speedyxjs
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| posted on 28/9/07 at 05:59 PM |
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Traction control
Need some info on traction control. Where to get it from, how easy to fit (im guessing not so  )
Two reasons really. Firstly im planning on putting a 4 litre supercharged engine in the locost after sva and also i was driving through jevington this
afternoon in the rain and the rear wheels kept spinning every time i tried to use more power
[Edited on 28-9-07 by speedyxjs]
How long can i resist the temptation to drop a V8 in?
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smart51
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| posted on 28/9/07 at 06:06 PM |
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There are 2 types of traction control. The first is simply a function of the ABS that puts on one or other of the driven wheels' brakes to act
a bit like an LSD. The other is a system that instructs the engine management to turn the power down, usually the ABS.
You need the ABS / ASR system from a RWD car to do it. The problem is that the tuning will most likely be wrong as your car will be dynamically
different to the donor. You may find the system cuts in too early or too late or may cope with cornering in an unpleasant way. I wouldn't
recommend fitting such a system.
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nitram38
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| posted on 28/9/07 at 06:11 PM |
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You will need wheel speed sensors, a brain and some form of engine cut.
This will be off the scale cost wise for an amateur builder.
You can buy a cheaper launch control device/rev limiter (microdynamics) meant for racing starts to stop excessive wheel spin, by limiting the revs.
You can use a clutch switch or push button to set your revs before pulling away. I have one fitted to the F1-2.
Not much use on the road though as you will soon get fed up with using it.
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martyn_16v
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| posted on 28/9/07 at 06:33 PM |
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If you happened to be using Megasquirt to run the engine it does have a traction control feature, either by a simple 'if the engine is revving
up too fast you're spinning wheels' method or using wheel speed sensors. It is however one of those features that's a bit
'experimental', not that many people use it so you'd be working things out as you go along. Not for the faint of heart 
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NeilP
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| posted on 28/9/07 at 06:46 PM |
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IIRC the Z Car boys did a twin bike engined jobby that had independently driven front and rear wheels and therefore needed all kinds of jazz to keep
it out of the ditches. I recall that it was based on an Omex system and that came as standard with traction control (i.e. they just took it to the
limits of inputs/program.)
Twern't cheep - Bet you'd find more posts on the subject on Pistonheads
If you pay peanuts...
Mentale, yar? Yar, mentale!
Drive it like you stole it!
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britishtrident
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| posted on 28/9/07 at 07:42 PM |
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There is a National Semiconductor chip designed specially for this, it takes the signals from the ABS sensors compares them and sends output pin high
if the signals differ by too big a margin. Really simple to use.
Can't remember the number, Maplin used to sell it.
Looked it up LM2907 or LM2917
Data sheet is here http://www.national.com/ds.cgi/LM/LM2907.pdf
[Edited on 28/9/07 by britishtrident]
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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Simon
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| posted on 28/9/07 at 08:06 PM |
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Don't bother - got it on my ZT260, and turn it off every time I get in the car.
Cuts the engine too quickly and can make for a very uncomfortable ride. More care with right foot is the ideal way to control spin!
ATB
Simon
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caber
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| posted on 28/9/07 at 08:45 PM |
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Traction Control = graduated control of right foot!
Put a heavier throttle spring or accellerator pedal spring on and/or change the leverage ratio between pedal movement and throttle cable movement.
Human brains work much better and have many more feedback sensors than any computer!
Caber
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chockymonster
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| posted on 28/9/07 at 09:06 PM |
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Racelogic make a very intelligent Traction control system. It can be fitted to cars with no ABS.
PLEASE NOTE - Responses on Forum Threads may contain Sarcasm and may not be suitable for the hard of Thinking.
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Liam
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| posted on 28/9/07 at 10:00 PM |
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quote:
Originally posted by britishtrident
There is a National Semiconductor chip designed specially for this, it takes the signals from the ABS sensors compares them and sends output pin high
if the signals differ by too big a margin. Really simple to use.
Can't remember the number, Maplin used to sell it.
