alex70

Prolly not a big deal, but wanted to share an experience from yesterday.

I was doing about 75-80 on an overpass, (55 to 73 SB for the locals) and a nice jolly fellow in a 6 series decides to cut me off by inches, then practically slam the brakes on! Wow. In turn had to hit the brakes hard (at 75) while on a moderate left-hander and the car handled perfectly. Thought I was going to swap ends for a fraction of a second. Glad roads were dry at the time at least. although would not have been doin' 80.

My other car, santa fe probably would have swapped ends and rolled...

Chers-

Rich

Rob Edwards

Was he on the phone?

That's the overpass on which I always think about how accurately torqued my tie rod ends are.

As I come through the corner at , uh, supralegal speeds.....8)

alex70

Hey Rob-

No, not on the phone, just an a-hole driver.

Nice ramp for an 80'ish excursion (unless you're getting cut-off), also the 5N to chapman exit has a nice s curve, as a nice lift in the 5N to 1st 4th santa ana exit.

I should also bump the old thread on the 87 for sale... on the way..

Bret928

I've had a couple of white knuckle Depend’s moments similar to yours Rich. And like you (after my heart rate drops back down to normal), I've always been impressed with the braking ability of my "non-ABS" 78 Shark.

I'd been thinking about doing a brake upgrade but I keep asking myself Why? So unless I install a supercharger or something for now I think I'll just keep the brakes as is and maybe treat them to a paint job to freshen them up and maybe some stainless steel braded brake lines.

Bill51sdr

The S4 & later brakes really are quite a bit better than the others. You would notice quite a difference in braking ability with ot without ABS.

alex70

Not sure if the ABS engaged, but did remind me of the phrase from Will Smith in bad boys 2 about a specific sphincter in the posterior region being "puckered up" ( not sure if I can say butt hole on the board although Im referring to mine so please no-one be offended, not calling someone a butthole)

Bret928

I’m sure ABS would be a big difference on the later 928's. I’m just impressed with the braking & lack of drama (lock-up & back end swinging around) from a none ABS equipped vehicle. In fact I think it feels much more “in control” and stops better than some of the vehicles I’ve driven with ABS.

V2Rocket

Sorry, I missed what you said, I was too busy admiring that avatar..

Daniel Dudley

When in your other car, you are supposed to punt. That will keep you on the road at least.

123quattro

A good chassis make everything work better. Electronics can only bandaid so many issues.

littleball_s4

Yesterday I found a curious graph in a text book from brembo. It plotted both engine and brake power for 5 cars, including a F1. The book is from 88, I think.

Guess what? the 928 was one of the five, and it has 1000KW of braking power (I undestand it is the max power the brake system is able to dissipate without melting). The F1 had about 800, with more than double engine power. The porsche had by far the best braking to engine power ratio.

But, unfortunately, the "stability" you achieve when you stomp on the brakes is not a matter of size, but of how much brake balance you have on the rear. It's a compromise: straight line stopping power vs corner braking stability.

My S4 has always had the brake balance a lot to the front so it doesn't swap ends even if the ABS fails. That's bad for straight line braking distance (nothing you can feel until you try to outbrake a car with similar tires). That's why so many people change the limiter valve, specially for racing.

The "size" of the brake system does not matter until you make more than 2 heavy brakings in a row. For street driving + panic stops a smaller system than the one in the S4 is more than enough.

Ispeed

I have had a few panic stops on my street bike; 2 12" rotors in the front with 4 piston calipers. Holy cow, lots of brakes.
The S4 is unreal too. On fresh pavement it hauls down from speed quick.

SharkSkin

That's an interesting stat, but I think that to put that into perspective you ought to compare braking power to curb weight. Do that, and I think you will find that the F1 car has much, much better brakes.

JEC_31

I haven't heard of braking power expressed in KW before. Fascinating - is this Brembo book an available title?

I have played with front/rear brake bias for road racing - but only on Gran Turismo...

But Sharkskin is right, the 928 must need that much more braking power to convert lots more mass x velocity into heat to dissapate. No rear AC units weighing down the F1.

123quattro

1000 kW of power is a ton of heat. This would be the peak rejection capability and not sustainable. Pieces and parts would start to catch on fire in short order in that situation.

F1 cars can sustain slightly better than 3g of braking. 1g of that is due to aerodynamic drag. Road cars brake at 1g of decel. Aall of that is accounted for through the service brakes.