carlos_hiraoka

Andy, can the stock 6 (IIRC) position rotary subaru selector (the one that comes with every car that has being fit with one of this electronic diff's) be used instead of the 5 position rotary selector you are placing on th dasboard (this is to comply with Group N rally rules) ?????
and also in the standard version how exactly does the "active" mode work ?????

Carlos H.

[Edited by carlos_hiraoka - 8/1/2002 2:57:34 PM]

johnfelstead

I will if i manage to get it on the car. I havent had a reply yet.

[Edited by johnfelstead - 8/2/2002 3:10:50 PM]

carlos_hiraoka

LOL

Carlos H.

[Edited by carlos_hiraoka - 8/3/2002 3:23:43 PM]

TONKA MAN

edited by JF to keep this to topical discusion only.

[Edited by johnfelstead - 8/18/2002 3:44:55 PM]

Adam M

just spoken to stuart at townend about this at length.

Bloody nice bloke have to say.

Right this will be mostly for us manual centre diff people, but basically they have two diff options!


the first is an atb type centre diff that seems to be popular in northern ireland, obvioulsy this can be retrofitted to any car!
It comes with uprated straight cut droplinks so can make your car a little whiny! It is rated to very very high torque though.

the second is a fully programmable and mappable control for the centre diff.

It takes inputs from things such as boost, throttle position, brake and handbrake. It then operates on these inputs and decides on the best position for the centre diff (it has no input from steering angle of any kind).

The centre diff ranges from fully open to fully locked and comes with a four position switch 4th being fully locked and first being the standard non removable map that they have developed and supplied the car with. The other two are self programmable and mappable via a lap top, I am guessing via an rs232?? supplied.

The system is bypassed by the using the handbrake as with the normal set up.

All I can say is stuart was very excited about this, they have an engineer previously from pectel who has coded the electronics. He has tested this on rallies, and has managed to improve by 2 secs a mile which is worth enormous development time and cost (think this time was recorded over a gravel stage).

It comes in the form of a separate ecu one third the size of a jecs which is supplied with a few feet of braided wiring with instructions to link into the correct loom wiring.

btw, the brake input is a digital input from the brake pedal, and therefore does not need a retro fitted potentimeter.

Stuart is currently unsure how happy the hydraulic centre diff wil be about this constant changing, but as of yet there have been no problems.

I am guessing it is a similar set up to the lancer evo 7s adjustable centre diff for tarmac gravel and snow.

I am tempted to try it and have been told supply and fitting is £450. It will be sold cheaper for self installation.

Sorry to anyone if I have made any mistakes, thi sis just what I can recall from the conversation. I didnt write things down, so may well have missed/fabricated something subconsciously.

TEG Sport

Hi All.
Nice to see some 'Active' (excuse the pun) interest in these units.

I'll just clear a few things up, as I am the one that's designed this unit with Townend Garage.

> Right this will be mostly for us manual centre diff people

This is not quite right. The unit has been designed so that it does not need the original Subaru Centre Diff Control ECU or wiring. It can link into this if your car has it fitted i.e. STi & STi RA models. If you don't have an electronic centre diff i.e. UK model or basic WRX - then all you need to do is acquire the actual electronic diff unit that fits in the rear of the gearbox, and the unit we have designed will connect straight into this without needing to spend about £500 on the original Subaru controller.

As for the new ecu itself - heres how it does it's stuff:-

The unit liks into the engine ECU to collect data on what the engine is doing. It also connects to the original brake pedal switch, and the original handbrake switch.

It comes in two versions - Standard & Pro.

The Standard version has only two modes - 'Active' or 'Manual' and is selected by a toggle switch we fit on your dashbord.

The Pro version has a 5 position rotary selector (like your fan speed switch) which lets you change between 3 differant settings as well as Fully Unlocked or Fully Locked.

The unit uses the data it collects from the engine ECU to find a position on a 3D Lookup table. This table tells it what percentage of lock you want applying to the diff. This is overridden by the unit seeing either the footbrake or the handbrake being applied. Then the unit access another set of tables to determine what the 'Under Braking' percentages are. If you want, there are also options to allow for 'Left Foot Braking' if you're into this - as the control algorithm is different.

The unit connects to a laptop via the standard RS232 serial port. The supplied software, allows you see what is going on as well as checking that everything is working correctly. You then 'Map' the unit by changing the valus in the tables, as well as some 'Option' seeings that tell the unit what type of engine ECU and control stratergy you want. You can load and save your maps onto disc, so you can try different calibrations without any hassle.

Costs are as follows :-

Standard Version : £450+VAT (includes installation and mapping)

Pro Version : £495+VAT (includes installation and mapping)

If you have any more questions, let me know on this thread.

Andy - TEG Sport

David_Wallis

Which ecus is it compatable with? also as mentioned above is it available as a diy fit, and how much discount do you get if so?

Also what sort of warranty is there?

David

Adam M

sorry, I was implying that those who already have the diff hardware in place might be more interested, not just the standard diff control.

a few questions.

