WolfpackC63

Took my P31 to the track for the first time 2 weekends ago. VIR with the PCA Carolinas region. 4 20 minute sessions Saturday, 3 30 minute sessions Sunday. Tires were Hankook RS4s (245 front, 275 rear), brakes Zimmerman cross drilled & slotted rotors (nobody sells blanks for this car) and CarboTech XP12/10 pads (f/r). Was a bit chilly at VIR that weekend! 23°F Saturday morning, and still only 37°F at 1:30 when I went out for the third time. A little warmer on Sunday thankfully. First time out with this car and with super cold tires, you better believe I eased into things. Car did really really well. There are many places where I know I'm leaving time on the table but am okay with that because a) one of those turns is where I balled up my BRZ and b) the margin for area in some of the places is very small and I don't want to damage this car. Beyond that, I'm not a pro so I know there's probably a lot of time left that I'm not even aware of. Holy heck the car is fast, REAL FAST. I was able to go around 12 seconds a lap faster than in my Cayman. Car felt super stable in the climbing esses: on my best laps I entered them at over 130 and left around 110. Lap after lap, the car reached close to 150 on front straight and over 160 on the back straight.

Any concerns about engine oil temps getting too high (tracking in the fall was by design to help prevent this) were thankfully unfounded at this event as I never saw higher than 266°F. Likewise the transmission never overheated though it did appear to jettison some fluid out of the vent hole (noticed residue later on underbody panel, exhaust pipes and 1 drop of fluid on garage floor. Brakes, however...oh boy. I had thought there was some sort of venting for the fronts (I mean it's an AMG) but there is not. As such, hauling 4000 lb down from 150-160 lap after lap did some damage. Measured back in paddock my rotor temps were 800°+ and I started boiling brake fluid while on track both days (fluid was fresh before event). Sunday morning I did another full brake fluid flush with Motul 660, but it still boiled.

Post event consumables condition:

• Tires look great, many events left in them
• The front rotors are shot. Cracks everywhere
• Front brake pads are down to 6mm, rears 9mm. Should be good for another event.
• rubber caliper piston dust shields are pretty rough. 3 per side all cracked. Planning to rebuild them all before next event.

Going forward I plan to custom make some front brake ducting (starting from the blanked off areas of grille that flank the oil cooler), purchase titanium shims and replace the front calipers' piston dust boots. I (admittedly) cheaped out on the front rotors by not using the 2 piece ones with aluminum hats. I know that helps out a lot with weight but does it do anything for heat dissipation? The rotors I used I purchased from FCP Euro, so I'm not worried about replacement cost (other than shipping). Is it worthwhile to "go up" to the Brembo 2 piece rotors they have for $380/each?

Stock suspension on car (82,000 miles). Engine has longtube headers from VRP, no resonators or cats, underdrive pullies, ROW airboxes and an ECU reflash. Here's a video of my fastest lap (please disregard the overlay data as it's 1-2 seconds out of sync and all speed values are off entirely from tire size difference).

You Tube

Here's the full session (roughly 23 min)

You Tube

BTW I'm always open to advice, both for driving technique and car modification tips. I'm especially thankful (in advance) for any brake cooling suggestions.

Hope you guys enjoy the video. I was the only AMG out there and got many compliments from other drivers about the sound of the engine, and in general for tracking a big sedan.

lo-fi

Excellent. What were your impressions of the stock suspension on a track? Obviously with 82k it isn't the freshest setup but still curious as to what you thought about it.

12C63

That’s good to hear about the brake cooling issue.
I’m going to research this now & fab something up to increase brake cooling.

WolfpackC63

Really good IMO. Felt pretty tight and just killed it in the climbing esses. I could bomb those gators and the car just took them. Gained on more Porsches through that section than I lost. Between unfamiliarity with the car and the cold weather conditions I avoided tracking out wide in a few turns where you go pretty hard onto curbs/gators but the car probably would have been fine soaking up those bumps. For reference I rebuilt the suspension on my Cayman around 100k miles after it felt too floating at this same track. (FYI Cayman was my previous fun/track car before the C63).

