2017 GTi PP at VIR

[Mini7]

OBD11

My Current XDS setting.

 

[donefor]

Traction control off does not turn off xds. Traction control essentially cuts power when a slip is detected or applies brakes in very specific cases, while xds works by braking individual corners. They are related systems but the logic for them is separate.

I wish i could find a VW reference that makes this crystal clear. The explanation of XDS on volkswagen-newsroom is thus:

The XDS electronic differential lock improves the traction and handling of front-wheel-drive models. In technical terms, the XDS system, initially developed for the Golf GTI, is an extension of the electronic differential lock (EDS) integrated in the ESP system. As soon as the electronics detect excessive unloading of the inside wheel of the driven front axle during fast cornering, the ESP hydraulic system builds up braking system pressure in a targeted way on this wheel to restore optimum traction. This way, the XDS acts as a limited-slip differential to compensate for the understeer typical of front-wheel-drive cars during fast cornering. Thanks to XDS, handling becomes more precise and more neutral.

I interpreted this as meaning XDS is a subcomponent of ESP, hence ESP off, XDS off - but apparently this ain't so. Which is good news, i guess... going to give it another go with XDS off and see how well the pads hold up. Thanks for the info.

 

[victorofhavoc]

I wish i could find a VW reference that makes this crystal clear. The explanation of XDS on volkswagen-newsroom is thus:

The XDS electronic differential lock improves the traction and handling of front-wheel-drive models. In technical terms, the XDS system, initially developed for the Golf GTI, is an extension of the electronic differential lock (EDS) integrated in the ESP system. As soon as the electronics detect excessive unloading of the inside wheel of the driven front axle during fast cornering, the ESP hydraulic system builds up braking system pressure in a targeted way on this wheel to restore optimum traction. This way, the XDS acts as a limited-slip differential to compensate for the understeer typical of front-wheel-drive cars during fast cornering. Thanks to XDS, handling becomes more precise and more neutral.

I interpreted this as meaning XDS is a subcomponent of ESP, hence ESP off, XDS off - but apparently this ain't so. Which is good news, i guess... going to give it another go with XDS off and see how well the pads hold up. Thanks for the info.

There's no clear vw source that gives the kind of answers we're looking for. You have to understand that "traction control" in common vehicles is a load of poo. Unless you're looking at a proper race logic system (like those found on a Koenigsegg), it just cuts power, and in some very extreme cases of rapid yaw it will apply the brake to all wheels. Esc sport merely inreases the allowed yaw angle before intervening.

The xds system works based off of lean. If the car leans left, the right wheel gets brake. Just based off of the logic of how the two systems work, they aren't tied to one another. Since the logic is separate and there's no reason to turn off xds with esp (it would hinder performance in cars with no diff), they simply leave it on. In fact if you set it to strong, turn off the traction control nannies, and take a corner hard and fast, the little skidding car light will flash at you. Set it to weak, and it won't flash anymore.

Edit: their idea of integrated into the esp system is the same as "integrated into the abs system" since in reality it's the abs pump that controls which wheel and how brakes are applied. Abs is far more advanced than it used to be.

 

[Mini7]

I meant to add this link to Vorshlag’s forum.

https://www.vorshlag.com/forums/for...werbrake-big-brake-upgrade-kits-from-vorshlag

 

[Mini7]

There's no clear vw source that gives the kind of answers we're looking for. You have to understand that "traction control" in common vehicles is a load of poo. Unless you're looking at a proper race logic system (like those found on a Koenigsegg), it just cuts power, and in some very extreme cases of rapid yaw it will apply the brake to all wheels. Esc sport merely inreases the allowed yaw angle before intervening.

The xds system works based off of lean. If the car leans left, the right wheel gets brake. Just based off of the logic of how the two systems work, they aren't tied to one another. Since the logic is separate and there's no reason to turn off xds with esp (it would hinder performance in cars with no diff), they simply leave it on. In fact if you set it to strong, turn off the traction control nannies, and take a corner hard and fast, the little skidding car light will flash at you. Set it to weak, and it won't flash anymore.

Edit: their idea of integrated into the esp system is the same as "integrated into the abs system" since in reality it's the abs pump that controls which wheel and how brakes are applied. Abs is far more advanced than it used to be.

I make liberal use of curbs at VIR and get lots of “lean”. LOL

With a big rear bar, there is hopefully less need for XDS on track. When pushing hard I still get a little understeer in the dry.

 

[victorofhavoc]

I make liberal use of curbs at VIR and get lots of “lean”. LOL

With a big rear bar, there is hopefully less need for XDS on track. When pushing hard I still get a little understeer in the dry.

I feel the same. I'm moving to a 255 front and 235 rear tire to balance the heat. I've found that laps 1-3 I have a balanced car with tires getting to temp, 3-7 I have perfect balance with a slightly loose rear end, and around 8-12 I get understeer with a square setup. I'm also running the yoko a052 now, which are significantly better at handling heat and they do take longer to get up to operating temp. Moving to more rake and wider front should solve a couple issues for me, but I'm also very sensitive to changes. I can literally feel when some tar is stuck in the wheel or gforce has caused the weights to slide.

A rear bar helps a lot, but based on some reading and wisdom from better drivers, I'm wondering if a ridiculously stiff front bar may be in order when I move to coils...?

