ABS/Antilock brakes - possible to retrofit? - Page 2

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  1. #11
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    Quote Originally Posted by gamble View Post
    What tires are you running? Tires with an I by the way, none of the Y stuff :P

    ABS would be cool but there is no way for it to be done cheaply. Would have to be an adjustable aftermarket setup to be tuned, and even then would take a ton of work to tweak and get right.

    Your best bet honestly is to ditch the 14's and get some modern 16" or taller tires. 14's just don't get any new compounds anymore, while modern sport tires are almost as good as full on race tires were a decade ago. Same thing goes for motorcycle tires. You can get ones that look classic on smaller wheels, but they won't handle or stop as well as modern stuff for sure.
    No, I think you'll find that only you guys spell it with an 'i'

    Dragon is running 225/60R14s, which as you say are old rubber. The front tyres are Toyo F5's, with a date code of 2002, but they have good tread and are otherwise in good condition. The rear tyres are Pirelli P6s, with a single-digit year code, which means 1990s at the latest, but I haven't had any grip problems with them. I've been advised one of the Pirellis is cracking on the sidewall inside edge, so that needs to be changed, but no comments on the fronts.

    I would like to run bigger wheels, but I do like the stock alloys. They're the only even-spoke alloy design I like. I'd love to up them to a set of L-type 15" wheels, since tyres that wide are readily available over here. My dad once had a quote for a set of 17" alloys to be fabricated in the same design, and I think it was around 1,500, but that was 10 years ago.

    ABS is fairly cool technology, and in isolation, the only major changes are the wheel hubs - thinking about it, all you really need there are precision-drilled slots in the existing rotors, which could be done with a CNC milling machine, and a magnetic sensor fitting securely to the hub. Everything else can be fitted into the existing braking system. No mistake, it's a lot of work and not cheap, but a 4-channel, 4-sensor would probably be the most straightforward to fit, and would give the best results.

    A bit of googling doesn't turn up much, but there are some references to people who've done it: http://www.hotrod.com/articles/hrdp-...-for-hot-rods/. No in-depth details though; maybe if anyone can suggest a car of similar size and weight distribution?

    All the brake controller is doing, fundamentally, is monitoring the wheels for rate of deceleration. Since there is a constant gap between the slots on the sensor disc, it can calculate the wheel speed based on pulses per millisecond from the magnetic sensor. It would make the task a lot more complicated, but it might be an option to adjust the gaps and slot size to manipulate the brake controller's cut-in points - of course, yes, I understand this is very risky for a safety-critical system and might only show up a problem right when it's needed (and would need some careful maths). In any case, all the controller is programmed for is to detect when the rate of deceleration exceeds the pre-programmed limit of the rubber, so it would be dependent on the tyre size and contact area. I only mention this because I actually studied ABS controllers as an example of concurrent programming in a software engineering class, so it makes sense in my head when I think about retrofitting it
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  3. #12
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    Quote Originally Posted by Khlause View Post
    Good tires and suspension like the others are saying is all very true.

    I have no idea what brake system you're running, but if its stock and any one of the following is wrong: bad wheel bearings, warped rotors, pads that give you poor feel, moisture /air in the lines, or slide pins that even bind a little; your brakes will be sketchy at best.

    ABS is possible, but it will be either expensive or it will be a challenging project.
    I do like a challenge

    Dragon's brakes are stock, since I've never felt they're underpowered. I have been told there's some play in the front wheel bearings, and I'm trying to get it scheduled with Toyota to have the bearings adjusted; they pointed out that the antiroll bar bushes are also degraded (not seriously) during the last inspection, but they're having some trouble getting the bolts (since the originals are pretty likely to snap when they're removed) so I'm trying to save labour costs by having both jobs done at once. If this could be a contributing factor to Dragon's brake performance, I'll stop driving it until it can be fixed; I already switched to the Subaru today out of paranoia!

    The discs are fine and the pads have plenty of material, although I did notice when I was braking that I couldn't feel through the pedal when the wheels locked, one of the factors that stopped me trying threshold braking in those few seconds. I bled the brakes late last year and Dragon has spent most of the last 12 months in either a climate-controlled warehouse or in a workshop, much less exposed to the weather than usual. I do have a fluid tester which I'll try.
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  4. #13
    CelicaSupra.com Member supraz's Avatar
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    Quote Originally Posted by gamble View Post
    What tires are you running? Tires with an I by the way, none of the Y stuff :P
    Gargravarr,
    Albeit totally irrelevant to the issue of ABS, Gamble has you here. You distinctly said 'shit', not 'shyte' on the video! Consistency is important with the Queen's English!
    Dale

