4 piston brake calipers ..., what are my options? Options

[SirAndy]

i'd like to go to a set of (bigger) 4 piston brake calipers on all 4 corners.

right now, i have '84 carrera hubs, rotors and calipers all around ...

what are my options? what's a direct bolt on, what does require adapters?
(IMG:style_emoticons/default/idea.gif) Andy

[J P Stein]

Forgive me for asking, but why?...just an urge to spend money?

[SirAndy]

Forgive me for asking, but why?...just an urge to spend money?

well, i'm not supposed to name names, but a few weeks ago, i went to a napa backroads drive with my 914 and i was following a certain car that was featured recently in certain magazine driven by a certain editor who wishes to remain anonymous.

of course, we were always driving within the posted speed limits!

i was following that certain 550 HP car and surprisingly was able to keep up for the most part, especially coming out of corners.
however, after about 15 minutes into the run, my brakes were fading rapidly and i had to back off ...

now i know there could be several reasons for that.
calipers could be sticking or needing a rebuild. i could have boiled the brake fluid. i might need cooling ducts. i might need better fluid. maybe my porterfield pads aren't agressive enough.

in any case, it seems if i start over again with a set of bigger (freshly rebuild) brakes and rotors, i should be ahead of the game and have less money in the bank ...
(IMG:style_emoticons/default/idea.gif) Andy

[Krieger]

I just remember that day was chilly too. I was going to suggest ventilation, but that still cost a couple of hundred clams.

[sww914]

Boxster calipers go right on with adapters. I think that they use Carrera front rotors and Boxster rear rotors. I've been watching Boxster calipers on ebay, most are going for $500.00 to $600.00 for all 4 and the adapters are around $200.00 per axle. What kind of brake fluid are you using? Is it fresh? A bit of water in the system will reduce the boiling temperature significantly. Porterfield pads for the Boxster calipers are about $150.00 per axle. Hawk blues are about $250.00 per axle. I just went through all this for a friend a couple of days ago.

[RJMII]

Boxster calipers go right on with adapters. I think that they use Carrera front rotors and Boxster rear rotors. I've been watching Boxster calipers on ebay, most are going for $500.00 to $600.00 for all 4 and the adapters are around $200.00 per axle. What kind of brake fluid are you using? Is it fresh? A bit of water in the system will reduce the boiling temperature significantly. Porterfield pads for the Boxster calipers are about $150.00 per axle. Hawk blues are about $250.00 per axle. I just went through all this for a friend a couple of days ago.

Do the front boxster calipers go on the 914 struts/spindles, or the converted to something else spindles?

Where are the adapters available from?

[sww914]

The front adapters that I'm familiar with only work on the struts with 3.5" caliper bolt spacing- S, SC, or Carrera struts. Andy said he had Carrera calipers, I assumed that he had 3.5" spaced struts, not the 3" 914 struts. The 3" spaced struts caliper mounting ears are in the way of where the Boxster calipers need to be so nobody that I know of is manufacturing any adapters for them. I saw a thread here where somebody had cut off the 3" ears and made adapters for Boxster calipers, but I don't remember who.

[SirAndy]

yupp, i got a complete '84 carrera frontend ... 3.5" spacing ...

(IMG:style_emoticons/default/bye1.gif) Andy

[LarryR]

That was a fun day we should start thinking about when to do it again.

Unless you go to bigger rotors bigger calipers are not going to buy you a lot in the fade department.

993 calipers are radial mount so you can take them to a machine shop to have the appropriate adapter made...

I was bringing up the rear that day but did get heavy on the brakes constently. However, my 930 brakes with pagid pads had zero fade. .... I dont think they work well for a 914 though.

I had Jay at german percision build me a set of adaptors before ... not to bad you can have adapters made from billit alluminum for like 150 per pair.

If you are going to a 17" rim I would suggest going to a 13" rotors with either 993 calipers, 993 TT calipers (big bucks), or another nice alternative is the 928 S4 calipers that are the same size housing as the 993 TT bug just a little smaller piston set up.

I think the only potential problem with any of the set ups mentioned above for the 914 is figuring out how to make the parking brake work.

[RJMII]

The front adapters that I'm familiar with only work on the struts with 3.5" caliper bolt spacing- S, SC, or Carrera struts. Andy said he had Carrera calipers, I assumed that he had 3.5" spaced struts, not the 3" 914 struts. The 3" spaced struts caliper mounting ears are in the way of where the Boxster calipers need to be so nobody that I know of is manufacturing any adapters for them. I saw a thread here where somebody had cut off the 3" ears and made adapters for Boxster calipers, but I don't remember who.