1. did you think of rigging up a steering angle sensor?

2. can you rig up a proportional braking set up?



[Edited by Adam M - 7/22/2002 4:15:57 PM]

Dave R

Can I use this with a Link ECU on a V5 Type R?

IE Will the controller be compatable with the Link rather than the Std ECU?

Cheers
Daver

Adam M

can answer this from what stuart said.

ecu makes no diff.

unit comes with its own ecu and taps into the loom.

Dave R

'The unit liks into the engine ECU to collect data on what the engine is doing.'

'The unit uses the data it collects from the engine ECU to find a position on a 3D Lookup table.'

If it needs to collect info. from the ECU then surely it will depend on which ECU you have?

Daver

Adam M

it taps into the info going from the sensors to the ecu by bridging into the wiring loom I think.

Hence doesnt matter what the ecu does with the info as the diff ecu still gets it!

Dave R

Great!! I'm up for one...

Deep Singh

This sounds really exciting.I presume this can be done on the STi7 aswell.

ian/555

Would this unit make the centre diff compatible with ABS brakes?

cheers ian

ChristianR

iTrader: (1)

seems good - what would be the extra benefits?

cwal1

Sorry to hijack this thread but does anyone have a location, contact number and or URL for Townend Garage. Woould anyone recommend them for an STI engine rebuild ?

Chris.

AndrewC

They are in Warton (nr Lancaster),

Telephone: 01524 733837.

Andrew...

Adam M

Ian555,

I dont think it would have any bearing on compatibility with ABS brakes .

David_Wallis

I was under the impression that you couldnt have an adjustable centre diff and abs?

David

Adam M

you cant, thats the point.

TEG Sport

Hi All,

I'll try and answer the questions above.

Engine ECU compatability :
Should be OK with any. We've tried it with the standard JECS unit, Motec, GEMS & Link - They all work fine. If you've got a different ECU, let me know what it is, and we'll try and get one tested.

DIY fit discount :
We will knock £50 off the price if you want to fit it yourself. You will need a laptop. The software runs under Microsoft Windows. We've tried it on 95, 98, 98SE, ME & 2000. It should work on NT & XP as well, but hasn't yet been tried.
You will also need to be able to wire the unit into the various points on the car. We supply a diagram that shows how to do this, put it is NOT Plug 'N' Play i.e. it does involve cutting into some existing cables etc.
We accept no liability for any damage or problems you cause on your car by fitting it yourself, nor will we replace the unit FOC if you blow it up by wiring it up wrong etc !!
My advice would be to let us do it. It doesn't take us long as we've done them before, and you'll leave knowing that it's fitted correctly - but the choice is yours.

Warranty :
The unit comes with a full 12 month warranty. But as I said above, if you fit it yourself, we will charge to repair/replace the unit if you damage it by incorrect installation.

Steering Angle Sensor :
We did think about this, and do some testing with it. The idea for the unit came from the work we do with our rally cars, and so because with a rally car on gravel you quite often have the car pointing one way, and the steering pointing another, it was getting VERY complicated to work out what you wanted the diff to do. So we shelved the idea. However, as it has worked out that the unit works very well on road cars as well, it is back on the development list - as is 'Launch Mode'!!

Proportional Braking Setup :
As with the Steering Angle idea, this has been thought of and tried - and it does work well. But it complicates the installation of the unit as you have to fabricate some way of sensing how much pressure you are placing on the brakes. On the test car, we used a pressure sensor in the brake lines - but the sensor alone cost more than everything else put together !! We are looking at having something made that mounts on the pedal assembly (some form of rotary potentiometer) but that is also on the development list.

Adam M is right about how the unit collects data from the engine ECU. It reads some of the sensors that the engine ECU uses and also listens to some of the outputs from the ECU. As long as whatever engine ECU you are using still retains these sensors & outputs, then all should be well!

Can this be done on the STi7? :
Yes. But - We've not yet had one up here to try it on, so we can't tell you how to wire it in. (Subaru seem to like changing all the wiring around every year!) So as a one off - the first person to bring an STi7 in for a unit, will get a very special deal on the cost of the unit!

Would this make the unit work with ABS ? :
We've not tried tried it on a car with ABS. Do you think it wouldn't be compatible? If someone can let me know what the problem is, (if there is one) we will have a look at it.

Details for Townend Garage :
www.townendgarage.co.uk

Any more questions - post them here !


Thanks

Andy

Dave R

BUT, as Adam is thinking, if when you go for the brake, the diff instantly unlocks then ABS would be free to do it's job without the locked centre trying to limit brake force distribution etc...

Bit of an **** to fit to a Type R/RA, but might be an option to other way if one would bolt the R/RA centre into an ABS fitted car... (flame suit zipped)

Daver

ian/555

Would it not be possible to use the wheel lock sensors that the ABS system already uses, to also tell the diff ecu to open the diff, like when you pull the handbrake.

As long as you are not doing this to a car with the larger 2 pot rear brakes, would it not work? Or am I missing some very important issue with ABS and lockable diffs. It must be possible as they can do this on the EVO which has ABS?

cheers ian

TEG Sport

Hi All,

ABS issue :
I still don't see a problem with ABS & adjustable centre diff yet. The normal type of maps we run in the new controller, put about 60% lock onto the centre diff under braking (handbrake is 0%). But this is adjustable, so we can make it go to 0% i.e. completely free. We find that on gravel, this isn't what you want as it makes the back end go light - but it might be OK on tarmac.

Who is it that says you can't have ABS and adjustable centre diff? has anyone tried it ?

Andy

Adam M

andy,

I dont know the mechanical reason that you cant, but for some reason, no cars which came with adjustable centre diffs have abs.

they are mutually exclusive on production subarus.

I had never conisdered why you cant retro fit the adjustable diff to a car with abs. I dont know anyone who has done this. Pat has fitted one, but he disabled his abs long ago.

I was led to believe that the wiring loom of the car is such that both cannot be fitted at the same time, rather than the abs in use would damage the diff.

To my knowledge the abs on our cars is not wheel dependent. The sensing means was three channel but became 4 channel on the later cars, but the anti lock means will surely apply to the complete braking system.
I still dont see why this is a problem as the diff is not damaged by anything you do with the brake pedal on a non abs equipped car, and all the abs does is oscillate the braking pressure you apply if it senses the wheels locked up.

I would love to be able to retrofit abs to the 22B, but am not even sure that the hbs can accomodate the hall sensors it uses.

To my knowledge the 22B rear hubs are lifted straight off the SVX which does support abs, but I am not sure about the front. they may be just standard. I woudl still ahve thought that retrofitting it is a nightmare.
Consider though that the P1 was an sti 5 type r, and that in order to supply it with abs, which was a necessity, they had to refit the non manual centre diff.


on another note andy,

is this going to be a work in progress? as I might consider buying it in the future, even for more money if a brake input and or steering input is included.


stuart was quoting improvements of 2 secs per mile on gravel. i was wondering if you have any similar empirical data for road use as my car will only ever be used on tarmac.

TEG Sport

Adam,

We've all had abit of a think about this ABS thing down here, and we can't come up with any technical reason why it won't work. That's not saying that there isn't one - just that we can't see what it could be. Most of the units we've fitted have gone on rally cars - which of course don't have ABS. The road cars we've fitted it to haven't had ABS on - but we have got a car in with ABS on it thats due for conversion to a Gp.A rally car, so if we've got time we'll try it on before we strip the car.

Development : Yes this is an ongoing project, but the next version won't be out for a while yet. We've just got too much other stuff on - like our own engine ECU which is way behind schedule! Any one with an earlier version will not have to pay the full price for the latest unit (as long as we get the original one back).

If your thinking about the idea of having one, give stuart a call and see if you can arrange a go with the demo car. It's got the 'Pro' version fitted, and so far everyone that has tried it, has come back smiling !!

Andy

Dave R

Group buy?

johnfelstead

very interesting, do you use the speed input and have the map capable of changing the torque split based on speed (and therefore gear selected)? This should allow you to map the split to progresively move to a RWD bias as you work through the gears, as at high speed you want a very RWD biased car, in the tight 2nd gear corners you may want more to the front unless you handbrake it then you will want RWD initialy with a progresive move towards more front bias as you come out of the power slide. ideally on hard braking into a slow corner you may want a good front bias then on initial turnin and power aplication a good rear bias to kill understeer followed by the front coming back in again. If it can do all this then i could have quite a lot of fun playing with the mapping and improve the handling and corner speed.

Is the map capable of having a progresive feedback of front torque after the handbrake was used?

I can see the need for one map for wet weather and one for dry too.

[Edited by johnfelstead - 7/27/2002 7:25:15 PM]

carlos_hiraoka

Hope the TEG guys can read this .....

Programable Subaru electronic centre diff's have been around some time now, among some Group N rally teams. This were used last year on one of the "oficial" Subaru Peru rally team Group N WRX. The electronic centre diff really worked nice but a problem was found ..... each time the gearbox oil exceeded a certain temperature the diff unlocked itself. The increase in temperature caused the resistance of the device to increase too, and it proved to be unreliable (remember I am talking about rally use) ..... I have had the chance to look the new centre diffs and this have modified coils and use 14.4v instead of 12v, this prevents them of malfunctioning even at high gearbox oil temperatures.
Therefore my question to the guys at TEG is if they are using a higher voltages or if they know of similar problems, probably for street and enthusiastic driving it may work fine, but for the guys that do a lot of track days and do a little bit more than 3 or 4 laps (or for those going to the Ring) the device needs to be reliable.
On the past weeked a Group N WRX (Spec C) used this centre diff and was almost 1 second faster per km. than a similar Group N WRX that didn't have this centre diff, the conditions were muddy.

Carlos H.