Sidenote: can anyone recommend a good caliper rebuild kit?

eschow

I have Carbotech XP10/XP8, and I couldn't fit the stock brake pad shims in. From what I've read, the titanium ones are the same dimensions as stock, so they wouldn't fit properly.

I'm also planning to do brake duct cooling. Not much room, but I may go through the front rebar

hachiroku

removal of the rear dust shields for the front rotors will help a lot. they prevent the brakes from actually channeling air into the braking system which cools them and evacuates brake dust which gets gummed up blocking airflow. maybe some ducting as well if you still are having overheating issues. titanium shims only marginally helps...airflow is the main issue. also an aggressive track alignment will also cut some time off your laps as well if you haven't already done so. the R compound seems to be helping a lot and you are a solid driver. keep it up! does your P31 have an LSD? upgraded oil cooler is an absolute must!

harry's laptimer is great, but after lots of research, i have found out that it does not allow time alignment with the gauges after the fact which is ridiculous. you really have to drive, record, review, time align, drive, record, review, time align over and over until perfect. also the brake and gas display is based off the G sensor of the phone. next track outing i'll probably utilize an external GPS since harry's will drop at times using the built in phone GPS.

if there is room for some ducting, this is what i may do to my car to get more airflow into the braking system. adding naca ducts to the engine belly pan. only issue is i daily my car as well, and with certain pads, if your braking system is too cold...not a good situation at all.



for those hardcore guys, i can look into manufacturing add on brake backplates for ducting sometime in 2022.

BLKROKT

Nice going. I miss driving VIR, it’s my favorite US track. Absolutely perfect for the C63.

Pretty easy to just weld a hose fitting on the OE dust shields. Cost like $50. (for the record, the hose fitting has an angled half-moon shape on the inside, which accelerates and directs the air right at the vanes not the disc face, as described in my thread linked below)

You’re gonna run out of room on the drivers side, there’s just nowhere to put a hose. I removed my smog pump and windshield washer reservoir and there’s room now to route it inside the frame rail and out through the crescent-shaped opening near the axle. It’s super tight, use 2.5” diameter hose max. (ignore old test fit picture from pass side with hose routed just outside fender lining - failed miserably)





Check out this thread for more info on the brake ducts and caliper rebuild if interested. I really have to get back on it…
https://mbworld.org/forums/c63-amg-w...-bumper-3.html

BLKROKT

Couple of other comments after reading again and watching:

1. Over 160mph on the back straight is very fast - that’s usually my barometer for a good sector time as it means I got Oak Tree right, and that straight is where I make up a lot of real estate on whatever car I’m following. The RT wing knocked off over 5mph there. Curious how you are handling the turn at Oak Tree, as I’m never happy with the gear I’m in. 2nd is too low and slows the car too much, while 3rd is usually too high unless I’m on the very edge of control (too fast). I usually treat it as a double apex, hitting the first and going out very wide left before cutting hard right for the straight. Takes some guts to keep your foot in it over the blind crest at 150+ and into the rollercoaster. I’m always super nervous about my brakes there after seeing a car somersault down the hill.

1a. Just watched your video, very smooth, you clearly know what you're doing. You take the same line I do around OT but seem to be able to turn in and hold a tighter line than me. And carrying 60mph+ through there is terrific. I remember that they weren't happy with the pavement - did they repave the track again since mid-2018 because it looks way way less bumpy overall but particularly there?

1b. Your car sounds so good bouncing off the left retaining wall coming out of OT. I can't tell you how many guys I passed on that straight who found me afterwards to tell me it's the best sounding car they ever heard.

2. Climbing esses right on point. I also tried 110mph going in then accelerating up to 130mph by the way out, but it makes that last right bend pretty sketchy as the car wants to get light there - think they are roughly equal, depends on your aero. It’s so important to commit, not coast and maintain speed at the very least, and ideally accelerate up that hill while getting in a rhythm. Have they fixed that nasty pothole yet on the inside (right) of the second ess (looks like it)? I assume you’re downshifting to 4th at the top and then turning early and going flat-out through T10? That’s what usually worked for me, 95mph+, sometimes sideways but trust the tires (maybe not in the cold though). By the way, adding a wing allowed me to carry an additional 10-15mph there, huge difference.

