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What's going on everyone. I have some great news. I'm sorry we have not been able to post a ton but it was an absolutely insane weekend at Road Atlanta. For one, we had issues getting there between weather and some break downs with our truck and trailer. So, where do we start with Road Atlanta. It's one heck of a track and very challenging. We had not been able to test our car before we got there and had to trouble shoot on Thursday to figure out how to deal with ESP/ABS. We wanted ABS but did not want ESP. To get the car to perform as desirably as possible we ended up disabling both by disconnecting a wheel speed sensor. I will have more photos and videos for everyone as soon as I make it back to Connecticut (current stranded in Atlanta until tomorrow) but we finished P1 in class 3 on Saturday and P1 in class 3 on Sunday while being 8th overall on Saturday and 5th overall on Sunday.
The field size was approximately 50 cars ranging from high power E46 M3's and Corvettes to E30's and Miatas. AER is highly competitive and absolutely grueling on cars given the run time they have to endure.
The car ran exceptionally well and remained consistent all weekend. The car is rock solid, had amazing grip, and beyond adequate brakes. Our only limiting factors now are power and weight. I have a lot more to share with everyone but want to get some time to piece everything together to show you what we have learned about this car. As I said in the beginning of this thread, we want to know this platform through and through and pass the knowledge on. Enjoy the live stream videos and photos for now.
Awesome stuff! I enjoyed reading all the stuff about the change over to a race car. Look forward to more!
Not too many people show all the steps and I can understand why, it's impossible to document and work at the same time. But since the W204 has been underutilized and no one would look twice at using one for what we are using it for we figured this is perfect for sharing with the community.
Finally rested and back to a normal schedule. I wanted to give everyone some insight on our first race with the car which also happened to be our first shake down. While we came out of the experience with great success on an untested and for the most part underutilized platform I think we demonstrated that the W204 is a capable car and can be competitive. I am going to give you guys an entire build list of what is currently on the car as soon as possible but I wanted to get into some of the technical aspects of the platform and some of the issues we had to overcome and some of the inherit pieces of the platform that make it a great car.
Technical issues:
ABS and ESP are overly aggressive - We removed the factory steering wheel switches from the car entirely. This meant we had no way to turn off ESP. We worked with someone from Atlanta who went through the car on Friday before practice and we learned that it's basically impossible to have ABS with ESP inactive. Mercedes programmed their ESP system to look at yaw angle and wheel slip. This meant that our car would be limited leaving the system in place. Our temporary work around for this meant that we would lose ABS to lose ESP. We disconnected the rear right ABS wheel speed sensor and this turned both ESP and ABS off while preventing the car from going into ABS.
ABS at Road Atlanta would have been needed to maximize braking into some of of the turns but ESP was too intrusive coming out of corners at WOT so we had to go without ABS. If anyone wants to track their C300 you can turn both off with to real drawback on performance by disconnecting the rear right wheel speed sensor. We are looking into running a standalone ABS system which I hope to go into more detail later.
Weight is an issue. We're at about 3000 pounds without fuel and a driver. We still have 40 pounds of wiring we can remove along with the factory windshield and back glass which probably add another 175 pounds. We can also eliminate that weight by running Lexan which we are considering if the budget allows for it.
We destroyed the front left tire both days. This is because Road Atlanta has several high speed, high load right hand turns. We wore the tire on the outer edge both days. This is because we didn't run enough camber. However, our camber settings in the front are maxed 100%. We're going to have to look to see what options we can have to add more camber adjustability. This will be important for other tracks and reduce tire wear.
We also had issues with front brake rotors. Since we are running C63 rotors our only off the shelf option was drilled and slotted. Of course, the rotors cracked around the drilled spots. We expected this too happen. We are currently looking around to find a company who can make rotor rings using the OE 2 piece rotor hat. I think we found a solution for that and hopefully we'll have rebuildable front rotors that can last under racing conditions.
Fueling took too long with the factory filler neck so we're looking on opening this up and removing restriction as much as possible. Each fill up was about 14 gallons of fuel and it took us close to 2 minutes to get fuel in the car. We'll be looking at the factory filler neck and seeing where we can improve the setup. Ideally a fuel cell would be ideal, but to keep the car at a reasonable budget we're opting out of a fuel cell at this time.
