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Discussion in 'A3/S3/Sportback (8P Chassis)' started by SamurAchzar, Apr 6, 2007.
The Quattro A3's do run at different pressure due to the weight in the rear. I think mine are 38, 35
The Audi garage reckon that the tyre pressures of 39 front and 30 rear (as on the inside of the fuel cap) are correct, which leaves the chassis of my S3 flawed on certain roads.
So, if you drive on smooth A roads, or B roads with loads of imperfections, the S3 is a blast to drive. You'll see the DSC light flashing quite a lot on the bumpier roads, but it hangs on in there. There's a fantastic feeling at the apex of fast corners, as the power shifts from the front to the rear. However, I'd advise a lot of caution on corners with big undulations, and don't even think about a series of rises on a roller coaster road if there are any corners on it. But, dull it isn't!
I'm learning to drive round the flaws.....
Do you think this is due in some way to the Haldex system
shuffling the power fore and aft? You know they do make special Haldex controlers now that greatly improve the 4WD. I'll get you a link if you want?
I can't remember which issue of evo it was but John
Barker was comparing the Mk5 Gti to the R32 and said he thought
the Gti had more faithful on-limit handling as well. So someone else
agrees with you- or at least agrees that there are issues to the Mk5 Haldex handling.
Also Autocar compared the S3 to the new Megane 26 and the Megane pretty much trounced it. They said it could put many car lengths between the two on demaning roads.
Think thats a bit over the top. The S3 came second to the Megane after beating about 12 other hot hatches. It also trounced the Megane on the track. Comparing on the road performance is hard as you have two different drivers with two levels of ability.
yes at a soaking roundabout with worn back tyres, or in the snow.
even guys with the haldex controller fitted dont get evo style power slides, so please dont buy one hoping for this, you'll be really dissapointed.
I test drove 2 different S3's on several occasions, including having one for the day...
It is quite easy to get the arse to hang out on the S3 on a dry road and powerslide if that floats your boat. It is also quite easy to f*** it up and understeer towards the verge if you get carried away.
When the rear axle kicks in with the 60/40 R/F split in the haldex, it feels like a rear wheel drive to me, and powerslides quite similarly, with the added benefit that the rear end never tries to over take you.
That isnt how the system works. There is no rear bias on haldex, it doesnt kick in when driving only from a standstill will it be disengaged. And if all four wheels are gripping the most it can transfer aft is 50/50. It will be transfering power aft the whole time the car is moving with more power aft the more you accelerate.
A difference of opinion then mate.
When I say "kick in" it might have been a bad word to use, what I meant is when the haldex is working at max driving the rears to their fullest.
The bumpf for all S's that I have found say that the S's haldex is modified to provide 60/40 in favour of the rears at its limit, having driven it it drives different to the standard quattro on the limit with a distinct rear wheel bias, my mate is an Audi master tech and he confirms this, as does the audi channel including demos of the S quattro set up doing this...etc. etc. etc. but I could still be wrong.
You are thinking of the other "S" cars that use a torsen centre differential. The S3 uses the Haldex AWD system and there is no rear bias on a haldex system its impossible unless the fronts arent gripping. The haldex controller basically conects the rear axle to the front via a clutch pack. With the clucth pack fully closed the front and rear axle are sharing the same power from the engine. With no centre diff as such there is no way to move more power aft and away from the front wheels.
i have also read and heard this, it is troo
are you sure.... how come AMD use to be able to upgrade the haldex to do the 60/40 to the rear then?
The way mechanics work aside, as you clearly have more knowledge of that aspect than me, I believe you are wrong.
Technicalities aside, it's reality with the Haldex 2 on the S's m8.
The Other S cars(S4,S6 and S8) use the torsen based differential setup which can be setup for rear/fwd bias. The 8P S3 uses Generation2 Haldex which cannot have rear bias(unless the fronts have less grip than the rears). It works the same way as the original haldex system but needs less torque difference to transfer power.
You can read about it here if you intersted http://www.haldex-traction.com.
The uprated haldex controller. Makes the haldex unit transfer more power to the rear before the original unit would have. That makes it feel more RWD biased which it is compared to the original car. But it doesnt have more rear bias than the front, the system isnt designed like that and mechanically its not even possible.
I don't doubt you know what you are talking about mate...
However, from what I am told, have seen and have felt with the S3 I cannot believe that it is just being made up by Audi etc.
