Am I daft to be considering a 996 GT3?

[braddo]

alfapork said:

Complete straight swap on a 996.2 GT3. No brackets, moving of calipers.

Actually looking back they're actually Mk1 Cayenne S discs (955/957) same size and bolt pattern as a 996.2 GT3 - 350 x 34mm 68.5 bore.

I bought a grooved only set from MTEC - who make for some of the OE brands.

https://www.mtecbrakes.com/brake-discs/porsche/cay...

If you want you can have them drilled/dimpled/c-hook instead, but grooved is enough for most track use and I wanted to get away from cracking/constant clearing of the drilled holes on the OE discs. £110 each, although at the moment I see they're out of stock.

The only difference is the position of the retainer screw. You can either not fit this at (it's just to locate the disc whilst the wheel bolts are off) or carefully re-drill the hole in the correct location for the GT3 hub. I didn't bother.

I added a set of DS2500 from Circuit Supplies, which were significantly cheaper than virtually any GT3 pad from the usual suspects.

Whilst I was at it, swapped out the fluid for AP Racing Radical 5.1.

After a bit of light road use to bed them in, I did an evening at Donington last week and they took all the punishment I could throw at them, you're pulling about 135 on the back straight before the chicane and probably about 120 on the approach to Redgate, so two big stops one after the other. No long pedal, pads and discs cleaned up quickly after with minimal squeal, much better performance than the factory yellow pads and admittedly past it OE discs that came off.

I've not driven a GT3 on Alcons or any other floating setup, but to be honest the limit of your braking is the grip of your tyre (Cup2 in my case) anything else is about modulation/feel up to the lockup point, which with the 6 pot standard setup is pretty good anyway on a dual purpose road trip/track car. I'm sure you'd need more on a more extreme or race car on a competition/slick tyre, but for a largely standard GT3 I can't see they're necessary.

This is great info, thanks.

I'm going to bear it in mind for my 997.1 as I believe they run the same brakes as the 996.2?

I am on standard discs with RS29s, which are great performance-wise, except that the drilled holes fill with brake dust on track days and I had to replace a quite new pair of discs because of a small crack between one hole and the disc edge.

[Heathrow]

Maxym said:

From the above I’m gathering that I’d be daft not to. I’m not going to rush into anything and TBH I’m very much enjoying my 991T. But I think the 996 GT3 is an itch I really should scratch.

Or what about a 997.2 GT3 (for more money of course)?

The extra torque is very handy on the road in certain conditions. I personally find the steering does not quite have the same feel in the 997.2 compared with the 996.2. It's a bigger footprint and more resolved car in many respects. You can clearly see the progression of the lineage when you drive them back-to-back. It does lack that old school connection of the 996 and I find I cannot hustle it in the same way. It's definitely easier to drive closer to its limits due to the electronic safety net. Horses for courses. There is no wrong answer here!

[MDL111]

Without having read the replies - imo the answer is likely to be “no”. I don’t think many people who have an inkling about cars and would consider buying a 996 GT3 now would regret it - you are probably well aware of the downsides and upsides of a 20 year old car. And even if you do regret it, it is not like it will have lost a fortune in value

[MDL111]

Just to add - my 996 is the most uncomfortable car of the ones I own, but it is still the one I chose pretty much every time I drove somewhere (including just to the shops). While it is not a GT3, I suspect it still is less comfortable than a GT3 (judging in comparison to my 997)

[nunpuncher]

MDL111 said:

Just to add - my 996 is the most uncomfortable car of the ones I own, but it is still the one I chose pretty much every time I drove somewhere (including just to the shops). While it is not a GT3, I suspect it still is less comfortable than a GT3 (judging in comparison to my 997)

You bought the CLR didn't you? If so its good to hear you are using it.

[MDL111]

nunpuncher said:

You bought the CLR didn't you? If so its good to hear you are using it.

Yes I did and while I am possibly selling some cars now, that one will stay. It is a great car to drive and I really like the 996 interior/exterior - such a small car. I think Richard did an amazing job building this car and he was right to leave the rear seats in - just makes it so useable on a daily basis (in my case my dog can sit in the back)

[Tripe Bypass]

Heathrow said:

Maxym said:

From the above I’m gathering that I’d be daft not to. I’m not going to rush into anything and TBH I’m very much enjoying my 991T. But I think the 996 GT3 is an itch I really should scratch.

