DaveK Posted June 16, 2007 Author Share Posted June 16, 2007 hey dave, how was the journey home? better than the one up i hope! It was thanks. Although - boy did it rain at one point! Quote Link to comment Share on other sites More sharing options...
DaveK Posted June 16, 2007 Author Share Posted June 16, 2007 Here is a pic of the Cusco master cylinder stopper on my car. http://img526.imageshack.us/img526/8040/attachment1phppj6.jpg The other alternative is the Carbing front strut brace which has a built in brace for the brake master cylinder. http://f10.putfile.com/7/18616374710.jpg If you get someone to press the brake pedal whilst idling, you will see a degree of flex in master cylinder assembly. Basically the brace minimises any flex, which helps firm up the pedal and transfer more of the power to the brakes. OK, cool. I'd never heard of such things. I'll take a look - but I may do that at the same time as the hoses / fluid change then. Quote Link to comment Share on other sites More sharing options...
Nic Posted June 16, 2007 Share Posted June 16, 2007 OK, cool. I'd never heard of such things. I'll take a look - but I may do that at the same time as the hoses / fluid change then. Dave, give me a shout if you need any more details. Quote Link to comment Share on other sites More sharing options...
DaveK Posted June 16, 2007 Author Share Posted June 16, 2007 Dave, give me a shout if you need any more details. Thanks - will do. Quote Link to comment Share on other sites More sharing options...
dangerous brain Posted June 16, 2007 Share Posted June 16, 2007 That kind of depends. I will only fit the 17s if I decide to go for the bigger brakes - they have no other benefit to me. If I stick with the brakes I've got, there isn't much point in swapping wheels - it just means my tyres will start costing me more. Erm actually you find the 17"s benefit you alot more than just fitting bigger brakes under. When you fit bigger wheels you fit smaller profile tyres to maintain the rolling diameter of the wheel assembly. When you replace rubber sidewall with metal wheel you get less sheer force loss across the wheel under cornering. There comes a point when you reduce the tyre wall so much the wheel assy can't hold the road anymore because there isn't enough tyre to cushion the roads bumpy surface. On a supra according to those in the know 17" wheels are the omptimum. Quote Link to comment Share on other sites More sharing options...
DaveK Posted June 16, 2007 Author Share Posted June 16, 2007 Erm actually you find the 17"s benefit you alot more than just fitting bigger brakes under. When you fit bigger wheels you fit smaller profile tyres to maintain the rolling diameter of the wheel assembly. When you replace rubber sidewall with metal wheel you get less sheer force loss across the wheel under cornering. There comes a point when you reduce the tyre wall so much the wheel assy can't hold the road anymore because there isn't enough tyre to cushion the roads bumpy surface. On a supra according to those in the know 17" wheels are the omptimum. I don't drive the Supra in a style where that's really an issue. It's my daily runaround, and there are disadvantages to 17s. Lower profile tyres give a slightly harsher ride and I assume 17s weigh more than 16s. If I do find it's the only way to get the braking I want, then I will fit them. But from a handling perspective it's not an issue at all - although I drive fairly quickly, I don't push the Supra when cornering etc. at all. Quote Link to comment Share on other sites More sharing options...
BarnyB Posted June 17, 2007 Share Posted June 17, 2007 I've got J specs brakes and always used the bog standard Toyota pads until the last set I bought which were called fast roads pads or something. I'm going to change back the standards because they squeal endlessly from the dust (thanks to 40mph limit in channel islands). The main reason I bought them is because the Supra is also the car I use on track days. But really couldn't say that fast pads felt any better than standard, this involved some very hard braking from somewhere in the region of 120mph at the end of the back straight. The thing is, they were smoking quite a bit when I pulled into the pits. Was told it was the copper something or other burning off so that might have something to do with why they didn't seem anything special. I don't quite understand why upgraded brakes are a good thing. If your tyres are sliding you are not going to stop any quicker even if you have tremendous brakes, surely it's all down to loosing grip on the road? So with the j-specs, you can brake hard enough that the tires start to skid and the ABS leaps into action etc. so why would you need more braking power, wouldn't wider or grippier tyres be the better solution Can anyone explain? Quote Link to comment Share on other sites More sharing options...
