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Discussion Starter #1
Would like to have some advice on big brake upgrade.
I have now sourced all the parts I need to do a complete brake overhaul and upgrade on my Passat, with multiple options for rotor sizes front and back.
I've heard that up to a 330mm(13.00) dia. rotor will be fine and I don't to worry about biasing. I'm really wanting to go with 355mm(14.00) dia. rotors. So with that option per what I've heard, I might have an issue with biasing.

Couple of questions, at what point do I have to really start worrying about brake biasing? If I put larger rotors on the back will that offset the difference of putting the 355mm rotors up front?


When I finally get to fitting this upgrade to my car I will supply pictures and all the info I've obtained to get to this point.
BTW, this is way beyond the W8 option I originally opted for.
 

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Which Passat? Not many options on a FWD for rear brake upgrades. Rotor size is not the main influence on brake bias, pads make a larger difference and calipers can have a reverse effect depending on piston displacement and master cylinder size.
 
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Discussion Starter #3
Which Passat? My 98 GLX FWD.
I've found a kit from Stop-Tech that has 355mm front rotors and keeps the stock rear rotor dia for the W8. I know the regular Passat GLS does not have rear rotors as big as the W8 from stock.
So with some knowns between the W8 and regular Passat I can come up with some rough calculations and keep things proportionate. I've found a few brake bias calculators on-line that take into account many, many options.

I think with that I can come up with some comparisons between what I have and what I'm trying to achieve.
 

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Don't forget that you will need a spare capable of fitting over the larger brakes.
 
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I did an upgrade on mine a long time ago (2004) with the Audi TT 225 set up, 312mm front. All that need to be changed was the rotors and the carriers and it worked out very well! i did EBC rotors, slotted and dimpled and EBC red stuff and blue racing brake fluid. To this day, that set up works very well! I have been thinking of upgrading once again to the 355mm upfront and place the 312 in the back, but more work is required for that to happen and we will be working on the power upgrade for her as well.
 

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What is it you are trying to achieve Andreas? Track car or DD? Less fade or shorter stopping distances? Wet or dry? Larger, heavier wheels and tires or oem? Does your driving style require bigger brakes?
 

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Discussion Starter #7
the 355mm upfront and place the 312 in the back, but more work is required for that to happen.
That's close to what I'm wanting to do.
Here's what I have:
Picked up a set of aluminum steering knuckles, wheel hubs, and 2 piston Lucas calipers from member vwb5t.
I also have a second set W8 aluminum steering knuckles, purchased a while back from eBay.
I just purchased a set of front 6 piston and rear 4 piston calipers from a 2004 VW Touareg. Those will be here next week.
I have the 355mm and 330mm front rotors but haven't gotten the rears yet. Still haven't decided what size. Will probably end up putting the regular W8 front rotor on the back.
With the Touareg calipers, I'll need to do some custom fab work to get those to bolt up to the A8 steering knuckles. Different size bolts. If my memory is correct, the Touareg uses 16mm and the Passat/Audi uses 14mm caliper mounting bolts.

I have enough parts here to do two front upgrades. I'm actually thinking of taking the second set and upgrading my wife's 2003 GLX front brakes to the standard W8 set-up.
 

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Discussion Starter #8
What is it you are trying to achieve Andreas? Track car or DD? Less fade or shorter stopping distances? Wet or dry? Larger, heavier wheels and tires or oem? Does your driving style require bigger brakes?
The reason for this upgrade on my car is simple, I live and drive in Phoenix. There are an alarming number of complete idiotic ass-clowns down here that don't have any clue on how to drive, and do 100 mph whenever they see a few hundred feet of open space on the road. A few months back I had a harrowing experience because of one these douche-bag ass-hats. I vowed to myself I would never let that happen to my wife and I again. Yeah I know I can't control other people, but being able to stop my car in a much quicker and shorter distance than factory is goal number 1!

This is a daily driver that sees rain maybe 6 times a year, a lot of highway driving. I have a set of 19" staggered wheels that I will probably put back on my car. I'd rather have 18" wheels but will see how much of an outlay I'm going to be up against first.
All this purchasing of parts for the brake upgrade (very cheap compared to a new kit like say Brembo) and all the other stuff I'm going to do to the car is ramping up quick. I'll need a new set of shoes for the 19" wheels. New rubber for the 19 inchers is cheaper than new 18" wheels and new rubber for them.
If I stick with the 19" wheels the size will be P235 in front and P265 in back. At the same time I will be swapping out the factory suspension and putting my PSS9 coil-overs in.

The reason for the (2) different front rotor sizes, if the 355mm front rotors create a squirrely braking condition I'll downsize the fronts to the 330mm. This isn't just about straight line braking. I need this car to be able to brake in any scenario. Which will be tested before I just go pound down the road.
 

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I installed a set of 13.1" rotors with stock calipers on a Supercharged B5.5 V6 4Mo sedan (it was ECS Stage2 or Stage3 many years ago). The owner used PBR Ultimate pads up front and PBR Metal Masters on the stock rear brakes. That car could stop like it ran into a brick wall, even with OEM brake lines. The 330mm will be plenty with decent pads.
 

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Hello Andreas,
"I need this car to be able to brake in any scenario." I don't know what this means, but it sounds scary. I don't know what driving in Phoenix is like, but reckless drivers are everywhere. Being able to stop on a dime "in any scenario" does not sound like an enhancement of your defensive driving skills. Yesterday, here in North Jersey, a driver of some kind of Ford SUV, decided an 18 wheeler was driving too aggressively in the left hand lane. The Ford got in front of the truck and hit the brakes (just ordinary Ford brakes, I imagine). The truck (air brakes) panicked and flipped onto the median divider and slid on the divider for half a football field. Fortunately, no one was killed. In the interest of fair play, both drivers were charged. There were no winners.
 