Or what about a 997.2 GT3 (for more money of course)?

The extra torque is very handy on the road in certain conditions. I personally find the steering does not quite have the same feel in the 997.2 compared with the 996.2. It's a bigger footprint and more resolved car in many respects. You can clearly see the progression of the lineage when you drive them back-to-back. It does lack that old school connection of the 996 and I find I cannot hustle it in the same way. It's definitely easier to drive closer to its limits due to the electronic safety net. Horses for courses. There is no wrong answer here!

On the steering front, is it less feel during the initial, just off-centre turning or through the whole steering effort?

[BrotherMouzone]

Tripe Bypass said:

Heathrow said:

Maxym said:

From the above I’m gathering that I’d be daft not to. I’m not going to rush into anything and TBH I’m very much enjoying my 991T. But I think the 996 GT3 is an itch I really should scratch.

Or what about a 997.2 GT3 (for more money of course)?

The extra torque is very handy on the road in certain conditions. I personally find the steering does not quite have the same feel in the 997.2 compared with the 996.2. It's a bigger footprint and more resolved car in many respects. You can clearly see the progression of the lineage when you drive them back-to-back. It does lack that old school connection of the 996 and I find I cannot hustle it in the same way. It's definitely easier to drive closer to its limits due to the electronic safety net. Horses for courses. There is no wrong answer here!

On the steering front, is it less feel during the initial, just off-centre turning or through the whole steering effort?

I seem to recall that 9x7 have variable rack?

[Heathrow]

Tripe Bypass said:

On the steering front, is it less feel during the initial, just off-centre turning or through the whole steering effort?

Very slightly less feel on the very initial turn-in "bite". Best way of describing it is that there is more filtering of the road surface through the steering in the 997. I notice it more on track, the 996 front axle is very communicative which give information about what the rear is about to do. Conversely a couple of times in the 997 where I've been surprised and almost caught out that the rear is on the move but it wasn't as obvious from the way the car was pivoting around me. It's difficult to be completely objective as the cars are running different set ups and I have more track familiarity in the 996 and as a result (despite it's lack of electronic aids) I instinctively trust it more! One thing I would also add is that the seating position in the 997 vis-a-vis the steering wheel location is much better than the 996 with it's lack of reach adjustment. Many people change the steering wheel, but not something I've personally done.

Both racks feel very different - the 997 is faster and obviously shorter lock to lock.

Caveat - we're talking fine margins here - objectively both cars steer very very well.

[Tripe Bypass]

BrotherMouzone said:

Tripe Bypass said:

Heathrow said:

Maxym said:

From the above I’m gathering that I’d be daft not to. I’m not going to rush into anything and TBH I’m very much enjoying my 991T. But I think the 996 GT3 is an itch I really should scratch.

Or what about a 997.2 GT3 (for more money of course)?

The extra torque is very handy on the road in certain conditions. I personally find the steering does not quite have the same feel in the 997.2 compared with the 996.2. It's a bigger footprint and more resolved car in many respects. You can clearly see the progression of the lineage when you drive them back-to-back. It does lack that old school connection of the 996 and I find I cannot hustle it in the same way. It's definitely easier to drive closer to its limits due to the electronic safety net. Horses for courses. There is no wrong answer here!

On the steering front, is it less feel during the initial, just off-centre turning or through the whole steering effort?

I seem to recall that 9x7 have variable rack?

Yep, 997/987 have a variable ratio rack with the teeth spacing different in the central four inches or so, 996/986 have linear ratio racks.

[BertBert]

Tripe Bypass said:

Yep, 997/987 have a variable ratio rack with the teeth spacing different in the central four inches or so, 996/986 have linear ratio racks.

I didn't even know that was possible. Don't the teeth on the rack and pinion have to match?

[nxi20]

marky911 said:

I currently have Alcons on JZM bells and the near side front has started knocking. By all accounts the bobbin will have worn its seating area away on the back of the bell so I’ll need new bells. I’m not doing that as I don’t track it and am happy to revert to one piece discs.