    On the other hand, 'Z' is pronounced 'Zed'. Therefore the correct pronunciation of the name of that southern Boogie band is "Zed-Zed Top"!
    Last edited by supraz; 11-12-2016 at 05:34 PM. Reason: Clarification
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  5. #14
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    Quote Originally Posted by supraz View Post
    Gargravarr,
    Albeit totally irrelevant to the issue of ABS, Gamble has you here. You distinctly said 'shit', not 'shyte' on the video! Consistency is important with the Queen's English!
    Dale

    On the other hand, 'Z' is pronounced 'Zed'. Therefore the correct pronunciation of the name of that southern Boogie band is "Zed-Zed Top"!
    By an interesting coincidence, I turned the radio off about 3 minutes before this incident, while 'Legs' was playing on my iPod
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  6. #15
    CelicaSupra.com Member supraz's Avatar
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    LOL,

    Sorry for high jacking your thread. Being between the mother country and the States I just love the differences in the languages.

    Supraz (Supra-Zed)
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  7. #16
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    Having owned my 85P since new, I agree with almost all of the above. Your oshit....... is funny as Hell. The incident definitely isn't. For me, it would definitely be one long ass half a word, ffffuuuuuuuhhhhhhh. Then perhaps nothing. Then maybe a final kkkkkk. Because you know how hard it is to stop in the middle of a f(iretr)uck! Hahahahaha. Too bad I can't keep my own sick ass comments to myself, isn't it?
    I've never rear ended anything. Everyone keep your sick ass comments to yourself. Every time I've ever had a close call in the Supra, I've been amazed to have always ended up stopped multiple car lengths before impact. Then again, I've always had the best tires. And, having grown up in Maine where for 5 months every year, you're looking out of one or the other side windows when going straight, I'm used to getting and being somewhat sideways. It definitely is a good thing to be comfortable with. So even when we lived in CA and used to go to Lake Tahoe most weekends to ski, I never used winter tires. Those Goodyear Eagle Gatorback VR's were always terrific, even in the snow. So I'm sure that my Maine experience helped train me to do everything at least smooth enough and not too abrupt to cause lock up or otherwise lose traction.
    However, since we moved to WA many years ago, I've had another thing to deal with. The mostly terrible drivers here seem to forget how to drive in the wet every year. So my worst fear is that whenever anything happens in front of me, I always have to be more concerned about mirror driving to avoid what's more likely to happen behind me. And in your case, wet, cold and likely a bit greasy is definitely a worst case scenario. But living in Europe, you at least have a bit of an advantage in that people there are generally a bit better drivers overall. Here, driver training concentrates on parallel parking and how close you can park to a fire hydrant. Not nearly adequate under any circumstances.
    So I switched to 5 lug hubs a few years ago and my front brakes are now bigger and better Infiniti Q45 stuff because it was part of that conversion. I also swapped in an aluminum MK III master cylinder (but kept the same booster) to better match the increase in piston area of these calipers. I very much like the slightly increased pedal effort it requires. Absolutely no conscious thought is ever required to apply more brake if the car isn't stopping as fast as expected. This is quite the opposite of some of the early American power brakes that would nearly lock the wheels up if you even looked at them. No one ever gets used to that.
    For street driving, the original brake setup is more than adequate, especially with the anti-dive suspension geometry these cars have. Yeah there's always going to be weight transfer forward under hard braking. But our cars are definitely not like the scenario Dave describes with pick ups. How those very simple systems work is indeed with a variable valve that restricts rear braking pressure more as the rear lifts. The valve is frame mounted with a lever connected to the rear suspension that restricts rear pressure more with more lift as happens in an unloaded condition, which is what's normal 90+% of the time.
    I'm good enough at threshold braking that ABS wouldn't be much of an improvement with one exception. And that would be if one side of the car was on a much different surface than the other, such as if you were partly off the road. I'm certain that todays smart ABS systems would handle that much better than I ever could. I understand your concern and desire for something better. But my personal opinion is the same as Klause and everybody else. Have the best tires you can and be sure that what else is mentioned is always in good condition. That's why I did the 5 lug conversion. I didn't like most of the larger 4 lug wheels available, especially the cost. There simply isn't any decent 14's available anymore. The only good 15's are track tires. Even 16's which I now have aren't that plentiful now, although I'm fairly certain decent ones will be available for some years to come.
    So I think you'd be much better off investing in some larger wheels you like and more modern and much better tires, especially in the wet, than spending a small fortune on a custom ABS setup. Consider that your instincts and abilities are definitely above average and that even though you've had a recent scare, you did very well under the circumstances. There's always the ability to see into the future though. That would have helped. You aren't telepathic, are you? You'd know because you'd get ESPN!
    Zed, Zed Top! Hahahahaha. Turning off your iPod just 3 minutes before your incident while listening to Legs was no coincidence, was it? Maybe you can see into the future and you just weren't aware of it. Al-U-Min-E-Um and Nuke-U-Lar to you too! But shit just never really is shyte, no matter where you live. You've proven that beyond anyone's doubt!
    Last edited by ray85p; 11-12-2016 at 07:55 PM.

