HPDE upgrade questions
02-07-2018 | 11:11 PM
#1
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HPDE upgrade questions
Ran my first few HPDEs last summer in my 981 Cayman 2.7 and had an absolute blast. Looking forward to this season and thinking about a couple of upgrades (not power, the car is definitely faster than I am at this point) These questions seem to have been asked in various threads here but I haven’t seen the specific details I’m looking for elsewhere so I apologize if these have been answered already.
1. I don’t have any cracks in my stock rotors yet, but I assume it’s only a matter of time before they crack or just wear out. I see that lots of people run on stock rotors but plenty more seem to have an upgrade of some sort here. I’m not expecting increased stopping power, just longer life/better reliability. There really aren’t many aftermarket rotor options for 981s but Girodisc seems to be pretty popular. New, they’re 3x-4x the cost of stock rotors with replacement rings being bout 2x,, but the best info I can find is only some opinions that they last “longer.” Can you honestly expect 3x the life? I get that a lot depends on how hard you brake, etc, but do any of you have a first hand account of their lifespan vs stock? Also, seeing as how the Girodiscs are larger than the stock 2.7 rotors, you need spacers so that the caliper fits correctly. Do these fail or cause problems? If there’s nothing wrong with using spacers to fit Girodiscs, I assume there’s nothing wrong with using spacers to fit a less expensive larger-than-stock aftermarket rotor but I have no idea how to determine what fits and what doesn’t besides diameter. Thoughts?
2. The conventional wisdom seems to be to install brake caliper studs. I’ve seen several threads here where people removed caliper bolts and the threads came along with them, or some mishap where they stripped the aluminum threads...is this really a case of “when” and not “if”? Going through pads (whether I stick with stock or upgrade to a track pad) more frequently because of track days (or just swapping between street and track pads) will obviously accelerate wear and increase the chance of mishaps but I have no idea if this is just precaution or a legit problem. Assuming I install studs, how big of a hassle is it to remove them later if I stick with stock rotors now but then install the larger Girodiscs/other at some point in the future and require longer studs? Am I just causing a big problem for myself if I don’t do it all at once? I assume that at some point the studs need to be replaced also?
Sorry if I’m a bit wordy, just wanted to get my questions out there. I’m not trying to build a track car, just make a couple of sensible upgrades for reliability and maintenance.
1. I don’t have any cracks in my stock rotors yet, but I assume it’s only a matter of time before they crack or just wear out. I see that lots of people run on stock rotors but plenty more seem to have an upgrade of some sort here. I’m not expecting increased stopping power, just longer life/better reliability. There really aren’t many aftermarket rotor options for 981s but Girodisc seems to be pretty popular. New, they’re 3x-4x the cost of stock rotors with replacement rings being bout 2x,, but the best info I can find is only some opinions that they last “longer.” Can you honestly expect 3x the life? I get that a lot depends on how hard you brake, etc, but do any of you have a first hand account of their lifespan vs stock? Also, seeing as how the Girodiscs are larger than the stock 2.7 rotors, you need spacers so that the caliper fits correctly. Do these fail or cause problems? If there’s nothing wrong with using spacers to fit Girodiscs, I assume there’s nothing wrong with using spacers to fit a less expensive larger-than-stock aftermarket rotor but I have no idea how to determine what fits and what doesn’t besides diameter. Thoughts?
2. The conventional wisdom seems to be to install brake caliper studs. I’ve seen several threads here where people removed caliper bolts and the threads came along with them, or some mishap where they stripped the aluminum threads...is this really a case of “when” and not “if”? Going through pads (whether I stick with stock or upgrade to a track pad) more frequently because of track days (or just swapping between street and track pads) will obviously accelerate wear and increase the chance of mishaps but I have no idea if this is just precaution or a legit problem. Assuming I install studs, how big of a hassle is it to remove them later if I stick with stock rotors now but then install the larger Girodiscs/other at some point in the future and require longer studs? Am I just causing a big problem for myself if I don’t do it all at once? I assume that at some point the studs need to be replaced also?
Sorry if I’m a bit wordy, just wanted to get my questions out there. I’m not trying to build a track car, just make a couple of sensible upgrades for reliability and maintenance.
02-07-2018 | 11:28 PM
#2
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From: Northern VA and Central FL
First - I get 3 to 4 times the life on Girodisc than the OEM disks. Note that the harder you brake the hotter they get thus the sooner they will crack. So someone in the Green run group will get more life out of their rotors than someone in the Red run group - and see less return upgrading to Girodiscs.
Second - The biggest issue you may find, at least I did with my 991, is that the brake calipers have a hard bridge for additional stiffness. Because of this bridge you can't change the pads without completely removing the calipers, older model Porsches don't have this problem and on those cars you generally don't remove the caliper until you replace the rotor. It's this constant disassembly / assembly that has everyone concerned. Removal causes wear but more importantly the odds of cross threading become a potential issue.