2a. Rear aero makes a huge difference at VIR. Can't recommend it enough, was able to carry a ton more speed throughout. Changes everything.

3. Your comment about leaving time on the table I couldn’t agree more with. I ran almost exclusively with traction in Sport. Once I got much wider and stickier rubber on the car, along with tons of neg camber, I didn’t notice any interference from the TC unless I was about to be in real trouble (although the TC makes low speed turning a little less fun/effective than it could be). Some of the keyboard warriors on here who literally know nothing will make snide little comments about it, but ignore. I don’t mind losing a second or two a lap if it meant I was going to be able to drive the 800mi back to NYC at the end of the weekend. Much like WGI, VIR is just way too dangerous and the consequences too high to try to be a hero at the speeds the C is capable of.

4. There are a couple of guys here that are VIR regulars. Def look them up, I’ll edit this and tag them in a bit.
@Duffer4126 tracks his C there and also mans the flag stations
@Bigtickets not sure if Eric is still on, but he scared the hell out of me on my first recon lap at VIR in his sedan, heck of a driver wow

5. Brakes. Get as much brake on there as you can, it makes a world of difference. You can never have too much. Especially as you would expect at the ends of the front and back straights. I’ve had great luck using SRF, never any problem. The RB BBK also gives you a lot more confidence as they can overbrake even r compounds. Would advise as much cooling as you can tolerate, braided lines, Ti shims, and stainless pistons with silicone boots on your rebuild. When I did my calipers they looked pretty bad.

5a. Caliper rebuild kit - go with Racing Brake for the pistons, seals, silicone boots. Zuffenhausen will have all the Brembo hardware you might need like bleeders and pins etc. I got my Ti shims from Hard Brakes, but I don't think they carry them anymore (although their Nissan GTR and/or CTS-V shims should be the same size and work, maybe with some minor trimming)

5b. I used Carbotech XP12 pads and found them to be just perfect. Have since switched to a GLOC compound equivalent to XP16 but I expect it to eat rotors. Think you'll benefit from two-piece rotors from a cooling perspective, but I can't compare as it's all I've ever used (P31 rotors then RB BBK).

6. Fluid venting. Likely puking from your rear diff. Get the AMG finned rectifier (diff cover) to help with that. Not much else you can do other than fitting active cooling (punp, cooler, lines, electric, etc) and it’s pretty involved. I'm still not 100% sure mine is right and it was a ton of work.

7. Harry’s LapTimer. I can never get the telemetry right either. All of it is junk, only the timer is ever right. The iPhone GPS is probably the culprit. I had an external antenna around somewhere but stopped caring until I can get a more permanent solution (was going to install directly into the upgraded Android display but gave up, maybe next year).

8. For comparison, have attached a video below from 2018 with a similar lap time to yours (this was at HyperFest, got a few fun laps in between rainstorms that Sat). Will try to also find my 2:02 from that Sun for reference.
The only very minor comments I would make are:
a) too bad that Porsche slowed you down so much through T1,
b) T3 I usually go wide right on entry setup, cut that apex with 2 tires on the kerb, then go 2+ tires over the out curb on the right into the paved runoff - found that was the fastest line for me,
c) for T4 I usually go deeper, then cut hard left as it allows me to get on the power sooner and stay mostly on it all the way out to the bridge - looking side-by-side I take quite a bit of time from you there from T2 to the bridge, in the damp - its a tough section to get right but I found too much coasting through there really hurt my lap times and to not to be afraid to give it the beans and get the car rotating more aggressively through that tight section,
d) just so impressed with how you handle the Oak Tree sequence - looking through that same video you gain back all that time from T10-12 and up to T13 - I suspect it's coming from good driving and line on your part, part aero penalty on me, and part better pavement for you - whatever the case it's great,
e) you can probably be almost flat out from T16-17 and up onto the front straight - the compression at the bottom of that hill will glue your car to the track on those right handers. Took me awhile before I trusted that one as I've seen too many cars go off there. I might also be in third down through there to force me to stay on the throttle and not coast because that's the time-killer, I've tried so many different ways and gotta rewatch more of my videos when I find them, but I'm almost certain I'm shifting to 4th right on track-out onto the straight (confirmed). Of course my lines may not be valid anymore as it looks like they finally got the surface right and you have good smooth asphalt on most of the turns.