That is great! thank you for the help.

I've located a complete SC front strut assembly (pair). Will I be able to use the original SC calipers on front, and boxster setup on rear? or is that a no no?

I am fine with the stoping power Andy will soon be getting rid of, I doubt I'll be driving like he does. (IMG:style_emoticons/default/poke.gif) (no offense, Andy) Only a 1911 going into car for now.

[Chris Hamilton]

Andy, are your rotors drilled?

[LarryR]

The front adapters that I'm familiar with only work on the struts with 3.5" caliper bolt spacing- S, SC, or Carrera struts. Andy said he had Carrera calipers, I assumed that he had 3.5" spaced struts, not the 3" 914 struts. The 3" spaced struts caliper mounting ears are in the way of where the Boxster calipers need to be so nobody that I know of is manufacturing any adapters for them. I saw a thread here where somebody had cut off the 3" ears and made adapters for Boxster calipers, but I don't remember who.

That is great! thank you for the help.

I've located a complete SC front strut assembly (pair). Will I be able to use the original SC calipers on front, and boxster setup on rear? or is that a no no?

I am fine with the stoping power Andy will soon be getting rid of, I doubt I'll be driving like he does. (IMG:style_emoticons/default/poke.gif) (no offense, Andy) Only a 1911 going into car for now.

SC is only a 2 piston caliper and the boxster is 4 piston so you would have more clamping power in the rear. Stock rears would actually work just fine with SC fronts IMO.

[PRS914-6]

Andy, I used 964 RS calipers with Wilwood rotors. You can buy the adapter from numerous sources The calipers are basically the same as a 993. To say the least, this thing has plenty of stop power.

On the front I used Fuchs 951 turbo wheels (8"). I don't think they will fit under a std. wheel. Give me a call and I can walk you through it.

Here is a picture of the front calipers and a comparison of the 911 rotors you are using compared to the Wilwood rotors. The rotors don't look that big until you compare it to the 911 rotor. The last is how close the clearance is even using the 951 wheels.

[dug]

Pads and fluid first!

Definitely don't bother to get bigger calipers without increasing rotor size. Increasing rotor size usually means more unsprung weight and possibly new wheels.

Knowing how small the rotors on my spec miata are compared to your rotors and calipers already. I'd say look at your pads, bleed the system with quality, high temp brake fluid and then maybe add some cooling before going bigger. Racers bleed their brakes often, I did before every race weekend. The only time I had fade was on the last lap of a 45 minute session at Miller in 90 degree weather. That drive was done on a cool day. You should not be having problems yet.

cheers,
dug

[JPB]

YES!!! Big brakes are superior to small brakes and ducting would not hurt either. (IMG:style_emoticons/default/happy11.gif)

[r_towle]

Take a look backwards for what I think...IMHO, is a fantastic setup.
It comes from a Volvo p1800.
The caliper was truely a dual circuit setup.
The calipers had two distinct lines going to each caliper both front and rear.
If you loose one circuit, you still have brakes on all four corners, just circuit instead of two.

the P1800 calipers are a bolt in application.

Rich

[Van914]

Andy,
I have Wilwood Calipers on my 914. They bolt right on the 3.5" struts. I use SC rotors gas slotted. No fade.
Van914

[SirAndy]

Andy, are your rotors drilled?

yes, front and rear, old pic, same rotors ... (IMG:style_emoticons/default/shades.gif)

[SirAndy]

btw. the brakes had been bled a week prior to the run with no significant driving inbetween.

i know that i probably can get my current setup to work well, but i'm seriously thinking about stepping up a notch and not worry about it any longer.

it'll also boost confidence at the track, i hope ...
(IMG:style_emoticons/default/idea.gif) Andy

PS: clearance should not be an issue once i get the new wheels mounted.

9 x 17 and 11 x 17

[davep]

Just be careful as to the piston sizes in the calipers you look at. There are a wide variety of size combos. Look up the chart that Bill Verberg has on the Pelican 911 forum. Bigger rotors have greater thermal capacity, but also greater inertial mass. Cooling the rotors you have would be a big first step. The energy dissipated has to go into the air eventually, and the faster you can get it there the better.