PGT Posted March 16, 2006 Share Posted March 16, 2006 so, EBD is akin tp the DSC on my MINI....with stickier tires, I can put more power to the ground on acceleration before the e-nanny kicks in and retards the fun (or in the case of the brakes, pulses the piston to keep the tire moving). Link to comment Share on other sites More sharing options...
Joel Gat Posted March 16, 2006 Share Posted March 16, 2006 Hello, Just to raise a quick point - in racing the WRX for SoA, we used the stock brakes initially, because our rules didn't allow BBKs. With the appropriate PFC pads, while the car was ballasted to 3300 lbs, we never once experienced brake fade. The clamping force generated by the stock brakes was more than sufficient. The heat capacity of the system, however, left things to be desired, and despite using krytox grease (originally designed to lube the wheel bearings on those carts that smelters use to bring molten ore out of the oven (ie, really freaking hot)) we melted the plastic bearing retainers inside the wheel bearings... every single time we went on track. The BBK (StopTech) put an end to melting the wheelbearings, reduced our rotor and pad consumption rate, prevented melted steering ball joints, etc. It also improved modulation and feel, which was critical given that we weren't allowed to run ABS. I will have more to add to this great thread a little later... Joel Link to comment Share on other sites More sharing options...
Joel Gat Posted March 16, 2006 Share Posted March 16, 2006 Hello, Oh, one other comment: I don't know the mu numbers for the stock pads or the aftermarket pads, but I certainly don't think the jump is as drastic as posted here. My personal experience is that you do not get a 10% or more increase in brake torque with a set of street pads. You might get a small jump - but in a single application of the brakes, do you really feel that huge of a difference that you (as in anyone in the thread) think there's a 30% increase in brake torque? I dunno... it sounds fishy to me... Joel Link to comment Share on other sites More sharing options...
jsalicru Posted March 16, 2006 Share Posted March 16, 2006 Well Joel, I see your point, and you make an interesting argument. I suspect a little bit of everything comes into play for the real answer. However, the case might actually be correct at higher temperatures where the stock pad is out of its effectiveness range and the track pad is right in the sweet spot. "some say, his arms are made of coiled adamantium fibers. And that he tops his cereal with nuts and bolts. All we know is, he's called the Jose." Link to comment Share on other sites More sharing options...
Joel Gat Posted March 16, 2006 Share Posted March 16, 2006 Hello, Oh, no doubt the stock pads can't stand heat. But before you get out of their heat range, they're not bad - not 30% worse than aftermarket street pads. The rated mu of a pad assumes it is at the correct heat range. A good race pad might maintain a high mu over a wider heat range, and must have a good mu at a heat that might melt a stock pad, but it probably has a poor mu at cold temperatures, and on the other hand, any street pad has to have a good mu at cold temps. You're cruising on the freeway, not using your brakes, the rotors and pads are at ambient air temperature, and a dummy in front of you decides to slam on his brakes for no reason (seems to be common around here, too). You slam on your brakes. You better have the best possible mu at this moment, right now, right here, right from ambient cold. And the OEM knows that. And the OEM pads are ideal for this exact type of situation. Add three more 60 mph stops and the OE pad turns into butter. A good performance pad might have close to the same mu but better heat tolerance, so might last through 6 stops like that in a row (but might not perform as well on the first stop). A good race pad will suck and eat a bunch of your rotor on the first 3 or 4 of those, but then should last through another 10 of them in rapid succession. Given the goals of the OEM - max performance in that one to three panic stops - you can bet that the actual mu of the pad is quite good and quite near what you'll get out of performance pads. They sacrifice longevity at heat for instant gratification and some reduced dusting and noise. That said, there are other factors at play, the worst of which is the tire, which, unfortunately, affects everything, right down to the maximum deceration allowable by the ABS. The ABS is tuned to let the wheel slow down no faster than the OE tire could slow down under the best of conditions (grippy warm asphalt). Any time you can slow the wheel down faster, the ABS won't let you, which doesn't matter for low mu surfaces, but does matter in a performance scenario. But that's off topic. My point is only that I think the mu numbers in this thread are off. Joel Link to comment Share on other sites More sharing options...
praedet Posted March 16, 2006 Author Share Posted March 16, 2006 Great points Joel, and I agree with everything you have said. The best part, is that the LGT has a good bit larger brakes and doesn't weigh that much more than the WRX, so heat capacity and fade resistance should be even higher! Adding in better 2-piece rotors gives even greater heat capacity w/ less chance of frying the bearings... But, mu for the WRX is generally documented between 0.35 and 0.39. The LGT is thought to have an even lower mu, somewhere between 0.25 and 0.35. That is why I used the numbers I did. I can go to the upper limit, 0.35, but a mu of 0.5 on the front w/ 0.35 on the rear will still push the bias to the front a great deal. Thanks, Ted Link to comment Share on other sites More sharing options...
jsalicru Posted March 16, 2006 Share Posted March 16, 2006 My point is only that I think the mu numbers in this thread are off. You could be right. However, in my case, I am interested in the bias more than the mu. The mu is held at a constant number throughout all the data provided in the first post. To those that do not understand, obviously not you Joel, that means that if you want to preserve that balance, when getting aftermarket pads, you must get the same kind for the front AND rear. "some say, his arms are made of coiled adamantium fibers. And that he tops his cereal with nuts and bolts. All we know is, he's called the Jose." Link to comment Share on other sites More sharing options...