The platform as a race car:
Simply put. The car handles incredibly well with off the shelf components. Everything on our car can be bought off the shelf online. Granted, it's not cheap but if you were looking to build a race car and didn't want to use a BMW or another common platform it can be done and it can be done on a reasonable budget. All bushings and mounts are currently OE. We will likely be looking to make solid mounts or monoball mounts at some point this season. With off the shelf components we were able to distance ourselves in the corner. The car is incredibly stable and predictable in the corners well beyond what we thought the car can do. Between the two link macpherson strut front suspension and the 5 link rear suspension it's a completely modern car and it has an advantage in the corners over Spec E36 and Spec E46 BMW race cars.
Brakes were more than we could ask for. We are running Brembo C63 P30 package calipers and rotors with Pagid yellow race pads. We changed the OE lines to Technafit stainless steel lines. Simply put, brakes on this car never got tired despite the fact that Road Atlanta is a major test on brakes. Again, we were running off the shelf components and braking was never an issue here. Other tracks throughout the year in my opinion won't be as much of a test on brakes as much as Road Atlanta was. As mentioned above we're looking at custom rotor rings so we can simply repair the front rotors instead of replace them all the time. I have photos of the 2 piece Brembo rotors with about 11 hours of race time on them if anyone wants to see them.
The car didn't burn oil at any point over the weekend. Between practice on Thursday and crossing the finish line on Sunday we added zero oil. Part of this is because the engine is low mileage and part of it is the ROWE oil we ran as well. The transmission did start to leak and was also incredibly hot. We got the car on the lift today to do a basic once over and there doesn't appear to be a single source for the leak. We'll have to investigate this further.
Overall, the W204 C300 is a very solid and reliable car for endurance racing. The car is slightly under powered but since the car has such high limits of handling and brakes we're able to make up for any gap in power in the handling department. This car is going to be developed over this season and we're looking to have a fully developed car by the third race of the year which is New Jersey Motorsports Park. Since working on the car we pretty much have a list of all fastener sizes on the suspension. If anyone wants a full breakdown of the fastener sizes please let me know and I'll share it here.
“We destroyed the front left tire both days.... Wore the tire on the outer edge....because we didn’t run enough camber.... settings in the front are maxed out 100%. All bushings and mounts are currently O.E”
Wow – resolving all above issues is exactly what we do. Whether for Street – premature edge tire wear or Track days – in the pursuit of “front row of the grid lap times”.
So contact us - would like to help out with sponsorship.... and it’s all off the shelf.
Front Strut adjuster kits Camber and Caster (Street/Race or Full Race). Unique patented design – fast adjust from engine bay – no need for strut removal each time to change settings. Combined with the 4 front K-MAC mono ball lower arm bushings – also adjustable and with twice the load bearing area of OEM for improved brake and steering response.
Result is the biggest adjustment range – up to 4.5 degrees (extra) negative Camber and 1 ½” extra track width. Allowing dramatic reduction in understeer in the quest to “hit those corner apexes” everytime and go deeper into the corners with increased traction and braking response.
Addition of “Rear Camber” also allows to fine tune/change tire contact angle at track side for maximum wear/traction – K-MAC patented design “single wrench” adjustment system.
Rear Bushing Kit (12) –for the multilink arms. Accurately locating rear suspension against unwanted flex/twitching and loss of traction – especially when applying power cornering or lane changing.
K-MAC has over 50 years experience in manufacturing high performance bushings and producing adjuster kits longer than any other company! It shows in all out heavy V8 competition racing – situations where “Race Safety” scrutineers ongoing inspections/evaluations rule – only K-MAC adjustable bushings are allowed to be fitted.
CHECKLIST (W204) incl. AMG and C207/A207 Black Series Front replacement top strut mounts – Camber and Caster adjustable. Highest 7075 grade alloy, no height increase, replaceable centers, separate radial thrust bearings for steering loads – suit OEM diameter springs or all coil overs (60-70mm ID).
Front 4 main suspension bushings – also precisely Camber and Caster adjustable. Allowing extra track width and 2 axis/mono ball design eliminating the OEM oil and air voided bushings for noticeably improved brake and steering response.
