997gt3north

- first days was wet and cold for the first 2 runs and then just cold
- next day was just cold that eventually became not cold but certainly not warn

After my 1st event 2 weeks ago at Limerock, I reported that the car was much more stable than I had feared but you could absolutely fell that the car likes smooth throttle inputs.

Since the first day, I had the suspension finally fully dialed into the track specs with the help of 2mm 996 spacers and I also made sure that the rear tires didn't get above 36/37 froms were around 33.

On my first outing at Limerock, I tried more of a trial braking style or a lift turnin style to set the nose - this time at the urging of my instructuror and another 997gt3 driver driving in the red group, I decided to experiment with an earlier braking and then fully back to trottle style with a crisp turnin. I think you can certainly get good / fast at both methods, but the early braking and then back on the throttle with a good crisp turnin I think is easier on the pucker factor and much less sensitive to the very initial temptation of the rear end to step out - again, I think both methods can be just as fast if practiced.

What I think is worth discussion and everyone reporting back is about the brakes - maybe this is a PCCB issue, maybe it is a new 997 caliper issue, maybe it is brake lines, maybe it is other?

The issue is as follows:
1) 2 weeks ago, after doing 3 sessions of braking at the top of 3rd gear into turn #1 I decided after my comfort was growing with the car to get into 4th gear and brake into #1 (basically braking from 130mph not 115mph).
2) after doing this for 2 laps, the brake peddle basically got soft (not drop to the floor sft, but definitely softer than it was before - which was very, very firm) and the pedal now had to be pushed another inch lower to get full braking
3) the problem with the above is that the opposite problem of heal toe now happens - brake is too low given I have a rennline pedal extension

Update
- Prior to the recent event I had the stock fuid flushed and replace to Motul
- to my unfortunate surprise, this did not give me that rock hard pedal feel that I so loved about the car when I first brought it home

Further update and more info
- at the track was a 997 911C4s with PCCBs
- he was a newbee and I had met him a few days before the event
- I guess he ws doing well out there and guess what happened on his 3rd session of the 1st day - he decided to change up into 4th gear, he carried more speed into #1 and then he said when he went to brake into the noname he said his foot nearly went to the floor
- he said he slowed down for a few laps and his pedal came back

More info
- there were 2 other 997 GT3s at the event (they had steels)
- I asked them both about their brakes - one was at Pocono and he too said that the pedal now engaged lower than when he first got the car


So, my questions are:

1) anyone else?
2) got any ideas?

thanks

krC2S

thanks for the report Paul..it was nice meeting you/running with you at LRP

hope this gets resolved soon

Khalid

997gt3north

- khalid thanks for popping by and saying hello
- basically the brake pedal was fine (good enough to do 1.06s at 8/10th) but I just want to get that rock hard pedal feel back if possible
- should be pretty easy to knock another 2seconds off that time by driving at 9/10s and adding some speed into the downhill and fully tracking out to the rumbles strips plus brake - currently I haven't gotten close to those rumbles and I'm braking pretty early into bigben as I don't want any surprises until I have better comfort with the car's dynamics

- let me know when yours arrives

paul

BobbyC

Paul, couple of questions and thoughts here...

1) Did you really bed-in the brake pads/rotors prior to the track
2) Braking at turn #1 did the ABS come on
3) Which brake fluid did you and others use

I'm wondering??? You did a flush and replaced with Motul so there shouldn't be any air in the lines...

Only thing I can think of is that "rock hard" pedal feel is perhaps only when pads/rotors are new. When bedded in and used the pedal does travel a bit more and while the brakes are equally effective the pedal feel just ain't "rock hard". I say this because the pedal on my RS (2k miles) PCCBs feels "rock hard", while in comparison the pedal on my Turbo S (31k miles) PCCBs feels "soft" but braking is effective.

Anyone else have any thoughts or insights?

krC2S

Paul..you have a PM

frayed

Soft pedal. . . definitely start with fluid. Problem is, brakes can be really finnicky depending on how they are flushed and some brake systems are terrible to remove all trapped air.

On BMWs I found that pressure bleeders provided an OK pedal, and a really good pedal could only be found with a good, old fashioned two person manual bleed. I'd to that first. . . your pedal should return.

I do not believe that the ceramic rotors have the thermal conductivity of iron, so they may shed heat slower putting more stress on the fluid.

rodneyr

You should not be having fading issues with our brakes in this type of DE session at Lime rock. I would have to agree with some of the above comments about the pads & rotors being bed-in'ed in properly or air bubbles on the brake line. At said, especially on Friday the track was wet and my ABS was going off like a wild animal. Saturday morning the air temp was still cold the braking was poor. However, my last session at 3pm was pretty good because the temp was about 50 degrees.

The other issue at lime rock is the main straight is very bumpy so under hard braking the ABS kicks in the the rear gets a little unsettled -- I don't know away around this. It took me all last year to get used to the car moving around, and not feeling planted.

I never experience brake fading in a 20-25 minute session at LRP and I always used ATE Super Blue. I recently switched to Castrol SRF because to not have to bleed the brakes as much. I would think with the PCCB's you should have even better braking than a 996 GT3 with Steel rotors. I would the dealer check out your brakes just to make sure you are not having any machanical issues. I will be back at LRP on Saturday for my 4th week in a row. Maybe this time I will not have to bring my ski gear.

iLLM3

Rodney what clubs are you doing your DE"s with?? I was suppose to be at Pocono's last Friday but my wheels/tires never came in, and running in those cold /damp temps on a new track in my GT2 on PS1's didnt sound so good!

I would love to meet a few of you guys , i love Limerock !!

997gt3north

Bobby C,

- I didn't truly bedin the pads like I use to do with my stoptech brakes on the other car - just a few highspeed stops on the highway - with my stoptechs I true bedin would give a really nice grippy feel but it wouldn't affect pedal travel
- I didn't have ABS coming into #1 but did into the uphill as if you tried to carry in more speed it is pretty bumpy back there
- I used the Motul RBF600 for the last weekend
- I did not get any fade it is just the pedal is not as firm as it was and now engages lower (I guess I can live with it but my Stoptech equiped car is definitely better and the brake pedal feel was just incredible when delivered - thats what I want back)
- I am going to try a manual 2 person bleed and then maybe steel brake lines

frayed

'north, steel brake lines typically don't offer any increase in stiffness over stock (stock are steel braided as well). But, I suppose brake lines are cheap so it can't hurt.

When you bleed, take your time and use a rubber mallet to tap each caliper to help coaxe trapped bubbles out of the caliper.

Good luck.

Mussl Kar

Got the PCCBs on my 997TT and no noticable difference after 2 days at LR and 2 days at NHIS. Stock fluid. Ran the RS at LR with no difference, will see if there is any change after this Friday, weather permitting.

BTW, pads were recalled on the TT and replaced after the third track day. Less squeaking now.