996 Giro disk upgrade experience

I�m looking for future upgrade to giro setup can rennlister give me any feedback with use fitment and effectiveness I know they are 2x the price of stock and as I am satisfied with my stock brakes this is for possible upgrades thanks

@Soul Performance I believe John has them fitted to his Cayman R.

Yeah I’m wondering if it’s even worth it in a 996 because the stock brakes are good I’m really just looking on feedback

Only advantage is unsprung weight. Pretty sure Giro is like any other two piece in the sense that the hat is forged and the rotor surface is iron vs the whole rotor being iron. If the weight savings is worth it to you then I don't think you can do better.

What's your use case? Track work, street miles, big brake flex at cars and coffee? Depending on how you use your car it may or may not be worth it.

I run them but only because i track the car. The unsprung weight and added cooling helps. For a street car i would buy regular rotors from fcpeuro and get free replaeents for the cost of shipping.

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a few more advantages also are .. better heat dissipation due to more curved vanes and the vane design. Also increasing size should help some with thermal capacity/efficiency. This all only really matters for track use

NYPOWR4 - 3 years ago I did the calculations for the physics. Long ago lost the worksheets, but I still remember the salient facts. As most everyone here knows, there are pluses to the Girodisc. The minus is buy-in and rotor replacement cost. Weight saving for unsprung a wash: Tire weights are a big variance, so you’d need to factor that. The physics say there’s a >5% brake power increase for swept area, but pad friction is also a big variable. Cooling is slightly better for thermal dissipation. Yada, yada. I constantly toy with the idea of the Girodisc or Martin’s mod, but there really isn’t a good reason, other than bling, for me to buy them. Every time I jump on the binders, I’m reminded of how sweet the stock brakes are. There are some “cool” ways to get better braking with less fade. I am aware you know this, but it doesn’t hurt to mention options for folks searching for info. $=coin level !=pain and effort level Note: All the cheaper options assume stock size slotted, drilled or both. By no means a complete list. Cheaper: 1. Wire brake fan switch for manual operation $$-$$$/!!-!!! 2. Upgrade the brake ducts $/! 3. Modify the wheel arch liners 0/!! 4. High temp fluid $/! 5. Upgrade master cylinder $$/!!!! 6. Higher coefficient pads $$/! 7. Upgrade brake lines $$/!! 8. Improve braking technique 9. Match proper tire compound to intended use, ie, don’t expect an A/S tire to stop as well as a 200 10. Proper cool down procedure for track or ax Costly: 1. BBK $$$$/!!! 2. Girodisc $$$/!! 3. Martin’s mod kit $$/!! 4. Martin’s mod kit with, upgraded MC, some C4S calipers and 330mm rear disc $$$/!!!! (Is it a possible combo?…throwing it out there) 5. Change out for 963 system $$$-$$$$/!!!! (assumes used calipers, new master cylinder, used uprights) Every time I look down the brake ‘upgrade’ rabbit hole, I remind myself of this list. I don’t track my car, so I play by the Cheaper 1-10 playbook. Does not mean I don’t Jones the Costly 1-5 list, and, in the process; waste a lot of brain processing time.

I will say... they're cool asf looking.

Yes I’m looking to track the car after I do the UIDS and solution later this summer I’m half way through the stock brakes so I was contemplating future idea

Thank you all for the info input

From your post it says that you are on the stock brakes so you might just try some track pads and fluid first – and get out of the drilled rotors if you can as they are less reliable on track. That said – if you know you are going to track regularly, the Girodisc upgrade is pretty useful for the 996 Carrera’s. The OEM rotors are 317mm diameter front and 298mm rear. The Girodisc setup uses spacers and increases the rotor size(s) to 340mm/325mm. This is a pretty good jump in rotor size which adds about 7-9% in brake torque. It also adds cooling mass and surface area which are the basic goals of most big brake kits. Race pads and rotors are around $1000, the Girodisc system with pads is about $2800, and of course there are full brake kits at about $7500 for both axles. Here is the 996 Carrera listing as an example. https://knsbrakes.com/c/car-items/6110_2004+Porsche+911+Carrera+%28996%29+Carrera%2C+Carrera+4+with+Iron+D iscs/_/