Will probably edit with more comments as I think about it. Such a great track, glad other C’s are out there tearing it up.

Dr.Speedfellow

Not sure I would bother trying to brake duct the car unless you are really willing to customize it a lot. These cars have been around for a while and I haven't seen anyone pull it off well even when they move things, remove things and cut up the front of the car. You need the air outlet (ideally from more than a single hose with bends in it) coming out in the CENTER of the disc where the internal vanes in the disc can pump the air through. And the center of the rotor has to be fairly well sealed off without extra material out where the disc ring is reflecting heat back to the rotor ring. These setups where the hose blows mostly or partially on the inner surface of the disc are not very efficient and can sometimes cause thermal inequalities between inside and outside of rotor. Most rotors crack or come apart due to uneven thermal loading not simply high temperatures. This is pretty much what the business end of a duct system needs to look like to be worthwhile and with plenty of forced airflow, full clearance of all suspension parts, etc. If you get much away from this results go down dramatically.




As Hachiroku mentioned above spend your time and effort removing the parts of the dust shield that you can. A high quality rotor with a good efficient vane design and high vane count can pump a decent amount of airflow through itself if opened up just to the available air inside the wheel. The dust shield just reflects a lot of heat back into the situation and minimizes air draw to the rotor vane design.
Also the thermal mass of the rotor makes a difference. You pretty much get what you pay for in terms of this and vane design. The lightest rotor is not always best in terms of dealing with high temp situations. So get the best rotors you can afford. People seem to like their RB brake setups obviously they are much better than stock but there are other options out there if you're willing to pay for them.

Motul 660 is good stuff and actually has slightly higher dry boiling point than SRF but SRF has an advantage in wet boiling point, so unless you use fresh brake fluid at every event SRF can be a little less prone to steam in the brake system as the fluid gets used and absorbs more moisture. I can use SRF that has a few events on it even at Daytona road course and Sebring without fail and they are both tough on brakes.

Also cross drilled rotors tend to crack as you found out, especially on heavy cars. 390mm slotted with no drill holes on mine.

Cwagon

To go with removing most of the dust shield what about adding air deflectors to the lower control arm similar to what Porsche do on a lot of their current products.

BLKROKT

Will try to dig up a pic, but I've had 996 GT3 Cup deflectors on my lower control arms since 2017 and don't think they're doing anything. With the way our arms sit, it's tough to get them low enough to deflect any material amount of air. Certainly can't tell any difference with or without.

It’s a decent idea, but you’ll have to either make them or have them made custom. The way all the Porsche deflectors are configured, there’s not enough adjustability (excess plastic) to modify them to work effectively on the C63. And the angle of the air channel isn’t quite steep enough either. The 996 GT3 Cup deflectors are the biggest they make.

I might look into mocking some up out of sheet aluminum, but it’s a surprisingly complex shape you need to create across multiple axis. And the mounting is always going to be tricky. And then of course, to get it low enough where it’s going to get airflow, it’ll likely get knocked off in street driving (probably why they’re fairly flexible plastic).

WolfpackC63

I wasn't running any shims at all, so... But the tight clearance is good to know! (could also slide them in after pads wear down a little, though kind of defeats purpose).

I think you mentioned the brake dust shield removal to me on the FB owner's group (name's Patrick Hansbury). Via cooling from that or adding a ducted system (those NACAs look nice!) I wouldn't worry too much about street driving for me. I don't drive the car much in winter and I swap back to street pads when not at HPDEs. Tell me more about a track alignment! I didn't think we had much adjustment options with the stock suspension. Yes my car is a P31 with the elusive factory LSD option! I'm pretty hesitant to add an oil cooler - also this is why I'm sticking to cool/cold weather events (plan to do VIR Grand Course in February) because I'm not sure how serious I want to get with this car (for tracking purposes) and there doesn't seem like a need to get one for street driving. Also thanks for the compliments.

I appreciate the tips for cooling, and while I haven't read it yet, I bookmarked your thread on brake cooling/ducting months ago!

