Page 3 of 7
Re: Noob questions
Posted: Wed Nov 24, 2021 10:11 pm
by TheTraveller
Porsche are designed and built, so that the brakes will stop you in half the time, it takes for the vehicle to reach any given speed. That’s pretty damn good, and more than adequate to bring our load loggers to a stop.
If you feel there might be some contamination of the discs, except any oil derivatives, just drive with your foot gently on the brakes, for a few hundred yards, to clear them.
Re: Noob questions
Posted: Wed Nov 24, 2021 10:24 pm
by Bluesnose1812
BanZ wrote: ↑Wed Nov 24, 2021 9:48 pm
Bluesnose1812 wrote: ↑Wed Nov 24, 2021 9:43 pm
Col Lamb wrote: ↑Wed Nov 24, 2021 9:21 pm
Actual tests of ceramics on multiple manufacturers models seem to result in ceramics stopping 10 foot shorter from 62 > 0 mph than standard.
The distance may be shorter but is it quicker?
The braking distance is what matters for safety.
Also time is a function of speed and distance in this instance so yes it should be quicker if braking from the same speed in a shorter distance.
I agree if retardation is linear at all speeds for steel and ceramics. However it could be that steel are better at high speed but fade whilst ceramics although slower to retard at high speed bite more at the end so stopping distance is shorter. I don't know the answer but just know that there are more variables than speed and distance. Energy dissipation rate must be the most important factor. I'm sure the mechanical engineers on here will put me right.
Re: Noob questions
Posted: Wed Nov 24, 2021 10:43 pm
by TheTraveller
I’ve suffered brake fade many times, but not on my Porsches. Competition pads can lessen this effect, but the more up the competition scale you go, the more heat is needed before they begin to stop. And from cold, they hardly stop at all.
Re: Noob questions
Posted: Thu Nov 25, 2021 6:42 am
by Rarecolour
TheTraveller wrote: ↑Wed Nov 24, 2021 10:43 pm
I’ve suffered brake fade many times, but not on my Porsches. Competition pads can lessen this effect, but the more up the competition scale you go, the more heat is needed before they begin to stop. And from cold, they hardly stop at all.
If you're fitting better pads then it's advised to change to a better brake fluid as well, this will help with brake fade.
Re: Noob questions
Posted: Thu Nov 25, 2021 10:06 am
by Wil
Nelladrahcir wrote: ↑Wed Nov 24, 2021 1:30 pm
Bedding in!!!! Seriously!??!?!? The stealers are gonna love you when you go in for a service!!!
I've no idea what this comment means?
Re: Noob questions
Posted: Thu Nov 25, 2021 10:55 am
by Deleted User 4325
The person posted....
"I gave the brakes a couple of good 70mph to 20mph hard stops within the first 2 miles of driving mine, I've never thought they were poor."
Interesting to find out the brakes work but my comment meant I would never advocate doing this to a new car as being new it will need to be bedded in gently.
I was then commenting on if they do this then how they drive their car generally and that the OPC Servicing Department aka Stealers would be happy with all the extra work for them.
I am a qualified professional driver and driving assessor with 30+ years experience.
Re: Noob questions
Posted: Thu Nov 25, 2021 11:11 am
by Wil
Nelladrahcir wrote: ↑Wed Nov 24, 2021 1:30 pm
Wil wrote: ↑Tue Nov 23, 2021 8:24 pm
Ok, so I’m new to Porsche and coming from long term institutionalised Mercedes ownership. I don’t know how anything works and I want to know.
First thing that struck me is the ambient lighting in the doors. There’s a bank of leds in there, but they’re not coming on. I can’t find anything in any menus to switch them on or off. What am I missing?
There’ll be more of this noob stuff as I come across it btw.
Thanks in advance.
Also, what does everyone think of the brakes? They felt pretty average to me on my drive home, but I’ve only done 20 miles, so they will probably improve with a bit of bedding in. I hope so anyway.
