Scott Posted October 23, 2011 Share Posted October 23, 2011 Trying to decide on brake setup. Planning on running a little more power so want to consider upgrades. VW Golf VR6 2600# Car runs a single piston caliper with a 11.3" rotor. Pads are rather large. promblem is mostly overheating of fluid and modulation. I have two options for change: 1) Wilwood 4-piston Dynopro setup with an 11" rotor - allows me to keep all my wheels but limits tire size. smaller pad but a lot better clamping. 2)Stoptech with st-40 calipers. of courst third option is stay with what I have and use TI shims (can have them made cheap) and change to better rotors. Thoughts? Quote Link to comment Share on other sites More sharing options...
obzezzed350 Posted October 23, 2011 Share Posted October 23, 2011 If stoptechs are an option, that is what I would do Quote Link to comment Share on other sites More sharing options...
moliver Posted October 23, 2011 Share Posted October 23, 2011 Change to a better fluid... Don't brake so much...brake hard for a short period of time to slow the car, then get back on the gas. Quote Link to comment Share on other sites More sharing options...
John Graber Posted October 30, 2011 Share Posted October 30, 2011 I think you have two issues. One is the overheating of the existing set-up, and the other is the potential higher demand of increasing power. So, first you need to get some cooling going. If they are not well ducted with solid backing plates you need to do that. Also running a good fluid will help a ton. Are the existing rotor well made and vented? Aftermarket rotors can be junk with thin walls and poor venting. Sticking with the OEM rotor may be best. Going to an aftermarket set-up maybe the answer, but you need to focus on the "hot" spot and not on the caliper. Higher thermal capacity will be derived from the rotor, not the caliper. Choose wisely based on the rotor which in your case will probably need to be wider and have a larger OD. I am not a fan myself of the Wilwood calipers, and given the German heritage here I would look into adapting a Porsche 944 Turbo, 951, 968, 964 4-piston caliper. You may have to utilize a high-end Wilwood rotor with a custom hat. Also, wheel size/clearance may be a big issue. Also, single piston calipers can often drag whcih would create heat and not allow the rotors to cool enough during use. Good luck. Quote Link to comment Share on other sites More sharing options...
Scott Posted October 30, 2011 Author Share Posted October 30, 2011 Thanks for input! I'll take fluid out of the equation. Been running Castrol SRF. Not sure there is anything better. It has been much better than Motul. That being said I have minimized the boiling of fluid by changing to the SRF and adding ducting to the caliper and rotor. I think the brakes are big enough as fade has not really been the issue. Caliper design has been. Push back and fluid temp have been my main issue. Then add a lack of modulation and it makes short hard braking difficult. Rotor design is not the best for my car they are externally vented and therefore hard to cool. I have been using an aftermarket rotor whose thickness is at least as thick as OE. The OE rotors aren't quite as good as they once were for the car. I could change to a slotted rotor next year with the class change. Wheel clearance is the issue. Only upgradable caliper that will fit is a Wilwood. It would not be my first choice either. My hope is they will dissipate heat better (billet alum vs cast iron) and give me better modulation. I don't want to replace four sets of wheels and change from my stack of tires I could use for practice. Quote Link to comment Share on other sites More sharing options...
hustler Posted November 1, 2011 Share Posted November 1, 2011 I don't really like the Wilwood Dynalite calipers but my options are severely limitted. The VW style "outboard venting" rotors are absolutely terrible for roadracing. I tried the Racing Brake inboard vented rotor and they lasted 1 day before fatally cracking. I suggest you look for something using the Wilwood "ultralight" 11.75" rotor. I switched to those on my car and caliper temps dropped from 550 to 310*f, the pedal feels the same every time, and the rotor rings are $32 each. Supposedly Stoptech is making a caliper with the same dimensions as the Wilwood Dynalite but stiffer and with better bleeders. If it uses "Outlaw" shaped pads I'll buy it. Quote Link to comment Share on other sites More sharing options...
Lucid Moments Posted November 1, 2011 Share Posted November 1, 2011 To the OP. Have you tried ducts? Lower the temp of the rotors and you will lower the temp of the calipers and the fluid. Certainly the cheapest solution if not necessarily the easiest. Quote Link to comment Share on other sites More sharing options...