The R32 also claims to have the same 60/40 rear bias on certain limited snippets that I have read...how can so many sources be wrong?
For instance: http://www.evo.co.uk/carreviews/evocarreviews/203044/audi_s3.html
That magazine article is incorrect. They explain that its haldex and then quote something it does not do(rear bias). You will never see Audi or VW for that matter with their Haldex powered 4-motion cars say they have a rear bias becuase its impossible without the front wheels slipping. It was explained in this thread here that you also posted in and its a good explination of the system.
Torsen provide the centre diff needed on the other Audi Quattro incl. S and RS cars can give a rear bias, you can see their application list here.. There is no S3 in the list because they provide the centre diffs for Audis Quattro cars and the S3 has no centre diff which is needed to move power fwd and aft. The A/S3 just has a clutch pack that connects the rear axle to the front with varying amounts of slip in the clutch packs depending how much power it is transfering.
Dandle is right, when the Haldex is fully engaged the transfer between the axles is 50/50.
But i would disagree with him regarding the power slides because even today i made a few quite easily (off course, the esp must be turned off).
I have examined the thread you linked to (and no I haven't posted in it), which tends to confirm thatmore than 50 percent of the torque can be transmitted to the rear wheels.
The aplication list you link to is irrelevant because we already know that it has a haldex gen 2 not a torsen, so pointless me looking.
Even links on the links you provide suggest that the haldex can transfer torque to the rears giving it a rear bias, therefore the chances of the car being able to have a 60/40 rear to front split when necessary seem pretty good.
Articles in Evo (as per the link), Auto Car, Top Gear, What Car, several German mags, umpteen websites, the Audi channel, Audi techs, Audi salemen (lol) etc. say the same.
Can you find something that specifically says the S3 is limited to 50/50 anywhere? Unlikely because Haldex themselves state that 100% torque can be applied to any of the four wheels if necessary,so 60/40 would seem easily achievable.
And just to quote a response from Haldex in relation to a question posed on the thread you linked to, querying whether torque could be transfered to the rear when just driving without slippage on the front axle havng occurred:
"During cruising which a constant velocity, we have the possibility to
transfer up to 40-45% of the torque to the rear axle, given nominal tyres.
During acceleration, the weight transfer increase the front tyre slip and
decreases the rear axle slip, giving us the possibility to achieve more or
less the same torque distribution as the dynamic weight distribution.
Generally speaking, depending on the vehicle somewhere around 60-70% is
possible to achieve during a full acceleration. Note that we are still
talking about a uniform surface, with no spin on the front wheels."
I might be reading this wrong but it suggests to me that at least a 60/40 front/rear split is achieveable according to Haldex.
Vice President, Marketing"
If I understand this post correctly, I guess you are saying it is marketing ******?
At the end of the day, the thread dandle points to confirms what I am saying, as do numerous articles, reviews, tech reports and Audi.
It doesn't bother me whether I am right or wrong on the issue, I just want to know, but everything points to the 60/40 rear/front split being an achievable reality.
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[FONT=Times New Roman,Times]Volkswagen-Haldex system[/FONT]
[FONT=Arial,Helvetica][SIZE=-1]Since the late 1998, Volkswagen replaced the viscous-coupling Syncro system with a new system called "4motion". First shown in Audi TT and Golf 4motion, the new system uses a multi-plate clutch center differential developed by a Swedish company, Haldex, and computer software from the Austria 4WD specialist Steyr-Daimler-Puch. At this moment, it is only offered for the transverse-engined Golf IV platform, but there is no technical reason prevents it from applying to Audi's longitudinal-engined models.[/SIZE][/FONT]
[FONT=Arial,Helvetica][SIZE=-1]The Haldex center differential is similar to Porsche 959's PSK system mentioned in the above, it is only smaller, simpler and cheaper thus making mass production feasible. The center differential is mounted near the rear axle and just in front of the rear differential. As shown in the picture below, its clutch consists of 6 discs ....[/SIZE][/FONT]
