left foot braking v10 RS6 Avant

[sallyh]

Hi all

Just had the experience of having to left foot brake in an automatic Jeep (accelerator pedal got stuck under floor mat and had to use both feet to control it until I'd worked out what on earth had had happened). Strangely enough, it was all quite easy and seemed much quicker than moving the one foot from left to right to brake and throttle as normal on an auto. Anyway, got me thinking on the RS6 so gave it a go and it also seemed a lot quicker to use one foot to control the brake and one to control the accelerator. But it was kind of uncomfortable (like the pedals weren't quite in the right place). Then I thought about my foray to the drag strip were the engine kind of cut out at about 2.5 RPM with one foot on brake and one foot on accelerator. I'd be very interested if anyone has been to the track and tried to use trail braking to control the understeer? Does the engine cut out? I'm no where near this skill level but any comment would be appreciated. Also I've heard somewhat lurid stories about all of this boiling the transmission fluid so would also be interested if anyone has any comments on this.

[JRS-RS6]

Not sure about overseas models but US model (2003 RS6) has a Tech Memo that the Brake always takes precedence over the Accelerator and that when both are applied boost is cut. This is the same thing (brake priority over accelerator) that GM just announced it will be doing since the governments response to Toyota's issues outlines that it will be mandated in all (new) cars sold in the US soon. Not sure if this helps.

[sallyh]

Hi

Yes, it does help. Probably a great safety feature if you know what to expect!

[Jimmy Joe]

Sallyh, I just read your thread today. I have been left foot braking since I started driving an automatic, awkward at first but when you get the hang of it it feels a lot safer
and faster in cut and thrust traffic. Also, it helps to curb turbo lag when you can anticipate your moves. Never been to the track with the Mexbeast, but if I do, I'll let you know.

[ntrcptr]

Its the best way to drive the beast.:incar::wo::rs6kiss:

[kismetcapitan]

wanna know how to get rid of that boost cut when both are applied, or at least have some amount of boost. Will surely shorten the life of my transmission, but there are times where I'd really like to rocket off the line without fiddling with that duck rat foot technique which is hard to perfect.

specially prepped GM 4-speed automatics have been used on JDM drag cars; with high stall speeds at around 4000rpm, brake boosting goes a long way in using an automatic to get rid of bogging the turbos off the line and a slushbox is no longer a liability, but a strength!

but when all is said and done, I prefer that the Achilles Heel of our cars is the transmission...and not some component of the engine!

[aussie rs6]

Hi all

Just had the experience of having to left foot brake in an automatic Jeep (accelerator pedal got stuck under floor mat and had to use both feet to control it until I'd worked out what on earth had had happened). Strangely enough, it was all quite easy and seemed much quicker than moving the one foot from left to right to brake and throttle as normal on an auto. Anyway, got me thinking on the RS6 so gave it a go and it also seemed a lot quicker to use one foot to control the brake and one to control the accelerator. But it was kind of uncomfortable (like the pedals weren't quite in the right place). Then I thought about my foray to the drag strip were the engine kind of cut out at about 2.5 RPM with one foot on brake and one foot on accelerator. I'd be very interested if anyone has been to the track and tried to use trail braking to control the understeer? Does the engine cut out? I'm no where near this skill level but any comment would be appreciated. Also I've heard somewhat lurid stories about all of this boiling the transmission fluid so would also be interested if anyone has any comments on this.

Hi Sallyh.

left foot braking and right on the accelerator with trail braking is the way to go with the 2004 C5 RS6 turning into tight corners. Helps steady the beast into the corners I have found.

I expect with your C6 RS6 being 180 kg heavier than a C5 RS6, understeer is more of a concern.

Left foot on the brake or hovering over it till needed and right on the accelerator also provides quicker reaction time when need to brake. The only way to drive any automatic. Why waste precious time driving right foot on accelaerator and then having to lift it off to move over to the brake.

I dont think you can avoid the 2500 rpm 'back off' when trying to do a brake torque launch from standing start.

