PDA

View Full Version : Mercedes 300SL brakes overheat



PostBox981
04-10-2015, 18:20
Today I tried the Merc a little on Nurburgring GP. First of all Iīd like to send a big thank you to SMS, as this car is simply fantastic! Engine sounds very much like 6-cyl-in-line-engines are doing, handling is great. I never had the chance to drive one of these in real life (what a surprise!), but it all feels very credible.

To my surprise after 2-3 laps brakes were running hot at over 700°C. Lots of fading and I didnīt have the slightest chance to keep up with the AI. I already had that same problem in the Escort before. Seems itīs a general problem with classic cars as brakes werenīt as strong as they are today. But... what can I do about it? I mean, in modern cars you can adjust the brake cooling but what can I do with the classic ones?

I tried to reduce brake pressure, but that means braking earlier and for a longer distance so the result is quite the same. Any solutions?

madmax2069
04-10-2015, 18:29
One thing you can do Is to rely more on engine braking then the brakes themselves (aka downshifting), using the brakes sparingly and downshifting can do just as good as using more brake pedal.

That at least will prolong your brakes.

Ove been on some tight tracks with the 300sl without too much issue from the brakes.

Gravit8
04-10-2015, 18:41
One thing you can do Is to rely more on engine braking then the brakes themselves (aka downshifting), using the brakes sparingly and downshifting can do just as good as using more brake pedal.

That at least will prolong your brakes.

Ove been on some tight tracks with the 300sl without too much issue from the brakes.

This car gets very little help from downshifting either as it's an old gear box and clutch too. Kind of a dog IMO.
Brake fade makes it impossible to compete with AI as they don't suffer same. Fun against other humans though.
Gotta baby it.

My brakes seem to operate pretty good til about 1,000. Fade happens above that.
I assume they are hotter at the front if your setup is default? That's what I got and kept inching the brake bias to rear to get more even heating front to back. I also turned up the diff lock. This car pretty stable under accelerate. Not a ton of power. I have not lowered mine yet, but that should help too. I'm sure a significant amount of weight transfer to front causes a lot of inefficient braking too.

artao
05-10-2015, 11:31
One thing I sometimes helpful is to actually apply brakes harder and a little early, then get off them quicker to give them more time cooling. Haven't tried this in the 300SL yet tho. Love the car tho, once I got used to how it handles and what it wants to do. .. and a little bit of setup tuning, to taste. I almost always soften tires a bit, as I find pCars defaults to be a bit too high for me.

PostBox981
05-10-2015, 17:38
One thing I sometimes helpful is to actually apply brakes harder and a little early, then get off them quicker to give them more time cooling. Haven't tried this in the 300SL yet tho. Love the car tho, once I got used to how it handles and what it wants to do. .. and a little bit of setup tuning, to taste. I almost always soften tires a bit, as I find pCars defaults to be a bit too high for me.

That sounds quite perspicuous to me. I also put the brake balance more to the rear which gave me shorter brake distances and still stable behaviour, slightly better temps on the front. Anyway, on both Nurburgring GP and Hockenheim GP brakes ran hot. Coasting a little using engine brake power is not much like racing, I guess. And, as said before, you canīt keep up with AI in same car.

I just wonder where this car has been racing in the 50s. Maybe tracks like Le Mans fit better as they have much longer straights.

3800racingfool
05-10-2015, 18:02
That sounds quite perspicuous to me. I also put the brake balance more to the rear which gave me shorter brake distances and still stable behaviour, slightly better temps on the front. Anyway, on both Nurburgring GP and Hockenheim GP brakes ran hot. Coasting a little using engine brake power is not much like racing, I guess. And, as said before, you canīt keep up with AI in same car.

Running with the AI in some of the historics is very difficult right now due to their simplified physics not registering brake fade. Perhaps this can be changed in a later patch by manually adjusting the brake zones for the cars. For human drivers, the key is to brake (very) early and only use about half your pressure before rolling into the turn as fast as possible. The 300SL can carry a lot of speed through turns (a lot more than you'd think) so use this to your advantage. This will keep the brakes manageable through most courses.

Also, make sure to remember that the car also loses a lot of power at the top-end. You'll want to shift a bit earlier than you normally would with more modern cars to keep the power up.


I just wonder where this car has been racing in the 50s. Maybe tracks like Le Mans fit better as they have much longer straights.

https://en.wikipedia.org/wiki/Mercedes-Benz_W194

Jussi Viljami Karjalainen
05-10-2015, 20:13
Yeah, old endurance racing. Not just Le Mans though, it won the 1000km of Nürburgring twice on the trot IIRC. EDIT: Didn't recall correctly, it was a very distinctly other car. =)

senn
06-10-2015, 03:12
Personally the brakes feel like those on an old car. I was finding that because the fronts had cooked, and the rears were still in the "peak performance" green temp range, it was possible to lock the rears with just braking. Combined with compression braking from downshifting, this can definately spin you out. Love that tho, feels like trying to manage a real car on the track, knowing all the nuances and different behaviours that make a particular car what it is :)

Shinzah
06-10-2015, 03:34
Personally the brakes feel like those on an old car. I was finding that because the fronts had cooked, and the rears were still in the "peak performance" green temp range, it was possible to lock the rears with just braking. Combined with compression braking from downshifting, this can definately spin you out. Love that tho, feels like trying to manage a real car on the track, knowing all the nuances and different behaviours that make a particular car what it is :)

Old cars should only be driven with the care and love of a pure heart ^^;

Or something else Zen. ^^;


Regardless, it's an old race car and drives like an old race car should drive.