  8. #17
    CelicaSupra.com Member drjim's Avatar
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    That was a pretty scary video, Rob. Glad you got through it OK.

    Just a note on the sway bar bushings. They're very easy to change. Even a sloooow old guy like me had both of the bar-to-frame bushings changed in about an hour. My sway bay end links were equally easy.

    I replaced the bar-to-frame bushings with ones from WhiteLine, and the end links with Energy Suspension parts, but I believe WhiteLine and SuperPro also sell them.

    I just can't see any reason to replace them with OEM Toyota parts when better parts are available.

    No reason you can't do it yourself, especially considering how much work you've done on Dragon already.
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  9. #18
    CelicaSupra.com Member ddd228's Avatar
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    I'm the MOST at risk for crashing,when I exceed my skill level!
    Little skinny-ass tires,but they are MISH-KAH-LINS.
    I have aftermarket (anti) sway bars,but stock brakes.
    The fronts DO lock up first. I need to be aware of what is going around around me all of the time!

    Yeah,it's funny as hell to see the locals try to drive in the snow,guys.
    People that have moved from Hawaii & Mexico,etc.

    Drifting in the snow is GREAT FUN!!!!! It is also encouraged to let you see how YOUR car acts,straightaway.

    That's a different subject,altogether.
    I think that we all had a 'shit your shorts' experience in traffic.

    Rob just did.
    His lightening-fast reflexes saved the Dragon from a horrible crash @ 33 MPH.
    The Dragon would be crunched beyond the radiator into that 'Range' and.... NOT to think about the damage to ROB!!! We love you,man.

    Shit man,I'm(We all are) glad that you able to avoid a bad situation.
    Like I typed B-4, I bow down to your driving skills.

    Zed-zed Top,indeed.
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  10. #19
    CelicaSupra.com Member ddd228's Avatar
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    The least expensive way is to adjust the BIAS of braking pressure.
    The issue is that the MK II system locks the front B-4 the rears. That is where the most weight is.
    An adjustable pressure regulator is the way to go,guys.
    ABS,my ass!

    So go with a $1,000 system? 20 hours of a retrofit? No.
    You are way thinking beyond the realm of practicality,here.

    Do all of our MK II's do the front bias lock up? Yes.
    Stock,I'll remind you.
    TYres may make up for some of the issues.

    The nose dive,during the HARD braking,will (As the engineers designed) cause more pressure towards the front brake system!

    Looks like the engineers were not quite so spot on,as we would like to think.
    Please think about the problem a little more. The front/rear brake pressure bias was not calculated to be neutral,IMO.

    Based on stock ride height,tires and as manufactured systems, this cannot be the safest braking system.
    We can do better to make our cars a lot safer.

    The upgrades to our components have made our cars better and safer.
    Engines,suspension and brakes.
    We can TUNE all of these systems to make a better and safer car that is fun to drive.
    What is wrong with safer and faster and better?

    Nothing.
    We have been doing improvements to our car for 2 decades.
    Let us continue.
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  11. #20
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    I'm not so sure about that, Dave. Toyota's engineers have long proven themselves very capable at car design. I'd be very hesitant to mess with the brake bias in a stock system, especially as everything else is stock. I trust that the engineers who designed it had it set up for optimum performance.

    In all cases, as you say, you want the brake bias towards the front wheels. Hence why the front discs are much bigger and have larger callipers than the rears. The weight transfer to the front is advantageous as it presses the wheels harder to the road (same reason RWD gets better performance on a drag start), and the 'node dive' from the weight of the 5M isn't exactly a bad thing. The brakes were performing as designed, it's the tyres that lost grip first. What I'm looking at here is a combination of factors, although I will accept that I wasn't going significantly fast, which should be one of those factors.

    At this stage, knowing the age of the rubber on the wheels, I'm having to accept that maybe I do need to do something about Dragon's tyres. I want to keep the stock look though.

    ABS does still have its advantages, so I'd still like to pursue it to see how practical it is.
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