Ta.
Bedding in!!!! Seriously!??!?!? The stealers are gonna love you when you go in for a service!!!
This is your post in full - hence my confusion. You quoted my post, not the one you're now referring to.
Re: Noob questions
Posted: Thu Nov 25, 2021 12:08 pm
by Col Lamb
Bluesnose1812 wrote: ↑Wed Nov 24, 2021 10:24 pm
BanZ wrote: ↑Wed Nov 24, 2021 9:48 pm
Bluesnose1812 wrote: ↑Wed Nov 24, 2021 9:43 pm
The distance may be shorter but is it quicker?
The braking distance is what matters for safety.
Also time is a function of speed and distance in this instance so yes it should be quicker if braking from the same speed in a shorter distance.
I agree if retardation is linear at all speeds for steel and ceramics. However it could be that steel are better at high speed but fade whilst ceramics although slower to retard at high speed bite more at the end so stopping distance is shorter. I don't know the answer but just know that there are more variables than speed and distance. Energy dissipation rate must be the most important factor. I'm sure the mechanical engineers on here will put me right.
One of the main benefits of ceramic discs is that the material has a higher coefficient of friction when compared against standard steel discs this results in a great braking force being applied by the ceramic discs for a given force applied to the brake pedal.
Energy dissipation in steel brakes is poor compared to ceramics hence brake fade or a drop off in performance being experienced by repeated application of a heavy force on the brake pedal.
On the other hand ceramics dissipate the energy more efficiently as the energy transfer to the ceramic discs results in them heating up with no significant loss of braking performance, watch the Formula 1 car’s carbon brakes glowing to see the result of this form of heat transfer process in action
We used ceramics extensively in one non automotive industry that I was working in and they revolutionised many of the processes due to the frictional and wear resisting properties of the material.
So endeth today’s lesson from this Chartered Mechanical Engineer.
Re: Noob questions
Posted: Thu Nov 25, 2021 1:38 pm
by TheTraveller
Col Lamb wrote: ↑Thu Nov 25, 2021 12:08 pm
Bluesnose1812 wrote: ↑Wed Nov 24, 2021 10:24 pm
BanZ wrote: ↑Wed Nov 24, 2021 9:48 pm
The braking distance is what matters for safety.
Also time is a function of speed and distance in this instance so yes it should be quicker if braking from the same speed in a shorter distance.
I agree if retardation is linear at all speeds for steel and ceramics. However it could be that steel are better at high speed but fade whilst ceramics although slower to retard at high speed bite more at the end so stopping distance is shorter. I don't know the answer but just know that there are more variables than speed and distance. Energy dissipation rate must be the most important factor. I'm sure the mechanical engineers on here will put me right.
One of the main benefits of ceramic discs is that the material has a higher coefficient of friction when compared against standard steel discs this results in a great braking force being applied by the ceramic discs for a given force applied to the brake pedal.
Energy dissipation in steel brakes is poor compared to ceramics hence brake fade or a drop off in performance being experienced by repeated application of a heavy force on the brake pedal.
On the other hand ceramics dissipate the energy more efficiently as the energy transfer to the ceramic discs results in them heating up with no significant loss of braking performance, watch the Formula 1 car’s carbon brakes glowing to see the result of this form of heat transfer process in action
We used ceramics extensively in one non automotive industry that I was working in and they revolutionised many of the processes due to the frictional and wear resisting properties of the material.
So endeth today’s lesson from this Chartered Mechanical Engineer.
By just keeping the steel discs, the improvements in braking efficiency is greatly improved, by altering the compounds in the brake pads. The difference is that more heat build up in them is needed before they become effective. It’s how the compounds they are made from and the binding materials used to compress them are changed.
Re: Noob questions
Posted: Thu Nov 25, 2021 3:36 pm
by happy days
IIRC, didn't Frentzen want Eddie Jordan to return his car to steel brakes as he thought they gave better feel? Or am I still delusional?