I think the car has around 575+ hp so that helps with the speed. IMO I'm slow coming out of most tight corners because I worry about losing traction before the car is straight. For Oak Tree I take the first section fast and like you mentioned go pretty wide, all the way out actually, before cutting in hard for the straight. I also don't track out over the gators because of traction concerns (see mention above). They may be unfounded fears but I'm still learning the car and this was the coldest event I had ever done (with any car). I took that turn in 2nd every time.

Thanks! And quite right, so many compliments from others afterwards.

I usually entered the Esses with the car near redline in 4th gear. Maybe 6500 rpm, and then I would just do maintenance throttle until the top. Didn't use 5th at all. Most of the through T10 I was going 85 mph at best, and while I know there's A LOT more speed to be had there, back in 2013 I oversteered there into the tire wall in a close to brand new BRZ and totalled it, so I still get the yips there.

Thanks! I'm lucky to only live 90 minutes away from VIR in Raleigh. Actually lived a few years in Astoria a while back though.

Greatly appreciate this advice, will look into it and will definitely not be going back to the track until this is addressed. My front pads still have 6mm left - I think that should be enough for another weekend. Plus the next event I'm planning to do (VIR again) will be Grand Course one day, which is easier on brakes.

Unfortunately I don't think that's the case. The fluid residue is well ahead of the rear diff. See pics:




Thanks so much for the comments and tips.

Appreciate the advice! Will continue to investigate options.

Here's a helmet cam POV of the same lap linked above. I like this better than the Harry's video.

Dogtag114

First big tip, quickly lose the "shuffle steering" (moving your hands around the wheel). Start doing it in daily driving to create the good habit. By keeping your hands on 3 and 9, you'll have better muscle memory in controlling your car and be better prepared for an emergency situation where you may need to react (your hands know where center is).

Jasonoff

Good tip! Man...I forgot how quiet this car can be on the inside

Dogtag114

I haven't seen a gutted C63! How much weight did you get out of this pig?

Jasonoff

About 800lbs. Will get more out over the winter season. Goal is to try and hit high 3100s but that may be a stretch.

2.5" duct to back side of OE shield pointing right at the inner vane. Running DTC60 pads in the front.

WolfpackC63

There's an argument to be made for both sides of that view. I've been taught by instructors over the year to keep your hands at 3 and 9 (the static positions, not dynamically on the steering wheel as it moves) so that if the car unexpectedly oversteers then you have greater range of motion with your arms to recover. If you keep your hands fixed at the 3 and 9 positions and have the wheel turned 180° when the rear end lets loose, there's nothing your hands are going to be able to do about it.

hachiroku

keeping your hands at 3 and 9 on the actual wheel's alignment will only make sense if you have quick steer where 90 degree's x 2 (left and right) is your max steering. you want to keep your hands from ever getting close to a point to require you to ever cross hand over hand. in emergent situations, if you're over extended with your arms, you will not have the mobility to correct. correction or releasing the wheel in an over extended reach will not give you the leverage to catch and control the wheel with the accuracy required.

in a drift situation, you want your hands between 2-5 and 7-10 constantly moving to allow for control and not overextend your reach. this will prevent the wheel from whipping unintentionally as you're always keeping your hands at the correct point of leverage to make steering easy. the range is broad because at times you may be gripping the wheel with one hand so you'll need to learn the correct leverage point for the lock to lock ratio of the vehicle as they will differ.

here is the time stamp of me driving and losing it due to driving street tires being past their temperature range on the track. with my arms not being over extended i was able to correct and regain control.

hachiroku

every driver's preference will differ and specific track will also determine what alignment settings to run. i have adjustable arms on my W211 E63, but generally prefer front camber to -3.5, front toe 0, rear camber -3, rear toe 0 as a solid base point. proper alignment will help eliminate push or understeer during turn in or powering out.

Dogtag114

Perhaps I’m old school on this and thoughts have changed, I’ll ask some other instructors next year.

By comparison, here is me losing it and keeping my right (and “over”) hand on the 9 position. If I’d have needed more correction, I would have gone hand over hand (I hope as I have never spun yet). My left released as it over extended.

