B6 S4 or B7 S4?

[WhyTwo]

Hi,

Looking for some advice please. I'm thinking of chopping in my 04 X5 3.0 petrol family wagon for an S4 avant and have a budget of up to £20K but would rather not spend it all if it's not necessary. I'm leaning towards the B7 as from my limited knowledge it has a higher spec interior and better brakes. But is the premium price worth it for that and the new grille?

Also, excluding petrol, is the S4 expensive to run in terms of servicing & maintenance? I guess it should be comperable to the X5? I'm only doing around 12K miles a year mostly motorway miles.

Thanks

[marctwo]

I think there is very little difference between the B6 and B7 apart from looks. Certainly the engine is the same which is most of what you are actually buying. Personally I didn't think the B7 was worth the extra but it's up to you.

With regard to cost, I don't know how much it costs to run an X5 but the S4 just cost me £325 for AVS2 (2nd variable service). Fuel economy (or lack there of) is a different matter. At best, on a long motorway journey at a cruise controlled 70mph I managed 29.7mpg. At worst, round town in heavy London traffic I have managed 8mpg.

[WhyTwo]

Thanks Marc. I guess it's just a matter of which aesthetics i prefer. I think I need to go and test drive both. There's a B7 I'm interested in that has tiptronic, is this a good or a bad thing? Never driven a tip before and no idea if it's better or worse for residuals and to live with. Coming from an auto X5 it might be a nice compromise.

Fuel economy doesn't bother me as I have a co fuel card. I average around 20mpg's in the X5 but I also run a Tuscan which is obviously not great on fuel (never tried to calculate it!) and expensive to service/maintain. A 30K service on the X5 was £500 and the 45K oil change service which is due now is still £200!

[marctwo]

I have the Tiptronic. Personally, I think it suits the car well. Like you, I do mostly motorway driving so don't really miss the manual too much. The Tip also gets better fuel economy than the manual due to longer gearing, although it is heavier and slower. The changes are quick and smooth and you can always use the paddle shifters if you want to. The Tip certainly cost more when new, and when I bought mine they seemed to be fetching more than the manual cars.

[psymonr]

As far as I'm aware, there were a couple of alterations to the B7, most notably in terms of maintenance is the auxiliary radiators. The B6 aux. rads. tend to corrode and need to be replaced, something to do with how the road surface water gets kicked up in the front of the car, the B7 seems to not suffer this. Other mechanical changes include the Torsen T-3 diff is fitted to the B7 which is default 40:60 front to rear drive ratio, unlike the B6 which is set 50:50 but can alter 40:60 or vice versa, also B7 has revised springs and dampers, newer ESP than the B6.
Aside from that, I don't think there is much, and I don't the interior is different,

also apparently the Tiptronic just edges the manual for mpg, but then, I suppose it is bad either way! So it is really personal preference

[T89 Callan]

The thing to remember is that the B7 may be better specced but if you go for a B6 it will be cheaper so you can get one with more options and then fork out to have bits added on. After I bought mine I had an independent company fit Cruise Control and it only cost £225.

I have a B6 S4 Avant and I much prefer the looks to the B7 and it is much more subtle looking.

The running costs have been cheap, last service including a new front wishbone (I wore it out thrashing round the alps) cost only £260 and the 1st set of tyres lasted 18k miles even though I was always thrashing it.

On the 'brakes' issue I did a 90 mile thrash through the alps and the brakes on my B6 were fine so I don't know how the brakes on the B7 could be much better?

I'd say make the choice based on what you prefer the looks of as there is not much else to seperate them.

[stobswood]

When I got my B6 S4 Avant a couple of years ago, I looked at the B7 but preferred the earlier grille and rearlights, as someone already said the earlier one is more subtle without the goatee beard look.

Tiptronic is fine and the engine suits it well, you can play with the paddle shift when you want to or leave it to its own devices and just drop a couple of gears into a corner if you feel the urge.

Just be careful with tyre choice - see my posting yesterday.

Overall a great car whichever you go for.

[Dr G]

Driven back to back (and I don't know this for a fact) but all of the major controls feel better on a B7 - certainly the steering has lost some of the mushy feel of the B6, change is more slick with clutch and throttle easier to modulate.

Could say that of any A4 B6 vs B7 really but whether those improvements are worth the big jump in price to you is another question.

Not all that many B7s around - by the time you'd added a decent list of toys you were near on RS4 money anyway. B6 between £13 and 17k is bloody good value mind

[WhyTwo]

Thanks for your input guys. Certainly some food for thought. Looks like I need to get out and test drive both. I'm leaning towards a tiptronic B7 but might have to convince the Mrs it's worth the extra money. No rush at the moment so maybe I'll bide my time and wait for the right one to come along

[jimmyb]

Also a small note the b7 v8 had a couple of small mods done to it dont ask what as i couldnt tell you something to with the camchain rattling a bit in the b6 ??????? but it wasnt a reliability issue tbh.

