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4 Channel Abs Anyone?


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#1 Custard

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Posted 24 March 2022 - 06:54 PM

So yesterday I had my first experience of the dreaded ICE mode.  Driving down a very steep and bumpy country lane and approaching it's junction with a major A road.  Car decided that it just wanted to go straight on at the junction and we ended up in the middle of the A road.  Thankfully no traffic on the A road but it could have been bad.  Took me completely by surprise.

 

Understandably, I am not keen to have that happen again as next time we might not be so lucky.  I am aware that I can easily disable the ABS be fitting a simple switch, but I think I would rather fit a 4 channel ABS unit if possible.  Wondering what exactly is the module that is required?  Is it the Lotus Exige one?  If so, is there a part number?

 

Does anyone know the best place to source one, either new or second hand?



#2 aquilaproejct

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Posted 24 March 2022 - 08:00 PM

Plenty of threads on here with the part number.
Basically you are looking for an S2 Exige or Elise with ABS with the matching part number found underneath the electronics. (Check threads for part numbers) Hydraulic block is not required. Only 2 channel Lotus was the Europa. If you get it new it needs to be activated in a car by someone with the Lotus programming tool (not a Vauxhall tool)

While the ABS is improved (cycle rate goes up and hard pedal improves) it's still not like a modern ABS system. Just a real good step in the right direction. 😁

#3 chris_uk

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Posted 24 March 2022 - 09:19 PM

i have a 4chan abs module on the car im breaking.. 

 



#4 Lee37vernon

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Posted 24 March 2022 - 09:20 PM

S108196012

That's what your looking for

#5 Strugs

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Posted 24 March 2022 - 09:52 PM

4 channel is much better than 2, but can still be caught out by bumps..

#6 Custard

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Posted 24 March 2022 - 10:14 PM

i have a 4chan abs module on the car im breaking.. 

 

Hi Chris, have sent a PM.


Edited by Custard, 24 March 2022 - 10:16 PM.


#7 Paulus H

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Posted 30 March 2022 - 02:03 PM

these are freaking transformative to the car.



#8 number-1

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Posted 30 March 2022 - 03:21 PM

these are freaking transformative to the car.

 

In simple terms.....how does this work? Is it just a different map on the ABS ecu? Or does the entire ABS ECU and hydraulics get replaced?

 

Ive had the ice mode a couple of times when the OEM ABS is turned on but In fairness, on track, with the ABS off its been pretty good but im thinking of a few euro trips so would rather have the ABS on for the wet days

 

N1
 



#9 Ivor

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Posted 30 March 2022 - 04:51 PM


these are freaking transformative to the car.


In simple terms.....how does this work? Is it just a different map on the ABS ecu? Or does the entire ABS ECU and hydraulics get replaced?

Ive had the ice mode a couple of times when the OEM ABS is turned on but In fairness, on track, with the ABS off its been pretty good but im thinking of a few euro trips so would rather have the ABS on for the wet days

N1
New abs unit as far as I'm aware

#10 blackoctagon

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Posted 30 March 2022 - 05:24 PM

number-1,
The part you need is just the controller on the top.
The hydraulic block/pump unit stays where it is, so you are not breaking into the hydraulic system, although i'd pop in fresh fluid if it's been a few years since your last change - it never hurts and it's an hours work tools-out to tools-in at most, and £20 or thereabouts. You can bleed the front brakes with the wheels on.

You remove the control unit by undoing the harness plug, removing the screws you can see on the top, lifting the controller off as vertically as you can (straight up).
You put the new one on by lowering it as vertically as you can where the old one came off, refitting the screws and plugging the harness back in.
I can't offer you photos, as I took none, but it really is that simple.

In terms of operation the differences, as far as i can tell, are that it is actively managing the rear wheels lockup/release in the same way it does the fronts.
The OEM one works as a two channel on the fronts only, and only has some rudimentary pressure limiting to the rear wheels, much as you would have had on an older non-ABS car when they had pressure limiting valves on the rear axle to prevent rear wheel lock ups in conditions where the car was braking heavily.

I noticed a big change when I changed to my new tyres - the 2ch was twitchy whereas the 4ch just feels strong and needs aggression or stupidity to provoke.

Edited by blackoctagon, 30 March 2022 - 05:26 PM.


#11 RC220

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Posted 06 April 2022 - 08:42 AM

Hi Chris,

 

do you still have that 4 channel ABS module by any chance?

 

Kind regards

 

Roy



#12 chris_uk

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Posted 07 April 2022 - 10:15 PM

Hi Chris,

 

do you still have that 4 channel ABS module by any chance?

 

Kind regards

 

Roy

 

Hi roy, im afraid its gone mate



#13 RC220

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Posted 08 April 2022 - 03:08 PM

Thanks Chris,

 

I should have been quicker out of the blocks!