Remember, once you make the initial purchase which is expensive but certainly much less than a big brake kit, you only replace the rings and re-use the hats, which cuts your costs in half from initial purchase cost. Not to mention, the girodisc rings will last much longer than oem sized solid rotors. From a visual standpoint, bigger rotors are better rotors. From a rust standpoint, you will have less to look at because the hats don't rust. From a cooling and weight savings standpoint, you will see huge improvement. But most dont need bigger rotors, because you really cant use them on the street because you just can't carry enough speed. Its like extra hp on our cars, tough to really use on the street. The track is a different story. But it will take you a couple of years to get fast enough to need more than oem brakes. However, once you have bigger brakes, you will never go back. That's for sure...

I put pricey rotors on my STi once upon a time. My thing with that car was that the engine was better than the brakes, which were better than the suspension; I spent my money in the opposite direction, first suspension, then brakes, then engine. The rotors were cool looking, and they may even have made the car stop better. But the pads were the really big difference. Which if I'm honest paled next to the downpipe + tune, which made the car into what it should have been all along! But that is a story for another day. Unsprung weight: I have experienced the difference it can make. I put ridiculously light (9.5 lbs!) wheels on my Honda Fit, replacing the 17 lb. factory alloys. Holy dear golly me, it was a revelation. The wheels just *danced* over the road. It was wonderful. For a Honda Fit. My point being, don't spend the money on Girodiscs because of their advantage in unsprung weight. Unless you're at 9.997/10ths, there is none.

I suppose spending $2400 to save 20lbs is a bit nuts, but I'm still thinking about it. Interested in people's experiences who have gone w the Girodisc setup.

they look really cool and if they are 5 lb lighter per wheel, they should enable the wheel to respond to bumps noticeably better

I bought a used set that were near new for $700 because i had martins big brake kit it made my rotor the same as the turbo and there r used versions of those out there at a deal.

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When put into that perspective I guess it's not too crazy. That ratio applies to wheels, swapping from a GT3 wheel + Tire to a OZ Alleggerita + Tire saves about 35lbs. While I agree 2400.00 in rotors is indeed high but when playing devil's advocate, we do it all the time for other things too. @NYPOWR4 , I'm probably going to do either the Giro or Brembo two piece so we're on the same boat.

Another advantage of the two-piece setup is that there is a lot less heat transfer to the hubs and to the wheel bearings. The downside of this is that the rotors get hotter because there is less heat transfer to other parts of the car. Again that's only relevant when driving on the track as you'll never get the rotors hot in any street driving.

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As I understand it, the weight loss isn�t close to 20lbs. The fronts alone are only something like 1lb lighter than the stock 318mm one piece rotors. Whilst everyone thinks the aluminium bell saves weight, the increase in additional rotor mass as a result of its diameter increase, all but nullifies the benefits of the lighter bell. As you�ve said, if you want to lose unsprung weight, careful choice of wheels is the best way to do so (and choosing the lightest, smallest tires available)

FWIW the weight loss was on the GT3, can't speak for other models.

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That�s a different ballgame altogether. The stock 350mm one piece rotors are boat anchors, and saving 5lbs per corner is doable.