I don't know why you've been told this but I would bet it's not that at all. The spring washers between the disc & the bell wear flat over time & they are easily replaced. You need 5 per side. The bobbins don't wear at all so you can re-use them when you rebuild the assembly.

Send me a PM & I can hook you up.

[marky911]

Morning,

I’ll be chuffed if that’s the case as I do like the setup.
I was just told by one or two places, even an Alcon supplier that if they’re knocking there’s probably some wear where the bolts and bobbins sit, so replacing the bolts, bobbins and springs won’t actually sort the knock.

I know you’re very knowledgeable with the ‘6GT3 and braking gear though, so I’m happy to go with your diagnosis.
I haven’t had time to whip the disc off yet, so I’ll do that first, strip and inspect, then send you a pm.

Thanks very much for the help.

(As I mentioned it must have been a kit from JZM as that’s what’s engraved on the bells. Not that that’s important, but you may be familiar with those exact parts. Thanks.)

Edited by marky911 on Thursday 10th June 05:00

[nxi20]

As you may know, we took over the Porsche Alcon distribution from JZM in 2014 & kept it for 5 years. I saw this exact problem several times, including on my own GT3 and went to the trouble of tracking down the only UK supplier of the spring washers. Replacing them does cure the rattle but obviously it's more profitable to condem the bobbins.

The only way you can buy the springs washers from Alcon is to buy the complete bobbin kit...

[Tripe Bypass]

BertBert said:

Tripe Bypass said:

Yep, 997/987 have a variable ratio rack with the teeth spacing different in the central four inches or so, 996/986 have linear ratio racks.

I didn't even know that was possible. Don't the teeth on the rack and pinion have to match?

The teeth on the pinion are helical cut and the teeth on the rack are at an angle so when it transitions it still makes proper engagement.

I don't know whether it was to slow the just off-centre or speed up the rest of the turn, it's over 17 years since I had the engineering drawings on my desk.

[braddo]

Tripe Bypass said:

The teeth on the pinion are helical cut and the teeth on the rack are at an angle so when it transitions it still makes proper engagement.

I don't know whether it was to slow the just off-centre or speed up the rest of the turn, it's over 17 years since I had the engineering drawings on my desk.

Like this?

[Tripe Bypass]

braddo said:

Tripe Bypass said:

The teeth on the pinion are helical cut and the teeth on the rack are at an angle so when it transitions it still makes proper engagement.

I don't know whether it was to slow the just off-centre or speed up the rest of the turn, it's over 17 years since I had the engineering drawings on my desk.

Like this?

Aye, similar.

[BertBert]

Tripe Bypass said:

The teeth on the pinion are helical cut and the teeth on the rack are at an angle so when it transitions it still makes proper engagement.

I don't know whether it was to slow the just off-centre or speed up the rest of the turn, it's over 17 years since I had the engineering drawings on my desk.

Excellent, thanks!

[Digga]

Tripe Bypass said:

braddo said:

Tripe Bypass said:

The teeth on the pinion are helical cut and the teeth on the rack are at an angle so when it transitions it still makes proper engagement.

I don't know whether it was to slow the just off-centre or speed up the rest of the turn, it's over 17 years since I had the engineering drawings on my desk.

Like this?

Aye, similar.

Ace! Every day is a school day.

[marky911]

nxi20 said:

As you may know, we took over the Porsche Alcon distribution from JZM in 2014 & kept it for 5 years. I saw this exact problem several times, including on my own GT3 and went to the trouble of tracking down the only UK supplier of the spring washers. Replacing them does cure the rattle but obviously it's more profitable to condem the bobbins.

The only way you can buy the springs washers from Alcon is to buy the complete bobbin kit...

Nick I removed and stripped the disc today and your diagnosis was spot on. Spring washers are ground flat.
PM sent regarding things. I’ve emailed you at [e-mail]. I hope that’s right.

I knew you had something to do with Alcon gear but read a comment somewhere that you no longer do it, otherwise I’d have contacted you first.

Anyway, goodstuff. Many thanks.

Sorry for the hijack Maxym. Your thread has helped me anyway.
As you were....