RobSheffield Posted June 17, 2007 Share Posted June 17, 2007 My car came from japan with UK brakes and stock Toyota pads (i think) I have been in a few cars with Jspec brakes and even though i was in the passenger seat i could tell a difference. The UKs have a fair bit more initial bite IMO. Quote Link to comment Share on other sites More sharing options...
DaveK Posted June 17, 2007 Author Share Posted June 17, 2007 I don't quite understand why upgraded brakes are a good thing. If your tyres are sliding you are not going to stop any quicker even if you have tremendous brakes, surely it's all down to loosing grip on the road? So with the j-specs, you can brake hard enough that the tires start to skid and the ABS leaps into action etc. so why would you need more braking power, wouldn't wider or grippier tyres be the better solution Can anyone explain? I've always said exactly the same thing on the 964 forum funnily enough when people are talking about fitting turbo brakes. In this case, I don't think my car will stop any quicker - but I want it to stop as quickly with less pedal pressure. Quote Link to comment Share on other sites More sharing options...
dangerous brain Posted June 17, 2007 Share Posted June 17, 2007 I'll say it again the J-spec brakes are more than man enough for legal driving speeds. Unless you repeatedly nail your brakes hard from a ton you really won't heat them up enough to suffer from brake fade. Its the brake fade thats terrible on J-spec brakes. I drive my car so hard on a track day that I overheat my UK spec brakes and get fade from them so J-spec brakes would be useless to me. Your argument for keeping 16"s is sound enough as well. 16-17 doesn't affect the comfort much but step up to 18 and you'll notice that. In your circumstance Dave I reckon uprating and servicing your current setup will work best. Quote Link to comment Share on other sites More sharing options...
RobSheffield Posted June 17, 2007 Share Posted June 17, 2007 Realistically tyres shouldnt be locking up at all, so i would advise getting that sorted before brakes Quote Link to comment Share on other sites More sharing options...
DaveK Posted June 17, 2007 Author Share Posted June 17, 2007 Realistically tyres shouldnt be locking up at all, so i would advise getting that sorted before brakes I don't understand this? At legal speeds - certainly below about 50 - I can stamp on the brakes enough to have the ABS kicking in, even on decent tyres. Quote Link to comment Share on other sites More sharing options...
RobSheffield Posted June 17, 2007 Share Posted June 17, 2007 Oh we can all stamp so the abs kicks in, but we dont often stamp on the brakes do we Quote Link to comment Share on other sites More sharing options...
DaveK Posted June 17, 2007 Author Share Posted June 17, 2007 Oh we can all stamp so the abs kicks in, but we dont often stamp on the brakes do we No - but I think the point was that the brakes are not the limiting factor in how quickly you can stop, since it's the tyres that are the limit. Quote Link to comment Share on other sites More sharing options...
RobSheffield Posted June 17, 2007 Share Posted June 17, 2007 I give up, go do what you want Quote Link to comment Share on other sites More sharing options...
matt k Posted June 17, 2007 Share Posted June 17, 2007 My ABS rarely cuts in, and the car stops phenomenomily, there are times when i've had brake fade though when driving like a t**t. Quote Link to comment Share on other sites More sharing options...
BarnyB Posted June 17, 2007 Share Posted June 17, 2007 Have devised a rather flimsy theory. Do the uk spec brakes apply more pressure resulting in wheels locking up in an earlier skid and earlier abs kick in so that you are effectively braking with the maximum amount on force pushing down on the ground through the tyre for longer, which even taking into account the that more skidding wil occur, results in faster net deceleration? Quote Link to comment Share on other sites More sharing options...
Homer Posted June 17, 2007 Share Posted June 17, 2007 In my experience, my jspec brakes works absolutely great and are as good as "UK" brakes when HARD stops are needed, even from extremely high speeds. However (and this is a big one), they can do this only once. They obviously heat up quicker so after a VERY hard stop you cannot expect them to do it again. For me, this means they are a liability on a track day (proven ), but are not a liability if comes to having to emergency braking; you just need to keep in mind that if you brake hard, you need to make time for them to cool properly before you can expect them to be useable under very hard braking conditions again. Basically: know the limits, but don't push them. BTW, the is based on my experience with excellent stock discs, braided lines, good 5.1 fluid and without a doubt the best one of the lot - Chris Wilson fast road pads. Quote Link to comment Share on other sites More sharing options...
