2017 GTi PP at VIR

[scrllock]

I've used both Motul 600 as well as Stoptech 600 with success. I will say however that I've had 2 occasions (one at VIR, one at Summit) where I got a bit of a softer pedal after some sessions with the Motul. Always was fine w/r to braking on track and went away/felt back to normal the next day at home/on street. Not sure what that is or if this is what DerHase has experienced. I get the 600 for free from FCP....15 bottles of that stuff and counting at this point as I do bleed/flush regularly/before each event. I don't believe I'm getting close to boiling it based on the dry boiling point and my caliper temps.

On the SL vs. others - I believe the VWs are spec'd for the SL fluid and my only concern with the stuff like Endless is just that, winter use with higher viscosity but I'm sure at least here in central VA where we don't get super cold it's fine. For now I'm sticking with the Motul RBF600 from FCP. I do know this....used ATE 200 in my Atlas and the MC was so squeaky I switched to their SL6.

if you're using FCP just send some back for LV and do a winter flush if you depend on ESC.

 

[MonkeyMD]

Never had any issues with RBF660. No pedal dropping. No oh shit moments. No fade. Even at COTA with 2 consecutive braking zones, 1 from about 120, other 145 with ambient temps at 105°. This is with ST40 brakes & XP12/10 pads

 

[victorofhavoc]

Like I said, I never once lost brakes entirely. Was just a weird thing that I noticed. I never had to bleed the full weekend. Honestly I wasn't expecting Endless to fix it, the change was moreso an experiment to see if it was fluid that was the culprit. I'd still have zero problem running Motul if it were the only thing available FWIW.

Were you getting bubbles or just brake pedal travel extending?

Thinner fluids have more tendency for pad knock, even on sliding calipers (especially when the sliding pins get dirty). I've had similar feel, but a bit of brush before the brake zone and full pedal comes right back. My tell tale sign is always how many bubbles result after the session or day.

As I've gotten faster, I've also started backing up my braking zone and using less brake. When I was slower I used to run until abs flashed every time, but I've started using less brake and become faster overall from being a bit better setup on turn in with more time spent modulating out. It took a pro sitting in the car with me and telling me "give up more to go faster" before that finally clicked for me, lol .

 

[Mini7]

I changed from Performance Friction brake fluid to SRF on the stock PP Brakes. The pedal would fall away in the last third of a session.
Have stuck with SRF with my BBK. I ran Endless on my Cooper S when I tracked it and really liked that.

Two things that still frustrate me with the GTi braking is the initial take-up of the brake pedal. I like a high and immediate brake pedal. The take-up is still there with the BBK but less pronounced. It gets progressively more towards the end of the session. The second is front to rear bias or rear instability under hard threshold braking, especially into T1 at VIR. I feel that there is still interference from the electronics. I have the regular OBD11 brake system mods. VAQ to increased traction. XDS to off with the wavetrac LSD. ESC to full off but still see the light flashing under yaw.

 

[victorofhavoc]

Rip out the yaw sensor...? You lose abs, but who needs it?

Have you tried xds set to weak? According to one of the tcr drivers I talked to before the xds off setting also messes with how the diff activates, but I don't know if that's totally true.

With the fixed calipers you probably need to brush the brakes before the braking zone. Pad knock is annoying...

 

[GTI Jake]

Rip out the yaw sensor...? You lose abs, but who needs it?

Have you tried xds set to weak? According to one of the tcr drivers I talked to before the xds off setting also messes with how the diff activates, but I don't know if that's totally true.

With the fixed calipers you probably need to brush the brakes before the braking zone. Pad knock is annoying...

I don’t believe there’s a sensor to pull, all of that most likely works off the four ABS sensors.

If you wanna try the car out Mk2 style with absolutely no interference pull the ABS fuse. You also lose cruise control & airbags, but for track duty who cares.

I used that to defeat TC at Zmax playing around with 1/4 passes, and there’s absolutely zero computer aided interference.