P/N 502616K
Rear Camber (and extra Toe) adjuster kit– unlike “upper Camber arms” instead replaces the lower arm inner bushes retaining therefore clearance top of tire to outer fender if adjusting to reduce premature inner edge tire wear or allows adjustment also to increase rear track width.
P/N 502226K
Rear Multi-link suspension Bushings ‘12’ to reduce rear end flex/twitching especially when applying power lane changing/overtaking.
Great job guys, and thanks for the detailed write-ups!
keep us all posted if you are able to come up with a solution to just replace the rotor rings on the factory P30 2-piece rotors. I know there has been dicussion on this and I'm sure several of us would be interested in a non-drilled rotor ring for our P30 brakes if you come up with a solution.
Looking forward to more updates as you continue to learn about this platform!
Great job guys, and thanks for the detailed write-ups!
keep us all posted if you are able to come up with a solution to just replace the rotor rings on the factory P30 2-piece rotors. I know there has been discussion on this and I'm sure several of us would be interested in a non-drilled rotor ring for our P30 brakes if you come up with a solution.
Looking forward to more updates as you continue to learn about this platform!
We're in the process of working on these. We're working on a solution for the P30 package rotors first but since there is expressed interest in other applications we will probably work with them for the other 2-piece rotors at well. Feels really wasteful to replace the entire rotor when you can just reuse the hat and install a new ring. We shipped them out the ring from our car so they're going to use that as a starting guideline. For racing we're looking to lighten up the rotor as much as possible. But that same technology can be used on a street car as well.
Originally Posted by Adi-Benz
Amazing job guys. Really well done!
If only you had the 4matic and your transfer case blew, so you could do a diy on fixing it LOL. #help
Our CEO has a 4Matic C300. We may be able to put a video together for that.
Originally Posted by INS1GNIA
Great documentation, it was amazing to read. Well done also, keep it up!
Thank you. More to come as we keep digging into this.
I have a few updates into progress made on the C300 as of this week. Some of this is race car or performance specific but some of the information I think will also benefit the community. Some of the goals at this time before the next race at Watkins Glen at the end of April is to have a functioning ABS system. We spent the better part of last week mapping out the wiring on the car so we can run a standalone. More or less, we have all the pins mapped out and once that info is confirmed I will share this information here. The goal is to use a Teves (ATE) MK60 ABS system which is commonly used in E46 M3's and some Volkswagen's. The beauty behind sticking with factory ATE designed parts is the hydraulic unit is essentially the same externally and we won't have to run any new lines. Essentially, it should just plug and play. This will take some time to set up, but once it's in should work very well as it can run independently from the engine control module. Also, since it's CAN enabled we can turn it on and off as we need it.
Front tire wear was a major issue at Road Atlanta. To solve this issue we have relocated the mounting holes in the front strut towers and now have anywhere between -4.5 and -2 degrees of adjustability up front. I wouldn't think this is useful for street cars but what I can say is the front strut towers are plenty strong on the W204 and the metal used is pretty thick. If you were so inclined to add further adjustability it can be done as there is enough material and room to shift the strut mounting locations inward slightly.
Another goal is to reduce weight from the car. Before Road Atlanta we didn't have time to eliminate additional factory wiring but we are now going through the entire car and removing anything and everything that isn't needed. The rear door window regulators were removed. We reused part of the window regulator (the piece that hooks onto the glass) as a mounting bracket and used steel to make an S bracket to secure it to the door panel. Simple but effective. We removed about 25% of the additional wiring that isn't needed and in total so far have taken out about 20 pounds of stuff that isn't needed. We want the car to be under 3000 pounds without a driver for the next race.
We also started experimenting with the intake manifold. The factory manifold with swirl flaps weighs about 12 pounds. It's also metal and retains heat. It's also a liability if the actuator arm breaks. We can address this issue by beefing it up or we can replace it entirely. We're going to be installing the 2009-2011 SLK350 intake manifold which is a simpler design. It also weighs in at 8 pounds. While it's a 4 pound weight savings the benefit here is reliability along with the possibility to improve mid to upper range power and torque with some tuning.
When we install the intake manifold from the SLK I will make sure we do a write-up. It should be pretty straight forward but to my surprise it's not a well documented piece despite the fact it's been talked about a lot.
On the fun side of things though, we've added the Mercedes illuminated star to the front grill.