Scooter Posted June 17, 2007 Share Posted June 17, 2007 BTW, the is based on my experience with excellent stock discs, braided lines, good 5.1 fluid and without a doubt the best one of the lot - Chris Wilson fast road pads. IMO with CW race spec pads on a TT they would not even be a liability on track.......... As said fade is where J-specs suffer...........fade occurs if the pads get hotter than their maximum range or when the brakes get so hot as to cause the brake fluid to boil........pads are the weak link...... nearly everyone experiencing brake fade IMO are experiencing the "pads" not being able to cope with the heat........ Quote Link to comment Share on other sites More sharing options...
dangerous brain Posted June 17, 2007 Share Posted June 17, 2007 You sure its not the fluid as well? Quote Link to comment Share on other sites More sharing options...
DaveK Posted June 17, 2007 Author Share Posted June 17, 2007 Well, it's good to hear that the J spec brakes should be capable of what I need. Fade isn't an issue - I don't drive in a way where that's a problem and the Supra will never go on a track. I'll get my J-spec's sorted at the next service. If it solves the problem, I'll have a set of 17s for sale! Quote Link to comment Share on other sites More sharing options...
Scooter Posted June 17, 2007 Share Posted June 17, 2007 You sure its not the fluid as well? i'm not sure no, but i think most people have pads that aren't up to the task as ones that are can be pretty expensive. Unless you have high temperature range pads then i don't think you can get enough heat into them and the calipers to cause the fade via fluid boiling. ie stock brakes with stock pads or say CW fast road pads, you will get pad fade before fluid problems so will slow down (or go off!) before boiling fluid can become an issue? Quote Link to comment Share on other sites More sharing options...
Scoboblio Posted June 17, 2007 Share Posted June 17, 2007 My j-spec brakes must've been in a shocking condition when I changed them, because the UK setup I've got now (braided hoses, CW pads, new fluid etc) is far far better in every respect. Ideal example: There're a couple of duel carriageways near here that are nearly empty at certain times of the day...... they're seperated by a roundabout at either end, and one in the middle. Myself and a friend would both come off the roundabout at the same time, him in his pug 406 coupe with brembos and me in the supra. I'd roar away from him and hit maybe 140 before having to brake..... but I'd have to leave a huuuuuuge braking distance, where as he'd fly past me and brake at the last minute. On the second roundabout forget it...... the brakes would be virtually mush by that point. So for spirited driving I really would recommend the UK brakes, gave me a lot more confidence to make the most of the car, no point having BPU power and no braking power IMO. All IMO of course, like I say maybe my j-specs were just rubbish. Quote Link to comment Share on other sites More sharing options...
Homer Posted June 17, 2007 Share Posted June 17, 2007 As said fade is where J-specs suffer...........fade occurs if the pads get hotter than their maximum range or when the brakes get so hot as to cause the brake fluid to boil........pads are the weak link...... nearly everyone experiencing brake fade IMO are experiencing the "pads" not being able to cope with the heat........ Spot on I'm so bored with the amount of times I've heard "you're doing XXXmph on roads and only have jspec brakes OMG!!!one!!!eleven!!!" There is nothing wrong with these brakes if you want to do ONE STOP. What you cannot do with the jspec setup is drive a HARD track again and again, they will suffer from fade as the pads and discs overheat. Of the many cars I've driven with "UK" spec brakes, only one has inspired more confidence On The Road than my current setup and that was with someone who had brand new stock discs, Chris Wilson road pads and relatively new fluid. The others were inferior in almost every respect. Quote Link to comment Share on other sites More sharing options...
Kranz Posted June 18, 2007 Share Posted June 18, 2007 What we really need is back to back tests using a measured stop from a set speed repeated until terminal fade sets in for each spec of brake i.e J Spec Vs UK spec. Measuring the G force, distance to stop and disc temperature after each stop would give a set of definative results. Quote Link to comment Share on other sites More sharing options...
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