 

[DerHase]

Were you getting bubbles or just brake pedal travel extending?

Thinner fluids have more tendency for pad knock, even on sliding calipers (especially when the sliding pins get dirty). I've had similar feel, but a bit of brush before the brake zone and full pedal comes right back. My tell tale sign is always how many bubbles result after the session or day.

As I've gotten faster, I've also started backing up my braking zone and using less brake. When I was slower I used to run until abs flashed every time, but I've started using less brake and become faster overall from being a bit better setup on turn in with more time spent modulating out. It took a pro sitting in the car with me and telling me "give up more to go faster" before that finally clicked for me, lol .

Never got any bubbles - just the extended pedal travel. It would "kind of" come back once cooled, but not 100% until after a quick bleed of the front calipers.

I'm also slowly getting more and more into experimenting with lengthening brake zones slightly. Found a lot of time in Oak Tree a few trips ago doing that and been trying to apply it a bit everywhere else.

I changed from Performance Friction brake fluid to SRF on the stock PP Brakes. The pedal would fall away in the last third of a session.
Have stuck with SRF with my BBK. I ran Endless on my Cooper S when I tracked it and really liked that.

Two things that still frustrate me with the GTi braking is the initial take-up of the brake pedal. I like a high and immediate brake pedal. The take-up is still there with the BBK but less pronounced. It gets progressively more towards the end of the session. The second is front to rear bias or rear instability under hard threshold braking, especially into T1 at VIR. I feel that there is still interference from the electronics. I have the regular OBD11 brake system mods. VAQ to increased traction. XDS to off with the wavetrac LSD. ESC to full off but still see the light flashing under yaw.

Yeah here is one panic stop I had at Fastivus - you can hear the "Shit shit shit!" I wouldn't call it unstable though - wagging around a bit sure but that's been my experience in every well set up FWD car.

https://youtube.com/clip/UgkxwpHQ7Aj0UbZQZoaS62gNpkPSgZF1Hp0Z?si=ZRuVzYWdsgTnJ_-X

Even with everything "full off" - you can see that the ESP intervention flag is being thrown. Also the brake overheat flag was thrown well earlier into the session so I'm not 100% sure that is affecting anything at that point either.

I'm going to try and throw some more stuff on my logging list before Friday and hopefully be able to play with some of it.

 

[victorofhavoc]

I don’t believe there’s a sensor to pull, all of that most likely works off the four ABS sensors.

If you wanna try the car out Mk2 style with absolutely no interference pull the ABS fuse. You also lose cruise control & airbags, but for track duty who cares.

I used that to defeat TC at Zmax playing around with 1/4 passes, and there’s absolutely zero computer aided interference.

Are you sure? I haven't found a car in the last 20 years that didn't have a yaw sensor. Typically they're somewhere on the interior transmission tunnel, usually around the center weight area of the car. I found the part number for an a4, but haven't dug to deep to find one for the golf: 8K0907637C

 

[GTI Jake]

I don’t believe there’s a sensor to pull, all of that most likely works off the four ABS sensors.

If you wanna try the car out Mk2 style with absolutely no interference pull the ABS fuse. You also lose cruise control & airbags, but for track duty who cares.

I used that to defeat TC at Zmax playing around with 1/4 passes, and there’s absolutely zero computer aided interference.

Are you sure? I haven't found a car in the last 20 years that didn't have a yaw sensor. Typically they're somewhere on the interior transmission tunnel, usually around the center weight area of the car. I found the part number for an a4, but haven't dug to deep to find one for the golf: 8K0907637C

There’s one way to find out, if we get some snow I’ll pull the ABS fuse & hoon around a bit.

 

[DerHase]

Are you sure? I haven't found a car in the last 20 years that didn't have a yaw sensor. Typically they're somewhere on the interior transmission tunnel, usually around the center weight area of the car. I found the part number for an a4, but haven't dug to deep to find one for the golf: 8K0907637C

It's the ABS module itself, not like anything in the past with a separate sensor to pull.

