Porsche 718 Forum banner

21 - 40 of 51 Posts

·
Registered
Joined
·
72 Posts
I would never take a car out on any track without upgraded high temp brake fluid.

The dealership will tell you the factory brake fluid is fine, but they are wrong. I've witnessed multiple 718 drivers with brand new (freshly flushed) Porsche standard fluid lose their brakes during track sessions.

I suspect the majority of Porsche service departments can only use Porsche factory fluids, parts, etc. They don't want to lose your business, so they will tell you the factory brake fluid is fine.

The Porsche standard fluid isn't terrible. There's just a high probability of brake failure when you're really pushing it doing track work over multiple days. I don't know of any Porsche racing teams/cars that don't upgrade to a high temperature brake fluid.

The Porsche standard fluid is fine for street/highway driving & short course fun days like PEC Atlanta.

I'm sorry that you damaged your car. I hope you can find a way to fix it. That sapphire blue color is one of my favorites.
 

·
Registered
Joined
·
30 Posts
Discussion Starter #22
I have no experience where I have driven that hard but even with very overheated front and rear brakes and the resultant brake fade, I would still expect at least some, albeit ineffective, very seriously degraded braking, not nothing. Also both rear and front brakes use fully redundant systems including fluid. So, I am curious what failure totally and simultaneously took out both redundant systems. Maybe very overheated brakes do indeed feel like nothing is happening but I do not have the experience to know that.
this is the worst experience anyone can have, driving 200+ km/h in a straight lane and then no brake :oops::oops::oops:
 

·
Registered
Joined
·
30 Posts
Discussion Starter #23
I would never take a car out on any track without upgraded high temp brake fluid.

The dealership will tell you the factory brake fluid is fine, but they are wrong. I've witnessed multiple 718 drivers with brand new (freshly flushed) Porsche standard fluid lose their brakes during track sessions.

I suspect the majority of Porsche service departments can only use Porsche factory fluids, parts, etc. They don't want to lose your business, so they will tell you the factory brake fluid is fine.

The Porsche standard fluid isn't terrible. There's just a high probability of brake failure when you're really pushing it doing track work over multiple days. I don't know of any Porsche racing teams/cars that don't upgrade to a high temperature brake fluid.

The Porsche standard fluid is fine for street/highway driving & short course fun days like PEC Atlanta.

I'm sorry that you damaged your car. I hope you can find a way to fix it. That sapphire blue color is one of my favorites.
I have done only 4 track sessions (30 minutes each) during 1 year and half of ownership, I believe its not much considering Porsche standards.
 

·
Registered
Joined
·
72 Posts
I have done only 4 track sessions (30 minutes each) during 1 year and half of ownership, I believe its not much considering Porsche standards.
Yeah, even though you believe that, you lost your brakes and damaged your car. I would try to learn from this bad experience and prevent it from happening again.

Like I said, i've witnessed multiple people lose their brakes on completely new factory standard fluid during only 1 day of track events (about 4 or 5 15-20 minute sessions).

It's your car and money. Just wanted to explain why you lost your brakes.....
 

·
Registered
Joined
·
46 Posts
I had a similar incident just a few weeks ago, and I am 100% sure it was due to old brake fluid. I had not flushed after my last track event, and did not plan on tracking for the rest of the year so I was not in a rush to get it done. A friend of mine that is on the board of a private track invited me and some other friends to do as many laps as we wanted to. Thankfully lots of run off space, but it took a long time to get the mud and grass from outside and inside the car.

I hope you get you car repaired soon.
 

Attachments

·
Registered
Joined
·
30 Posts
Discussion Starter #26
Yeah, even though you believe that, you lost your brakes and damaged your car. I would try to learn from this bad experience and prevent it from happening again.

Like I said, i've witnessed multiple people lose their brakes on completely new factory standard fluid during only 1 day of track events (about 4 or 5 15-20 minute sessions).

It's your car and money. Just wanted to explain why you lost your brakes.....
yes definitely a learning lesson for me.

Thanks man.
 

·
Super Moderator
Joined
·
1,778 Posts
Hope your misfortune ends up becoming a positive in the end, @Turki_GTS. I'm personally just glad you're around to post about it and learn from the experience -- both you and others.

Bottom line is twofold:
  • The OP is alive and healthy. That's all that really, truly matters here.
  • If you track your 718, use track-specific high-temp brake fluid. No exceptions. The best driver in the world can't maneuver around brakes that won't work.
 

