From: James at Pelican Parts [james@pelicanparts.com] Sent: Thursday, July 15, 1999 4:52 PM To: Timothy C. Watson Subject: Re: Hi Tim, If the car has a good, genuine, verifiable history with IMSA, I would be tempted to restore it and race it primarily as vintage (you can still do PCA/SCCA). Lockheed brakes are good; that's what my formula car has. But I suspect yours might be old, heavy, and technologically obsolete. Can you send a jpeg picture and/or part numbers? I may have a future use for them. If your car has 930 stuff on it already, that would be a good place to start. But I doubt the rear is 930 as it has a different trailing are and very few people are willing to do all the mods to make it work correctly. Also: 930s never had coilovers (sounds like a Bilstein RSR setup); but its sounds like somebody did a lot of work. The (late) 930, 944t, and 928 all had similar brake calipers; the big difference is the mounting and offset. You should verify some measurements before purchasing any parts: Caliper mounting hole centers. Distance from centerline of bolts to edge of rotor. Distance from caliper mounting surface to centerline of rotor. Distance from rotor mounting surface centerline of rotor. You'll need these figures, and more, when you start choosing parts. My '87 944 Turbo has a 295mm rotor; 95mm bolt centers, 36mm caliper surface to centerline, 70mm from bolt centerline to rotor. I may agree, even though you will likely have a light car, you may benefit from bigger brakes do to all tire you will have. I'm not sure I would go with 18inch wheels though. When choose wheels I give allot of consideration to the cost, availability, and projected future availability of tire. 18 inch tires may see the same fate as the 19 inch did. There is also that unsprung weight issue as well. I think 17 inch might be a better bet right now; just food for thought. There have been a large number of writings about brake conversions over the years (in Panorama and Excellence), but I don't specific references. There is a basic brake article in this months Pano, and I might refer you to "The 911 Performance Handbook" by Bruce Anderson (good book but no real detail about brakes). There is also a book by HP books, or Peterson(?), that deals specifically with brake engineering and theory that I recommend reading. In regards to your last paragraph: I'm not an engineer, nor have I done a conversion (I run my 911 in production classes). I know all the numbers are out there, as it has been done every which way possible. There is math for figuring out how much brake you need, and how to achieve it, I just don't know the math. Perhaps the "Brake Handbook" HP books will provide a better clue (I have a copy but I don't have access to it at the moment). I, like most people, copy others and go with proven systems. I think its pretty safe to assume that if 928 brakes can stop a 3500 lb. pig, your 2000 lb 911 should be no sweat. But you have to be careful not to over-do it like many other. If the pads can't heat up, the car wont stop, giving you no net improvement. Have you considered a duel master cylinder set-up? I can see this is going to be fun. You can try calling me at my shop if you like 210-732-5090; I will most likely be around through the weekend (but I come and go allot, and the phone is often tied up while I'm on-line. james > > Thanks for your reply. > > Yes I would be interested in your thoughts on developing a brake system. The > basic story is that I bought this car, a 1970 IMSA GTU car from somebody > that had it for several years and raced it primarily in club races and time > trials. Over the years he had modified the car extensively, lowering the > suspension and using what appears to be 930 parts and coil over shocks. I am > doing a ground up restoration to create essentially a GT4 car with a 2.7/2.8 > motor and 915 gear box. I may eventually upgrade to a higher horsepower > motor if I like the car. The car had Lockheed brakes on the front and > Bremtek brakes on the rear when I got it, both needing rebuilds. I thought > at this time I would go ahead and upgrade the brake system going to larger > rotors (I think they are 11 inches now) and the cleaner look of the Brembo > brakes, of course the price is higher than I expected and I am interested in > alternatives. I will also be changing the 16 inch rims out (older 10 x 16 > inch and 12 x 16 inch BBS wheels) to the newer BBS 18 inch wheels for > cosmetic as well as technical reasons. As far as weight, I am not sure. The > car has essentially been gutted of all interior and extraneous parts and has > carbon fiber fenders and hood so it is getting down there. > > Your 944 turbo brake system sounds interesting. Are there any technical > writings on the subject (ie especially about the adapters,part and part > numbers etc.) and do you think is is appropriate for my needs? What about > the master cylinders? > > Please drop me a line by email about your thoughts or my home number is > 559-298-3010, or send me a phone number and I will give you a call. > > Thanks, > > Tim Watson > ---------- > >From: james@pelicanparts.com (James at Pelican Parts) > >To: Wayne at Pelican Parts > >Subject: Re: > >Date: Wed, Jul 14, 1999, 4:01 PM > > > > >Hi Tim, > >My opinion is Big Reds are BIG HYPE. its just a Brembo caliper; no magic. A > >cheaper solution would be to use 944 turbo calipers (you'll have to get or > >make custom adapters); I think new they cost less than $200ea at the dealer > >and I see many sets for sale used for less than $400set. The real question > >is why do you want bigger brakes? What brakes do you already have? How much > >does your car weigh? What tracks do you run? How much horsepower do you > >have? What pads do you run? What kinds of speeds are you seeing? What brake > >fluid are you using? What size wheels are you running? I race a '79 SC, > >2,750 lbs., Pagid orange pads, ATE fluid, stock brakes, and I don't have any > >problems. I also have a formula ford with brakes that are smaller than a 914 > >brakes. You see, its all relative, and there are many questions to be > >answered. One of the things seldom considered when do brake conversions is > >the increase in unsprung (and overall) weight, which will require revalving > >the shocks, and the car will potentially handle worse. Examine ALL the > >trade-offs! ...and in the end: granted, the car may feel more secure to > >drive, but the reality is it won't stop any faster (how fast you stop is a > >function of tire friction). If you'd like, with more details I could help > >you develop a brake system best suited to your needs. > > > >Good luck, > > > >james > > > > > >> > >> > -----Original Message----- > >> > From: twatson@sirius.com [mailto:twatson@sirius.com] > >> > Sent: Tuesday, July 13, 1999 6:27 PM > >> > To: pelicanparts@csi.com > >> > Subject: > >> > > >> > > >> > Dear Sir(s): > >> > > >> > I have an older 911 that has been set up for racing that I would > >> > like to set > >> > up with the Big Red brake set up. Are there any relatively > >> > inexpensive ways > >> > to do this or any suggestions you might have? > >> > > >> > Thanks > >> > > >> > Tim Watson > >> > > > > > > > > >