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Discussion Starter #11
Hello Andreas,
"I need this car to be able to brake in any scenario." I don't know what this means, but it sounds scary. I don't know what driving in Phoenix is like, but reckless drivers are everywhere. Being able to stop on a dime "in any scenario" does not sound like an enhancement of your defensive driving skills. Yesterday, here in North Jersey, a driver of some kind of Ford SUV, decided an 18 wheeler was driving too aggressively in the left hand lane. The Ford got in front of the truck and hit the brakes (just ordinary Ford brakes, I imagine). The truck (air brakes) panicked and flipped onto the median divider and slid on the divider for half a football field. Fortunately, no one was killed. In the interest of fair play, both drivers were charged. There were no winners.
I completely understand where your coming from, and you're right. It is not an improvement of my defensive driving skills. But I want my car to respond the way I want it to without losing control. Better tires, bigger brakes and a suspension that is second to none will fit that bill nicely.
Phoenix is not the worst for epically bad drivers, LA, Atlanta and Houston have their fair share too. I've driven in the 3 previous areas mentioned, but it just seems as though Phoenix drivers drive much faster most people anywhere else.
I've been to Houston a number of times and they drive fast there, but even faster in Phoenix.

I know in reality my car won't stop for every type scenario or situation I get into, but I'm looking for a MAJOR upgrade from factory so I can stop with much shorter distances when all hell happens in front me. The two biggest things I see down here are people driving in the carpool lane and suddenly realize they need to be getting off on the next exit that's less than a football fields length. Those people suddenly slam on the brakes and cut across 6 lanes of traffic like they're making a right hand turn.
The other major offense I see is people wanting to get into the next lane or the lane your in and they just move over, like now! Traffic regularly moves between 70 and 95mph on average, bumper to bumper, when it's moving. When somebody just decides to move over, more times than not I don't have any place to go except slow down to avoid getting my front corner clipped off. I need to have my car slow down in an instant to avoid getting wrapped up with the asshat who just decided to get in front of me because the rear of his car hasn't cleared the front mine yet. That miniscule moment of time that I need to slow down to avoid being hit is to short of a time for the factory supplied brakes to perform what I need them to do. but then just as fast, I need to be off the brakes so the guy behind me doesn't end up in my trunk. I haven't even been here a year yet and I have seen more epic accidents than all my years living in WI combined.

Side note.
I don't really condone such high rates of speed in such congested areas, but when everyone on the road is doing 85mph in a 55 or 60mph zone, being the keeper of speed is not very safe either. That just causes everybody to run right up on the tail of the person who is driving by the legal limit, and then at the very last moment decide change lanes. You then end up with a continuous chain of people swerving left and right to avoid the 'slow person'.
 

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Discussion Starter #12
GrandpaBill

I was trying to think of an analogy in my previous post. It's like comparing a 1972 Ford Pinto to a current Porsche 911 Carrera. While the Pinto has the all necessities to go down the road, the Porsche is far superior in everyway. That's a comparison to what I'm trying to achieve. The Passat is a fairly capable car right of the box, but I'm looking for something much more refined.
 

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Your going to need a rear bumper replacement....
 
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Discussion Starter #14
The Touareg calipers came yesterday. Holy crap those things are HUGE! The 17Z brake pad is as big as the factory Passat caliper.
Will post pictures soon.
 

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Can't wait to see.

On a side note. I got cut off yesterday afternoon on a busy road with no warning (sometimes they put the turn signal on to let you know they are coming over whether you like it or not). The guy got a blast from my horn as a sign of disapproval. At about 50mph, the jackhole brake checked me to an almost dead stop. The TT/A8 caliper/rotor combo made it feel like I hit something, it stopped me so hard. Tires were scrambling for traction to keep the ABS from coming on. Anything that was laying on the seats was now on the floor. That's in a B5.5 wagon. Can't imagine what your new setup would feel like.

Your going to need a rear bumper replacement....
That was my first thought. You can brake hard enough, but the guy behind you most likely cannot.
 
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I just got back from a trip to Sweden in a Volvo V90 with all the assist features and heads up display (great for keeping you close to the ever changing speed limits there). Outside of Amal, (famous for this film that had to be renamed in English: https://en.m.wikipedia.org/wiki/Show_Me_Love_(film) ) a student driver had whacked a Bambi and stopped completely in the middle of the road right past a hill. All the alarms and brake assist turned this into a drop-the-anchor perfect stop non-event.
Only tangentially relevant but wanted to share. Something tells me I’ll be driving a gizmo-machine in the next few years.
 

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I'd like to know the before and after panic stopping distances. Years ago the SCCA use to do these test all the time, but I haven't paid much attention to that stuff in a long while.
 

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@AndreasPassat, with Touareg brakes you have enough brake power. Original rims do not fit on these. What do you need 19 or 20inch rims?
 

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Discussion Starter #20
@AndreasPassat, with Touareg brakes you have enough brake power. Original rims do not fit on these. What do you need 19 or 20inch rims?
In the end I'm wanting to go with 18inch wheels, But I'm not 100% sure those are going to clear the caliper.
I do have a set 19inch wheels that I can use if need be. My only reasoning for NOT using the 19inch wheels is the distance between the road and the lip on the rim. While most of the roads here in AZ are decent, compared to WI they are stellar, I'd like to have just a smidge more room. But then again, I ran the 19inch wheels in WI for almost 2 years without bending the rims. That's saying something. Might as well just use them and be done with it.
 
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