Lucid Moments Posted November 1, 2011 Share Posted November 1, 2011 I don't really like the Wilwood Dynalite calipers but my options are severely limitted. Just out of curiousity why don't you like the Dynalite calipers? I've been running them for some time on my car for some time with little issue. I'll admit they are not perfect. They aren't as rigid as I would like, and I would like a larger pad as well, but bang for the buck they are pretty darn good IMHO. Quote Link to comment Share on other sites More sharing options...
hustler Posted November 5, 2011 Share Posted November 5, 2011 I don't really like the Wilwood Dynalite calipers but my options are severely limitted. Just out of curiousity why don't you like the Dynalite calipers? I've been running them for some time on my car for some time with little issue. I'll admit they are not perfect. They aren't as rigid as I would like, and I would like a larger pad as well, but bang for the buck they are pretty darn good IMHO. I can feel the flex, the pads drag from the flex, I've replaced 3 mushroomed pistons, the bleeder screws don't seal unless they are scary tight, the brass fittings need thread sealant, you have to bleed all four bleeders a couple times per year...but they're the right price, they fit in my wheels, and the pads are cheap. Quote Link to comment Share on other sites More sharing options...
Lucid Moments Posted November 7, 2011 Share Posted November 7, 2011 I don't really like the Wilwood Dynalite calipers but my options are severely limitted. Just out of curiousity why don't you like the Dynalite calipers? I've been running them for some time on my car for some time with little issue. I'll admit they are not perfect. They aren't as rigid as I would like, and I would like a larger pad as well, but bang for the buck they are pretty darn good IMHO. I can feel the flex, the pads drag from the flex, I've replaced 3 mushroomed pistons, the bleeder screws don't seal unless they are scary tight, the brass fittings need thread sealant, you have to bleed all four bleeders a couple times per year...but they're the right price, they fit in my wheels, and the pads are cheap. I agree with every point you made except I've never mushroomed a piston Quote Link to comment Share on other sites More sharing options...
hustler Posted November 9, 2011 Share Posted November 9, 2011 I agree with every point you made except I've never mushroomed a piston Ever gone off at 100mph with zero pedal pressure? The second time I did that I broke the e-brake cable so I replaced them both. Ever since I switched to a significantly higher friction pad I haven't killed a piston. I have two caliper paper-weights in the office, lol. Quote Link to comment Share on other sites More sharing options...
Scott Posted November 9, 2011 Author Share Posted November 9, 2011 So I was leaning towards the Wilwood but you guys have me nervous. Quote Link to comment Share on other sites More sharing options...
Lucid Moments Posted November 9, 2011 Share Posted November 9, 2011 So I was leaning towards the Wilwood but you guys have me nervous. Don't be too scared. They aren't really as bad as all that. Yes they flex and that does cause minor issues but nothing insurmountable. And the flex is the worst part. I would like it if the bleeder screws sealed more easily, but they do seal and that is all that is important. On the upside they are inexpensive, and there is a huge selection of pads at very reasonable prices. Quote Link to comment Share on other sites More sharing options...
Scott Posted November 9, 2011 Author Share Posted November 9, 2011 So I was leaning towards the Wilwood but you guys have me nervous. Don't be too scared. They aren't really as bad as all that. Yes they flex and that does cause minor issues but nothing insurmountable. And the flex is the worst part. I would like it if the bleeder screws sealed more easily, but they do seal and that is all that is important. On the upside they are inexpensive, and there is a huge selection of pads at very reasonable prices. Thanks, for my car I take steps using the Wilwood stuff. Start with better calipers and slotted rotors. Then using the same calipers move up to a two peice larger rotor if needed. Otherwise it's buy BBK and all new wheels and tires. Do the bridge-bolts help with the flex at all? Quote Link to comment Share on other sites More sharing options...
ddg Posted November 10, 2011 Share Posted November 10, 2011 I'm running forged Dynalites with 1.38" pistons, OEM 11" Corrado Brembo rotors and a "90" quattro 20v 25mm master cylinder in my '84 Audi coupe (2325lbs. empty) . This is the ONLY setup that didn't have a mushy pedal, no matter what I did with the stock "G54" Girling calipers, master cylinder and brake lines, the pedal always sucked! I've never noticed any flexing, the pricing was stupid cheap, you can run a trillion different pads, and I don't have any problems bleeding either. According to Wilwood, you aren't supposed to open the "bottom" bleeder screws, they're a "symetrical' design so the bottom becomes the top on the oposite side of the car. My guess with the piston mushrooming is possibly exceeding the maximun pressure, Wilwood has a spec listed somewhere about maximum hydraulic psi. the calipers are rated for, I assumed this was for the seals.... Quote Link to comment Share on other sites More sharing options...
