jhg41977

I have been taking my 993 to DE events and i am having a great time. This past weekend i was at Sebring and noticed first my brakes were not coming in as strong when i pressed the pedal. Shortly after that the pedal became less firm. I was still slowing as needed, i communicated this to my instructor and since we only had a few minutes left we just took it easy and let the brakes cool down.

Now i need to work on the issue of heat i am told.

Currently i had Textar pads and stock fluid. I was running in green group but i was promoted on the second day to blue (up in NCR, thats yellow group)

It was suggested that i switch to Pagid yellow or Hawk pads (i do not remember which Hawk) as well as switch to a higher temp brake fluid. I looked up the Pagid yellow pads, pretty expensive at 350+/- for a 2 wheel set. The Hawks were considerably less money. I am also looking into better cooling methods (turbo ducts) for the front brakes.

What are your thoughts?

wildcat077

You should already have deflector scoops on your 993 for your front brakes ... unless somebody removed them !
As for brakes and fluid ,you get what you pay for ...

I would not skimp on quality over price for just the same reason your brakes failed at your last DE.As you get faster your brakes will work harder so good pads and fluid are a must !

Cheers !
Phil

Matt Romanowski

Cooling first, good fluid, and better brake pads. You have to pay to play, so good pads will not be cheap. I think OG Racing still has their Perfromance Friction sale going - probably won't beat that price.

Mark at Exotech is a great guy and somone to have check things out. He's very busy right now, so it might take a while to get in though. Hope you have snow tires for our first event!

Tom W

How worn are your pads? And how old is your fluid? Old/worn pads have less insulation effect and can allow more heat transfer. It sounds like you've done other DEs without issue, so, if it was me, I'd simply replace the existing fluid (using a good quality fluid) and replace the pads. If it happens again at the next event you know you have a problem to fix. If it doesn't happen again then you don't need to worry.

Glen

You will have air in the accumulator and you need to cycle the pump to force the air out. Do a search and there are a couple if ways to do that.

jhg41977

The front deflectors are in place.

I dont think price dictates quality in all instances. In this case are the Pagid Yellows ($386 front, $386 rear) really that much better than say the Hawk Blue ($229 front, $225 rear)?


Any recomendations on type/brand of fluid to look at?

certz

I used the Pagid yellows and Motul 600 for several seasons on my C2 with TT/RS brakes and without additional colling through the bumper ducts and never had an issue - still have to bleed the brakes regularly. The big brakes shed heat plenty fast enough without the need for additional cooling IMO. Last year I switched back to the stock C2 brakes for G class and I have switched to PFC's and ran 97's last year - I like them better than the Pagids - and will be switching to the 08's this year since the 97's are NLA for my fronts/your rears. I also added cooling ducts and have not had any issues with fade.

My recommendation - switch to a racing brake fluid and get PFC pads. With the big brakes you should not have any more braking issues.

certz

I know a lot of people that use ATE blue/gold and, like I said in my other post, I used Motul RBF600. Both good fluids, I have used both. I think the PFC 08/97 compounds (also endurance compounds like the Pagid yellows) are a little cheaper but not much - I think you will be able to add fries to your happy meal from the difference

If you want to go with the Pagids, I have a brand new set of yellows that I do not plan to use that would fit your rear calipers - I would sell them for $250 plus shipping.

As for the Hawk pads - I have 944 buddies that use them and like them, but all my 911 friends hate them. I have no experience with using them.

jhg41977

Previous DE sessions, four days at NHMS in NH, two days Lime Rock in CT and four days at Sebring in FL. Never had a problem until the last session of the last day here at Sebring. Air Temp was around 85F.

Before every event the brakes are bled. Since I had not had a problem before I went with the 'stock fluid' I think it was the ATE Gold.

I replaced the pads in October with Textar pads. I went to two days at NHMS in NH and four days at Sebring in addition to regular driving. Obrit Racing has been doing the tech inspections while I am in Flordia. I just got back from there earlier today and they said the front pads are down to about 25%. Since I am driving home in a few weeks I did not change the pads or fluid. (Is this a bad idea?)

From the posts I have read about brake ducting to cool the brakes, it seems most people just put the ducts in the bumper and do not duct them to the wheel well in any way. To me, this seems pretty in-effective. I havent been able to post showing ducting to the wheel well though.

I looked up the different brake fluids (Thanks Matt for a link to some info). The Motul looks like I get an extra 85F boiling point or so.

Thank you all for the input, now for more reading.

Bill Verburg

Your issue is likely the result of heat

heat comes from, in no particular
speed
weight
overbrakeing

ways to handle heat, in no particular order
double up on the brake scoops

offload some heat from the front to the back w/ RS rear calipers

use RS aluminum front heat shields or Cup 1/4 shields

*use higher temp brake fluid, there are lots of good choice, I like Motul and Prospeed and Endless, SRF is the ultimate but also in price

*track pads I like Pagid RS 19 yellow(It is a known no issue pad) but PFC has good pads too, others tend to have issues of one sort or another but are generally cheaper.

lose weight, both personally and from the car

brake less

certainly open the passages from the front to the wheel wheel, it won't hurt but 99% of the ducts I've seen are too small to be of any use. The sole exception was Gasser's 993 setup put together by the folks at 'ProSystems' in NC

* are things I'd do first

RSAErick

Wow, I'm surprised that street pads even lasted that long! Street pads aren't typically designed to operate in the heat-range that track driving generates. In my experience, street pads have no longevity on the track. The beauty of track pads, is that their wear characteristics are much better than street pads for track applications. Even at a higher cost, I would argue that they are more economical than street pads.

And at 25% pad, you are possibly transferring too much heat to the calipers.

I'd guess that once you go to track pads with some meat on them, that you probably won't need additional cooling for the sweet brakes that are on that car. Lot's of great recommendations here for the best tracks pads for your car, but I would suggest that the most important thing is that they are designed for this application.

Good luck!

swftiii

You are increasing speed and the brake workout. The stock fluid and pads are not up to track duty, but it is an easy issue to remedy.

I had a C4S for the better part of 8 years and grew up at the track in that car. If you follow the advice of others here with pads and fluid you will never have any fade with the Big Red setup. As my speeds and brake workouts increased (included a couple club races and running in instructor group), I moved to Castrol SRF fluid and Pagid black/yellow pads and never had an issue. I would do an SRF fluid flush every 6 months and change brake pads when the pad was as wide as the backing plate. I found I would go through pads at the rate of 2 fronts to every set of rears.

Enjoy the braking on that car.

-Skip

jhg41977

Just spoke w Craig at Rennstore. Ordered the Pagid yellows and Motul600. Thank you for all your input, it has been helpful!

morsini

This was the cause of your issue. Racing pads do a better job of not transmitting the heat to the caliper and thus the fluid. With street pads down to 25% much of the heat is directly transferred to the fluid. That is why you're not allowed out on the track with less than 50% pad. Checking your car between runs is a necessity.

Glen

Make sure you get the air out of the accumulator or it can get ugly at the worst possible time regardless of cooling and pads. You have to cycle the abs pump to get it out. Will require the Porsche tool think its called ps2? Or you can do it by key cycling on and off while a friend helps you bleed. Regular brake bleed process will not remove air bubbles hiding in the accumulator...