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> Need more brakes?, What's the logical upgrade>
freestone
post Jul 6 2004, 09:53 AM
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Car currenrtly has a 2.7 engine and runs 914-6 brakes in back and SC up front.

How do I get a better brake feel? How do I add more stopping power, and is that necessary as I potentially upgrade the engine?

Has plenty of rubber.
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Joe Ricard
post Jul 6 2004, 11:38 AM
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I would think you should have all the braking you may ever need. The way I see it these cars are so lite stopping is very easy. More HP does not equal need for more brakes.

Stupid questions like what do you do with your car most.
When was your last brake service.
What kind of pads are you using

Ans: Race car every weekend = get something bigger in the 4 piston caliper massive rotor and matching hydraulic system. (just throw more money at it as I have come to learn).
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freestone
post Jul 6 2004, 11:45 AM
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I run the car almost exclusively on the street.
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Andyrew
post Jul 6 2004, 11:47 AM
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If you havent got th 19mm m/c, get that.
Rebuild the calipers, get new pads..

What you have is enough. IF you wanted more, you could go 944 turbo fronts, and that would be all you would ever need.

Andrew
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SirAndy
post Jul 6 2004, 12:16 PM
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QUOTE(freestone @ Jul 6 2004, 08:53 AM)
How do I get a better brake feel? How do I add more stopping power, and is that necessary as I potentially upgrade the engine?

here's what i did, in that order:

19 mm master cylinder
'86 carrera front brakes, vented and crossdrilled rotors, carrera calipers
'87 carrera rear brakes, vented and crossdrilled rotors, carrera calipers
replaced brake bias valve with a open "T"

braking is perfect now (IMG:style_emoticons/default/wink.gif)
Andy
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SirAndy
post Jul 6 2004, 12:18 PM
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oops, forgot the pic ...

(IMG:http://www.914world.com/bbs2/uploads/post-2-1088655444.jpg)
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lapuwali
post Jul 6 2004, 02:54 PM
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As stated, the need for braking power is mostly down to car weight and available traction. If you can lock your current tires, you have enough brake power. Any more brake power, and you're simply overwhelming your tires sooner, which does nothing for stopping ability. If you can lock them repeatedly, you have enough heat capacity to avoid fade. If you find you have to press harder and harder as you repeated come to a stop from high speeds, then you need to look into better fluid, better pads, and maybe better rotors.

You asked specifically about brake feel. If the pedal doesn't feel right to you, then it's possible you have to deal with hydraulic compatibility. If the pedal is uncomfortably "long" and/or feels squishy, then you may have a master cylinder that's too small for the calipers you're using. If the pedal is wooden and hard, then you may have a master cylinder that's too large for the calipers you're using. There's a post I made awhile back on the subject you can search for.

If you can't lock your tires no matter how hard you press the pedal, then I'd start with brake pads (find softer compound pads), and make sure the current pads aren't glazed or contaminated.
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scotty
post Jul 6 2004, 03:57 PM
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If you haven't replaced the rear proportioning valve, that's probably the problem... I have a 19mm MC , SC brakes up front, and have replaced the valve with a "t" -- this setup transforms the brakes (IMG:style_emoticons/default/smile.gif)
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TimT
post Jul 6 2004, 04:07 PM
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My car is set up like Andy's now

QUOTE
19 mm master cylinder
'86 carrera front brakes, vented and crossdrilled rotors, carrera calipers
'87 carrera rear brakes, vented and crossdrilled rotors, carrera calipers
replaced brake bias valve with a open "T"


except that I have an adjustable bias valve for the rears.

Its taken me awhile but I think I have the front/rear balanced to a point that I can brake deep into a corner..

So since I have this more than adequate braking system sorted what would any normal person do? Leave it alone!!!

So Im installing the following:

944 Turbo Front calipers
944 Turbo rear calipers
23mm master cylinder
944T front drilled rotors
Carrera rear rotors
and a spacer to move out the front hubs so the discs will clear..

The calipers are being modified by Doug Arnao (VCI) to a true radial mount..

So now I get to climd the whole brake learning curve all over again


(IMG:style_emoticons/default/beer.gif)
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anthony
post Jul 6 2004, 04:42 PM
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Sometimes I think people confuse the pedal pressure required to stop a 914 with the braking system being inadequate. We don't have power assisted brakes in these cars. My 914 requires quite a bit more pedal pressure than my newer VW to make it stop on a dime. And as others have suggested, if the pads and rotors are old and glazed, then having the rotors surfaced, getting new pads, and bleeding the system works wonders.
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Jeroen
post Jul 6 2004, 08:42 PM
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Bigger brakes won't add stopping power
The modulation will be different and give you the feel of more braking power, but your actual braking distance will be the same

You only need bigger brakes when you suffer from a fading pedal (brakes overheating)
I don't think you'll run into that problem with your current brakes on the street...

cheers,

Jeroen
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SirAndy
post Jul 6 2004, 09:00 PM
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QUOTE(Jeroen @ Jul 6 2004, 07:42 PM)
but your actual braking distance will be the same

this is NOT entirely true, of course ...
(IMG:style_emoticons/default/wink.gif) Andy
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Aaron Cox
post Jul 6 2004, 09:46 PM
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i have an interesting brake issue.

rebuilt m calipers up front, stock / 4 rears , pads from pelican.

i just put falken azenis sticky stick tires on, and can no longer lock up the brakes easily....

car grips the road like a mofo on crack....but stopping fees...inadequate <_<
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SirAndy
post Jul 6 2004, 09:48 PM
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QUOTE(acox914 @ Jul 6 2004, 08:46 PM)
car grips the road like a mofo on crack....but stopping fees...inadequate <_<

welcome to the world of sticky tires! (IMG:style_emoticons/default/biggrin.gif)

now you need bigger brakes!
(IMG:style_emoticons/default/wink.gif) Andy
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Aaron Cox
post Jul 6 2004, 09:50 PM
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lol...huge difference betwwen 165 bike tires.

i JUST upgraded to M calipers....

volvo 240 anyone?
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skline
post Jul 6 2004, 10:34 PM
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The Volvo pad is almost twice the size of the M caliper. I was a little shocked to see how small the M caliper pads actually are. What is the big deal with the M calipers? And I hear the S caliper is smaller yet with smaller pads. In fact, the 320i pads are even bigger than the M ,
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Aaron Cox
post Jul 6 2004, 10:55 PM
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well if only 2/3 of the volvo pad even touches the rotor....which is better? how do you fix that?
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skline
post Jul 6 2004, 11:04 PM
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That is an exageration, there is only about 1/4 inch overhand, not even close to 2/3rds.
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DrifterJay
post Jul 6 2004, 11:05 PM
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I thought you fixed that?
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skline
post Jul 6 2004, 11:18 PM
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enough to run it like it is for now.
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