LittleBlueGT Posted March 16, 2006 Share Posted March 16, 2006 My Bobcats have better bite at freezing temps (first stop) then OEM. They have a better mu at lower and higher temps then OEM. The trade-off is noise and longevity. But the higher mu is definitley noticeble. I would say a 25% difference. there are other factors at play, the worst of which is the tire, which, unfortunately, affects everything, right down to the maximum deceration allowable by the ABS. The ABS is tuned to let the wheel slow down no faster than the OE tire could slow down under the best of conditions (grippy warm asphalt). Any time you can slow the wheel down faster, the ABS won't let you, which doesn't matter for low mu surfaces, but does matter in a performance scenario Everybody seems to say that ABS prevents lock-up (which it does) but it determines lock-up as the max allowable deceleration. That means that awesome tires might not give you the best braking that they are possible of due to ABS. Full tune of 68HTA, KSTech 73 MAF, Racer X FMIC and ID1000s................by the DataLog Mafia!!! Link to comment Share on other sites More sharing options...
sandwood Posted March 17, 2006 Share Posted March 17, 2006 this is the email I sent to racingbrake and their response (basically they agree and say to use different pads front and rear with their setup): RESPONSE: The thread only shows the calculation on different set up and assume both front and rear pad have the same coefficient of friction. While if you go to track usually you would use more aggressive pads for front than rear, so our kit would end up to be pretty close to stock bias. Try the current set up yourself. If you have HPS (come with our kit) front which has higher Mu than stock rear so the over all bias would be same as stock. Or if you upgrade to HP+ for your front you may have to upgrade rear pads to HPS as well. Nothing to worry or concern, RB offers you complete satisfaction. Once you test in the track I believe you will better understand there is a difference between theoretical discussion and practical application. By the way the torque unit s/b ft-lb, not lb/in. -----Original Message----- From: Sent: Thursday, March 16, 2006 10:37 AM To: info@racingbrake.com Subject: Contact Form I would like to draw your attention to a thread at http://www.legacygt.com regarding bbk kits for our cars. The thread indicates that the bbk kit you sell for the legacy gt, and which I have on my car, may not be a good match to the stock rear brakes. I would very much like to hear a response from you about this as it concerns me - particularly for the next time I take my car to the track. Thank you. getting out of the legacy game Link to comment Share on other sites More sharing options...
jsalicru Posted March 17, 2006 Share Posted March 17, 2006 That's not a good assumption on the brake pads. I ran Hawk HPS all around, will this time too. BOXRPWR runs RB's kit with HPS all around also. "some say, his arms are made of coiled adamantium fibers. And that he tops his cereal with nuts and bolts. All we know is, he's called the Jose." Link to comment Share on other sites More sharing options...
sandwood Posted March 17, 2006 Share Posted March 17, 2006 Yeah, I told them they should issue some sort of disclaimer. I think it's ridiculous. I'm going to get HP+s for the front before I go to the track, and Kevin should too. although, having said that, maybe he will post here and share his experiences with them on the track running HPS all around...? getting out of the legacy game Link to comment Share on other sites More sharing options...
PGT Posted March 17, 2006 Share Posted March 17, 2006 If we could get mu data on the Hawk pads, we might be able to run the numbers. I've been unsuccessful so far. Link to comment Share on other sites More sharing options...
jsalicru Posted March 17, 2006 Share Posted March 17, 2006 Kevin hasn't reported any problems to me regarding the braking using HPS all around. I doubt he will change to HP+ up front. He drives with HPS all around on a daily basis. Of note, I don't think he brakes hard enough at the track to really bring out these problems. Nevertheless, I do plan on suggesting a switch to HP+ before his next track day. This next track event has big straights that will probably really induce some heat on his pads/discs. "some say, his arms are made of coiled adamantium fibers. And that he tops his cereal with nuts and bolts. All we know is, he's called the Jose." Link to comment Share on other sites More sharing options...
jsalicru Posted March 17, 2006 Share Posted March 17, 2006 If we could get mu data on the Hawk pads, we might be able to run the numbers. I've been unsuccessful so far. Even on HPS pads I'm willing to bet the cold mu is about the same as stock. . On my STi I could feel a noticeable change in mu when I heated up the pads when I say... got off an offramp. "some say, his arms are made of coiled adamantium fibers. And that he tops his cereal with nuts and bolts. All we know is, he's called the Jose." Link to comment Share on other sites More sharing options...
praedet Posted March 17, 2006 Author Share Posted March 17, 2006 That is a really funny, and sad, response. With mildly aggressive Hawk pads, the mu should be at least 0.45. Using that with the stock rears gives you a set-up that is more front biased than stock. Going to a mu of 0.5 w/ stock rears, gets near 80/20. If they have a specific set-up that is best, they should let people know when they buy the kit... Ted Link to comment Share on other sites More sharing options...
