bulletpruf Posted September 18, 2011 Share Posted September 18, 2011 Fellas - I have to admit that brakes are not something that I'm intimately familiar with and could use a bit of help here. Car is a 71 Javelin, 401, 4 sp. About 400 rwhp. Will be street driven some, but more of a track car (full cage, gutted interior, etc). Going to run 17 x 9 wheels. Rear will be a NASCAR type full floater 9" (1 deg negative camber, I think) on composite leaf springs with a panhard bar. The folks who are building the rear will need to know what size rotors to use. I will have to source the rest of the brakes myself. AI is limited to a 14" rotor, IIRC, so I'm guessing that's what I will be using on the front. What about the rear? Is 11.5" or 12" good enough for the rear or do I need to go larger? Realize that the front brakes do most of the work, but need decent rear brakes b/c the fronts will eventually fade. Any recommendations on a setup that won't bust my budget? Thanks! Scott Quote Link to comment Share on other sites More sharing options...
Members Jay A. Posted September 18, 2011 Members Share Posted September 18, 2011 Scott, On my AI mustang I have a rear rotor that is one of the most popular out there. It will work with simple adapters that are common for 9". it is a 11.75"x .81" with a 8x7" bolt circle. You can find many brands as it is a very common circle track rotor for under $99. I think mine is straight veined and cools very well. my rear brakes to a lot of work and these hold up very well (probably 1-2 seasons). Look at Coleman for all the brackets and hardware for your 9" application. One of the smaller 4 piston or 2 piston calipers is all that is needed. Piston sizes, rotor diameters, and master cylinder sizes should all be considered when choosing calipers. a balance bar or proportioning valve for the rear will be VERY important to adjust your rear bias. I use Hawk DTC-70 front and DTC-60 rear. Am currently using an new DTC-X (secret high friction) compound on front and DTC-70 on the rear. Good luck! Jay Quote Link to comment Share on other sites More sharing options...
bulletpruf Posted September 18, 2011 Author Share Posted September 18, 2011 Scott,On my AI mustang I have a rear rotor that is one of the most popular out there. It will work with simple adapters that are common for 9". it is a 11.75"x .81" with a 8x7" bolt circle. You can find many brands as it is a very common circle track rotor for under $99. I think mine is straight veined and cools very well. my rear brakes to a lot of work and these hold up very well (probably 1-2 seasons). Look at Coleman for all the brackets and hardware for your 9" application. One of the smaller 4 piston or 2 piston calipers is all that is needed. Piston sizes, rotor diameters, and master cylinder sizes should all be considered when choosing calipers. a balance bar or proportioning valve for the rear will be VERY important to adjust your rear bias. I use Hawk DTC-70 front and DTC-60 rear. Am currently using an new DTC-X (secret high friction) compound on front and DTC-70 on the rear. Good luck! Jay Jay - Appreciate the info. That's pretty much what I'm looking for - something common, inexpensive, and proven. Will check Coleman's site. Will definitely be using a proportioning valve. Thanks Scott Quote Link to comment Share on other sites More sharing options...
bulletpruf Posted September 18, 2011 Author Share Posted September 18, 2011 Ok, here's what I think you're talking about for the calipers - http://www.colemanracing.com/Caliper-4-Piston-Series-III-P4509.aspx And rotors here, right? http://www.colemanracing.com/Brake-Rotor-8-Bolt-7-BC-Floating-P3579.aspx Looks like I'll need these brackets to mount the calipers to my cambered rear (1 degree negative): http://www.colemanracing.com/Caliper-Bracket-Clamp-on-Cambered-P4658.aspx Proportioning valve here - http://www.colemanracing.com/Proportioning-Valve-Brake-Bias-Knob-Style-Wilwood-P3630.aspx Thanks, Scott Quote Link to comment Share on other sites More sharing options...
drivinhardz06 Posted September 18, 2011 Share Posted September 18, 2011 Wilwood 4 pot FSL caliper (very inexpensive), 7420 20mm pads, 12x1.25 rotor (or pick your dia, the FSL goes up to 13" I believe) I can send you a pic of this set up on an AI mustang Quote Link to comment Share on other sites More sharing options...
