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SLC43 AMG Track Use

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648 views 34 replies 11 participants last post by  CornerCravingDriver  
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#1 ·
Hello all,

I am heavily considering an SLC43 AMG as my next vehicle purchase. I've searched quite a bit but haven't been able to find much information from people who have actually tracked these cars.

Has anyone here run an SLC43 at autocross or on track? If so, what modifications or maintenance items would you consider necessary?

I assume upgraded brake pads and high-temperature brake fluid are a must, but I'm curious if there are any known weak points or concerns beyond that. For example, my previous car was an MR2 Spyder, which required an aftermarket baffled oil pan to prevent oil starvation during sustained cornering. I'm trying to determine whether there are any similar issues to be aware of on the SLC43.

For context, I'm specifically looking at cars equipped with the AMG Handling Package. My intended use would be spirited mountain-road driving, autocross, and some higher-speed autocross-style events that utilize portions of local road courses. I also plan to run a dedicated set of wheels with 200TW tires, similar to what I've done with previous cars.

Before I commit to purchasing one, I'd like to make sure I understand any track-related considerations, limitations, or recommended upgrades. Any firsthand experience would be greatly appreciated.

Thanks!
 
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#3 ·
I just recently did a test drive with one and thought it was great. It is just for fun, I won’t be competing really other than autocross but that’s all more for me to improve.
 
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#7 ·
I’m sure that makes it even better on track. Would you be able to point me to Where you’ve seen people discuss this? I really just have not been successful in finding anyone tracking these so I’d really appreciate it if you knew where that info was! Or if you know anybody who does track one I’d love to contact them.
 
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#13 ·
LeonardoDaBenz said:
I'm guessing here but the fact that they're too heavy might be a clue. Over-steer is an issue as well (I can testify to that) and rear bracing won't help there.
Click to expand...
I mean people regularly track cars this heavy and heavier haha. Just going to run you more for consumables. I like oversteer, just have to be smart with your inputs to avoid going too far. It’s fun though.
 
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#17 ·
If you are seriously into having fun on the track and want a convertible, I would chose the AMG GTC Roadster. It's twice the money, but also twice the fun. I have had one. Amazing car. View attachment 666902
[/QUOTE]

I am sure it’s a great car, but as you said, it’s twice the price. That is not something that I can just stretch to… I don’t think anybody looking at a used SLC43 can stretch to a used AMG GT product for the most part…
 
#18 ·
I've tracked my SLK55 here in the UK at the famous Brands Hatch circuit, probably not a direct comparison as my would be heavier with the V8. To sum up it was a blast down the straight catching and overtaking other track-focused lesser powered cars, but come cornering forget it as I was eaten up by the light-weight stuff.

Here's my video:
 
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#19 ·
That was a great watch! You are correct, probably a little heavier with the V8 on the nose, but still gives me a better idea of how these cars perform on track. Have you taken it to the track since?

Did you have any issues with anything getting too hot or similar?

Thanks!
 
#22 · (Edited)
I tracked my R171 SLK55. Modifications done ;

endurance race pads (which squeek when cold, only for track use) - ~$150 for front only
sub-frame brace (under, behind) - cheap
engine bay brace - cheap
D2 sports suspension (camber and height and rebound adjustable) - cheap
Motul RBF 660 dot 4 brake fluid - replace after 4-5 intensive track days unless old fluid comes out well
(because of a leak in the old radiator) - custom full aluminium radiator
17 inch rims + 245 wide semi slicks (road legal, but on the border) - square setup to save costs
Goodridge braided brake lines - every wheel
MB spec engine oil. Replace when needed, not after 4 years of track use

The car already had a valve at the rear muffler to open with a button - more sound, more freedom for the exhaust fumes to go

During the tracking the brakes were fine, with the endurance pads, cooling was fine because it is a 5 km track with long straights and sweeping corners; providing a lot of cold air flowing over the radiator.

I didn't push the car to its limits. I didn't even use manual shifting, the 722.9 is notoriously slow or not listening (when downshifting) so I left it in ... C - auto. This didn't give top performance, but I feel it protects the drivetrain while I still have 98% of the fun. Choosing a proper driving line, braking properly (late and hard - can only do with track oriented brake pads) is more important than being 0.2 seconds faster at the end of the straight because you shifted manually at 6750 rpm (SLK55 redline).

Proper helmet, like ARAI/BELL, pick the LIGHTEST possible to reduce neck injury on sudden impacts. A heavy helmet will hurt your neck.

Proper timing GPS - I have a Colombus P-9 which has a 25 Hz update interval of your position (and much more accurate than regular GPS), instead of your phone which might have just 1 or 5 Hz. This gives very accurate position and speed data which you can plot of a map of the track. Especially after several laps the data will show how and where you drive and then you improve upon the data by comparing with others with a similar weight car and tires. In some turns you might think 140 km/h is the safest maximum, but others go 160 km/h so you can push more. You can try that 'by trying' but that takes a lot of laps (at least for me as beginning amateur).

For autocross ; high accelleration, low speeds, I would absolutely recommend to double, triple check, the cooling system since your engine will run very hot but there is less cold wind going through the radiator to cool it. I don't know if there are mods around which would always keep the radiator fan running during a lap (and after) to preemptively cool the system; not when the oil/engine is already too hot.

If possible get a HANS system with the helmet. And that means you need a helmet with HANS connectors on the side. It will restrain your vision (cannot easily turn left and right) but again - you only have one neck and neck replacements are kinda expensive these days.
 