 

[Crild]

I make liberal use of curbs at VIR and get lots of “lean”. LOL



With a big rear bar, there is hopefully less need for XDS on track. When pushing hard I still get a little understeer in the dry.

I'll enjoy hearing about when your airbag blows.

 

[Mini7]

A052’s will likely replace my NT01’s on my track wheels. Do you have any video? What is the steering response like? I’d be interested in the wear rate. A052’s also seem to run wider than other tires in the same size. Keep us posted.

Hah! We have had the sway bar vs spring rate debate. I’m curious as to how much of the performance is down to the driver feeling more confident because of the faster reaction to transitions and less body roll.

Their is a reason Porsche and M3’s run a staggered setup. Balancing grip over both axles with tires coming up to the required temps for optimum grip.

 

[Mini7]

I'll enjoy hearing about when your airbag blows.

Get the popcorn ready........and enjoy!!

 

[Mini7]

330x32 PB Template

Hey John, hope this prints out OK for you to test with your wheels.

Potomac Audi is running right after your Track Daze DE. They will not likely allow us in until after 5pm. It will be on the Full course for the whole weekend.

 

[sean.mason.75873]

For reasons of being able to rotate tires, I'd rather run a square setup and adjust rear rotation with less rear toe in.

Sent from my SM-G970U using Tapatalk

 

[victorofhavoc]

A052’s will likely replace my NT01’s on my track wheels. Do you have any video? What is the steering response like? I’d be interested in the wear rate. A052’s also seem to run wider than other tires in the same size. Keep us posted.

Hah! We have had the sway bar vs spring rate debate. I’m curious as to how much of the performance is down to the driver feeling more confident because of the faster reaction to transitions and less body roll.

Their is a reason Porsche and M3’s run a staggered setup. Balancing grip over both axles with tires coming up to the required temps for optimum grip.

Unfortunately no video as I broke my mount recently and just haven't replaced it. I threw my tool box on it on accident when I was loading up the hatch, and it was a specific sized rammount with extenders and pieces I bought one at a time. 100$ mistake .

I think these will last about the same as the Dz3, longer than the 71r, and less than the rs4, but they are definitely faster! Tirerack talked about them being a tire to contend with the 71r, but these aren't geared for autocross and they don't heat up and grease quite as quickly, so their comparo on a 30s course is useless. Off of the 4 sessions I've run with them, I'd say they take more warm up and are more sensitive to proper driving technique. You can't just mash the brake and expect a proper stop, you have to know where the threshold is. You also can't simply chuck them around like you can the 71r. They take more precision and reward it more fully.

Suspensions, chassis, tires all go hand in hand. It's pretty easy to screw up a great street car by just throwing parts at it, haha. That's why I like to solve things one limit at a time. My brakes are completely toast, so that'll be a project for next year! I'm looking into the powerbrake setup you've got but can't seem to find any sellers. I'm also looking into the stoptech competition line or trophy series. Trophy is cheap for the 328mm comparatively!

For reasons of being able to rotate tires, I'd rather run a square setup and adjust rear rotation with less rear toe in.

Sent from my SM-G970U using Tapatalk

No argument here. My reasons for wider front are about heat maintenance. If I ran 255 square I'd have the same issues as with 235 or 245 square, just at a later point in the session. The stagger has less to do with rotation and more to balance out when the tires are fully at temp and how much heat they can hold/expel. 60:40 distribution + fwd + braking + 300hp hates the front wheels, and I'd rather not run 40psi + and 1000lb springs if I don't have to.

If I had to run square, I'd probably go for a very stiff front bar, stock rear, -2 rear camber with slight toe in, -3 front with slight toe out, and a square spring setup. That's just based off of my personal "feel" with this platform. I know a guy that runs close to that with square tires on his older a4 race car, which has similar chassis characteristics to the mk7 gti. Granted he's on 1300lb springs...

 

[donefor]

Hey John, hope this prints out OK for you to test with your wheels.

Potomac Audi is running right after your Track Daze DE. They will not likely allow us in until after 5pm. It will be on the Full course for the whole weekend.

It's perfect, thanks!

Will be keeping an eye on the work calendar and weather forecast around that time, could present an either/or situation...

 

[Mini7]

Car Log

Here is a log of some of the consumables I keep track of on the GTi

245-40-18 Michelin Pilot Sport 4S tires 6-track days + 17,400miles: Needs Replacement

Front PowerBrake Rotors 11,500 miles 5-track days (200-laps)
Front PB13 5-track days: need replacing (200-laps)
MPS4S 235-40-18 tires have 21,330 miles + 4-track days: need replacing
Rear Pagid Rotors have 11,500 miles 5-track days
Rear RS19 Pagids have 39,200 miles + 18-track days (12mm pad left)
Rear OEM Rotors had 46,500 miles + 13-track days at time of replacement (no thermal cracking)

PP front rotors needed replacement every year 6-7 track days + 15-20,000 miles due to thermal cracking

 

[Mini7]

So a quick update.

Stopping by Öhlins tomorrow to pick up my coilovers. Going with 8k springs front and rear to start. Getting my car ready for my fall DE’s.
Ordered Vorschlag’s Camber plates. Those should be here next week.

Going to order the SuperPro bushings for the rear lower control arm and the rear trailing arms.