Sports Diff and Anti Roll Bars

[fast-ferret]

Hey all - I have a B8.5 S4 with sports diff but feel like I'm getting some body roll which I'd like to remove, couple of questions:

1. Do those with sports diff only feel you get much roll?
2. Is it a bad idea getting ARBs in conjunction with the sports diff?

Cheers!

 

[Dippy]

If it helps...
1. None - but mine is an S5
2. Well your car already has one. I understand that the S5 has a slightly better ARB than the S4 (but this is not something I know much about).

 

[RyanJonS4]

I have sports diff and I would say I do get a bit of body roll, but it’s not necessarily a bad thing.

Sports diff equipped cars have the smallest diameter OE bar available. I think a jump up to an upgraded aftermarket bar may be a little too much and could possibly make the rear a little to ‘light’.

There is a slightly bigger bar available which I think came on smaller engined b8’s which would be a decent place to start and can be bought pretty cheap off eBay. I’ve considered doing this but then I’m happy with the little body roll I have so think I’d be messing just for the sake of it!

 

[jdp1962]

Hey all - I have a B8.5 S4 with sports diff but feel like I'm getting some body roll which I'd like to remove, couple of questions:

1. Do those with sports diff only feel you get much roll?
2. Is it a bad idea getting ARBs in conjunction with the sports diff?

Cheers!

I can't see any reason why the Sports diff would impact on body roll.

The S4 already has anti-roll bars front and rear. You can reduce body roll by fitting stronger anti-roll bars, but depending on whether you do front, rear or both, you'll normally see a change in the amount of understeer as well. Whether the Sports Diff can still reduce or eliminate that effect, I don't know.

 

[jdp1962]

@RyanJonS4, you beat me to it.

 

[fast-ferret]

Sorry I said ARB didn’t I - I meant “thicker ARB”, I.e an aftermarket one. The eurocode bars look good - seems that people adjust the back to be stuff and the front softer which reduces the understeer and roll.

I’m tempted to slightly lower it as well actually so it’s probably sensual me to do that first I guess? I have adjustable dampers so I can only use springs to adjust height as far as I know, not sure if this messes with the dampers too much.


Sent from my iPhone using Tapatalk

 

[Cerbera9]

My S4 has DRC and sports diff and I’ve since fitted H&R lowering springs and H&R ARB’s with the front set to soft in conjunction with a CR-15 brace and Michelin Pilot 4S tyres and it’s made a big difference, understeer is eliminated and the turn in is sharper. The handling now inspires so much confidence.

 

[arad85]

Have an S5 with 034 ARB and sports diff. (and CR15). MUCH better steering than before - understeer is (almost) eliminated. Not noticed a change in body roll though.

 

[fast-ferret]

I’m tempted to slightly lower it as well actually so it’s probably sensual me to do that first I guess?

Just noticed this, hilarious

 

[fast-ferret]

My S4 has DRC and sports diff and I’ve since fitted H&R lowering springs and H&R ARB’s with the front set to soft in conjunction with a CR-15 brace and Michelin Pilot 4S tyres and it’s made a big difference, understeer is eliminated and the turn in is sharper. The handling now inspires so much confidence.

Good to hear mind sharing what springs you went for, and do you have a pic of the drop? I don't want it slammed - just nicely lowered. You went for both the H&R ARBs?

How much do you think each mod made, for example I'm not personally sure how much the CR-15 makes on its own (nor the ARBs or lowering for that matter) - curious which mod gave the most benefit.

 

[Neil Wilkinson]

Is it only the S models that have sports diff? I’ve got an A4 S Line special edition (lowered). How would I tell if got sports diff?

 

[fast-ferret]

My S4 has DRC and sports diff and I’ve since fitted H&R lowering springs and H&R ARB’s with the front set to soft in conjunction with a CR-15 brace and Michelin Pilot 4S tyres and it’s made a big difference, understeer is eliminated and the turn in is sharper. The handling now inspires so much confidence.

Also how is the ride quality? It's my daily driver and the wife would give me stern looks if it turned in to a bone shaker

30mm sounds like a decent lowering, which would mean these fit the bill - http://www.europerformance.co.uk/pages/products/product_info.mhtml?product=75013;car=audis4

 

[desertstorm]

Eibach springs will give you a better ride quality than H&R springs. uprated roll bars effectively increase the spring rating on the axle as you are connecting both sides of the suspension together. I bought The H&R roll bars for mine and fitted the front and rear , even with a soft setting on the front hit a drain or pothole and you know about it. In the end I went back to a standard front bar and kept the rear.
The brace on the front makes a good difference, I made my own and it does noticeably tighten up the front end improving turn in.

 

[jdp1962]

Is it only the S models that have sports diff? I’ve got an A4 S Line special edition (lowered). How would I tell if got sports diff?

Sports diff wasn’t standard on any model. It was a expensive, and therefore rare, option.