Unfortunately pulling the ABS fuse will also do away with electronic brake force distribution (brake bias adjustment) - keeping that would be a VERY good thing to do.


I absolutely do not recommend doing it - but on the Mazda2, the guys who run B-spec install the airbag module upside down (in cars that do NOT have any airbags anymore!!!) because it confuses the ABS module as to which way is up and down, but keeps ABS itself in-tact. Not sure what effect there is on EBD though - I'd IMAGINE that still having all 4 wheel speed sensors it could potentially have a failsafe calculation that can infer g-forces based on rates of decel, or it just might not work at all.

 

[victorofhavoc]

Well that explains why so much of the dash Christmas trees and it throws 18 faults when you melt a sensor. Silly stuff

 

[tigeo]

With the awd wagon, I've had a bit of minor "butt wiggle" in the T1 braking zone at VIR coming down from the low 130s (and she does have a BIG ASS!) but nothing severe or that caused ESC to kick in/flash the lights with ESC Off and the typical brake module mods that folks do (straight ahead brake stabilization + hyrdaulic brake assist both to off....that I am not convinced actually do what folks think). It really seems the GTI has more going on w/r to that being fwd....at least based on all the comments I've read....maybe also in-part due to its lower weight? Keep in mind I've been on at best w/r to tires, the Accelera 651s so next month will be the first time on "real" 200s (my new Nexens) that were v. good at Fastivus so I have high hopes these will rock it at VIR. I did feel more squirminess in that brake zone a few years ago at my first few HPDEs at VIR on the UHP all seasons which makes sense. Overall I'd say my car is v. stable braking with the APR BBK up front and the stock 272s out back.

 

[DerHase]

With the awd wagon, I've had a bit of minor "butt wiggle" in the T1 braking zone at VIR coming down from the low 130s (and she does have a BIG ASS!) but nothing severe or that caused ESC to kick in/flash the lights with ESC Off and the typical brake module mods that folks do (straight ahead brake stabilization + hyrdaulic brake assist both to off....that I am not convinced actually do what folks think). It really seems the GTI has more going on w/r to that being fwd....at least based on all the comments I've read....maybe also in-part due to its lower weight? Keep in mind I've been on at best w/r to tires, the Accelera 651s so next month will be the first time on "real" 200s (my new Nexens) that were v. good at Fastivus so I have high hopes these will rock it at VIR. I did feel more squirminess in that brake zone a few years ago at my first few HPDEs at VIR on the UHP all seasons which makes sense. Overall I'd say my car is v. stable braking with the APR BBK up front and the stock 272s out back.

Wheelbase makes it unstable. Your added weight out back likely helps (stability) simply because you've got more weight on the rear, and both cars have similar deceleration capabilities so the rear won't get as light.

My Mazda2 under hard braking was... Eventful... at another ~5.6in shorter than the MK7 at 98in. MK7 is 103.5-103.6in.

The 2 only had ~400 or 450lb on each rear corner. With driver. It wasn't far from lifting both rear tires off the ground in hard braking zones Better tires required turn down the rear damping to settle it some.

 

[Mini7]

2023 Rugby World Cup Final

Not sure if there are any rugby players/rugby fans on here….???
Huge final! This is going to be a humdinger.

 

[GTIfan99]

Anyone know specifics of the incident at the Daytona Audi event over the weekend that killed 2?

Some groups are better than others at separating groups by talent and speed.

I wasn't thrilled at the last SCCA event I did there. We had everything from a Mazda 2 to heavily modded ZL1's and GT500's. The closing speeds were hairy. I was hitting 148 mph and they had to be hitting well over 170, with the 2 topping out at maybe 100.

I enjoy Daytona and Sebring, but the speeds you see give my butthole clenching action a workout without a cage, fire system, proper seat and all the other safety gear.