2012 P31 C63 Coupe Trackrat, 2019 GLE63S Coupe Beast
Great thread here, watching with interest. I'm also doing the Glen April 22-23, but that's probably not the weekend you're there.
While you're trying to squeeze all you can out of this chassis, and have the ability to take everything apart, you might be interested to give these Spoon Rigid Collars a try. Just got my set, and they're supposed to stiffen up the subframe quite a bit.
Great thread here, watching with interest. I'm also doing the Glen April 22-23, but that's probably not the weekend you're there.
While you're trying to squeeze all you can out of this chassis, and have the ability to take everything apart, you might be interested to give these Spoon Rigid Collars a try. Just got my set, and they're supposed to stiffen up the subframe quite a bit.
This past Monday we went ahead and installed the SLK350 intake manifold on the car. This is a modification that had been discussed briefly in some threads for the M272 engine on this very forum. For those of you unfamiliar with the modification it is an entirely different manifold than the stock one offered on the C300 or C350. Instead of being aluminum and having swirl flaps and vacuum actuated internal flaps the SLK manifold omits those features and is entirely made of plastic. It's a simpler design that seems optimized for air flow and volume. The SLK350 makes about 30 more horsepower than the C350 despite being the same M272 E35 engine. Tuning plays a part in power here as well but the basic controls are the same.
Our reason for doing the swap is to remove a potential weak point in the stock manifold by removing the vacuum chambers as well as the arms which actuate the swirl flaps and flaps inside the engine. As we all know, the stock manifold has several documented failures. In racing simplicity is everything and removing this liability from the mechanical side of the equation we're simplifying the overall car. The SLK 350 manifold is documented to be a direct swap.
If you look at the Pierburg manufactured M272 manifold there are three areas where electrical connectors plug into on the manifold. On the front of the manifold there is a connector that plugs into a solenoid and on the rear there are two hall sensors that monitor the position of the swirls flaps. The position of the swirl flaps is used by the DME to control the vacuum solenoid up front which in turn controls the actuation of the levers on front of the manifold. One of our concerns on this swap was how the engine would perform or respond to having these three connectors on the engine harness unplugged. We thought we would see a CEL and have stored fault codes as a worst case scenario. The SLK 350 M272 manifold is manufactured by Mahle.
The manifold removal is not that big of a deal and only a few tools are required:
E12 Torx Socket
T30 Torx Socket
17mm flare wrench
Side cutters
Needle nose pliers
Wobble extensions
First step in removal of the factory intake is to disconnect and remove the DME sitting on top of the engine. This isn't too difficult as the electrical connectors have a locking mechanism that slides out. Once disconnected put off to the side in a safe place.
We also disconnected the secondary air pump along with the secondary air hoses just for convenience. The 5 fasteners that secure the air pump and related bracket are T30's.
Every fastener you'll encounter here is either an E12 or a T30. Out of the 20-30 fasteners we removed there are only 4 variations. This makes keeping track of what goes where pretty simple. I commend Mercedes for making this as simple as it can be in terms of keeping track of fasteners. Many other cars I have worked on use all sorts of types of fasteners in varying lengths/configurations near the manifold area.
The T30 screws mostly secure the fuel rail and DME brackets to the top of the manifold. The E12 screws secure the electrical conduit and a few engine grounds. What we did is work on disconnecting the electrical connection primarily on the right side (bank 1, left side when facing the engine) of the engine. We disconnected the cam adjuster magnets, ignition coils, cam sensors and valve cover ground. We removed all of the e torx bolts that secured the engine harness to the intake manifold/valve covers.
The fuel feed line is secured top the fuel tail by a 17mm nut. Use a flare wrench to remove.Before doing so purge any fuel pressure in the system via the schroeder valve on the fuel rail. I used a shop towel and a flat head screw driver to soak up the fuel as I relieved the pressure.
Once the harness is loose and you can move it freely the next step is to remove the mass air flow sensors and throttle body elbow connector on the back of the intake manifold. This will give you room to angle the manifold up and out of the engine valley at the front of the engine. Once the rear of the manifold was taken care of and we removed all vacuum lines we removed the E12 bolts that secure the manifold to the cylinder head. There were 10 in total. I grouped these together separately. We then essentially lifted the intake manifold up by the front while making sure the engine harness remained out of the way.