hustler Posted November 14, 2011 Share Posted November 14, 2011 Everyone is right, you can't find another caliper for a reasonable price (until Stoptech releases the unicorn I've only heard of from rumor. I'm running forged Dynalites with 1.38" pistons, OEM 11" Corrado Brembo rotors and a "90" quattro 20v 25mm master cylinder in my '84 Audi coupe (2325lbs. empty) .This is the ONLY setup that didn't have a mushy pedal, no matter what I did with the stock "G54" Girling calipers, master cylinder and brake lines, the pedal always sucked! I've never noticed any flexing, the pricing was stupid cheap, you can run a trillion different pads, and I don't have any problems bleeding either. According to Wilwood, you aren't supposed to open the "bottom" bleeder screws, they're a "symetrical' design so the bottom becomes the top on the oposite side of the car. My guess with the piston mushrooming is possibly exceeding the maximun pressure, Wilwood has a spec listed somewhere about maximum hydraulic psi. the calipers are rated for, I assumed this was for the seals.... Your biggest problem is the rotor with the outboard venting. I ran that rotor and it really sucked, they cracked after a couple days and held a lot more heat (500*+ caliper temps). I switched to the 11.75" Wilwood rotor with the same caliper and the pedal is phenomenal every time and caliper temps never go higher than 310*f. This will also significantly improve bearing life. I felt no improvement in pedal feel from the bridge bolt. There are a lot of theories on why the piston mushroomed, I think pedal pressure was part of it. Lots of endurance racers have this problem with $$$ Brembos from running the pad to the backing plate (look at the huge piston length and enormous pads for real racecars). You can always throw an extra backing plate in there to run down all of the pad without extending the piston so much. Quote Link to comment Share on other sites More sharing options...
ddg Posted November 14, 2011 Share Posted November 14, 2011 Everyone is right, you can't find another caliper for a reasonable price (until Stoptech releases the unicorn I've only heard of from rumor. Your biggest problem is the rotor with the outboard venting. I ran that rotor and it really sucked, they cracked after a couple days and held a lot more heat (500*+ caliper temps). I switched to the 11.75" Wilwood rotor with the same caliper and the pedal is phenomenal every time and caliper temps never go higher than 310*f. This will also significantly improve bearing life. I felt no improvement in pedal feel from the bridge bolt. There are a lot of theories on why the piston mushroomed, I think pedal pressure was part of it. Lots of endurance racers have this problem with $$$ Brembos from running the pad to the backing plate (look at the huge piston length and enormous pads for real racecars). You can always throw an extra backing plate in there to run down all of the pad without extending the piston so much. I'll look into the rear vented rotors; I looked up "Racing brake" and their rear vented rotors, interesting design. I'll have to do some tempature measurements to see what my caliper temp is..... Quote Link to comment Share on other sites More sharing options...
hustler Posted November 14, 2011 Share Posted November 14, 2011 Everyone is right, you can't find another caliper for a reasonable price (until Stoptech releases the unicorn I've only heard of from rumor. Your biggest problem is the rotor with the outboard venting. I ran that rotor and it really sucked, they cracked after a couple days and held a lot more heat (500*+ caliper temps). I switched to the 11.75" Wilwood rotor with the same caliper and the pedal is phenomenal every time and caliper temps never go higher than 310*f. This will also significantly improve bearing life. I felt no improvement in pedal feel from the bridge bolt. There are a lot of theories on why the piston mushroomed, I think pedal pressure was part of it. Lots of endurance racers have this problem with $$$ Brembos from running the pad to the backing plate (look at the huge piston length and enormous pads for real racecars). You can always throw an extra backing plate in there to run down all of the pad without extending the piston so much. I'll look into the rear vented rotors; I looked up "Racing brake" and their rear vented rotors, interesting design. I'll have to do some tempature measurements to see what my caliper temp is..... Stay away from those rotors. I bought a set at $300 or so and the cracked on day #2. I had the best luck with Raybestos brand rotors from Rockauto Quote Link to comment Share on other sites More sharing options...
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