bulletpruf Posted September 18, 2011 Author Share Posted September 18, 2011 Wilwood 4 pot FSL caliper (very inexpensive), 7420 20mm pads, 12x1.25 rotor (or pick your dia, the FSL goes up to 13" I believe) I can send you a pic of this set up on an AI mustang Good input. A pic would be great. You can post here or e mail to me at [email protected] Thanks! Scott Quote Link to comment Share on other sites More sharing options...
nape Posted September 18, 2011 Share Posted September 18, 2011 Wilwood FSL4i calipers are now under $150 if you cruise ebay for a vendor. The plus to these is that the crossovers are internal to the caliper so the calipers aren't L or R anymore. They have 4 bleed screws so you don't even have to move hardware and allows you to only carry one spare. Pads are cheap @ ~$160ish for DTC-70s. I run these on the front. If you're looking for ultimate bang for your buck, look on ebay for used Wilwood IR-GT calipers. Most come from NASCAR teams so they are still fresh and the calipers only weigh 1.2lbs each. Pads are still cheap and they are adjustable for size using spacers between the two main body pieces. Most of them will be setup for 1.25" rotors but you can pull 1 spacer and they're sized for .810, pull another one and they're good for .390. These are what I use on the rear and don't pay more then $300/pair for them used. Both of those calipers share the common 3.5" lug spacing. You can find bolt on brackets but I didn't like them because it was hard to square the caliper, you still need to tack them on anyway, and they weigh more then the caliper. Using weld-on brackets keeps the weight down and allows you to perfect the caliper alignment. As far as squaring them for weld, just get a 1/8" pipe nipple and attach it to an air line to your compressor to put pressure on the pistons to hold them and tweak from there to make sure the pistons are all equal distance. As far as rotors, I also use 11.75" x .810, 7" x 8 bolt circle. I tried 12.19" x .810" but it gave me too much rear bias with DTC-60s. The cheap Wilwood $40 straight vane circle track rotors work fine on the rears and ought to last years. A 1.25" rotor is just extra weight on the rear of an AI car unless you're driving an extremely heavy car. On the proportioning valve, I don't like the screw in style because it's easy to forget which way to twist in the heat of the race and by how much you adjusted it. Wilwood makes a lever action valve that makes it a no-brainer to know how much bias you dialed out and also to make sure no one changed it on you. I don't worry about competitors screwing around with it, but we'll let the neighborhood kids sit in the car in the garage and you never know what they're doing while making VROOM-VROOM noises. Quote Link to comment Share on other sites More sharing options...
bulletpruf Posted September 19, 2011 Author Share Posted September 19, 2011 Wilwood FSL4i calipers are now under $150 if you cruise ebay for a vendor. The plus to these is that the crossovers are internal to the caliper so the calipers aren't L or R anymore. They have 4 bleed screws so you don't even have to move hardware and allows you to only carry one spare. Pads are cheap @ ~$160ish for DTC-70s. I run these on the front. If you're looking for ultimate bang for your buck, look on ebay for used Wilwood IR-GT calipers. Most come from NASCAR teams so they are still fresh and the calipers only weigh 1.2lbs each. Pads are still cheap and they are adjustable for size using spacers between the two main body pieces. Most of them will be setup for 1.25" rotors but you can pull 1 spacer and they're sized for .810, pull another one and they're good for .390. These are what I use on the rear and don't pay more then $300/pair for them used. Both of those calipers share the common 3.5" lug spacing. You can find bolt on brackets but I didn't like them because it was hard to square the caliper, you still need to tack them on anyway, and they weigh more then the caliper. Using weld-on brackets keeps the weight down and allows you to perfect the caliper alignment. As far as squaring them for weld, just get a 1/8" pipe nipple and attach it to an air line to your compressor to put pressure on the pistons to hold them and tweak from there to make sure the pistons are all equal distance. As far as rotors, I also use 11.75" x .810, 7" x 8 bolt circle. I tried 12.19" x .810" but it gave me too much rear bias with DTC-60s. The cheap Wilwood $40 straight vane circle track rotors work fine on the rears and ought to last years. A 1.25" rotor is just extra weight on the rear of an AI car unless you're driving an extremely heavy car. On the proportioning valve, I don't like the screw in style because it's easy to forget which way to twist in the heat of the race and by how much you adjusted it. Wilwood makes a lever action valve that makes it a no-brainer to know how much bias you dialed out and also to make sure no one changed it on you. I don't worry about competitors screwing around with it, but we'll let the neighborhood kids sit in the car in the garage and you never know what they're doing while making VROOM-VROOM noises. TJ - Good tip on the proportioning valve and great tech on the calipers. I'll see if I can find the IR-GT calipers on eBay. Thanks! Scott Quote Link to comment Share on other sites More sharing options...
