. It is a feature, not a benefit.

For those that are not familiar with marketing class/school jargon, here is the difference. A FEATURE is something that defines the product, differentiates it, is a specification. A BENEFIT is something that actually gives the buyer an improvement in some area. They are not the same and often features are used to sell something and offer no benefit.

This is how I feel about adjustments on street coil-overs. For the race track, we have 3-way/4-way motor sport remote reservoir coil-over systems on our cars (Moton, Sachs, JRZ, etc). We also have suspension engineers and test days to dial them in. This is a HUGE job, requiring a lot of time, engineering and driver input.

For the street, IF (and this is the big question) the coil-over set is designed as a complete package on the road and track, and designed and engineered to be ideal for that chassis, then you are fooling yourself to think you can improve on that. For example, the engineers at H&R develop these kits and test on the autobahn and Nurburgring. They are full time professional suspension engineers. You are NOT going to do it better then they will. The reality is that customer adjustments 99% of the time make the suspension handle worse then if it were set-up and fixed from a proper engineer (ie: H&R).

Now, you might be able to adjust it and "feel" that it is better, but most of the time "feel" makes the car too stiff and too low and while it feels great, it is losing traction and grip.

Another "feature" that people talk about is being able to set their coil overs stiff for the track and soft for the street. This is great marketing spin, but in the real world it is a huge compromise. You see the spring rate will not work correctly in one of these positions. So you are left with a damper that is too soft or too stiff for the spring, resulting in a poor ride on the street or the track.

Does that make sense. I tend to rant on this as I think that the internet and the marketing guys at some suspension companies intentionally mislead customers in order to sell something that they do not need.

I have been to the factories in Germany and have seen how these companies do development and R&D and IMHO nobody for a street car does it better or more completely than H&R.

As your first paragraph notes, I agree 100%. That is the goal. To give you a car that is improved in any arena. It will not be a race car, but it will be better on the street and track.

What makes you saw that the V3 is the "best" entry level kit? I think that is very subjective. I know they market it to be, but that does not make it so!

Again, downforce will only help in medium to fast sweepers. You get more value from improving the mechanical grip first. Aero should be last.

Could not agree more. Specifically rear toe.

Thanks
Brad

 

Brad: Thanks for the comprehensive post.

 

Brad, the timing of your comments could not be better for my case. At a track event in Sebring this August, I met a time attack race team who operate a performance shop a couple miles from my house. My car had just been aligned in April by the dealer but I wanted to let these guys do a custom setup that I will test at Roebling in a couple of weeks. Once he had my car on the rack he called me over to see the settings as they were when I brought it in specifically because he could not believe how much rear toe in had been set by the MB tech. If I understand the physics involved, that much rear toe in would wear the tires much quicker and make it very difficult to get the rear end to follow steering inputs given to the front wheels. Why would the dealer target the settings in such a way?

 

Great explanation but i wanted to add a tiddbit for those of you that is thinking about rotational mass vs unsprung weight...

"When a twisting force (torque) is applied to a spinning part (e.g., drive shaft, axle, wheel), some of the torque is expended overcoming the rotational inertial of the part being twisted. This torque is not part of the force that eventually makes it to the point where the rubber meets the road.

Hence, reducing rotating mass not only gives you the benefit of reducing mass in general, but gains the additional benefit of reducing losses of torque used to overcome inertia. This is true for sprung (e.g., drive train) as well as unsprung (wheels) mass.

The focus is often on the unsprung mass, and more specifically wheels and tires, because the moment of inertia is dependent on the distance between the axis of rotation and the spinning mass distribution in the wheel, tires, and brakes. Because wheels, tires, and brakes have different mass distributions, they will have different moments of inertia, and different moments of inertia means different amounts of torque will be used in overcoming the inertia. So, there is no single ratio you can come up with regarding the "equivalent" weight reduction between sprung mass and unsprung rotational mass. All you can state, without making measurements, is that removing unsprung rotational mass is usually better than removing sprung non-rotational mass.

Also, since removing unsprung mass should improve handling, there may also be a handling fudge factor involved. Having a more responsive suspension could be equated to a HP advantage to some extent.

Bottom Line: Given the choice between removing or reducing sprung mass or unsprung mass (and particularly unsprung rotating mass), it is generally better to remove the unsprung rotating mass. Benefits will vary." .. friend send me this a long time ago..

 

I agree 1000% and will also throw this little one from a popular source:


Sprung vs. Unsprung Weight
Let's start with a definition: Sprung weight is any part of the car that is supported by the suspension, and only moves when the suspension is active. That means that unsprung weight is any part that is directly connected to the road without cushioning from the spring.

The reason it's important to differentiate between the two is because removing unsprung mass is a more effective move than shaving sprung mass. There is no rule of thumb, like "for any 1 pound lost for sprung weight, it's like 10 pounds unsprung weight," or any conversion like that. With the exception of rotating mass, less unsprung weight will not make you go any faster in the quarter-mile than if it were sprung weight, but it does have handling benefits. The lighter the wheel and other unsprung components, the easier it is for the tire to follow bumps in the road. On a vehicle with extremely high unsprung weight, the inertia of the wheel and associated assembly can't move fast enough to follow the road, resulting in a jarring, crashing ride. What's more, a heavy wheel/tire combo requires a heavier spring and shock package to control it, upping the ante with even more weight, bigger brakes (still more unsprung weight), in a situation that spirals out of control.