The vacuum lines that connect to the front of the intake manifold go to the secondary air valves. To disconnect these from the manifold use needle nose pliers and depress the quick release tabs. The vacuum lines can be stubborn but this is basically how you remove them. Once they are free lift the manifold up and out of the engine.
At this point we took a photo of the empty valley on the V6 You can see the knock sensors now exposed. As a side note, it's a good idea to block of the inlet ports on the cylinder head. We used blue painters tape to do so. You don't want anything falling into the cylinders by accident.
This is the stock manifold. If you haven't seen one in its entirety before you can see the liability on the front of the engine. For street use this setup is great as it provides low end torque and smoother throttle response. For racing or performance applications this can easily break from sustained operation causing the car to go into limp mode
We swapped the fuel rail over onto the SLK350 manifold (it's a direct swap) so no big deal there. We also installed the new throttle body and throttle body elbow. The SLK350 manifold used a throttle body from the M273 V8 engine and by default you have to also swap over the elbow connector as well to fit the larger throttle body. The parts numbers required for the conversion are as follows:
2731410325 - throttle body
2731400118 - elbow connector
The SLK350 intake manifold is slightly more compact despite the fact it is a larger intake in terms of air volume. This is because all the vacuum stuff at the front on the standard M272 engine is omitted for the SLK350. Once dropped in it looks right at home.
Torque spec is 9Nm to ensure that intake manifold is properly tightened to the cylinder head. Installation is more or less the reverse of procedure. Just make sure vacuum lines and other small pieces are routed as needed. More or less the best tip I can give here is the parts should fall into place on their own. If something doesn't line up it's likely because something isn't where it needs to be. Reinstall all the fasteners working from the bottom up. Make sure any grounds you removed are installed again. Final step is to install the mass air flow sensor on the intake elbow which in this case is the standard one that comes with the C300 (it's shared by both the M272 and M273 engine). It clips into place.
We are in the middle of deleting secondary air on this car since we don't really need it (emissions are not a concern for a race car ) but for the initial start up we reinstalled the secondary air pump and hoses to ensure no vacuum leaks or lean running conditions. We used one of our iCarsoft scan tools to look at live data with the manifold installed and the engine running. Our initial concerns in regards to the three electrical connectors not being plugged on on the factory engine harness were put to ease.Outside of not having our ambient temp sensor unplugged there was no fault, no check engine light, and no issues with short term or long term fuel trim. Essentially, the manifold is plug and play and the engine management doesn't seem to care that two reference signals don't read anything (hall sensors on the stock intake manifold). We also took it for a quick spin in the parking lot with a few WOT pulls and the car operated with no problems. We will be further testing this in another week or so under more strenuous conditions. Here are a few photos of the scan tool data with the manifold installed:
All in all, this was a pretty successful and fairly straight forward install. The benefits of the swap are to be determined upon further testing.
In addition to the intake manifold swap we also received our new front rotor rings to inspect. We had some custom work done to them which included some extra machining as well as adding slots for better venting. These rotor rings compared to the stock Brembo rotor rings are a 4 pound weight savings per corner which is pretty impressive. Anything you can do to reduce rotating mass is always beneficial in terms of handling and performance. Here are a few teaser pics:
Custom ring:
Original Brembo ring:
Here are some additional pictures including test fitment of the original Brembo aluminum hub:
We're going to be doing additional testing on these but we're hoping we'll be able to offer them for sale for P30 package 2 piece rotors soon. Replacing the rotor ring will be much more cost effective than replacing two entire rotors. Plus, since they're also a little bit lighter than stock rotors there will be a benefit there as well.
Awesome write up and love the detail .... Just wonder how practical this would be on a daily driver for some extra pep ... Keep up the fantastic work and love the car .... Can't wait to see what's next
Any information on the steering wheel? Specifically what hub you're using? I've considered swapping out my OEM for something sportier but finding a hub has been a nightmare.
Looking forward to seeing the final details on the rotor rings ... those look great and will obviously be more durable at the track than the stock drilled and slotted ones!
Awesome write up and love the detail .... Just wonder how practical this would be on a daily driver for some extra pep ... Keep up the fantastic work and love the car .... Can't wait to see what's next
Yes would love to find out the daily drivability of that intake manifold. Still no CEL?