praedet Posted March 17, 2006 Author Share Posted March 17, 2006 What Hawk pad is one step down from HP+? Ted Link to comment Share on other sites More sharing options...
jsalicru Posted March 17, 2006 Share Posted March 17, 2006 praedet: Could you make the ratio calculation using a front RB kit and a rear Rotora 2-pot 1-piece? That combo might be another nice one. "some say, his arms are made of coiled adamantium fibers. And that he tops his cereal with nuts and bolts. All we know is, he's called the Jose." Link to comment Share on other sites More sharing options...
jsalicru Posted March 17, 2006 Share Posted March 17, 2006 What Hawk pad is one step down from HP+? Ted HPS. There's a Ceramic compound too, but I rarely see it available and it seems to be more of a dust-free type of thing than anything. "some say, his arms are made of coiled adamantium fibers. And that he tops his cereal with nuts and bolts. All we know is, he's called the Jose." Link to comment Share on other sites More sharing options...
praedet Posted March 17, 2006 Author Share Posted March 17, 2006 Yeah, I will do that set-up. I am also going to be adding some stuff to the first post, so give me an hour or 2. iON was cool enough to check the thread and give me some more info! Ted Link to comment Share on other sites More sharing options...
sandwood Posted March 17, 2006 Share Posted March 17, 2006 more from Racingbrake: Although you can see the difference in calculation but you can hardly feel the difference. If you check Stoptech's site you will find that's how they emphasize on the bias, but would that mean other manufacturers' brake kits have problems? of course not. We build the kits based on our application experience not simply by calculation, we also found out lots of OE set up was not the best in the brake balance. Normally people put more aggressive pads in front than rear, while some choose to use the same pads. So depending how you feel your replacing front to HP+ may not be necessary. But in case you need HP+ just let us know and we will give you a price break. Just know there are so much variables that can also affect the "bias" than simple theoretical calculation. We follow the general practice as most motor companies do which is to have 2/3 in front and 1/3 in rear. getting out of the legacy game Link to comment Share on other sites More sharing options...
praedet Posted March 17, 2006 Author Share Posted March 17, 2006 real quick, Do you all want the stock brake pads to stay at 0.3, or move to 0.35? Link to comment Share on other sites More sharing options...
praedet Posted March 17, 2006 Author Share Posted March 17, 2006 OK, I have redone the format. I will typr exactly what everything means later tonight, but I added a comparison of what "ships" vs. matching pads. Matched pads are a mu = 0.5. Stock pads are now mu = 0.35... Hope this is better! Ted Link to comment Share on other sites More sharing options...
jsalicru Posted March 17, 2006 Share Posted March 17, 2006 Rotoras are shipped with street pads unless otherwise stated. My opinion here... Honestly, you should consider doing the ratio with the mu being consistent all around. AKA, using a constant mu as a control number. RB apparently expects people to keep stock pads or use one grade lower, however, I don't believe that it is something regularly done. People I know typically use the same type of pads all-around unless they KNOW they need to use different types all around in order to achieve a balance. "some say, his arms are made of coiled adamantium fibers. And that he tops his cereal with nuts and bolts. All we know is, he's called the Jose." Link to comment Share on other sites More sharing options...
jsalicru Posted March 17, 2006 Share Posted March 17, 2006 Also, 0.5 might be a bit high. I don't think its something that would compare when both pads are under the same temp. When a track pad has the temperature for 0.5mu a street pad might only had 0.2 due to it being past its efficiency range. If you look at Project Mu pads you will notice that their street/track pad starts at a mu of 0.4 Basically, there are SO MANY variables when it comes to different types of pads that I really don't think it should come into play in these charts. Hence the idea of setting them up as if ALL the brake setups used the exact same brand and model of pad. "some say, his arms are made of coiled adamantium fibers. And that he tops his cereal with nuts and bolts. All we know is, he's called the Jose." Link to comment Share on other sites More sharing options...
jsalicru Posted March 17, 2006 Share Posted March 17, 2006 Here's a list to use for example: Project Mu pads. B-Force, a mild street/track pad has a 0.32~0.42μ Applicable Rotor Temp: 0~500 deg. Celsius http://www.mackinindustries.com/md/projectmu/Resources/databforce.gif Type HC Plus. mostly a street/track pad has a 0.40~0.60μ Applicable Rotor Temp: (F&R) 0 to 800 deg. Celsius http://www.mackinindustries.com/md/projectmu/Resources/typehcdata.gif Level Max 900, a track pad only has a 0.42~0.62μ Applicable Rotor Temp: 0~900 deg. Celsius http://www.mackinindustries.com/md/projectmu/Resources/datamax900.gif "some say, his arms are made of coiled adamantium fibers. And that he tops his cereal with nuts and bolts. All we know is, he's called the Jose." Link to comment Share on other sites More sharing options...
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