CPU M Rossi
06-10-2015, 04:01
Old cars should only be driven with the care and love of a pure heart ^^;

Or something else Zen. ^^;


Regardless, it's an old race car and drives like an old race car should drive.

and to add to that they are drum brakes

PostBox981
07-10-2015, 19:49
Personally the brakes feel like those on an old car. I was finding that because the fronts had cooked, and the rears were still in the "peak performance" green temp range, it was possible to lock the rears with just braking. Combined with compression braking from downshifting, this can definately spin you out. Love that tho, feels like trying to manage a real car on the track, knowing all the nuances and different behaviours that make a particular car what it is :)

I understand itīs an old car with old technology and it is not very surprising to see the brakes overheat. I wasnīt complaining and yes, it feels very much like an old car, which is great. Just wondered if I could do something different to decrease the problem.

Ralph B
07-10-2015, 20:18
With a smooth and forward looking drivingstyle it's possible to keep the brake temperatures within a acceptable range. Sometimes it can get a somehow critical, but I'd consider it as completel reasonable for such an old car with drum brakes. I think, it's much better implemented as for the RUF CTR, which really suffers under massive overheating problems. The Merc has to be pushed for some while to reach a critical level, while the RUF brakes overheat on some tracks only with one hard braking maneuver within the first lap. And this car is more than 30 years younger and has internally ventilated brakediscs on all four wheels!

Sir Digby Chicken Caesar
07-10-2015, 20:48
If you lock the brakes they can cool while you're slowing down. But then your tires go. :)

PostBox981
08-10-2015, 17:33
The Merc has to be pushed for some while to reach a critical level, while the RUF brakes overheat on some tracks only with one hard braking maneuver within the first lap.

On both tracks I mentioned I got those damned brakes boiling in lap 2 easily. Part of doing a fast lap is to brake late and on the limit, braking earlier and weaker makes you slow down earlier and waste time. This is why I was late on the brakes and which lead to brakes fading away in lap 2. Anyway, I will review my driving style in case of classic cars. :-)

Calabresi
13-11-2015, 17:24
This car actually is like that, and have overheating problems at street also, so imagine at race, Iīm racing with it quite sometime, and I donīt care when Iīm practicing or racing multiplayer human, but AI damit, they do not suffer of overheating Iīm sure, cause they brake 5-10 meters ahead and have spare to press more if needed, as you can see if you braking from 230 km/h to below 100 at the very last moment til you start turnin they have more to press yet. I can race the 1st place car with any other car at 100% but this Merc.

Said that the only wish I have is DEVīs fix AI advantage.

This thing is overheating to almost 800°C almost at Imola last downhill straight or Le Mans second long straight, at around 700° it dont lock even on grass. Thatīs ok, but again, the AI.

Krus Control
13-11-2015, 18:03
Yeah even if you baby the sh*t out of it the brakes will still go. At a track like Monza you will have brake fade in 1 lap no matter what you do. It's the nature of the beast I'm afraid. I like Digby's suggestion to lock up. But fade is so severe that you won't even be able to lock up after just 3-4 minutes. Also the engine is quite easy to blow on downshifts. It makes for great short races online, but since the AI don't seem to suffer from this, racing them tends to be no fun. The brake fade seems too severe in this, the Yellowbird, and the Mustang 2+2. It happens in the Escort as well but is 100% manageable. I know these cars would have this problem but it does seem a bit exaggerated, especially in the 300sl.

Calabresi
13-11-2015, 19:51
Well, even with that, Iīm racing 1 hr race (paused) as I write and AI at races seems to go very conservative even after my impressions above, and I got a pole using drag. Itīs being fun cause they brake much later and we kept fighting some laps, but the sense of unreal keep bothering, I prefer more capable AI and being subject at this overheat also as in mulitplayer humans race. After 15 minutes I got around 15 seconds ahead. Itīs fun, but can be better.

Sir Digby Chicken Caesar
13-11-2015, 20:00
Yeah even if you baby the sh*t out of it the brakes will still go. At a track like Monza you will have brake fade in 1 lap no matter what you do. It's the nature of the beast I'm afraid. I like Digby's suggestion to lock up. But fade is so severe that you won't even be able to lock up after just 3-4 minutes. Also the engine is quite easy to blow on downshifts. It makes for great short races online, but since the AI don't seem to suffer from this, racing them tends to be no fun. The brake fade seems too severe in this, the Yellowbird, and the Mustang 2+2. It happens in the Escort as well but is 100% manageable. I know these cars would have this problem but it does seem a bit exaggerated, especially in the 300sl.

I've since driven the car and I'm not sure I locked the brakes once, because they're weak. I didn't have much problem with heat doing hotlaps at Oulton Park Fosters, but others said they did. It could be a driving style thing, I basically always mashed them for short periods combined with engine braking from downshifting.

They didn't use brakes as much in racing in the 60s as they do today, right? I'm thinking they just would have lapped slower because they coasted and used the engine to slow down more than today...And you can go faster with modern driving, but only briefly, while the AI (going by posts here, not experience) are programmed with modern driving but no brake fade.