·
Registered
Joined
·
299 Posts
Stupid question for the day.... Why not just put in track-specific high-temp brake fliluid at the factory?
Porsche is more likely to add that to their dizzying array of options. :rolleyes:
 

·
Registered
Joined
·
93 Posts
Unfortunately I had an accident with my 2018 718 CGTS during a track session at the Bahrain International Circuit. I was doing a short session at the track (30 minutes session) and after 25 minutes of tracking the brake failed, I was at the straight lane and when I had to break and take the turn, there was no brake at all, i tried pressing couple of times but there was nothing, so my car went into the track gravel and i had to downshifts with the paddles to slowdown the car before I hit the track fence at the end, which causes the damages you see in the photo. Unfortunately my insurance company does not cover the damages because the accident happend inside the track. The car now sit at the dealer to assist the damages. I asked them to check the car log to see if there is any brake technical failure, I did not see any warning messages before or during the track session, it just happened suddenly (zero brake ). I appreciate your input in what might caused this issue. the car has 27,000 km with almost 1 year and a half of ownership (still under warranty), last service done at 15,000 km at Porsche dealer.
View attachment 25077
That sucks, plain and simple. If you've been tracking, rule of thumb is to change brake fluid at least once per year, and more often depending on the number of days at the track. I took my 2018 718B to NJ Motorsports Park 3x in 2019 for 6 days, and I plan to change the brake fluid before this year's first event. I also purchase separate track insurance for each event; yes, it doubles the registration cost, but I know that repairs to my car and the track are covered (after paying the deductible). I spoke with my main insurer and they told me they'd cover the first claim due to damages incurred at a track, but then they'd drop that car from my coverage. Good luck!
 

·
Registered
Joined
·
30 Posts
Discussion Starter #31
Hope your misfortune ends up becoming a positive in the end, @Turki_GTS. I'm personally just glad you're around to post about it and learn from the experience -- both you and others.

Bottom line is twofold:
  • The OP is alive and healthy. That's all that really, truly matters here.
  • If you track your 718, use track-specific high-temp brake fluid. No exceptions. The best driver in the world can't maneuver around brakes that won't work.
that's true, thanks for your advice.

I will share with you what was the exact problem once I hear back from Porsche.
 

·
Registered
Joined
·
30 Posts
Discussion Starter #32
That sucks, plain and simple. If you've been tracking, rule of thumb is to change brake fluid at least once per year, and more often depending on the number of days at the track. I took my 2018 718B to NJ Motorsports Park 3x in 2019 for 6 days, and I plan to change the brake fluid before this year's first event. I also purchase separate track insurance for each event; yes, it doubles the registration cost, but I know that repairs to my car and the track are covered (after paying the deductible). I spoke with my main insurer and they told me they'd cover the first claim due to damages incurred at a track, but then they'd drop that car from my coverage. Good luck!
will do thanks man.
 

·
Registered
Joined
·
3 Posts
will do thanks man.
With all respect to everyone in this thread - use of sport / race brake fluid is not enough. This case looks like typical issue of stock brake pads of 718, we see such cases each year.

The root cause is in a bad friction of stock pads, which causes overheat of whole brake system: pads, discs and, finally, brake fluid.

So, yes - if you do track days you have to change brake fluid regularly and use sport fluid, but without replacement of stock pads this all will end up the same way sooner or later (depending on driver skills / overbreaking mistake before turns).
 

·
Registered
Joined
·
633 Posts
With all respect to everyone in this thread - use of sport / race brake fluid is not enough. This case looks like typical issue of stock brake pads of 718, we see such cases each year.

The root cause is in a bad friction of stock pads, which causes overheat of whole brake system: pads, discs and, finally, brake fluid.

So, yes - if you do track days you have to change brake fluid regularly and use sport fluid, but without replacement of stock pads this all will end up the same way sooner or later (depending on driver skills / overbreaking mistake before turns).
You'll need to explain how brake pads can cause overheating of the system. There will be heat transfer from the brake material through the backing plate into the piston and finally to the fluid, but I can't imagine how brake material can affect that more than 1-2% points at most. I would expect you'd need much more to have a noticeable affect. Foot pedal (ie: brake fluid) pressure over the long term - yes, that will affect it. Remember that PV=nRT, and T=PV/nR and therefore T is proportional to P.

Thoughts?
 

·
Registered
Joined
·
93 Posts
You'll need to explain how brake pads can cause overheating of the system. There will be heat transfer from the brake material through the backing plate into the piston and finally to the fluid, but I can't imagine how brake material can affect that more than 1-2% points at most. I would expect you'd need much more to have a noticeable affect. Foot pedal (ie: brake fluid) pressure over the long term - yes, that will affect it. Remember that PV=nRT, and T=PV/nR and therefore T is proportional to P.

Thoughts?
I agree; I had to change stock brake pads after just one 2-day event that included pretty hard braking, but that didn't overheat anything where the brakes failed. I just had to replace the pads and was good-to-go.
 

·
Super Moderator
Joined
·
1,778 Posts
You'll need to explain how brake pads can cause overheating of the system. There will be heat transfer from the brake material through the backing plate into the piston and finally to the fluid, but I can't imagine how brake material can affect that more than 1-2% points at most. I would expect you'd need much more to have a noticeable affect. Foot pedal (ie: brake fluid) pressure over the long term - yes, that will affect it. Remember that PV=nRT, and T=PV/nR and therefore T is proportional to P.

Thoughts?
Yeah, @aklepikov ; I'm calling a bit of BS here unless you can supply:
  • Who/what the 'we' in 'we see such cases each year' is. Sounds like you work for someone who might be more authoritative than you, yourself, appear to be to us. Care to elaborate?
  • What the heck 'bad friction' means. If it means it's producing more heat, OK -- but Porsche isn't going to warranty a performance car's parts for as long as it does if it couldn't handle heat buildup up to extreme use. The 718's brake systems have been on other, older models for several years already. They are proven, both on the street and on the track -- including the OEM pads but not including the OEM fluid because high-temp DOT 5 race fluid is too volatile for OEM use.
 