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What I have found is that the unsprung weight loss using floating hats on a stock 996 Carrera is substantial (~14-15lbs). You can also save another couple of pounds (~4-5) going to an aftermarket big brake kit caliper versus 996 oem. There is your 20 lbs. I know this because I have run a Brembo GT big brake kit on my 996.2 Carrera since 2007. 355F x 345R. Its lighter than 996 GT3 and Turbo brakes and more powerful. Hasn't been a 996GT3 or 996 Turbo with stock brakes that has been able to out brake me on the track. Different story if they have upgraded their brakes to an aftermarket kit. Yes, this is common. Everyone is looking for an advantage on the track. OEM is great for the street and the first few years of tracking. But it all changes after a few years on the track. A floating hat system and big brakes in general aren't for everyone, because you can't use their capabilities on the street. Its like adding 100 more HP to your 996, you can't really use it on the street either. But you can use more powerful brakes and engine on the track. But I will tell you this, if I would never track my 996 again, there is no way in he'll I will ever get rid of my floating hat system. Even with replacement rings being more expensive.

I actually put them on so let me give my review. 1. They look hot! 2. They are lighter, but not enough to really make a difference. 3. I mostly just drive the car for fun on the street, but that means when I do drive it, I drive it. The additional diameter is noticeable in hard braking. There is more "bite" for sure. 4. I don't drive on the track so I can't comment on thermal properties of them. 5. They look hot! I did only put them on the front of the car as the rear are only a few mms larger and I wanted to control costs a bit. So in the rear I did Sebro slotted rotors to match the front slotted. All in I spent about $2K for all 4 corner rotors and pads.

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14-15lbs weight loss from the fitment of Girodics to a 996 C2 ? I don't think so. A stock 318mm one piece rotor weighs in at 19.5lbs (8.9kg) : https://www.pelicanparts.com/More_In...94&SVSVSI=996J The replacement 2 piece floating Girodisc front rotors weigh "approximately" 2kg less : https://www.cargraphic.de/ihr-fahrze...-4/pergda1031/ so lets call them 14.9lbs (6.9kg) or a weight loss across the two rotors of 8.8lb (4kg) A stock one piece 299mm rear rotor weighs 14.6 lbs (6.6kg) The Girodisc replacement weighs 14.9lbs (6.8kg) https://www.cargraphic.de/ihr-fahrze...-4/pergda2033/ Or no weight loss at all (which is confirmed with a look through previous Rennlisters posts who've done the swap) so replacing the OE rotors with the Girodiscs back and front will lose 8.8lb, or just over half the figure you've mentioned ? As for your Brembo kit, that may well be lighter by the figure you've mentioned, the calipers will no doubt be lighter, and whilst the rotors will be larger diameter and most likely thicker, they also tend to have a narrower anulus and better/more efficient internal venting, both of which help reduce their weight dramatically. Any comparisons with Brembo big brake kits is not comparing apples with apples. Stock 996 Turbo brakes (4 pots and 330mm rotors) are probably some of the most undersized brakes I've seen on a Porsche, they're a joke. No doubting their power (if they're in fine fettle) but their ability to manage prolonged track use and the heat generated during such use, is questionable to put it mildly , so if you couldn't outbrake a car with them on track with your Brembo BBK, I'd be shocked.

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This stuff gets tiresome after awhile. Best of luck to you.

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Strange response, would you care to elucidate ? You quoted some figures for weight loss that I thought seemed inaccurate, I've taken the time to establish the weight of the original rotors and the Girodisc replacements. The figures don't bear out your claims, so rather than other RL's purchasing them thinking they're going to lose the amounts of unsprung weight you erroneously claimed, they'll hopefully appreciate that for all their undoubted performance benefits, the Girodiscs are not 14-15lbs lighter than the OE rotors.

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By your response, sounds to me that you work for Sebro. You need to take it up with Girodisc as to their claims of weight savings. While you are at it, do the same with every exhaust, software and intake manufacturer as well. My explanation was to explain as to were the 20 lbs of weight savings comes from a two piece floating hat system and a reference to the Brembo GT kit (floating hats and calipers) including references to the additional benefits of more stopping power with bigger brakes for those that either need it or want it for the track. Relax bud, you run your Sebros and I will run my floating hat system. Bet both of us will be happy. And I do wish you the best.