Third - Studs prevent you from having to carefully align the caliper holes with the upright holes as you thread the bolts. Plus if you have Girodisc rotors you can leave the spacer on the bottom of the stud - note: aligning the caliper hole AND the upright hole AND the Girodisc required spacer will drive you nuts, particularly at the track. As for the stud length, the spacer itself is about 1/8 thick and the studs will most likely cover the extra length.
I use this same setup, Girodiscs up front with studs (Porsche GT3 Cup car studs) and Sebro slotted rotors,with studs, for the rears.
Second - The biggest issue you may find, at least I did with my 991, is that the brake calipers have a hard bridge for additional stiffness. Because of this bridge you can't change the pads without completely removing the calipers, older model Porsches don't have this problem and on those cars you generally don't remove the caliper until you replace the rotor. It's this constant disassembly / assembly that has everyone concerned. Removal causes wear but more importantly the odds of cross threading become a potential issue.
Third - Studs prevent you from having to carefully align the caliper holes with the upright holes as you thread the bolts. Plus if you have Girodisc rotors you can leave the spacer on the bottom of the stud - note: aligning the caliper hole AND the upright hole AND the Girodisc required spacer will drive you nuts, particularly at the track. As for the stud length, the spacer itself is about 1/8 thick and the studs will most likely cover the extra length.
I use this same setup, Girodiscs up front with studs (Porsche GT3 Cup car studs) and Sebro slotted rotors,with studs, for the rears.
02-07-2018 | 11:34 PM
#3
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Thanks for the info, very helpful. Your comment about Girodiscs up front and Sebro slotted rotors in the rear made me think: there’s no 981-specific Sebro (or other) slotted rotors that I’ve found but apparently my rears are the same size as 987s, so that would be stock sized rears with larger Girodiscs up front...does that cause any kind of problem when braking hard? Balance/stability, ABS, anything?
02-08-2018 | 12:47 AM
#4
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Go find a Miata that is either track prepped or prep it yourself. Anything you do to a street car is a compromise either for comfort on the road or handling at the track. The Miata will pay for itself before the end of the first year ast they are cheaper to modify and cheaper to put tires on.
02-08-2018 | 01:41 AM
#5
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Another reason to use caliper studs - the caliper bolts are a torque to yield bolt and should not be re-used. That's $38 in just new bolts for every pad or rotor change.
I know, some ignore the manual and re-use the bolts. Some don't. Studs are simple & easy.
I had Girodisc rotors on my Cayman R & they were great.
I know, some ignore the manual and re-use the bolts. Some don't. Studs are simple & easy.
I had Girodisc rotors on my Cayman R & they were great.
02-08-2018 | 07:31 AM
#6
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Thanks for the info, very helpful. Your comment about Girodiscs up front and Sebro slotted rotors in the rear made me think: there’s no 981-specific Sebro (or other) slotted rotors that I’ve found but apparently my rears are the same size as 987s, so that would be stock sized rears with larger Girodiscs up front...does that cause any kind of problem when braking hard? Balance/stability, ABS, anything?
BTW - I found that changing pads had more impact on brake feel than the rotors did.
02-08-2018 | 08:42 AM
#7
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Originally Posted by rlm328
Go find a Miata that is either track prepped or prep it yourself. Anything you do to a street car is a compromise either for comfort on the road or handling at the track. The Miata will pay for itself before the end of the first year ast they are cheaper to modify and cheaper to put tires on.
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02-08-2018 | 10:11 AM
#8
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Go find a Miata that is either track prepped or prep it yourself. Anything you do to a street car is a compromise either for comfort on the road or handling at the track. The Miata will pay for itself before the end of the first year ast they are cheaper to modify and cheaper to put tires on.
02-08-2018 | 02:28 PM
#9
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In all honesty, it's not a bad reply to the usual questions of building out a track car. And I would love to build out a miata, it would be a ton of fun and a great learning experience. But I'm not trying to build a track car, I'm trying to make maintaining my street car that I track a bit easier. I also don't have the room to store and work on a 3rd car, or a tow vehicle and trailer.
And like Glyndellis, I don't really fit in a miata...
And like Glyndellis, I don't really fit in a miata...
02-08-2018 | 02:48 PM
#11
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I'd run your stock rotors until you need to replace them. Then make the decision based on how long your stock rotors lasted. If they lasted a good long time,spending the premium on the Giro discs might not be worth it. I've only had older cars that didn't have a fixed caliper bridge, sounds like getting the studs would be a good idea. Just the fact they make the brake job easier would make them worth it to me.
02-08-2018 | 04:48 PM
#13
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Thanks for the info, very helpful. Your comment about Girodiscs up front and Sebro slotted rotors in the rear made me think: there’s no 981-specific Sebro (or other) slotted rotors that I’ve found but apparently my rears are the same size as 987s, so that would be stock sized rears with larger Girodiscs up front...does that cause any kind of problem when braking hard? Balance/stability, ABS, anything?
02-08-2018 | 04:51 PM
#14
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