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?
Andy

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 ...
Andy

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

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?

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.

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

Andy

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.

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. (no offense, Andy) Only a 1911 going into car for now.

Andy, are your rotors drilled?

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.

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.
Click to view attachment
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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

YES!!! Big brakes are superior to small brakes and ducting would not hurt either.

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

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

yes, front and rear, old pic, same rotors ...

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 ...
Andy

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

9 x 17 and 11 x 17

Click to view attachment

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.

So they were bled recently that's good.
What kind of pads are you running?
Street pads fade a lot sooner than race compounds.

dug

My spec miata came with Carbotech's and they were amazing.
When they wore out, I tried Hawk Blue's. I don't like them as much.
The difference is less subtle than I thought it would be.

dug

porterfields. rear pads are more agressive than fronts to balance out the brakes. they bite really well, i somehow doubt it's the pads. they still have more than 75% material on them ...

Andy

Andy what fluid you using?

I ask because I had a significant braking issue in my Suburban a few years ago. Going over a mountain they were boiling bad enough I could smell the fluid in the cabin and had almost NO brakes. After chnging to a synthetic fluid ( no other alterations) I have yet to experience this again. BIG truck + big tires + downhill needs something better than standard dot 4

my 930 brakes with pagid pads had zero fade. .... I dont think they work well for a 914 though.

why?

Me and Aaron Cox did it back last Oct. You'll have to do a search to find it though.

Don't overlook a second fluid flush and pad check. Many times it is no more than making sure everything is how it should be. As for bigger, well a Saturday night short track stock car at 3400lbs with 12.9" Wilwood's glowing red for a full main with 4x calipers is adequate so it should be more than plenty for any 914. Some of those cars run fluid re-circulators, but for roadracing/heavy Sunday's I doubt they're necessary.

Andys

I am running Pagid oranges with blue race fluid. I have 911 fronts and stock rears with no proportioning valve. I have not had my car on the track yet but I have done some spirited driving over the passes that I think are like what you went on. I didn't feel any fad at all and the brakes alway had great bite. The Boxter upgrade sounds really good though However, I can lock up my wheels with R compounds with what I have. Not sure that much brake is really neccessary on our cars.

+1 on the Wilwood calipers. I use them on a track-only 914/6. I have bigger rotors on my car, but I believe the Wilwood Superlite calipers essentially bolt right up to the 3.5" strut with Carrera rotors. Wilwoods perform very well in my experience, but need more frequent rebuilds. The ones I have require flipping the pads top-to-bottom after every 1-2 events. This is due to uneven wear because the piston sizes are not staggered like on Porsche/Brembo calipers. Porsche/Brembo brakes are probably a higher quality, lower maintenance option than Wilwood and probably give similar performance if you don't mind spending the extra $$.

Scott

When I have brake questions I sometimes go here. Doug is a 914 guy at heart. I have seen some of his work and its great. 930 Turbo brakes would be for me if you are upgrading from 3.2 Carerra brakes. 951 calipers over Carerra rotors aren't quite perfect. IIRC, the 951 calipers are for a 28mm rotor and 3.2 Carerras have a 24mm rotor.

Heck.. how about some 996TT brakes

http://www.vehiclecraft.com/Brakes/vciweb0.htm

I have to disagree. I have my V8 525HP tube chassis beast at 2650lbs now and I have ran Pueblo race track 6 track days now, PLUS some track days at Willow Springs big track on the same set of rotors and same stock replacement pads from Pelican now for a total of around 10-12 hard track days. I have zero fade in any session, and about half pads currently.

I would bring the car down from around 140-145 after the front stretch of Willow (one time from around 155mph but that was before the cage so I only did it once).

At Pueblo I go into turn 1 at 130-135mph and in short order drag it down to around 85-90 and don't cook the brakes at all. Car is awesome with those brakes. Front calipers bolt right on, the rears I had machined at Vehicle Craft and bought their floating rotor setup for the front and stock turbo rear rotors. Fit under 15" wheels too (tho' Andy won't have to worry about that with the 17s).

YMMV, and to be clear, I have a tilton pedal assy with adj bias, so I can fine tune quite a bit including pedal feel with MC diams. I run a .700" front mc and .625" rear mc currently, which was recommended by Tilton based on total piston area of the front and rear calipers and feels great.

edit - forgot the funny part... last track day my buddy was looking at the brakes and rotors because he just cooks his and he said "wow, the brakes work awesome at least... about the only thing tho' " Sad but true, it is about the only thing I haven't had a single issue with on the car.