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Sheesh, I need to relax ??? That's quite a leap you've taken, I establish what, if any weight loss the Girodiscs offer (purely as you appeared to be suggesting there was up to 15lbs) You'll remember your previous comment ? and now I work for "the competition" because I've called your blanket/erroneous statement out For the record, I have no dog in this fight, be that working for Sebro (I presume a German company, whereas I live in the UK) nor indeed owning a 996 fitted with Girodisc or Sebro rotors ... Having hope clarified that the use of two piece rotors on a stock 996 doesn't automatically convey a substantial loss in unsprung weight, perhaps we can move on ?

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Let it rest bud. You cut out the next line which referenced the brembo gt kit not the giros. Everyone can read the post. Time for you to add some value by telling us what you did to your 996 brakes. It's all about having skin in the game.

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I'm not sure why there is an argument in the prior posts. I'm sure all of us would like to know the true answer regardless of which brand "wins" on weight. The prior post quoted below I think also claims that the weight is a "wash" (if I am interpreting his comment correctly):

Wonder what the weight difference would be with a 350mm turbo rotor from Martin's kit vs a 380mm GT4 Giro rotor that will be going into my car next year.

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Sebro Panamera 350/28 is about 10.6kg. Same for 997 T rears. Send Girodisc an email requesting the brake and hat weight.

Well I bit the the bullet and bought myself a Father’s Day girt and bought a set for my car so I’m stoked even if they save me 2 lbs they look cool as f… and in the process I needed new brakes anyway so it’s a win win regardless thanks for all the input

Yeah, I put calls into Giro as well as other brake manufacturers and vendors too get all the component weights to compare and contrast with factory oem weights. Now is the perfect time to build out a grid that can be used to compare and contrast sizes, costs, weights, benefits, etc. There are alot of brake manufacturers today, which means lots of choices from rotors to pads to calipers depending on what you are trying to accomplish. Congrats Mike. Looking forward to hearing about them and seeing the pictures. Maybe you can formally weigh everything when you swap them to compare weights to the claims from the manufacturers.

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Martin said they�re the same but If it matters mine are 997 T rears. I�ll just weigh them when I get them.

Definiteky will be good to know. The more info we can accumulate the better for everyone. Maybe we get a spreadsheet together like the one that was produced for engine rebuilds. Most really don't need big brakes or weight savings, but it's always nice to know.

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Nice you will love them for sure. When I put mine on I did weight the old and new and there was less than 2lb difference so I really didn�t think that would really matter much. However the larger overall diameter gives the caliper more �force� to clamp with and that is what makes a difference. Could I lock the old ones? Yes. But can you also lock the brakes on a 1984 Chevette? Yes. That doesn�t mean the car can stop shorter. It is the control you have right before they lock that matters. With a larger rotor you have more leverage, so more force, so more control which results in a shorter stopping distance. Tires help here too�..Anyway, post some pictures when you get them on and enjoy!

It’s telling me they are 2 weeks out lol blame anyone of the following corona economy monkey pox Brandon falling off his bike all are winners

Ok just got notified my giros are coming ok so now I need pads to go with them what do you guys recommend aggressive street driving some DE is my near goals thanks boys

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Great news Mike! I have run Pagid Yellows for years on the street and track. They are expensive but they will stop you, can handle excessive heat and I never ever had a fading issue ever on the track. But, they will make dust, and will make some noise when cold. One of the most commonly used pads on the track due to their effectiveness.

2nd on the yellows. They make noise and they do dust but if u have seen my track vids they get the job done. A small price to pay for confidence when going from 130 to 70 repeatedly.

I run PFC 8 in the front and 11 in the back. Although I don't drive on the street. Textars in my 986s. Call Clark at Apex Performance (sponsor).