 

Kind regards

Roy



#14 TheRealVXed

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Posted 13 April 2022 - 06:14 AM

Just fit a switch to turn off the ABS. This also works in the wet as well as the dry, and makes the braking much better.  It is also the cost of a £1 switch off amazon and 10 minutes of work.  And not even ABS will save you on ice anyway  :jump:



#15 Ivor

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Posted 13 April 2022 - 06:20 AM

Just fit a switch to turn off the ABS. This also works in the wet as well as the dry, and makes the braking much better. It is also the cost of a £1 switch off amazon and 10 minutes of work. And not even ABS will save you on ice anyway :jump:

My replacement light switch panel has a spare switch for that very purpose

#16 RC220

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Posted 13 April 2022 - 09:49 PM

I am just going to disconnect 3 of the sensors at the wheels after the MOT.  Speaking of which, 24 August is the earliest I can get as it has been sorn'd for a while - but I am on the cancellation list.  In NI we have to go to official MOT test centres and they are booked up for months after being closed for ages due to covid.  I still need to get new tyres and fix the bleed problem with the brakes as I can't get these working properly, oh and a geo set up.  But, at least it is on its wheels and running and moving now and with loads of new parts.  Just needs fettling ... 



#17 number-1

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Posted 14 April 2022 - 03:40 PM

number-1,
The part you need is just the controller on the top.
The hydraulic block/pump unit stays where it is, so you are not breaking into the hydraulic system, although i'd pop in fresh fluid if it's been a few years since your last change - it never hurts and it's an hours work tools-out to tools-in at most, and £20 or thereabouts. You can bleed the front brakes with the wheels on.

You remove the control unit by undoing the harness plug, removing the screws you can see on the top, lifting the controller off as vertically as you can (straight up).
You put the new one on by lowering it as vertically as you can where the old one came off, refitting the screws and plugging the harness back in.
I can't offer you photos, as I took none, but it really is that simple.

In terms of operation the differences, as far as i can tell, are that it is actively managing the rear wheels lockup/release in the same way it does the fronts.
The OEM one works as a two channel on the fronts only, and only has some rudimentary pressure limiting to the rear wheels, much as you would have had on an older non-ABS car when they had pressure limiting valves on the rear axle to prevent rear wheel lock ups in conditions where the car was braking heavily.

I noticed a big change when I changed to my new tyres - the 2ch was twitchy whereas the 4ch just feels strong and needs aggression or stupidity to provoke.

 

Thanks for the detailed reply mate. It sounds a simple swap.The hard part is finding one i guess?

 

Does anyone know if this upgrade still works with the Race TCS fitted?
 



#18 Lee37vernon

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Posted 14 April 2022 - 10:54 PM

Makes no difference to the race tcs

#19 TheRealVXed

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Posted 27 April 2022 - 08:01 AM

I am just going to disconnect 3 of the sensors at the wheels after the MOT.  Speaking of which, 24 August is the earliest I can get as it has been sorn'd for a while - but I am on the cancellation list.  In NI we have to go to official MOT test centres and they are booked up for months after being closed for ages due to covid.  I still need to get new tyres and fix the bleed problem with the brakes as I can't get these working properly, oh and a geo set up.  But, at least it is on its wheels and running and moving now and with loads of new parts.  Just needs fettling ... 

 

On the bleeding, I had to get Hofmanns to do it 3 times before they were right following the ABS unit going dry during a caliper upgrade.  Still looking for a solution to remove the ABS unit altogether...



#20 blackoctagon

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Posted 28 April 2022 - 09:50 PM

On the topic of removing the ABS;
I once had an Audi S3 (1st gen) that had a disturbingly soft brake pedal and after a long campaign of remove and replace/rebuild for literally every part of the braking system I was down to the ABS unit. Those ATE/Teves MK20 units essentially went bad after a few years and had fluid bypassing issues so your brake pedal pressure was getting taken up like a sponge before putting pressure to the calipers. A new unit was a £800 proposition and most were new old stock so I was not keen just to splurge without testing.

What I did was to get an aluminium block and drill passages into it.
I put in two 'master passages' and tapped them for the two feeds from the master cylinder. Into those passages I tapped two more holes (front left + right rear and front right + left rear, respectively) and that served as a split circuit.
That then allowed me to test the theory of the bad ABS unit by seeing what a 'direct' brake would feel like.
The downside was that the pressure to the rears was not limited and the rears locked really easily. This did not trouble me as it was just a test of my sanity vs. the ABS unit, but to make it usable I would have added pressure limiting valves to the rear brake lines - in my case there was probably a Audi/VW/Skoda valve available from a lower model (ABS was still an option in a lot of the cars from that period).

For your VX i'm not sure how you would do it for the rears - normally the movement of the trailing arm/5th link arrangement in a regular car and a little linkage actuate such a valve. There may be pressure limiting valves you can buy and then adjust, so you could go and do some testing on a private road and set it up to your tastes.
The only other option I could see would be a heavily imbalanced brake set up - 4 pot fronts on big discs on sticky pads and standard at the rear, or something like that.
I can't commend either, though.

After that it would be a dual master cylinder system and dial in your pedal bias, like a race car. I'm sure someone will have done that. If not on a VX then on Lotus.



I did get a secondhand low mileage TT 4wd unit for £65 and it was better but not great. I bought a few and chopped them up but never found a viable rebuild solution and I see the Audi/VW community still struggles with this issue.
They sold replacement valve blocks for the later MK70 Teves unit at a fair price, but I don't think anyone has put a MK70 in to any of those cars (delighted to be found wrong though).

Those of you who know that VAG cars generation, especially the 4wd models, know removing the ABS will light up the dash like a Texas bubblegum machine so no ABS was never a solution, plus the ESP and 4wd needed all sorts of feedback from the wider system so you'd lose valuable functionality.




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