bulletpruf Posted September 30, 2011 Author Share Posted September 30, 2011 Wilwood FSL4i calipers are now under $150 if you cruise ebay for a vendor. The plus to these is that the crossovers are internal to the caliper so the calipers aren't L or R anymore. They have 4 bleed screws so you don't even have to move hardware and allows you to only carry one spare. Pads are cheap @ ~$160ish for DTC-70s. I run these on the front. If you're looking for ultimate bang for your buck, look on ebay for used Wilwood IR-GT calipers. Most come from NASCAR teams so they are still fresh and the calipers only weigh 1.2lbs each. Pads are still cheap and they are adjustable for size using spacers between the two main body pieces. Most of them will be setup for 1.25" rotors but you can pull 1 spacer and they're sized for .810, pull another one and they're good for .390. These are what I use on the rear and don't pay more then $300/pair for them used. As far as rotors, I also use 11.75" x .810, 7" x 8 bolt circle. I tried 12.19" x .810" but it gave me too much rear bias with DTC-60s. The cheap Wilwood $40 straight vane circle track rotors work fine on the rears and ought to last years. A 1.25" rotor is just extra weight on the rear of an AI car unless you're driving an extremely heavy car. Talked to the folks at Wilwood. They don't like the IR-GT for my car - recommended something with a larger pad like the W4A (expensive). The FSL's are quite affordable - - about $150 each at Summit. This is sounding like a better deal for me at this point. Frank at Speedway Engineering is building my 9" floater. He likes the 11.75" X .810 rotor as well, and I can get the FSL's set up for an .810 rotor, too. Thanks, Scott Quote Link to comment Share on other sites More sharing options...
bulletpruf Posted September 30, 2011 Author Share Posted September 30, 2011 Spoke with Wilwood again; explained that I wanted a quality brake that didn't bust my budget. They recommend the lug mount FSL with 1.25 or 1.38 pistons - something like this: http://www.wilwood.com/Calipers/CaliperProd.aspx?itemno=120-11126. That's compatible with the 11.75 x .810 rotor, too. That works for me. Scott Quote Link to comment Share on other sites More sharing options...
nape Posted September 30, 2011 Share Posted September 30, 2011 Make sure you balance the sizes of the pistons F/R and to your master cylinder so you don't end up with crappy pedal feel or two prop. valves in series to band aid something that could have been solved in the design phase. Meaning know what size rotor you will run in the front for sure so you can pick a corresponding piston diameter in the front, which will let you match the rear. The larger diameter your rotors, the less piston diameter you need. Proper Prior Planning Prevents Piss Poor Performance. Quote Link to comment Share on other sites More sharing options...
bulletpruf Posted October 7, 2011 Author Share Posted October 7, 2011 Make sure you balance the sizes of the pistons F/R and to your master cylinder so you don't end up with crappy pedal feel or two prop. valves in series to band aid something that could have been solved in the design phase. Meaning know what size rotor you will run in the front for sure so you can pick a corresponding piston diameter in the front, which will let you match the rear. The larger diameter your rotors, the less piston diameter you need. Proper Prior Planning Prevents pee-piddily-diddily Poor Performance. Going with the Wilwood FSL's with 1.38" pistons, 11.75" x .810 rotors. Summit's price was $150 per caliper, but they were backordered, so I ordered them directly from Wilwood for an extra $11/caliper. Sending them directly to Speedway Engineering so they can ensure correct mounting. Wilwood recommended 13" rotors up front with 1 3/4" pistons. Thanks for all the input. Scott Quote Link to comment Share on other sites More sharing options...
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