Heard back from Girodisc on the actual weights of their Front 340 and Rear 325 replacement 2 hat system for the Porsche factory Front 318 and Rear 298 brakes. In this example I used the weights on Pelican Parts website and part numbers for Porsche Genuine parts. Girodisc F 340 ~18.4 lbs each R 325 ~15.6 lbs each Total is 68 lbs Porsche Genuine F Left 318 20.82 lbs (996-351-405-01-OEM) F Right 318 21.39 lbs (996-351-406-01-OEM) R Right & Left 299 15.73 lbs (996-352-401-04-OEM) Total is 73.67 lbs Using these sources, Girodisc looks to save ~ 5.67 lbs in unsprung weight. Don't know why the right front Porsche Genuine rotor weighs more than the left. But that is what Pelican had listed. Also note that there was a typo originally showing the weight savings to be 6.67 lbs. It is 5.67. Fat finger mistake on my phone.

One of the advantages of the multipiece brake rotors is the fact that they will transfer significantly less heat to the hub and wheel bearing thus prolonging their life. I have run the Giro rotors for a number of year and they are excellent. I ran the 380F and 350R versions. Another great choice are the AP racing rotors pictured below. I have run those for the last 6 years. The cost of the APs is higher up front but the replacement rings are a bit cheaper than the Giros. Pretty much a toss up long term.... " target="_blank">

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Thanks man. Good to know about AP. Giro told me today that for my Brembo GT kit, while the Giro disc's will be a perfect fit to the Brembo disc's, I will need to use my brembo hats. Giro hat won't fit. Curious if that would be the same for AP. Either way it's no big deal, but a good to know before taking the brakes apart.

Checked out APR. They are doing some very cool stuff with brake kits. Looks like they may be limited to 380 and 350 discs, but wouldn't be surprised if they don't roll out other disc sizes before long. The brake options available for our cars today is staggering.

I just realized after you all posted the info that Giros come in OEM+ sizes. Holy crap I should really pay attention to things more often.

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I won't let is rest bud, because that's patently not what you implied. I quote you verbatim : "What I have found is that the unsprung weight loss using floating hats on a stock 996 Carrera is substantial (~14-15lbs). You can also save another couple of pounds (~4-5) going to an aftermarket big brake kit caliper versus 996 oem. There is your 20 lbs." On a thread about Girodiscs you state that the use of rotors with floating hats would lead to a substantial (-14-15lbs) drop in unsprung weight, you then go on to state that use of a bigger aftermarket caliper from a BBK will result in further losses in US weight. Nothing in that paragraph in your post implied you were referring to anything other than Girodiscs. Not content with arguing the point and getting increasing verbose (whilst bizarrely accusing me of working for Sebro ...) you then decide to dig yourself an even bigger hole by contacting Girodisc, who it appears confirmed that what I'd stated initially with regards to there being a negligible reduction in weight "BY USING THEIR (Girodisc's) FLOATING HAT ROTORS", was actually correct. Now, can we play nice from hereon ? You've somewhat aggressively asked to see my "skin the game". Here you go : 365mm x 34mm AP floating discs mounted on set of custom bells (made by the guys who produced the rotor bells for the McLaren MP4 -12C) They're not hugely lighter than the 350mm one piece OE discs, but they're enough ..- Fitted to this : Which in turn is fitted with this (a 997 Cup engine tweaked to produce 460 hp) : Now with all that cleared up, perhaps we really can get back on (and remain) on topic ?

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You are an interesting one. Not more I can do for you other than send you a set of reading glasses. I do like your brake kit and it's good to see that you are in the game. Best of luck to you this season.

Let’s all whip them out and see who’s still standing LOL you boys are entertaining to say the least but Atgani your car is amazing and setup perfectly but I don’t own a GT3 wish I did GC996 you are my 996 guru you have a car I wish mine to be and more track knowledge then 99.9% of the people here so I moved on to the GIro one for better braking and 2 looks but the most was the price I got I asked for a Father’s Day discount and I got a good one so I’m happy I will post my progress on brakes probably next month

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Game, Set�. MATCH! �Nuff said Awesome car btw! Are you sure it�s yours? � (just stir run� the pot boys�)

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What did he win?

What else... A new set of GiroDiscs! 😁