#23 ·
As previously discussed, I can name a dozen cars better suited for your track endeavor. But, having said that, here's my two cents...

In a prior life I spent time racing in the SCCA and instructing at Porsche Club Driver Education events in my 911. My experience has been that before pretty much ANY group will let you out on any autocross/race track, you will need to pass tech. With convertibles, one such is the "broomstick" test. Basically, that involves laying a broomstick from the "A" pillar to the roll hoop. Your helmet has to be 2" (or more) below the broomstick. No way would I ever pass this test in my SLK55.

Now, for Boxsters, there were aftermarket roll hoop "extensions" that would pass muster. But as you can imagine, these extensions had to be structurally sound and couldn't exactly be removed without leaving "a trace", so to speak. Further, the Boxster removable hardtop could not be installed to satisfy requirements (making it a coupe), unless it was permanently affixed to the car. I doubt VERY seriously that a retractible hardtop would meet any of these requirements, so plan on running with the top down and meeting rollover protection requirements.

While I appreciate the deep dive you are taking into the mechanical upgrades/changes that are needed, I would also do a very careful review of the safety requirements and maybe even make a few phone calls.

Good luck with your journey.

Paul
 
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#25 ·
You are correct, I will have to make sure I fit and pass the broomstick test with a helmet on. I am short, so I am hoping this will help. I may bring my helmet with me to a dealership and see how I fit…

I understand it’s not the “best” option for track work, but it’s the best bang for buck option I’ve found in terms of performance and age, as well as being actually comfortable for a long drive. It hits all my “requirements” haha. I couldn’t get a Boxster of similar vintage for even $10k more unless it had 200k miles.

Thanks!
 
#24 ·
I think it would be a blast on the track with a slightly lighter nose than the SLK55 giving less understeer. My SLK55 is great fun on the track but severely limited by its slow transmission, jerky manual downshifts and lack of a LSD. It gets very hot under the bonnet. I wrapped the exhaust manifolds and that makes a huge difference to engine bay temps. The brakes take a beating - the silver AMG/Brembo 6-pot calipers are now gold from the heat. But honestly, a lighter car will be quicker any day on a short, twisty track. My S2000 is just so much faster and precise through the turns and is the better car for the track, but not for the drag strip!
 
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#27 ·
I think the same! I was restricting myself to newer vehicles anyhow, but the 9G-tronic being a large improvement has definitely made me happy I was looking at the 43. I come from driving manuals since I’ve had my license, and this would be my first automatic. I knew I wouldn’t be satisfied if it wasn’t a quick shifting and instantly responsive auto. Luckily, having driven a 43, I thought the trans was great!

I do think the six being set further back than the 55’s glorious V8 will help a lot for mid-corner push, and it definitely felt great in corners when I test drove. Lack of an LSD is still a problem with 43 series cars unless you get the handling package, which I will not compromise on haha!

I am looking forward to seeing how the car fares as far as heat goes, I have seen many track their C43 cars with the same engine and trans but an extra 300lbs, I think the car may do just fine without any necessary upgrades. I guess it will depend on my track and how I utilize the sessions.

I am sure the brakes will take a beating. I am just glad they are designed with such use in mind. I do plan to swap out the pads and fluid before I do a full track day.

I will agree that something like an S2000 would probably be a bit better for pure track use, I have driven an AP1 and it was great. I don’t think the 43 is super far off, however, considering it’s added practicality and ability to more so “chill” on the highway. Plus, my suitcase won’t fit in the S2000 trunk, haha.
 
#26 ·
To be honest, you can track any car. Even some 110 hp old FWD banger from the 90s. Brakes are still most important ; you don't want fading, you don't want your braking fluid to boil off. Acceleration and top stop are less important than stopping. Heavy cars, light cars, it's all fine. Have good tires and at least TPMS sensors which show your their current temperatures. Before any track day LOWER your tire pressure since they will go up like crazy. Adjust them after a few laps so you're not running around with 70C tires at 3 bar. If possible get a laser thermometer so you can check temps if you don't have TPMS sensors with temps in them. Safety is important but if you don't drive your car well beyond 85% of its (and your) capacity and if you don't race, but just do time attacks then roll bars etc are nice to have but really not necessary unless you have no idea what you're doing. It's hard to flip a car. While the 722.9 shifts slow and doesn't listen to your input, it works fine in the end and doesn't seem to overheat much. Also the 55 does seem to get hot, but the cooling is sufficient even after 25 minutes going at full power lap after lap. The track matters of course, if it's mostly turns then you can't go full power ; the rears won't have enough traction or the front won't turn in due to too high speed. In my case my tires were definitely the limiting factor, even with semi slicks I couldn't go faster since the tires were squeling like a horde of unhappy pigs. I only put on 245/45/17s' and for certain the 55 can use 265s or even wider if they'd fit on the front! I'd never ever run on road tires ; they'll wear in less than 20 laps and then you're down a lot of money while they actually didn't give much grip unless you run Michelin Cup 2's. But those are even more expensive.

I'd definitely get some OBD displays, those old fashioned gauges which can you tape on your dashboard with IAT/boost pressure/oil and coolant temperature easily visible so you can slow down before things get out of hand. I've seen people drive in 2500 kg EVs on the track (the track changed their policy afterwards since they were afraid of EVs going off and then causing a massive fire) so you can have fun in anything. Modified Peugeot 206s with just 1 seat and zero interior and a straight pipe are actually faster than most production cars since they "don't have to brake in turns" - so it seems.
 
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