I hear on the grapevine that you have run 1/4 mile in 11.99 secs. Can you advise if your C6 V10 RS6 is still standard?

regards,
john

[sallyh]

Hi all, particularly aussie rs6, was looking for the time slip and it was actually 11.9452, so lots under 11.99! And I beat the GTR and the R8 Spyder! And I'm going on a diet for next time! Back to reality, no, the car is not stock, it has been moderately tuned by Peter Fitzgerald at Evolve Technique. All fantastic for the drag strip but for the track it results in higher terminal speed which really stresses the front brakes, despite the carbon ceramics. I can zoom away in the straights very easily but braking in the corners there is always some pesky Porsche or other light weight fast car (invariably cheaper as the owner will tell me) passing me. Letting pressure out of the front tyres is a real challenge as they get so hot that it is very hard to take the valve caps off, even with gloves. You can imagine that I am not trying left foot braking with all this happening, it would make the fronts heat up even more. Yes, the C6 from my experience understeers a lot, in a very predictable fashion, on the track.

Anyway, you live and you learn, perhaps if I had not tuned it, I'd be left foot braking around the track and going faster (but slower at the drag strip), but having tuned it, faster on the drag strip, but in reality when I'm meant to be limited to a max. of 110 kms on the freeway, it does lug a lot, and can over take relentlessly, and it is an absolutely amazing car.

[ZCD2.7T]

Hi all, ....was looking for the time slip and it was actually 11.9452, so lots under 11.99!..

To me, that's very impressive for such a heavy car!

I'd read in some test that the stock sedan was good for about 12.1 or 12.2 @ 119 mph, so for your (heavier) Avant to be quicker than that is amazing.

What was your trap speed?

Did you happen to do before/after dyno runs, or do you know what the alleged HP increase is from the tune?

I just think it's way cool that someone would take a car like that to the strip - fun stuff!

[aussie rs6]

Hi Sally,

On club tuning days at the track and the strip here in Perth - never racing as that would void warranty, I found that at the track, the front and rear brakes would get very hot on the c5- lots of smoking when stopped and boiled the brake fluid once. That was exciting, i give you the big tip!.

I am remedying the front brake over heating in my C5 by installing C6 front brakes, VW Phaeton brake scoops, Dot5.1 brake fluid and by all accounts that should correct the front brake overheating problem.

VW Phaeton brake scoops or equivalent on your C6 might help, if they can be fitted.

Martin at Unit20 in UK (Grizz) may have advice as to how to improve brake cooling on your C6 as Grizz also has a modified C6 V10tt.

C6 brakes and phaeton scoops on my C5 should also reduce the load and heat on the rear brakes (?).
I have searched RS6 forums and read that if you want to reduce the heat on your brakes all round at track days, then turn the esp off as the esp brakes the individual wheels to regain traction resulting in a lot of extra individual wheel braking and heat generation.
There is the risk I assume that turning of the ESP on the track might result in a controlled spin or exit stage left into the bushes if you overcook it, although Quattro would most likely save the day. Turning of the esp would I surmise on your C6 leave lots of black strips coming out of corners with injudicious use of the loud pedal!

There is an entertaining video clip on the forum from a fellow forum member in Texas showing how to carry out a "controlled spin" while driving in a spirited manner on the track!

regards,
john

ps I just missed out on the daytona grey sedan, 21,000kms, C6 RS6 at Brighton Audi. Sold last Saturday-rats!

[sallyh]

Hi ZCD2.7T

Thanks for your kind comments. From what I've been told, the C6 Avant at 2.025 tonnes is too heavy for the dyno, so I do not know the hp increase. But to me it certainly does feel a lot faster after tuning. The trap speed was 120.64 mph, or 194.152 kph. And it was a huge amount to fun to be able to legally do this sort of stuff, and get a proper time for it.

Shame about missing out on the Daytona Grey sedan at Brighton Audi aussie rs6. I'll ask the guy who did the tuning about the brake scoops but I am not terribly hopeful as they truly, especially the fronts, get extremely hot. In particular, the driver's side front, the wheel weights melted off. I turn the ESP off (but apparently it is not truly off until you take a fuse or somesuch out, anyway, as "off" it can be) and this certainly does save the rear brake pads a bit, but the front still gets extremely hot. My front calipers have gone a strange bronze colour, changing from the original silver of the carbon ceramic caliper. To add insult to injury, the standard brake calipers for the C6 are black, so the heat issue would not show up as colour changes for them.