Jasonoff

Seme, even in a twitchy AF S2000. Sometimes you even need to release the wheel so it can snap back quicker.

Skip to 2:35 below and see where I almost put it into the lawn. Yes it's a 10 year old video lol.

WolfpackC63

I'm talking about stock suspension though. I didn't think we had any camber adjustment? I prefer negative camber but again with stock suspension didn't think that was an option. Sidenote related to that, at the HPDE (topic of this discussion) a guy there said he had some E63 front camber plates for sale and said he was pretty sure they fit on my car. Does anyone know if that's the case?

Link doesn't appear to work.

ALFAitalia

Jason....your video is sown as not available....

hachiroku....I disagree. I think you would caught that slide much faster if you had not been moving your hands around the wheel so much (shuffling). On a track day my hands don't move from 9 and 3 o'clock positions except on the very sharpest hairpin bends....only two track I go to have a bend that sharp (Brand's Hatch and Donington park) and even then Id rather tighten the turn with a bit more throttle then have to move my hands if there is the space and I can go fast enough. . If you are already at the limit of your arm movement when it cracks into a slide its the opposite way you need to steer so running out of steering angle should not be an issue.


Copied rom a race craft site I visit..

Whether you’ve got a nice flat bottom steering wheel or not, make sure to keep your hands at 9 and 3. Don’t shuffle or slide the steering wheel through your fingers and never cross your hands over each other while driving.

Why? Well, this way you’ll always know exactly how to get your car pointed straight again.

Everyone has experienced what it’s like to forget exactly which way your tires are pointed, especially when maneuvering around a parking lot. A harmless error, it’s easily corrected at low speeds. At 60 MPH, that half-second can be bad news.

Keeping your hands at 9 and 3 will also prevent you from using too much steering input. Your car’s steering system was designed for low speed maneuvering on the street, but when you’re on a track, small inputs go a long way.
Also

Dangers of Shuffling Your Hands

When you shift your hands, you typically move your arm to the top of the steering wheel. When one hand is on the side of the steering wheel, and one is on top, it is easier for a driver to make more significant inputs than we want to on the steering wheel. This can lead a driver to turn too much, which can be especially risky on high-speed corners.

The most significant negative factor that it can lead to is a driver overcorrecting when those small corrections are needed. Most overcorrections directly lead to a spin or worse, a crash. We know a spin is just a crash without a bang, and we still need to take them just as seriously.

Many drivers may argue, “I can’t turn enough if I don’t shuffle my hands.” The big thing to understand for drivers that believe this is that at a certain point additional steering can actually become counterproductive. It is what we call “turning past the grip threshold.” Check out the following video by professional racer and Racers360 Coach, Dion Von Moltke, to learn more about the subject here: turn-the-steering-wheel-too-far.

Understeer, like oversteering, is what we feel when the front tires threshold of grip breaks and the front tires start to slide. Once they slide, you are asking the tires to do more than it has the grip to do. Adding more steering wheel input after the tires start to slide, you are now asking the tires to do even more. Since the front tires are already sliding, the additional steering will never help the car turn more, it is useless and leads to negative consequences.

The big thing to understand as simply as possible is, once you start to feel that understeer you can stop turning. This is the rule and there are a few very rare exceptions to it. That additional steering input puts more wear and heat into your tires and can also lead to an ugly snap oversteer on a corner exit.

When you understand the big reasons why it is so important to keep our hand positioning at 9 & 3 o'clock, drivers will become more disciplined in doing it. Pros at every level, in every type of car, do this. When I see pro drivers in autocross, they manage to keep their hand at 9 & 3 o'clock on the steering wheel. The great thing about this is that this safety measure is true for both racecars and streetcars - for any situation when you are driving.

Jasonoff

My bad. Youtube changed all old unlisted videos to private in a security update a month or so ago. It's fixed now.

BLKROKT

Camber plates should fit fine on stock suspension. I ran KMAC camber plates for a season or two on OE struts. Well worth it.


Brands was my local for a few years. Druids is a tough 180deg bend for those who don’t know. Same for Melbourne and Goddards at Donington Park. I also rarely take my hands away from 3 and 9. Keeps the paddles where you want them too.