997.2 base cab - upgraded the front brakes to 6pot/350mm using 991.1S calipers and 997tt 350mm front rotors 2 years ago, nice upgrade actually

Now going to complete things with 997TT rear calipers and 997TT 350mm rear rotors and 27mm master cylinder, all parts on hand

Asking myself now if I should/need recode the PSM to GT3/PCCB or whats best to adjust ABS/PSM to the more rear biased brakes?

TIA
Klaus

 

Interested in that upgrade a couple years ago. Do you have a list of parts or write up in it?

 

Mostly in my head and some notes for now - will compile a list and post next few days

 

Coding of the ABS/PSM is impossible. Only way to affect to the braking bias is to select rear calipers with as large pistons as possible and fronts as small as possible.

EDIT: I stand corrected...I played with PIWIS last week, and indeed, on 997 this is possible. 996 requires hardware changes.

 

PSM can be set to multiple settings by model of car and brake using PIWIS .. i.e. GT3/PCCB, not sure tho what exactly gets set.

There are some references spread across this and other places over the web but nothing conclusive, I did find some Porsche
TB pointing out the need to code a car to PCCB in case those brakes get added aftermarkt .. I played around with Piwis today
and yes, the PSM area asks for car type first, then for i.e. RS, GTS, PCCB, but not much documentation to be found.

As break bias shifts further rearwards from Carrera to Turbo to GTs and the PCCB is typically using a rather balanced size on
the early 997 types between rear and front rotors I will probably code GT3/PCCB unless someone better in the know chimes in

Laters
Klaus

 

did the 991 calipers bolt right up to the hub with no spacer or adapter?

yes, part numbers would be amazing!


I have 350 all around just using spacers and the TT rotors on my GTS. No coding was done..

I cannot answer your question with any authority but I think front to rear bias would be hard set physically in the master cylinder... not a software thing...


GL!

 

I have 997.1 turbo calipers and rotors front and rear on my base 997.2 Carrera. Did no recoding and feel the setup has a good balance. I still have stock master cylinder. I planned on switching to the GT3 master cylinder but decided against it as I like the slightly lower brake pedal position of the carreras over the GT3 as it makes heel toe easier on the street.

 

Thanks for your feedback PJP13 & mikemessi on the (no) need for coding and yes, its all plug and play, no hassle, heres the part numbers:

997.2 "base" brake upgrade (S/GTS will be the same)

Front

Rotors (350x34)
Porsche 997.351.405/6
Zimmermann 460.1576.20/1577.20

Caliper
Porsche 991.1/2S - 991.351.423/424 - thats what I am using
Porsche 997.1TT/GT3 - 996.351.431.90/432.90 easy pad change

Pads (for the 991.1/2 calipers)
Porsche 991.351.947.02
Textar 2551901 (what I am using now - GG rated)
TRW GDB2089 (used initially)
Ferodo FCP4664H (DS2500) not tested yet but supposed to fit

Bolts
M12 x 1.5 x 85

Rear

Rotors (350x28)
Porsche 997.352.405/6
ATE 24.0128-0265.1 / 24.0128-0264.1

Caliper
Porsche 997TT 997.352.425/6

Pads
Porsche 997.352.949.00
Textar 2445403 (what I am using, GG rated)
TRW GDB1792

Master Cylinder
Porsche 997.355.910.30
TRW PMN166

Bolts
M12 x 1.5 x 95

Klaus

 

I was not aware the 991.1 front calipers were a straight swap for the 997. Do you have the caliper bolt spacing width? Is it 142mm?

 

Yes Presto, the 991.1/2 S 6pot calipers @142mm nicely fit 997.1S, 997.2S and 997.2 base uprights (not the 997.1 base tho)

Klaus

 

Great info, thx Klaus!

 

Are you sure on the ferodo front pads? as per below website 991.1 and 991.2 carrera s takes FCP4955H
https://apexperformance.net/ferodo-porsche/

Front calipers full part number are the below i assume?
991.351.423.15
991.351.424.15

what about brake lines? do 997 stainless steel ones fit or do we have to buy the 991 equivalent?

 

FCP4664H vs FCP4995H, prefer the 80mm radial height of the 4664 vs the 75mm of the 4995s, rotors went from
340mm on 991.1 to 350mm on 991.2 so the 5mm increase in height of the pads would make sense, the .1 pads
will leave some rust ring at the outer edge but should work as well, and yes, quite some confusion on these ...

991.351.424.15 - there are also some .11s, .12s, .13s and whatnot around, not sure Porsche ever documented
what exactly they are changing over the years on the lesser 2 ending numbers, as people might try to get their
calipers from different sources and not just buy the latest version new at the dealer I feel better without those.

Good point on the brake lines .. and I am not 100% sure whats best, 997.2 base originals are a bit too short, the
991.1S are a bit too long, there is a good detailed thread on brake lines buried in the deths of rennlist tho:

https://rennlist.com/forums/997-foru...l#post14363221



The middle one is probably the best bet

Klaus

 

That's my link above. Pretty simple swap all things considered but, yes, unless you make your own hard lines you'll need to swap those per my chart on that post.

Coding via PIWIS for bias seems like overkill, but to each his/her own. I used different pads that match the bias I like and that has worked well for both on and off track.

 

Thanks for the feedback and when I was approaching the project I much appreciated your work and documentation on it!

With Piwis on hand I will probably just code PMS to the nearest model type and be done

Thanks again
Klaus