[FONT=Arial,Helvetica][SIZE=-1]They are immersed in oil bath to reduce friction. Actuation is made by hydraulic pressure. Normally the input and output shafts rotate with a speed difference (could be implemented by different final drive ratio), therefore the discs are rotating relative to each other. When no pressure is applied, the clutch is not engaged thus torque will not be transferred to the rear axle. Increase the pressure on the multiplate clutch, the latter will be partially engaged, thus sending torque to the rear axle. The more the clutch engages, the more torque transfers to the rear axle.[/SIZE][/FONT] [FONT=Arial,Helvetica][SIZE=-1]Computer determines how much torque to be sent to the rear wheels. Normally it is 50:50, but in tight corners when wheels on one of the axles is slipping, the driver can easily feel the torque is transffering from one to another axle. Volkswagen claimed 100% torque could be sent to either axle.[/SIZE][/FONT]
[FONT=Arial,Helvetica][SIZE=-1]Compare with 959's unit, Haldex's unit has 7 fewer discs in the clutch. This makes the Haldex unit more compact and cheaper. The down side is not capable to handle as much torque (959 had 369 lbft, Audi TT has 206 lbft). Besides, 959's discs were organised as 6 pairs of independent clutches, each actuated by individual hydraulic actuator. The Haldex has just one actuator acting on all six discs, again, this saves weight and cost. However, I suspect if it could vary the amount of torque split as precise as independent clutches.[/SIZE][/FONT]
[FONT=Arial,Helvetica][SIZE=-1]Based on the journalists comment about the handling of Audi TT and Golf 4motion, it seems that the 4motion system performs even better than the traditional Torsen-differential Quattro. The age of Torsen Quattro is passing away.[/SIZE][/FONT]
Some other technical info available shows that the clutch clamping effect is controlled by a build up of hydraulic pressure - which, in theory, does not need "wheel-slip" as a prerequisite to be able to send torque rearwards. Thus, the control unit can, at it's own discretion and depending on how it is programmed, decide on what goes where by controlling the fluid flow and clamping characteristics of the clutch pack set-up limited centre. diff.
Technically speaking - a rear wheel drive bias IS possible, although only likely to be more noticeable during heavy driving when the front wheels slip and drive transfer to the rear is greatly increased in a fraction of a second.
That is not a rear bias setup though that is the front wheel slip increasing in relation to the rear. Rear bias as the the RS4 etc is when under normal driving conditions the rear recieves 60% of the power and the front are transfering 40%, haldex cannot achieve this as if the clutch packs are fully locked then the same potential goes to the front and rear, the only time the rear can recieve more power is if the fronts are wasting it. There is no centre diff(as such) to move power backwards or fwds just a clutch pack to engage the rear up to a maximum transfer same as the potential as the front. Dont forget a centre diff recieves the power and moves it to the front or rear axles on a torsen based car. The front wheels on a haldex car are already driving all the haldex unit can do is tap into that power there is no diff at the front to move all the power to the haldex unit.
I don't think I said it wasnt possible to do power slides in and haldex quattro car. Just that it isn't 60/40 rear biased. It can have 100% power to the rear but the fronts wont be grippoing at all I.E on ice.
Dandle, m8, it sounds like you are back pedalling a little, as I believe earlier you were saying that it couldn't transfer more than 50% aft, but now it can (if I read you wrong earlier my apologies).
At the end of the day, I didn't say it was permanent 60/40 f/r, but I said the car could drive with that bias when needed.
Every bit of evidence provided on this thread and threads provided by you support that, whether it be car reviews that have access to technical data, the VP of marketing from Haldex specifically eluding to the fact that under hard acceleration without any wheel slip the haldex may even be good for 70/30 f/r, people who know, net articles etc, Audi...the list goes on.
Perhaps we should just leave it here?
Ok you believe what you want but your car does not have its power biased to rear drive like other S cars. That is what rear bias is, be it 60/40 or 70/30. Your car drives with power mainly going to the front wheels and power in varying degrees going aft. No point in agrueing any more you believe what you want but thats the way it is. The S3 uses a front wheel drive biased system.
Im not back tracking at all I was just correcting you that it isnt a 60/40 rear biased system. The system cannot take power away from the front wheels and give it to the back wheels all it can do is share the power the front wheels have(if the fronts are wasting some power then the rears will be driving more i.e. ice or cornering really hard but its still not a rear biased system) it would need a centre diff (i.e. Torsen) up front to reduce power to the front wheels and send it to the back.
No hard feelings either way I hope but I dont think were getting anywhere here either.
By the way im not slating the system I have it on our A3 and I love it. It really is a great way of powering a 4wd car.
Heavy depreciation in comparison to what???
