Changing rear calipers!

[Danglerb]

I'd put the S4 calipers on the shelf until I was ready to change the fronts as well.

Even the pre S models have excellent brakes, upgrading on a street car makes no sense to me.

[jheis]

Originally Posted by Danglerb

Even the pre S models have excellent brakes, upgrading on a street car makes no sense to me.

Bull****.

[Pete R]

Originally Posted by jheis

Bull****.

Actually He's 100% correct. Once your brakes have enough force to lock up the tires, you have enough brake. Your stopping distance is a function of tire grip not brakes. The only practical reason to put on bigger brakes is to absorb heat, heat that won't be generated on the street. Other than trying to be cool, big brakes really serve no purpose on the street.

[Plexus928]

Originally Posted by MPDano

Same rotors?

when I uprated my rear brakes (1982 model)I went to 968 4 piston which share the same exterior dimensions as the later 928 brakes (different piston size) I had to delete the rear splash shields as the rotors required were bigger. taller- and also thicker
A quick check of rear rotors on ebay
1979 -85 289mm high, 20mm thick
!985-95 299mm high, 23.9mm thick
also from memory the spacer required to centre the callipers was around 3mm

[Plexus928]

Originally Posted by Pete R

Actually He's 100% correct. Once your brakes have enough force to lock up the tires, you have enough brake. ............... Other than trying to be cool, big brakes really serve no purpose on the street.

With bigger brakes you get the "force" a lot faster. and they look cool

[jheis]

Originally Posted by Pete R

Actually He's 100% correct. Once your brakes have enough force to lock up the tires, you have enough brake. Your stopping distance is a function of tire grip not brakes. The only practical reason to put on bigger brakes is to absorb heat, heat that won't be generated on the street. Other than trying to be cool, big brakes really serve no purpose on the street.

I suppose that's why Porsche is continually upgrading the brakes on all its cars... There were at least 4 upgrades over the 928's production run.

There's more to braking than being able to "lock up the tires." Hell, even drum brakes will "lock up the tires" - at least once before they fade to nothing. There is also brake feel, control, and yes, heat management. Upgrading to S4 or better brakes is one of the most worthwhile improvements you can make on an early car - whether you drive it on the track or not.

There is nothing particularly bad about the brakes on the early cars, the 4 piston Brembos just work better.


James

[jheis]

Originally Posted by Plexus928

I had to delete the rear splash shields

As I recall, I also had to delete the rear splash shields. S4 shields may fit, but I just left them off on my car - they don't really serve much purpose in CA.

James

[Pete R]

I agree, they look WAY better. I have s4 brakes on my car. Yes, Porsche keeps upgrading the brakes, you have to do something to justify price increases and match the other cars you're competing against. If you want to spend the time and money for a different feel going to the quicky mart that's fine. I don't agree they "work better" unless your threshold braking on the street. I've done the upgrade, there's no real difference other than appeal. But back to the OP doing half the upgrade, especially just the rears IMO is a BAD idea.

[Plexus928]

Originally Posted by Pete R

But back to the OP doing half the upgrade, especially just the rears IMO is a BAD idea.

I agree, having floating piston brakes on the front and 4 pots on the rear will SERIOUSLY upset the bias. another angle, don't the 1983's have diagonal brakes? wouldn't this make the braking even more scary with more grab on the back?( '82's had diagonal system, I deleted and changed it to front/ rear.)

[Danglerb]

Originally Posted by jheis

There is nothing particularly bad about the brakes on the early cars, the 4 piston Brembos just work better.


James

Not something you would ever notice in street driving. Not something a good driver would even notice on most tracks with a stock car.

Porsche upgrades to sell new cars to current customers, its called marketing. The newest models also weigh hundreds of pounds more and have a higher top speed. Make repeated stops from 15 mph faster than an early model will go and yes, you could use new brakes.

[adam928]

Thankyou all for your information!
It in very interesting to hear different points of view. I have the rear brembos ready to go, and have sorced a full front set-up at the right price. Just waiting for the guy to get to a point where the car doesn't need to be mobile

My shocks are the adjustable type, so looks like I may be able to keep them!

I will still change the rears first though, just to get mobile, and just take it fairly easy. I'm sure I'll soon feel any problems under braking, if the system is badly compromised!

[Plexus928]

Do it properly first time, trial and error can go badly wrong.

[Danglerb]

One of the beauties of the 928, that car was hit really hard in the rear, but look at the doors, most likely they still open and close, no damage to the people areas (my sympathy as always for any in the back seats).

[adam928]

Maybe I'll do all 4 corners at the same time!!!!!


Sent from my iPad using Tapatalk

[Danglerb]

If you want to play with your brakes, there is nothing stopping you.

[Plexus928]

Originally Posted by Danglerb

One of the beauties of the 928, that car was hit really hard in the rear, but look at the doors, most likely they still open and close, no damage to the people areas (my sympathy as always for any in the back seats).

Apart from pre teen double amputees,No one can fit in the back seats

[QUOTE=Danglerb If you want to play with your brakes, there is nothing stopping you
Don't need brakes, just point it at a tree.

[jheis]

About 10 years ago I was rear-ended by a Ford Contour while stopped at a red light.

The Ford was probably doing about 20 mph at the time of impact. Both doors were pinched shut - I had to crawl out through the window.

Repair estimate was $21,322.09! (loved that .09).

[Danglerb]

Looks like a tweak running down from the B pillar, sign of a 928 being toast.

OTOH you are still around.

[jheis]

Bought it back from my Insurance Co. for salvage value - too good a car to through away.

I had a friend with a frame shop. Told him to do the initial pulls and then we'd decide where to go - either track beast or street car. Turns out the rear suspension points were not tweaked. After my frame guy did his magic, all it needed was new bumper shocks, cover, tailights, some finish body work, a new paint job and lots of time and TLC.

Car & I live on to this day.

[Plexus928]

Originally Posted by jheis

About 10 years ago I was rear-ended by a Ford Contour while stopped at a red light.

The Ford was probably doing about 20 mph at the time of impact. Both doors were pinched shut - I had to crawl out through the window.

Repair estimate was $21,322.09! (loved that .09).

I like a garage that has Persian rugs on the floor. What is the 1930's beastie parked next to the 928?