·
Registered
Joined
·
392 Posts
I dont totally rule out what @aklepikov says.
Where the additional friction comes from is the additional pedal pressure required to achieve similar stopping.
 

·
Registered
Joined
·
633 Posts
I dont totally rule out what @aklepikov says.
Where the additional friction comes from is the additional pedal pressure required to achieve similar stopping.
I believe pressure will be the same between oem/race pads and the temperature change due to that braking cycle will be the same. It's just the car's rate of change that will be different with oem pads. That could cause the brakes to be used for a longer duration, effectively causing more heating. If the fluid is going to boil, race pads could conceivably help. However, with proper high-temp fluid, there will be no boiling and the non-oem pads will make no difference.
MOO
 

·
Registered
Joined
·
864 Posts
Hmm. I haven't read this thread for a week or two. Okay, a few points.

MattC, your equations a few posts up are the Ideal Gas Equation. One thing you surely don't want is gas (I don't mean petrol) in the braking system! In any case, it doesn't apply to liquids. As to whether brake pad material can affect heat transfer into the brake fluid, well, maybe. The heat generated at the disk will be whatever is required to slow the car, i.e. to convert kinetic energy into heat. If you can slow the car at all because heat has not changed the coefficient of friction between pad and disk, then you'll get the same amount of heat. The question is where does it go?

Different materials do transfer heat at different rates. A pad with a high transfer rate would heat up the caliper and thus the fluid faster. Whether different pads are different enough I wouldn't know. It would require measurements or specs from the manufacturer. My guess is there isn't so much difference, but perhaps experience says otherwise.

A second factor, possibly more significant, is how the disks themselves disperse the heat. They are out in the wind, of course. Heat transfer is proportional to temperature difference. If you brake hard and the disk temperature shoots up quickly the heat will dissipate more quickly while the disk is still so hot. On average around a track the temperature is probably lower with harder braking because you have to release the same amount of energy but you do so in a bigger burst right as you brake. But then, drivers brake according to their comfort level on the track, and will largely do the same thing regardless of pad material as long as the brake performance seems the same. During that burst the greater temperature puts more heat into the caliper and thus the fluid. So does the pad material matter? If you were braking all around the track you'd never give the brakes time to cool, but most drivers don't do that. A driver may brake earlier and longer if the performance isn't there, which will raise the average temperature while keeping the maximum temperature lower. So I'm guessing the pad material doesn't matter so much but bad driving technique could matter.
 

·
Registered
Joined
·
633 Posts
Hmm. I haven't read this thread for a week or two. Okay, a few points.

MattC, your equations a few posts up are the Ideal Gas Equation. One thing you surely don't want is gas (I don't mean petrol) in the braking system! In any case, it doesn't apply to liquids. As to whether brake pad material can affect heat transfer into the brake fluid, well, maybe. The heat generated at the disk will be whatever is required to slow the car, i.e. to convert kinetic energy into heat. If you can slow the car at all because heat has not changed the coefficient of friction between pad and disk, then you'll get the same amount of heat. The question is where does it go?

Different materials do transfer heat at different rates. A pad with a high transfer rate would heat up the caliper and thus the fluid faster. Whether different pads are different enough I wouldn't know. It would require measurements or specs from the manufacturer. My guess is there isn't so much difference, but perhaps experience says otherwise.

A second factor, possibly more significant, is how the disks themselves disperse the heat. They are out in the wind, of course. Heat transfer is proportional to temperature difference. If you brake hard and the disk temperature shoots up quickly the heat will dissipate more quickly while the disk is still so hot. On average around a track the temperature is probably lower with harder braking because you have to release the same amount of energy but you do so in a bigger burst right as you brake. But then, drivers brake according to their comfort level on the track, and will largely do the same thing regardless of pad material as long as the brake performance seems the same. During that burst the greater temperature puts more heat into the caliper and thus the fluid. So does the pad material matter? If you were braking all around the track you'd never give the brakes time to cool, but most drivers don't do that. A driver may brake earlier and longer if the performance isn't there, which will raise the average temperature while keeping the maximum temperature lower. So I'm guessing the pad material doesn't matter so much but bad driving technique could matter.
Jim:
You are of course correct re Ideal Gas Equation. I knew there was something wrong there. Old EEs should not meddle in the world of MEs! However, I still believe that in general the thoughts are correct. In order to lose the brakes due to air in the lines requires one to heat the brake fluid above it's boiling point. That is how compressible bubbles are introduced into the system. If you have a non high-temp brake fluid, either brake compound can cause boiling. If you have high-temp brake fluid that is impervious to boiling, neither brake compound will cause boiling outside of exceptional circumstances.
Correct me if I'm wrong please. It's been many years since I've thought about this stuff & I'm sure I've forgotten more than I remember! :)
Thanks!
 
21 - 40 of 51 Posts
Top