 

[fast-ferret]

Eibach springs will give you a better ride quality than H&R springs. uprated roll bars effectively increase the spring rating on the axle as you are connecting both sides of the suspension together. I bought The H&R roll bars for mine and fitted the front and rear , even with a soft setting on the front hit a drain or pothole and you know about it. In the end I went back to a standard front bar and kept the rear.
The brace on the front makes a good difference, I made my own and it does noticeably tighten up the front end improving turn in.

Ah ok I’d probably go for Eibachs then. With a drop of something like 20mm or so do you think you would notice much of a negative impact with potholes etc?

Sounds like the brace is a no-brainer. I also saw about making your own - seems easy enough.


Sent from my iPhone using Tapatalk

 

[fast-ferret]

Has anyone used the Eurocode bars by the way? They’re a good price at the moment, would have to get them shipped over but still a fairly good price.


Sent from my iPhone using Tapatalk

 

[martinmanyhats]

Have an S5 with 034 ARB and sports diff. (and CR15). MUCH better steering than before - understeer is (almost) eliminated. Not noticed a change in body roll though.

S4 here, but otherwise same setup as above and same results.

 

[fast-ferret]

S4 here, but otherwise same setup as above and same results.

Good to hear - by the way what do you think to the billlet transmission insert, did it make much difference?

 

[martinmanyhats]

I'd go as far as to saw "astonishing", and in a good way . Almost completely eliminated the transmission movement that turned up following the power/TCU upgrades, at least as far as every day driving is concerned.

 

[fast-ferret]

I'd go as far as to saw "astonishing", and in a good way . Almost completely eliminated the transmission movement that turned up following the power/TCU upgrades, at least as far as every day driving is concerned.

Is yours stronic or manual? Concious I'm hijacking my own thread here

 

[martinmanyhats]

I think you are allowed to hijack your own thread . S tronic - will update my sig.

 

[ianv5]

Ah ok I’d probably go for Eibachs then. With a drop of something like 20mm or so do you think you would notice much of a negative impact with potholes etc?

Sounds like the brace is a no-brainer. I also saw about making your own - seems easy enough.


Sent from my iPhone using Tapatalk

Eibach 30mm lowering springs will only drop the S4 10mm.

 

[ruairi83]

I have a brand new front h&r anti roll bar for sale in classifieds if anyone interested pm.

 

[fast-ferret]

Eibach 30mm lowering springs will only drop the S4 10mm.

So now I’m confused. Isn’t the measurement meant to be the amount the car is lowered by? I feel I’m probably wrong


Sent from my iPhone using Tapatalk

 

[jdp1962]

So now I’m confused. Isn’t the measurement meant to be the amount the car is lowered by? I feel I’m probably wrong


Sent from my iPhone using Tapatalk

Yes, but the starting point is the bog-standard SE A4. The S4 is already 20mm lower then that, which only leaves 10mm further to drop.

 

[Cerbera9]

H&R springs offer three different drops if you check the website for the correct spring part numbers depending on if you select OE sport Spring, Sport Spring or Super Sport spring.
http://www.hrsprings.com/applications

 

[fast-ferret]

Yes, but the starting point is the bog-standard SE A4. The S4 is already 20mm lower then that, which only leaves 10mm further to drop.

Aha gotcha - thanks for clearing that up. To be honest I don’t think it needs dropping much further myself, not sure how much you’d feel 10mm more while cornering or whether it’s mainly aesthetics.


Sent from my iPhone using Tapatalk

 

[unclebob555]

Aha gotcha - thanks for clearing that up. To be honest I don’t think it needs dropping much further myself, not sure how much you’d feel 10mm more while cornering or whether it’s mainly aesthetics.


Sent from my iPhone using Tapatalk

I ve fitted Eibach springs to my B8.5 S4 and after they settled i measured it and they had actually dropped by 18mm at the front and 15mm at the rear.
You can notice the difference by looking at it, but the ride quality is second to none.

 

[fast-ferret]

I ve fitted Eibach springs to my B8.5 S4 and after they settled i measured it and they had actually dropped by 18mm at the front and 15mm at the rear.
You can notice the difference by looking at it, but the ride quality is second to none.

Did it reduce body roll much would you say?


Sent from my iPhone using Tapatalk

 

[Cerbera9]

Changing the springs will only do so much you need to change the anti roll bars to control the body roll and keep the car flatter through the corners.

 

[fast-ferret]

Seems like people really rate the eibach springs. I’m wondering to myself - do they actually decrease harshness of the ride or sinply that they don’t increase it by much? Never had lowering springs before and noticed that some (Eibach included I think) are progressive, so potentially they could make things feel better?


Sent from my iPhone using Tapatalk

 

[unclebob555]

Yes they do reduce body roll to an extent but like Cerbera9 says, you will also need to uprate the antirollbars
To stabalize the car even more on cornering.