When looking at buying our A4 I looked at alternatives. I could have had a similarly equipped Vectra for about £3k less but predictions were that it would loose 50% of its value in the 1st year. The A4 on the other hand was predicted to loose 50% of it's value in 3 years. That's as good as it gets on this type of car so not exactly a disaster.
We are just sellling one of my A4 1.9TDI Sports at work. Just coming upto 3 years old and 65,000 miles (a bit high). Nice colour etc etc. £8k, cost £23k when new. The A4 is also being replaced next year. It will soon be down to less than 50%. Our new shape 320d has lost 40% of its value in a year!!! The heavy discounting of BMW is not helping. When I had my S3 underwritten against an A4, the A4 lost a whole heap more.
So to paraphrase all the above posts...
You can now power slide a new haldex series 2 kitted car...
its true Jay, man down the pub said so
Well I guess you can't complain about depreciation when the car has double the average mileage. If it had been a Vectra or Mondea it would be worth peanuts now.
As for the BMW, manufacturer discounting is a PITA and you can't do anything about it.
Yeap! not a permanent AWD drive although most of the time some drive is on the rear wheels because 265hp too much for front ones alone. Definitly not rear biased it is front biased if you can say that...
Very good and effective system though and you can see its benefits when cornering and in the wet. Not a "pro" setup like an Evolution but good all round.
Power slide? hardly possible. You can provoke the rear by braking hard and accelerating and get some slide but there is nothing about "power" on that one...
P.S.: I have an S3 but I try no to have a S3 biased opinion.
Powerslides aren't for this car. Nevertheless it can be provoked to get the tail to slide a little. The haldex system is quite twitchy in the limit, maybe in part because it's not fully mechanical like the torsen, making it even more difficult and dangerous to powerslide. My brother S3 mk1 stepped the rear a few times and it's not easy to regain control, but he handle it well, that G40 he had for a long time was a great teacher.
So its really a S3 vs GTI vs R32...
R32 is nice, a Golf with an Audi interior and decentish handling but its a lot of money for a Golf and the depreciation is horrendous, for a few grand more your looking at Porsche's and its easy to guess which ones going to hold its value. The S3 is amazing, good handling, looks, build quality and the depreciation isnt too bad, one of my neighbours owns one and Ive never wanted someones else car so much in all my life but again its a lot of money and you have to own it for a few years to get back on the original outlay, if 4wd is the major selling point your probably better off going for a decent secondhand Evo or Scooby WRX (which loose money quicker than Robert Maxwell, 12k buys you something that was 25k a couple of years ago) but with these you dont get the German insides or build quality.
As for the GTI, youve driven it quite a lot so no need to tell you about it...
(my GTI will be for sale towards mid June if your interested!!!!)
Well, this seems to have produced a lot of healthy debate....
From my perspective, relating to my original question about the dodgy handling on the limit going around corners with a couple of undulations at the apex, I have taken the Service Manager from my Audi Garage out for a drive, when I was able to demonstrate the problem. He climbed out one hour later, shaken but not stirred. He claims it is a "handling characteristic" of the new S3 - and says the rear dampers are so stiff, that they don't full load up with the first bump, and are then unable to react quickly enough to the rapid move when encountering a second bump a fraction of a second later. The affected rear wheel looses traction and the rear steps out of line. Judging from his colour when he got out of the car it was not a nice controllable power slide, but something far less predictable! He didn't feel it was related to the Haldex system.
I note the comments about power moving to the rear, and certainly on fast smooth bendy roads I can feel the power shifting to the rear much more noticeably than on my old (previous model) S3, which makes it a delight to hustle along quickly and safely. However, there is no comparison to the sensation that I get when I take my M3 (current model) on the same roads and I don't think I would feel that I could confidently or easily provoke a powerslide in the S3 on public roads. For those of you who watch Fifth Gear, Tiff did manage to produce some impressive tail outs on the track at rapid speed, but none of these was really a sustained powerslide. It certainly looked very quick and controllable on a nice smooth track.
Overall, it's much more fun than the old S3, but whereas that car used to bottom, if taken at speed, on the bumpy Yorkshire moor roads that I love so much, this new S3 just can't put the power down without getting out of shape at the same speeds.
I love every other aspect of the car, so I'm thinking of asking Kim Collins at QST about the suspension and a possible upgrade......
Link to new S3 on fifth gear: