Hi all, Well even though I should be focusing on my Hayubusa throttle body/dry sump car build I am having soooo much fun with my "Alpha Dog" 308 that I've decided to mod some more bits on 'er . Just to summarize, the "Alpha Dog" has a rebuilt motor with high compression pistons and EFI, and the suspension tweeks are QA1's, larger sway bars, and a race alignment. I just recently installed some 140 treadwear Hankook tires and have been running with some really fast bikes on the mountain (these guys trailer their machines up ... everyone else, car or bike, I just smoke ). Going up the mountain I am starting to get some overheating problems which I will address ... going down the mountain the brakes are on fire when I get to the bottom (full race R4 Porterfields) ... the incredible thing is that the guys on these bikes are only getting about a 3-4 block lead on me ... they'll grunt away on the straights and then I'll pick away at them corner by corner . So, if I get my overheating under control again, and upgrade my brakes, they'll be telling the story about the "other car" that is as fast as them besides the Aerial Atom with the twin turbo Penske built V6 ... I never ran with these guys over the past few years because I never expected to be "in the same ZIP code" as them, but after I swapped to this sticky rubber and punished some serious competition at the P club I felt the "Alpha Dog" might have some more in 'er ... man I am impressed! So, a fellow chatter/x chatter sent me some brakes off a 993. They are Brembo 4 piston ... about 32 mm diameter pistons. I have found some Wilwood hats and rotors that I think will be pretty easy to modify and make work. The only issue I'm fighting with is the size of the pads on these calipers. Originally I just wanted to install bigger rotors with the stock calipers but the width of the pad exceeds the rotor by +1/4" ... the 993 calipers are better but for only $150-$250/pc depending on the caliper I could just buy Wilwoods which would probably be easier to adapt ... so I'm going back and forth on that one. Sure I could buy Girodisc or Superformance kits but I'm thinking long term and the hat I've selected has many available rotor configs for thickness, diameter, and cost. I've been running some numbers on piston area, etc. ... if I install an adjustable brake bias will this solve any balance issues or can the master cylinder volume/size be a significant factor/restraint? Cheers, Sean
Question for someone that is familiar with the Superformance package: Are the rotors "floating" on the hats? Are replacement rotors available here in the U.S. or what is the bolt pattern? What are the size and thickness? Also what are the size of the pistons in the calipers they supply? Was brake balance effected? cheers
I'm considering doing the same thing !! and have a set of Brembo calipers ( off a Delta Integrale ) They have different size pistons ( top and bottom ) and not quite as big as the " Big Red " Porsche variant ? If my car were more of a race car I would convert to dual master cylinders with a balance bar ?? But seeing as my wife needs to be able to drive it , it needs a booster ?? I stand corrected , but I thought the Wilwood caliper was the only one sized correctly to our master cylinder ? Bret who is doing the 288 GTO conversion found a bigger master cylinder off a Fiat van I think ?? I was considering using the Superformance disc and fabricating the rest !! ( we always want to do it the hard way ?? ) But buying all the bits is most probably cheaper in the long run ? How is your master cylinder bore to caliper piston ratio working out ? There was a very informative thread from Gyrodisc I think that dealt with this ? I think it was Dave H who had had some sweet caliper adaptors machined , maybe he can comment ?
Mr. Duck, You are going to ned a bigger Master Cylinder. I am going to run the 25 mm Master Cyl. off of a 328. and, T Ruts is now offering a NEW, 25.4 mm Benditalia Master Cyl. Good luck, Edwardo
Yes ... funny ... I've become so familiar with my Prototrak (I don't sell them ... just have programmed G code CNC's for years and luv the "intuitive" nature of this machine for prototype/small volume vs. G codes ) that I swear it takes me as long to make something from scratch and "go for a drive" as it does to sort thru the misinformation on the forums and internet . My "secret sponsor" sent me a larger master cylinder also. Yes Martin/Girodisc had a very good thread on this and I wish I could just write him a check for his kit. Anyone know which discs he used? The discs I'm looking at range depending on your options from 11.75" $33/disc to $300/disc ... I bet the $33 disc on a proper hat is better than the stock ... I really want to test those things ... the cheap hats from Summit are tempting but they are not "floating" ... any thoughts on this? I'm all over the place on this right now ... I thought I had time to whip up some caliper brackets today for the 993 calipers but I might not. cheers edit: regarding correct Wilwood caliper, is that what Girodisc runs? I've been absorbing all the specs and there a lot of combos of piston sizes etc. but just about have the product line "sorted in my head".
Here is a bolt in replacement 25.4 mm master cylinder, standard is 22 or 23. http://cgi.ebay.de/360365163363 I found this a few years ago and installed succesfully but not driven the car, some fchatters have used them since with no problems, note how the seller added the ferrari 308 reference.
I think girodisc uses willwood calipers in front were they filled in the willwood lettering and painted, because nobody wants to show of a willwood caliper on a Ferrari. If the 993 calipers are not radial mount, the later calipers may be a better option, monobloc radial mount I think on the Boxster, 996,997 in different sizes. I could easily adapt 996 twinturbo calipers but they may be a bit overkill and regular Boxster are the smallest, Boxster S is a bit bigger and may be same as 996 non turbo but I´m only guessing so you have to double check if you want to use them.
I use the calipers of a f360 all around combined with the disks/hat combi of the superformance set. I did put in a proportioning valve. btw i use the mastercilinder of Bert Ebay-link. Works well Result: the car DOES brake now
I have Coleman Series IV brakes and rotors, same size, all around with a dual Tilton master/ brake bias adjuster. Car stops on a dime - little effort with no booster. Never any issues with brakes on the track. They just fit inside the 16" wheels. If interested, I can dig up the part numbers. Downside, no emergency brake. I've been thinking of plumbing up an electric brake lock in the rear hydraulics, but haven't got around to it.
I just thought Bret was one of the guys I gave the lead to the Fiat master, isn´t Bret the guy who is building the more serious GTO looking 308. It is always hard to remember nicknames on a forum, unless you know the real people and met them in real life, all this internet forum postings, I find it hard to remember who I replied to earlier and I already bought and sold parts to forum members and had a good experience and then forget completely that I know them when replying to their posts.
Thanks for the replies everyone. I really like your setup Paul but I'm trying to use as many of the factory bits as I can ... and the fact someone sent me these 993 calipers isn't helping with taking the easy route and duplicating what some of you guys have. So I made a bracket that mounts the 993 caliper ... the outer edge of the brake pads are making contact right at 12.25". I'm thinking this rotor right now: http://www.summitracing.com/parts/WIL-160-0277/ 12.19" o.d. and inner dia is 8.56" meaning the width is about 1.815". The 993 pads are right about 1.9" ... I don't think that little bit of overhang will be too much of a concern. There are bigger rotors than that but this is the cheap flavor for now. For guys that have Superformance rotors ... can you tell if the hats float the rotor? There are some cheap hats from Summit to experiment with but they aren't floating ... thoughts? A guy PM'd me ... thanks! ... I'll send you the pad sizes and info so you can give me an idea of where I'm at master cylinder wise and balance. I haven't read Girodisc's details but I'm still curious how much the adjustable bias helps with all this. My 911 has one with pretty long steel braided lines that run inside the car ... the long line hasn't caused any feel issues from what I can tell. cheers
A couple napking calc's: Area of stock piston ... about .24 sq in. Area of 2 pistons on 993 caliper ... about .26 sq in I'm looking at 12.25 rotor so the moment arm where I'm grabbing will be larger ... more pad area also ... I'm thinkiing I should not need a larger master cylinder. My problem has been overheating not stopping power but I have been running full race pads. I took some pics to post. cheers
Shoot ... I misinterpreted the offset spec's at Wilwood ... we need 2.3-2.4". I can make these myself but trying to use something everyone else can easily get. cheers
http://www.hrpworld.com/index.cfm?tpc=Rotor-Hats-Billet-Aluminum-GN&form_prod_id=613&action=product these can't be floating though?
What are you using for brake fluid and venting the rotors? Do you have any brake ducts in place? I just looked at your summit racing link. Why drilled rotors, especially on the track? (Other are welcome to comment on this point.)
FWIW, I've been using ATE Blue for years on the track in both the 308 and the Z06 - never an overheating issue. The Z06 has aftermarket brake ducting in the front. No brake ducting on the 308. One more thing, I do a complete brake fluid change before each track event.
Here's some pics from a lunch break project that turned into ... well ... ya know . cheers Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
Yeah ... so Wilwood has 2 thickness ... .810" and 1.250" ... these calipers will take up to 1.100". I was chatting with one of my buddies that works at a pretty big shop that makes hats and rotors (all big $ stuff too expensive for me) ... I'm not sure if he did me a favor ... he shared with me how much they buy rotor "blanks" for that are the big $ race flavor that they machine ... he asked me "Why don't you just machine those yourself ... I'll send some to you." I'm really leaning toward this now because then I can optimize the rotor thickness and I'll be using some of the best rotors available at a fraction of the cost. He was mentioning some Aussie company as the preferred source for rotor blanks ... I've heard the name thrown around also but it escapes me right now. The other thing that may complicate all this is the fact that if I'm going to make my own hats, I may be able to mount the caliper in the stock position and run a thicker 10.5" rotor if there's room for the rotor mount bolts at the edge of the hat ... my buddy is going to send me some of the floating mounting hardware that they use. I need to let this all gel a bit. cheers all, Sean
Quick comment on the drilled rotors -- don't use them on the track, period. They crack as a result of the extreme heat that is generated on the track. I had it happen to me with a set of Wilwood cross-drilled rotors, and I've seen lots of others who experienced the same thing. Stick with either regular flat rotors or if you want, slotted rotors. There have been extensive discussions on drilled rotors in the racing section on CorvetteForum, and the almost unanimous opinion is don't use them on the track. YMMV, but I won't go near a set for the track. They look pretty on the street as "bling", but I would never trust them on the track.
One thing I should mention about my wheel / brake setup. I changed from wheel bolts to lug bolt and nuts. Just ran the lug bolts in from the rear of the hubs with loctite. No issues. Makes life alot easier and might open up more options for you.
