Metal Hippy™
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| posted on 9/11/02 at 09:46 PM |
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That's funny, it was my recollection that it was banned at the end of 1993, williams ran it, no one else bothered.
Maybe I'm wrong, but I don't think so.
President of the Non-conformist Locost Builders Club. E-mail for details...
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stephen_gusterson
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| posted on 10/11/02 at 02:01 PM |
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DTM cars had ABS.
(German Toring Cars).
At six pages, is this the longest thread ever?
And just about ABS, which only 3 - 4 builders are doing!
atb
Steve
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Spyderman
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| posted on 10/11/02 at 05:16 PM |
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quote:
Originally posted by stephen_gusterson
At six pages, is this the longest thread ever?
And just about ABS, which only 3 - 4 builders are doing!
atb
Steve
Yes what a waste of space!
You must be running in a lower resolution on your monitor. It's only 2 pages long on mine.
Terry
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Metal Hippy™
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| posted on 10/11/02 at 06:35 PM |
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Depends what settings you've got in your profile page thing.
You can set how many posts on one page.
President of the Non-conformist Locost Builders Club. E-mail for details...
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johnston
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| posted on 10/11/02 at 07:45 PM |
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do i get a prize for startin the longest thread
all i wanted was a yes or no its not worth the hassle
so sorry for startin all this
[Edited on 10/11/02 by johnston]
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stephen_gusterson
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| posted on 10/11/02 at 10:36 PM |
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I will let you know next time I have to brake like crap!
The extra work is basically
1. Stripping out the loom and leccys from donor.
2. Mounting the abs block transversely because its big and long.
3. Modifying hubs from the donor to fit the car. Need to make different wishbones too. This would be similar for anyone not using cortina hubs.
Thats about it really - simple easy to wire and pipe up system.
HOWEVER one thing I have learnt (and my car is a totally non book one!) is that any deviation from the book is gonna cost you time!
I would have finished a std car long ago.
ATB
Steve
[Edited on 10/11/02 by stephen_gusterson]
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johnston
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| posted on 11/11/02 at 11:37 PM |
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ok my plans are so far
volvo 240 est donor
torsion bar front springs
hopefully full body work (inspired by alan b )
so is that clos enough to the book
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P38420
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| posted on 12/11/02 at 09:51 PM |
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I am desiging the electrical circuit on a V6 Locost and when I install it I will put ABS on the car.
It'll be switchable though 
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cymtriks
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| posted on 13/11/02 at 11:56 PM |
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Many small sports car makers do not fit ABS. I've heard that they generally can't afford to develop it for their small volumes. This implies it's
harder than you think. Apparently the systems need to be made to suit not only a cars weight but also its wheel sizes. ABS is generally thought to
make pedal feel slightly worse due to the need for extra bits in the brake system.
Just for interest the trick is not to prevent a wheel from locking up or to keep it rolling. These are popular wrong ideas about ABS. One of the
strange things about rolling contacts (of which I have years of experience in dealing with) is that a certain amount of skid actually increases grip.
So braking is best with a wheel that is partly rolling and partly skidding.
Unfortunately this situation is very unstable and transient so the best compromise is to slam on the brakes thus inducing ever increasing skid and
grip until the tyre lets go and total skidding and wheel locking is imminent and then release the brake and start again.
This is what ABS and cadence braking do. They keep the tyre passing through its maximum grip point, just before it stops partly skidding and breaks
away completely. The skidding and rolling bit is a red herring, it's the grip that counts and you get grip with a mixture of skidding and rolling.
The overall resultant braking force for intermittent maximum force separated by skidding and reapplication of the brakes is equal to the best that
could be acheived by keeping the brakes continuously at the point just below the transient high grip point.
So ABS won't actually stop you any quicker than expert none ABS braking.
It looks like it isn't a goer for the lowcost though.
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Alan B
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| posted on 14/11/02 at 01:39 AM |
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Totally irrelevant but related....I just designed a machine for
assembling ABS sensors.......
Sorry big pic...
