S4 Mods

[DavidT]

Interesting point on the brakes Joshie.

I totally agree that they inspire no confidence because they never feel like they want to stop the car, even from cold.

I did however drive round Castle Combe at full tilt on my standard brakes and never had the pedal hit the floor or boil the fluid. The pedal felt different from corner to corner, more/less spongy or further up/down and I started touching them early just incase. If I pressed hard enough though, they worked - was quarry the one with no run off ? [img]images/graemlins/blush.gif[/img]

I was very careful in warming them up over a couple of laps and then driving 10 minutes on the road (off the circuit) at 60mph to cool them.

All that said, they turned blue, warped and the S & RS car specialist at my local dealership was taking the piss out of me when I collected the car from them after some work on Friday - fair enough.

Mine are the latest spec ones they did on the S4 - of the three - apparenty so maybe that makes a difference, I dunno.

Roll on Porsche brakes, almost on order.

David

[Joshie]

All that said, they turned blue, warped and the S & RS car specialist at my local dealership was taking the piss out of me when I collected the car from them after some work on Friday - fair enough.

.........And your car is standard, when you start upping the power output the car goes faster, your overall speed at a tight circuit like Castle Combe is much higher and you have to loose more speed to get you around the corners - hence HEAT. Thats my point - with more horsepower you need more stopping power [img]images/graemlins/thumb.gif[/img] [img]images/graemlins/grin.gif[/img]

[DavidT]

Agreed mate. I am doing brakes and suspension, then engine and exhaust mods.

[Dippy]

Mine are the latest spec ones they did on the S4 - of the three - apparenty so maybe that makes a difference, I dunno.

So were mine - my car was one of the very last old S4s made. Yes I believe that Audi improved the brakes, but IIRC only in terms of the compound used on the pads.

THE problem with the S4 stock brakes is that they only have 2 pots per caliper. That is surprising given the size of the disks & pads. Clearly these 2 pots have difficulty keeping a uniform pressure on the pads and so stopping power is restricted. As far as I can see that's the main reason why 4 and 6 pot calipers are so much better.

However that's just stopping power. You guys know more than me about brake fade (and I'm quite happy not to know [img]images/graemlins/smirk.gif[/img]). Certainly the fact that stock disks seem to need replacing every 30,000 miles of street use suggests that basically they're too soft?

[Golich]

"Brake fade is something you can adjust your driving to suit."

Obviously, if your on a track day then clearly the standard brakes are nowhere near up to the job.

I've only been on one track day. In 14months. The A roads I run on generally allow the brakes to cool enough not to cause any real problems all though they do groan and bit and decay.

As for the TTB, you could be right about small tears. But speaking from experience. I noticed a significant drop in power in my stock S4 for from a 10mm tear.

This was never discovered by the dealer despite numerous visits and complaints. So I took the car to AMD. They tested the car and found it was 40bhp down. A month after they chipped my car the Intercooler pipe came slightly off the TTB because the jubilee clip wasn't screwed tight enough. Again I noticed a significant drop in power. But that's just my experience.

I wa going to buy a Samco TTB. But the stock one has been fine for over a 6 months now. So at £7. I'm happy to carry a spare but if it becomes troublesome then. Off it will come. [img]images/graemlins/boots.gif[/img]

[Dippy]

Of course one of the advantages of the APR bipipe is that it has no flex, so the volume stays the same. Hence you get better throttle response than with a flexible TBB.

[Joshie]

Of course one of the advantages of the APR bipipe is that it has no flex, so the volume stays the same. Hence you get better throttle response than with a flexible TBB.

.....and I suppose that if you think about it Audi saw fit to develop a sealed aluminium unit for the RS4. They clearly felt that a rubber TBB wasn't up to the job [img]images/graemlins/shocked.gif[/img]