Looked it up LM2907 or LM2917
Data sheet is here http://www.national.com/ds.cgi/LM/LM2907.pdf
[Edited on 28/9/07 by britishtrident]
It's all very well detecting the wheelspin, and very easy to do in a basic way as you point out, but it's the sophistication of what you
do next that really matters. The traction control on my Omega both brakes the rear wheels independantly and restricts the engine (by cutting sparks),
so you'd think it would be OK. In practice however it's terrible! I never really notice the braking of the rear wheels, just the engine
totally dying for close to a second at any hint of wheelspin. If i'm a bit heavy on the gas leaving a junction, the engine will die leaving me
effectively stranded for what could be a dangerous amount of time if I was the kind of driver who took risks at junctions! It's better off
turned off to be honest. In fact in last winter's snow i only got out of my steep drive by turning it off! TC basically wouldnt let me use the
engine! It's only any use for keeping in shape what might otherwise have been a slightly surprising, but probably controllable shimmy of the
rear end when i'm a bit careless on a wet roundabout for example.
Contrast that to what's fitted to my mates current VW golf diesel which even with a boy racer max rev clutch-dump from a standstill manages to
impressively keep the front tyres on the limit of grip without killing the engine and bogging it down. My Omega traction control would be horrible
for any kind of spirited driving - it's just way too intrusive. Fitted to a locost it'd be horrible!
So basically i'm saying a high level of sophistication is required to produce a TC system anything better than a complete waste of time.
It's really only current production car systems and i guess the expensive performance/motorsport aftermarket kits like the racelogic one
mentioned that are worth bothering with to be honest. Anything from an older production car or a diy effort would be to barbaric to bother with
imho.
Liam
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bimbleuk
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| posted on 29/9/07 at 05:54 AM |
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*** Correction to the Racelogic reference below it was a system GEMS wrote for use on WRC cars and GEMS make the OMEX ECU***
I've got an OMEX with traction control and I believe it was licensed from Racelogic. So its actually quite a sophisticated system and needs
programming properly. So far we've played with it on the rollers (by spraying water to break traction) but haven't got round to doing
proper road testing. Anyway I have a dial to set the amount of traction control applied similar to the Lotus 2-Eleven reviewed by Plato recently
(Google for the vid).
As above the ECU can simply work from engine acceleration or with wheel speed sensors as well.
Oh and its also got launch control and full throttle shifting just like the Racelogic box which retails for over £600 alone!
[Edited on 29/9/07 by bimbleuk]
[Edited on 4/10/07 by bimbleuk]
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ceebmoj
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| posted on 29/9/07 at 08:01 AM |
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Hi all,
As discussed there are several ways of implementing traction control and assuming the car is 2wd. You are looking at the difference in speed of the
two wheels on the driven axle. The difference in speed between the driven and undriven wheels. The maximum rate of acceleration in any gear.
You are then essentially just balancing the parameters the mathematical sophistication with witch you balance the parameters and how aggressive you
restrict power will greatly affect your drivability and road manners of the car. You may also whish co consider allowing a certain amount of wheal
spin(adjustable from the dash)
If you can program or are good with electronics or programming building a good traction control system is not out of reach
Blake
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zilspeed
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| posted on 29/9/07 at 11:46 AM |
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Fly by wire throttle would make it much more do-able in a smooth and progressive fashion.
Modulating throttle has to be better than spark killing.
That will be why the VW TDI system works so smoothly.
As far back as 1994 they have had an electronic 'throttle' and obviously there's no spark to kill.
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nitram38
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| posted on 29/9/07 at 09:31 PM |
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I have looked at the racelogic system but for a non abs car it costs about £750 + vat if you include the wheel sensors.
It is about £535 for just the brain and adjustable version.
I think £250 for 4 wheel sensors is a bit ott. I am sure that maplins will supply a hall sensor that will do the same job for a lot less.
What I do like is the adjustable version which you can change percentages from your dash e.g, 0% (off) 5%, 10%, 20% etc. with a dry or wet setting
and launch control.
Looks like it could be useful on wet roads?
They do have a dealer option so a posible group buy?
Racelogic Traction Control Here
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ceebmoj
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| posted on 1/10/07 at 07:47 PM |
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quote:
Originally posted by zilspeed
Fly by wire throttle would make it much more do-able in a smooth and progressive fashion.
Modulating throttle has to be better than spark killing.
That will be why the VW TDI system works so smoothly.
As far back as 1994 they have had an electronic 'throttle' and obviously there's no spark to kill.
Desle systems are compleatly difrent as you can controle the injection point to modulate engine powere. you can do the same with a petrol engin
however you need to be more cerfule because of temps. howevere you can restrice throttle opening speed and also ues histareaces to smooth throttle
input.
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martyn_16v
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| posted on 1/10/07 at 08:33 PM |
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I would be very very very wary of doing any kind of throttle control, unless you really know what you're doing (in which case you probably
wouldn't have been asking this question). OEM systems use several layers of redundancy to ensure things don't fail in a dangerous state...
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