I would test both and make a judgement based on that. Personally prefer the looks of the b6 to the b7 esp in saloon format from the back the new b7 lights at the rear just dont look right.

http://www.youtube.com/watch?v=NGvi9HCkTko

ETA: Also servicing is quite reasonable and iirc the same as on my a4 which is variable upto 18k miles between services depending on mileage versus time.

Edited by jimmyb on Wednesday 8th July 21:03

[Teutonic_Tamer]

marctwo said:

I think there is very little difference between the B6 and B7 apart from looks. Certainly the engine is the same which is most of what you are actually buying. Personally I didn't think the B7 was worth the extra but it's up to you.

The changes between the B6 and B7 are considerably more than just 'looks'. OK, they both share identical engines, transmissions, brakes and suspensions. But there are some crucial improvements in the 'electronics' on the B7, which arise from the complete installation of full, dual K line canbus systems, rather than the slight mis-matched partial dual K line canbus on the B6. As a result of this, the B7 gains in the following areas:

The B7 has the vastly more advanced Bosch ESP 8.0 system (compared to the B6s 5.7). This means much faster reaction times (for all functions), and also includes 'disc wiping'.

The B7 gains dual stage and dual trigger airbags.

The B7 has much improved SatNag, and other ICE head units.

The B7 has a better climate control panel and ECU.

And the B7 has dual rear foglamps - better in the UK in general, and much safer if you go over to mainland Europe.

[Teutonic_Tamer]

psymonr said:

As far as I'm aware, there were a couple of alterations to the B7, most notably in terms of maintenance is the auxiliary radiators. The B6 aux. rads. tend to corrode and need to be replaced, something to do with how the road surface water gets kicked up in the front of the car, the B7 seems to not suffer this.

That is interesting, thanks for sharing. Maybe the improvement on the B7 is simply down to the front bumper?

psymonr said:

Other mechanical changes include the Torsen T-3 diff is fitted to the B7 which is default 40:60 front to rear drive ratio, unlike the B6 which is set 50:50 but can alter 40:60 or vice versa,

Wrong on a number of issues. Firstly, apart from a very limited few S4s (and ONLY with manual transmission) at the end of the production run, the vast majority of B7 S4s had the Torsen T-2 standard symmetrical 50:50 centre diff. This has a 'default' torque distribution of 50% to the front and 50% to the rear. And as grip levels vary, then the torque distribution between front and rear can infinately and dynamically vary, but only upto a maximum of 25:75 or 75:25. The simple mechanics (due to something called the 'Torque Bias Ratio' or TBR of 3 to 1) of the T-2 can not aportion more than 75% of torque to either axle.

Secondly, with the Torsen T-3 asymmetric diff first used on the B7 RS4, the torque distribution is quite different to the T-2. The standard 'default' is to send 40% to the front and 60% to the rear. And due to the way the T-3 is differently engineered, it will always 'try' to send more torque to the rear. Furthermore, and due to the fact that the T-3 has a greater TBR of 4 to 1, it can apportion torque with a greater difference. So with a T-3 centre diff, when grip levels dictate, it can send upto 80% to the front and 20% to the rear - all the way through to 0% at the front and 100% to the rear (OK, to be extremely pedantic, it will never operate at exactly 0:100, simply because any automatic torque biasing [ATB] differential needs to apply 'some' torque to both sides, just to work - so in reality, at its most extreme, will probably work at 0.5:99.5).

So basically, if you want a B7 with tiptronic, you will NOT get a T-3 'asymmetric' centre diff.

psymonr said:

also B7 has revised springs and dampers,

Nope. They are identical to the B6.

psymonr said:

newer ESP than the B6.

Correct.

[Teutonic_Tamer]

T89 Callan said:

On the 'brakes' issue I did a 90 mile thrash through the alps and the brakes on my B6 were fine so I don't know how the brakes on the B7 could be much better?

The ONLY change on the brakes (apart from the ESP discussed elswhere in the thread) is simply that Audi found a tin or two of gloss black paint. The physical dimensions of the discs and caliper hydraulics are identical. OK, there are slightly revised front brake pads, but these can also be fitted to the B6 too!

[Teutonic_Tamer]

stobswood said:

When I got my B6 S4 Avant a couple of years ago, I looked at the B7 but preferred the earlier grille and rearlights, as someone already said the earlier one is more subtle without the goatee beard look.

