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-   -   Sliding or floating?? (http://forums.pelicanparts.com/showthread.php?t=536788)

nob721 04-14-2010 11:33 AM

Sliding or floating??
 
Gents,

I have hit a conundrum. I have a set of front floating calipers from my 80 Euro, and a set of front fixed calipers from my 81 US. I do realize, that the floating calipers require a 3.8 boost ratio where as the sliding caliper requires a 3.0 internal ratio - but does anybody have an idea of the pros and cons of either brake system? What would you guys choose? Of course, rear brakes are sliding calipers on both cars. And although I would like a big brake conversion, legislator and sticker price kind of rules that out here in Denmark.

Thanks
K.c.

Danglerb 04-14-2010 12:42 PM

Without some real issue I would not mess with the factory brakes.

MPDano 04-14-2010 03:01 PM

I am unsure of which one come stock on the OB's, but it would really all depend on what you plan on doing with the car. If it's just a driver and never going to hit a track, then leave them alone like Mike says. They stop pretty good with a little extra foot pressure. If they will be tracked (DE, AX, etc), your gonna wanna put bigger brakes on their. They "will" fade as the little steel calipers don't dissipate heat very well. I'm upgrading my brakes to S4 Calipers as I plan to Autocross my car. Although I probably didn't answer your sliding/floating question ;)

tisilrad 04-14-2010 07:51 PM

The sliding brakes are no good, do not use them. Save money and upgrade to S4 or big reds from a gts..yeah they are expensive, but worth it.(and you can sometimes get really good deals on e-bay for sets..

nob721 04-14-2010 11:24 PM

Right then - guess the wifes holiday is out of the question. I better start saving for big brakes. Thanks gents.

K.c.

MPDano 04-15-2010 05:57 AM

Quote:

Originally Posted by nob721 (Post 5296413)
Right then - guess the wifes holiday is out of the question. I better start saving for big brakes. Thanks gents.

K.c.

Don't dis the wife. Gotta keep them happy. You can find deals here, eBay or CL. You just have to be patient. I just got a pair of front S4 Calipers here for $100. Going to do the G2 Paint this weekend. Albeit, I will need Rotors, Adapters, Pads and Brake lines, but it will be worth it in the end. I'm doing my conversion slow. I can't afford it any other way ;)

nob721 04-15-2010 08:26 AM

Funny - the wife agrees with you:)

I have the same problem. Have to save money, restore the car slowly, but maintaining high quality. Life would be much easier with a stash of money somewhere :)

Danglerb 04-15-2010 09:06 AM

Quote:

Originally Posted by MPDano (Post 5296579)
but it will be worth it in the end.

In what way?

Street performance will be unchanged, and even on most SoCal tracks when pushed to the limit, the differences will be limited.

Upgrading the factory Ati brakes is on my same list as buying some expensive wheels (the after I win the lotto list).

MPDano 04-15-2010 10:29 AM

Quote:

Originally Posted by Danglerb (Post 5296858)
In what way?

Street performance will be unchanged, and even on most SoCal tracks when pushed to the limit, the differences will be limited.

Upgrading the factory Ati brakes is on my same list as buying some expensive wheels (the after I win the lotto list).

I was specific to AX and DE. In AX, theres a lot of hard (very hard) braking and then the cars just sit in a line waiting for the next 4 laps. They never have a chance to cool down like they can if your car is rolling. The Stock Steel Calipers and Small Rotors just can't disapate all that braking heat before the next run. Brakes fade when they get hot. Am I wrong on this? Going from a Single (or two) Piston to a 4 Piston Larger Caliper and Larger Rotor is huge. also, aren't the Brembo S4 and Big Red Calipers made of Alloy? Alloy vs Steel cools faster. I'm not a 928 Guru, but it sounds like it makes sense to me.

Mike, have you ridden in a car running in an Autocross. If not, you have to first hand see how hard they use their brakes. After seeing that, I know for a "fact" that my stock brakes would not be able to handle it.

Danglerb 04-15-2010 11:32 AM

Heat pretty much is energy, and energy is pretty much velocity squared. Short tracks don't get enough speed to overheat brakes unless you have a LOT more power than an OB has. My understanding is that some tracks have combination's of longer straights and slow turns such that the brakes heat up at the end of the long section and the slower section doesn't have the air flow to fully cool them before the next section of braking. Worst case the speed is just low enough not to cool well, but high enough that the next turn heats them more, with a long stretch prior to it for the initial heating.

Its been a LONG time since I went cone mowing, not sure if the world is ready for my return. ;)

MPDano 04-15-2010 11:39 AM

Quote:

Originally Posted by Danglerb (Post 5297155)
Its been a LONG time since I went cone mowing, not sure if the world is ready for my return. ;)

Not unless you change out those small brakes of yours ;)

Danglerb 04-16-2010 02:13 AM

Quote:

Originally Posted by MPDano (Post 5297174)
Not unless you change out those small brakes of yours ;)

I don't think I should let small brakes stop me.


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