Awesome write up and love the detail .... Just wonder how practical this would be on a daily driver for some extra pep ... Keep up the fantastic work and love the car .... Can't wait to see what's next
Thank you. Glad you enjoy the thread. So far we have seen no issues in terms of engine performance with the manifold. The car in general seems to be much happier with the SLK manifold on it. We'll see how it performs on the track but we're going to bring the old manifold in case we need to swap back. I think it will be fine.
Originally Posted by Knightmare69
Any information on the steering wheel? Specifically what hub you're using? I've considered swapping out my OEM for something sportier but finding a hub has been a nightmare.
I will get you details on the steering wheel hub and update here when i figure it out.
Originally Posted by Mgloznao
Yes would love to find out the daily drivability of that intake manifold. Still no CEL?
Based on our minimal testing there seems to be no ill effect. No CEL or pending codes from the swap. However, we just deleted secondary air so we will likely see codes for that. But emissions equipment is not needed in AER and getting rid of it freed up a ton of space in the engine bay.
Last night we did some additional work on the C300 in preparation for Watkins Glen. Basically we worked on the following:
Secondary air delete
Electric fan wiring
Brake duct cooling
Front rake rotor installation
For starters, the secondary air delete it to further simplify the car in terms of mechanics. Secondary air isn't a reliability concern but for our purposes it's one more thing in the way that doesn't need to be in the way. Emissions compliance is not a concern with this car and we will eventually be removing the cats as well. For the secondary air delete we made some block off plates out of thick aluminum stock using the secondary air valve's as templates:
We call this CAD (cardboard aided design) For the block off plates we used standard issue 6 point M6x20 grade 10.9 hardware to mount the plates and installed new gaskets to ensure no vacuum leaks. The final result looks like this:
Compared to what the engine bay looks like with the secondary air pump, hoses, valves, and associated brackets this freed up a ton of room. We also installed a vacuum cap on the intake manifold nipple which is normally used by the secondary air valve control solenoid to open/close the valves on start up. All that is needed is a 4mm cap to block off this source of vacuum. We also labeled all the connectors that are loose in the engine bay for quick reference in the future if needed.
We have received some interest on the brake rotor rings from several sub forums here on MB World. I wanted to give you some additional looks at this in this post. We're going to run these at Watkins Glen and see how they perform. If they do what we expect they will do it won't be long until we offer these as an option for vehicles equipped with 2 piece rotors. The goal here is to improve durability and reduce weight.
First, we'll do a comparison between the two piece rotor, one piece rotor, and the rotor which we designed for racing:
From left right right we have our rotor (assembled with the Brembo hub) Brembo ring, and OE one piece rotor. The rotor ring we're going to run is slotted only compared to the OE rotors which are slotted and drilled. Drilled rotors have a tendency to crack when they get very hot. We can't replace rotors after every single race. You will also notice the internal venting on our rotor has much larger vanes which should allow for additional cooling capacity. In addition, the thickness of the braking surface has also been minimized which save us close to 4 pounds per rotor when comparing the original Brembo ring to our ring. A 4 pound reduction is unsprung weight for each corner on the front is significant for just the rotors alone.
Our reason for going this direction is we want to retain the floating 2 piece Brembo design but also want long term durability and reliability of the brake rotors. In comparison to the stock drilled rotors we expect to get 2 weekends out of these specially deigned rotor rings as opposed to one race (half a weekend). Below is a picture of the one piece rotor we ran on Sunday for 7 hours of race time. You can easily see the cracks around the drilled areas and surface cracks all over the surface:
Swapping out the aluminum hub from the factory Brembo ring is pretty straight forward. All you need is an 8mm wrench, 8mm socket, 10mm e torx socket, ratchet, and in lb torque wrench. The bolts Brembo uses are heat treated and grade 10.9. We are using 94 in lbs as the torque spec for the hub to rotor ring for now based on standards available. Here are a few pictures of the assembled rotor before the installation:
Here are some photos of the rotor installed on the car:
02-13-2017, 11:30 PM
For the block off plates we used standard issue 6 point M6x20 grade 10.9 hardware to mount the plates and installed new gaskets to ensure no vacuum leaks. The final result looks like this:
