Mr. RS

Morning,

Looking for some feed back from other RS owners with regards to braking.

Has anyone else experienced the "Booty Luscious" antics under heavy braking?

Only experienced it once on the road but on the track it is more prevalent and very off putting and has reduces my confidence considerably.

After a lot of thought and a few discussions with people more knowledgeable than me I am beginning to think it might be a brake bias issue.

As the weight transfers forward there is too much rear bias which makes the rear move around. One solution could be to lower the rear of the car to reduce the weight transfer but that would be masking rather than curing the problem.

Can the brake bias be altered, will it affect the ABS? Am I entering uncharted territory?

The ABS also seems to cut in very early. Could it be linked with the problem above?

Would a proper geometry sort these issues?

Interested to hear other opinions before I change anything, if it is a common problem I might pass it back to Mr Porsche and see what they think. I don't think it is my crap driving (could be wrong) as I did not get this with either the Mk1 or 2.

After having Porsches for many years you sort of take for granted that the brakes are going to be fantastic, when they merit comment I feel there must be a problem.

Maybe I should just buy the Journoman Applicator and be done with it....

P.

Mr. C4

Hey P.,

I can only comment on the ABS locking up issue.

My Mk. 1 Clubsport keeps doing the exact same thing with my Pirelli Rosso's but as soon as I swap to my sticky (soft compound out of medium and super soft available) R compound Dunlop D01J's, the locking up is gone. If I remember correctly, your RS is sporting Pilot Sport Cups or Corsas right? I have had Pilot Sport Cups on the car but do not feel that they offer the same grip as the Dunlops. I don't think this issue is ABS related, rather loss of tire grip.

Ciao,

Johannes

Mr. RS

Johannes,

Dead right on the Corsas, you are the second person to point me in the direction of the Cuppies as a cure all for my braking malodies.

I hope there is another option as having to buy a second set of wheels and tyres plus storage and fitting them is going to get very boring very quickly.

Going to try a full geomatry with a slightly more track bias and a little less ride height first to see if that changes my wayward rear end.

Will keep you posted,

P.

Bass GT3

Hey Paul,

Speak to our hero, Journoman. When we were thrapping around Bedford the other week, he did complain that the RS suspension felt a bit soft, whether he used the patented left foot applicator or not. perhaps you are experiencing a lot of load transfer, causing the back to go a bit wobbly. Since i had the JRZ units fitted to mine, any major discrepency between front to rear settings makes the car very nervous under hard braking, ie more than 3 clicks difference.
Journoman is now talking of replacement suspension units, bless him, but he is looking for that last faction of a second. Apparently, the GT2's in attendance hadn't read the script, where they get their *****' tanned by a GT3, but he still complained.
I just squealed like a sally!

See you at Glorious Goodwood,

Steve B

Mr. RS

Steve,

I have tried to contact Journoman (wot a guy) through the illustrious Titanic organ but to no avail.

After his latest sensational scoop on the challenge of Power on understeer in Hot Trolley magazine I wondered if he had retreated to his safe house to let things blow over.

Or perhaps is it his comments on the rear view mirror of certain GT2's being blocked by the drivers appendage that has caused his mysterious disappearance.

Mind you I though that a pre requisite of being a Porsche driver was that your appendage could in no way be large enough to obscure a hand mirror let alone a rear view one...

Have put a general feel out for others that have the wayward rear as my rear was truly exercised during braking at the end of the Bedford straight into the chicane. Applying a turn of lock to avoid the armco certainly reminded me of pre decimal days (half crown thruppany bit...).

Looking forward to the glorious 12th!

P.

Sun Ra

was Journoman visiting the states last weekend?

NJ-GT

You should remove the ABS fuse and get Hoosier R3S03 in
245/35R18 and 305/30R18

Mr. RS

Watt,

Who know where Journoman will next appear, spreading the Gospel to the faithfull few.

Jersey. Hoosiers are a bit difficult to get here in the UK, not sure that a 305 would fit in the arches either. Think the closest we have would be the Cuppies. Still think the problem is Geometry, interested to see who else has experianced this particular challange.

P.

Hubert

I wouldn't play with the brakes electronic bias settings, but would suggest that you either 1. run a slightly more aggressive pad in the rear than youre currently using, 2. add more toe IN on the rear , or 3. add both more toe IN on the rear , and more camber viz a vie lowering the rear.
If I may, with all due respect, disagree that altering the rear geometry to solve this problem is not a band-aid; it's an elemental part of a properly setup car; i.e., a car that suits the drivers tastes. In your case, youre unhappy with the loose rear end under braking; therefore, using your suspension set up to make the car more bespoke to yourself is part of normal tuning. Just like running different tires, or wing angle or seat pos. or whatever... a band-aid solution is a driver driving over and beyond a problem b/c the car lacks the techical/development depth to appropriatly suit him.

As an addendum, you could also (premptivly) play w/ the shock setting front and rear; maybe your rear are too stiff, and your fronts to soft, since they're allowing the nose to dive considerably enough to allow the rear to get light, and high enough, to dance. I'd do this next time out before I invested big $$$ into getting your car realigned and cornerweighted, or investing in different brake pads, or even tires (as one source has told you.)

Mr. C4

P.,

I have tried the cups and find them too hard and slow in heating up and are now on Dunlop D01J's (very nice) and will be trying the Yokohama A048 next time since they are now available in Porsche sizes and support Porsche racing in the US.

Speak to Peter at Performance Wheel Supplies, www.performancewheelsupplies.ltd.uk for questions re. the Dunlops.

Ciao,

Johannes E.

Mr. RS

Hubert,

Looks like I am going to be playing with my settings then!

Still interested if anyone else has experianced the bouncing rear.

P.

GuyR

Mr RS.

Mmmmm......

It must of been a different Trackday at Bedford I went to on that same day in my Black GT2, as I didn't get overtaken on the track by any of the GT3s or RSs there, although I overtook a few quite comfortably (the RS disappeared in my mirrors, albeit slowly).

My GT2 also got very wiggly under braking at the end of the main straight, although it is very bumpy there.

The owner of the silver GT2 (a very good friend of mine) who you referred to also reads here and the GT3 Titanic Register and will be discussing your attitude with you when he sees you next. In order that you may recognise him, he is the bloke that is 6ft 4in, about 19 stone and collects guns for a hobby.

Guy

bob_dallas

I'd recommend an alignment as already stated and possibly trying some new rubber as well. I haven't used the Corsa so I can't speak from experience there.

WRT the bouncing rear - that can be a nice thing if it's not a car... I experienced something similar in my "plain old" MK II GT3. It would occur during heavy braking when I was not as smooth with the application of threshold braking. In other words - I jammed on the brakes a little hard coming from a high speed straight into a low-speed section. Weight transferred too quickly, ABS engaged, and the rear end hopped a little bit. Mine was easily corrected by proper threshold braking, takes a few extra milliseconds to apply the brakes more smoothly but does wonders for the stability of the car and laptimes. Not sure if this is your problem but you might try a little smoother on the brakes next time. Just to be clear - it doesn't take an extremely exagerated motion -- I wasn't stabbing the brakes, it was basically just not smooth enough.

The car seems more sensitive to this than some cars - I attributed it to the progressive springs allowing a little more weight transfer than I like but it's easily compensated for with proper technique.

Hope that helps.

bob_dallas

oh, and I strongly second the advice not to try and play with brake bias or anything of the sort. You can try varying the pads but I wouldn't even attempt to monkey with the electronics or ABS system.

Mr. RS

Guy,

Was at Bedford last Saturday no GT2's in attendance. Tried a differnant line into the corner, more to the left, and that made the problem less prevelant.

I suppose my concern is what is going to happen at Paddock... Bumpy as hell down hill and little run off, I can imagine a slight bit of puckering


As for your last paragraph, may I suggest you re read my post as I beleve you may have taken my poor attempt at humour out of context.

I am always happy to discuss.

Regards

P.