2020 NEXT GENERATION 992 SPY PICS & RELEASE
#3901
#3902
You really trying to say the difference between electric and hydraulic power steering is not noticeable??? You must be one of these super cushy GT customers Porsche are chasing after now... lol
#3903
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#3905
I’m wondering how PEBB (Porsche Electrical Brake Boost - just made that up) is going to fail safe. With the ‘old-school’ vacuum boost you had enough ‘stored vacuum’ in the booster for 1 - 3 fully boosted stops if the engine was dead. I wonder if PEBB has a separate little battery for an emergency ‘dead-stick’ stop? Does it rely on the main battery for dead-stick operation? What happens when the alternator goes? Etc.
#3906
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Good question. But I was playing around with my Audi... and shut the engine off while the car was still moving and the steering (electric) still worked normally... so there has to be power still for the brakes on an electric system. I tried the same thing on a hydraulic power steering car and as soon as I turned off the engine the steering got super heavy.
Interesting about the Audi with 'lectric steering. It has to be using a battery. It doesn't unconditionally follow that electric brakes would HAVE to be battery backed but, it would make easy sense. What Model/MY?
Last edited by worf928; 12-03-2018 at 05:31 PM.
#3907
Right. There's no mechanism - at least I've never heard of, or seen one - on hydraulic steering that will enable power assistance if the engine is dead. Whereas, with the brakes, the brake booster is a 'reservoir of vacuum' thus enabling a finite but non-zero amount of power assistance even if the vacuum source (engine) is no longer there..
Interesting about the Audi with 'lectric steering. It has to be using a battery. It doesn't unconditionally follow that electric brakes would HAVE to be battery backed but, it would made easy sense. What Model/MY?
Interesting about the Audi with 'lectric steering. It has to be using a battery. It doesn't unconditionally follow that electric brakes would HAVE to be battery backed but, it would made easy sense. What Model/MY?
#3908
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Brand new Audi TT-RS... but I assume what I found out would apply to their whole lineup. Whatever allowed the steering to keep working when the engine was off I assume would also be applied to the electric braking system. Would be interesting to see what happens when that back up source runs out tho...
#3909
I did that with a boat I owned a while back. Wired the bilge pumps around the main batt switch.
#3910
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The 1990 Range Rover had electrically boosted brakes. That era Range Rover was my first experience with an electronically boosted brake system.
I assume things have moved on since then () but the system was hooked up to the battery so even with an alternator failure it still worked and had an accumulator to store pressure. Ignition would fail before the pump. It functioned as manual non-power brakes if the electronic power booster failed. I never saw or heard of one fail where you did not get a warning light first.
Honestly, other than the cost of replacement parts, I did not hate it. Pedal was very firm and had great initial bite, and once you got used to it, it was easy eoungh to modulate. It felt and worked about the same as hydroboost that would see on 3/4 ton and up pick up trucks. Compared to the similar era vacuum boosted ABS in the discovery, it was much superior in function.
I think it is all down to pedal feel, but unlike steering where hydraulic (or manual) inherently gives better feel because of variable feedback pressure, I see no reason why that would be true with brakes. NSX has a drive by wire brake system which I hope porsche’s is not. We shall see.
I assume things have moved on since then () but the system was hooked up to the battery so even with an alternator failure it still worked and had an accumulator to store pressure. Ignition would fail before the pump. It functioned as manual non-power brakes if the electronic power booster failed. I never saw or heard of one fail where you did not get a warning light first.
Honestly, other than the cost of replacement parts, I did not hate it. Pedal was very firm and had great initial bite, and once you got used to it, it was easy eoungh to modulate. It felt and worked about the same as hydroboost that would see on 3/4 ton and up pick up trucks. Compared to the similar era vacuum boosted ABS in the discovery, it was much superior in function.
I think it is all down to pedal feel, but unlike steering where hydraulic (or manual) inherently gives better feel because of variable feedback pressure, I see no reason why that would be true with brakes. NSX has a drive by wire brake system which I hope porsche’s is not. We shall see.
#3911
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I agree with you. I read recently, I believe about the GT3, where Porsche admitted it was a mistake to not make rev matching defeatable. I hope they will come to their senses with the 992. I wish that rev matching was a stand alone option. I hate it. Half the joy of driving a manual is rev matching yourself.
#3912
Drifting
I agree with you. I read recently, I believe about the GT3, where Porsche admitted it was a mistake to not make rev matching defeatable. I hope they will come to their senses with the 992. I wish that rev matching was a stand alone option. I hate it. Half the joy of driving a manual is rev matching yourself.
#3915
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