ETTO.

stobswood said:

Tiptronic is fine and the engine suits it well, you can play with the paddle shift when you want to or leave it to its own devices and just drop a couple of gears into a corner if you feel the urge.

The 'auto' is very much a personal preference. However, I do have to state that the Audi S4 (B6 and B7) is not as good as similar auto offerings from BMW. The same is true with the current S6 slush box. However, the auto on the new RS6 is simple awesome!

stobswood said:

Just be careful with tyre choice - see my posting yesterday.

Linky please!

stobswood said:

Overall a great car whichever you go for.

Agreed.

[Teutonic_Tamer]

jimmyb said:

Also a small note the b7 v8 had a couple of small mods done to it dont ask what as i couldnt tell you something to with the camchain rattling a bit in the b6 ??????? but it wasnt a reliability issue tbh.

The timing chain issue was only really a problem on yankie cars which are adamant at using inferior quality oils, often with a higher viscosity. For the considerably vast majority of British/European S4s, which used the correct low viscosity 503.00/503.01 oils, the timing chains did not develop any problems.

[psymonr]

Teutonic_Tamer said:

That is interesting, thanks for sharing. Maybe the improvement on the B7 is simply down to the front bumper?

Yes, as I can recall, it was simply a ducting issue, which was revised in the bumper design, though this is speculative from owners of the B6 and B7 on the tyresmoke forums (principly there, but echoed on some others), but it would probably explain why there are little to no reports of aux radiator failures on the B7 on the forums I have seen,

Teutonic_Tamer said:

psymonr said:

Other mechanical changes include the Torsen T-3 diff is fitted to the B7 which is default 40:60 front to rear drive ratio, unlike the B6 which is set 50:50 but can alter 40:60 or vice versa,

Wrong on a number of issues. Firstly, apart from a very limited few S4s (and ONLY with manual transmission) at the end of the production run, the vast majority of B7 S4s had the Torsen T-2 standard symmetrical 50:50 centre diff. This has a 'default' torque distribution of 50% to the front and 50% to the rear. And as grip levels vary, then the torque distribution between front and rear can infinately and dynamically vary, but only upto a maximum of 25:75 or 75:25. The simple mechanics (due to something called the 'Torque Bias Ratio' or TBR of 3 to 1) of the T-2 can not aportion more than 75% of torque to either axle.

Secondly, with the Torsen T-3 asymmetric diff first used on the B7 RS4, the torque distribution is quite different to the T-2. The standard 'default' is to send 40% to the front and 60% to the rear. And due to the way the T-3 is differently engineered, it will always 'try' to send more torque to the rear. Furthermore, and due to the fact that the T-3 has a greater TBR of 4 to 1, it can apportion torque with a greater difference. So with a T-3 centre diff, when grip levels dictate, it can send upto 80% to the front and 20% to the rear - all the way through to 0% at the front and 100% to the rear (OK, to be extremely pedantic, it will never operate at exactly 0:100, simply because any automatic torque biasing [ATB] differential needs to apply 'some' torque to both sides, just to work - so in reality, at its most extreme, will probably work at 0.5:99.5).

So basically, if you want a B7 with tiptronic, you will NOT get a T-3 'asymmetric' centre diff.

I think I dangerously over simplified the point I was attempting to make, my error, thank you for the much more in depth comparison and correction,

psymonr said:

also B7 has revised springs and dampers,

Teutonic_Tamer said:

Nope. They are identical to the B6.

Thank you for the correction again, not sure where I thought I read this then,

[Fort Jefferson]

psymonr said:

psymonr said:

also B7 has revised springs and dampers,

Teutonic_Tamer said:

Nope. They are identical to the B6.

Thank you for the correction again, not sure where I thought I read this then,

You've been reading about the B6 A4 and B7 A4. Most of the B7 stuff was used/tested on the B6S4. (allegedly)

[Teutonic_Tamer]

Fort Jefferson said:

psymonr said:

psymonr said:

also B7 has revised springs and dampers,

Teutonic_Tamer said:

Nope. They are identical to the B6.

Thank you for the correction again, not sure where I thought I read this then,

You've been reading about the B6 A4 and B7 A4. Most of the B7 stuff was used/tested on the B6S4. (allegedly)

Yes, that is correct - the B7 A4 range takes its suspension geometery, along with lighter weight alloy suspension components - which were first used on the B6 S4.

[rapidophile]

Interesting topic.

How can you identify which of the B7 S4 Manuals has the T3 40/60 diff set up?

Must be a lot better handling and dynamics than the T2, no?

[Fort Jefferson]

rapidophile said:

How can you identify which of the B7 S4 Manuals has the T3 40/60 diff set up?

Try this thread.