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interestedparty
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| posted on 14/11/02 at 02:47 PM |
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I hope that's just a prototype, Alan, 'cos I can spot loads of mistakes, for instance, the squeezing things are back to front, and the hopper where
you put the flour in is too narrow for a half-hundredweight bag to go in and the bit where the operator rests his feet needs to be a bit higher etc
etc
John
As some day it may happen that a victim must be found,
I've got a little list-- I've got a little list
Of society offenders who might well be underground,
And who never would be missed-- who never would be missed!
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Alan B
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| posted on 14/11/02 at 04:00 PM |
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That's funny you say that John, because all custom machines are prototypes really
And yes....a few mistakes....
You may have 1000 design decisions to make....get 990 right and you are doing well.......then hope you can fix the last 10..........
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stephen_gusterson
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| posted on 14/11/02 at 08:14 PM |
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quote:
Originally posted by cymtriks
Many small sports car makers do not fit ABS. I've heard that they generally can't afford to develop it for their small volumes. This implies it's
harder than you think
It looks like it isn't a goer for the lowcost though.
The fact that the granada mk3 had the teves system fitted for years would kinda prove this wrong.
The teves system has just a computer, a valve block and four sensors. The back brakes operate as one circuit. There is no load sensor.
The system has no idea if the car is carrying a six stone midget, or a family of four with a bootfull of suitcases and a caravan on the back.
It merely tries and senses if a wheel is locked, and then releases the brake until it moves again.
It works. Millions of cars, inc the xj-s jaguar, used it.
There are more modern systems, like that fitted on the C class, to pass the Elk test, that add stability control. On these cars the dynamics are more
important and I would expect there to be a plethora of load and position sensors. On a simple ABS system there does not need to be.
As far as pedal feel is concerned, que?????
That would mean, for instance, all BMW, jaguar and mercedes cars have duff feeling brakes. A lot of cars have abs as std now, and I dont think there
are any brake feel issues.
My 318 hardly provides any feedback into the pedal that the system has come on. It feels like a normal brake system.
My xj-s, my Mazda 323 , my wifes megane, and my rover 600 before that all had abs with perfectly normal feeling brakes.
The granada system, however, feels like a ratched vibration into the pedal.
Sports cars tend to be minimalist. Thats possibly whay ABS isnt fitted. Does not the lotus Elise have a alu floor and no carpets?
http://www.ksb.co.uk/ferrari.htm
The link above is an add for a Ferrari 355 with ABS.
You think they would know better, would you not
http://www.bba-reman.com/fordabs.htm
the above link describes the operation of Ford ABS - of which the following is an extract :
The electronic Anti-lock Braking System is made up of a conventional brake system with split
dual-circuits and an ABS actuator. The ABS actuator for all vehicles except Maverick consists
of the following components:
- Hydraulic actuator.
- ABS brake pressure pump.
- ABS module .
The Maverick ABS actuator consists of the following components:
- Hydraulic actuator.
- ABS brake pressure pump.
Four wheel sensors supply the wheel-speed signals required for control. These signals are
compared by the ABS module with physical limiting values stored in the ABS module.
During braking if the wheel speed of one or more of the wheels approaches the locking limit,
the ABS module activates the corresponding ABS solenoid valve. This leads to a drop in
brake pressure in the respective brake cylinder. If the wheel speed now exceeds the locking
limit, the ABS control module switches on the brake pressure. The pressure in the wheel
cylinder assembly is rapidly increased by the ABS brake pressure pump according to the brake
pressure applied by means of the brake pedal. During the pressure build-up phase the ABS
solenoid valves are deactivated. Depending on the condition of the road surface and the length
of time of the braking procedure this procedure can be repeated many times per second, and is
called the ABS control frequency. The maximum control frequency of the ABS system is
approximately 20 Hz.
ABS control is not active at road speeds of less than 5 km/h (3 mph). The '96 Fiesta fitted with
the electronic brake force feature is a new part of the integrated system that limits the slip of the
rear wheels before the anti-lock braking system comes into effect. By comparing the slip of the
front and rear wheels, the system optimizes the brake distribution for maximum driver control
regardless of vehicle loading.Due to the system automatically compensating for all conditions of
vehicle loading, there is no need for a load apportioning valve.
atb
steve
[Edited on 14/11/02 by stephen_gusterson]
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