Cayenne/Q7 rear calipers on the front?

[DAS_STIG]

Don't the q5 and macan front calipers sit behind the hub while the mk7 golf and audi s3/a3 sit in front of the hub? Meaning your bleeders would be upside down if you swapped one to the other?

Thanks

Sent from my SM-G900V using Tapatalk

This thread focuses on rear calipers. Also, you can swap blenders and crossover tubes to make them not be upside down.

 

[nono0044]

This thread focuses on rear calipers. Also, you can swap blenders and crossover tubes to make them not be upside down.

Doesn't look like the crossover tube and bleeders can be flipped. It's not symmetrical in the back.

I wonder how carbonfold's coworker managed to get around this problem. Did he just use the left caliper on the right side of the car, and vice versa?

That's only if the mounting is symmetrical, and the pistons are the same size, right?

See photo of his mounted:

https://www.dropbox.com/s/63gzq4o97zruvg3/Photo Mar 02, 4 00 48 PM.jpg?dl=0

 

[DAS_STIG]

Doesn't look like the crossover tube and bleeders can be flipped. It's not symmetrical in the back.

I wonder how carbonfold's coworker managed to get around this problem. Did he just use the left caliper on the right side of the car, and vice versa?

That's only if the mounting is symmetrical, and the pistons are the same size, right?

Sorry wasn't thinking on previous post. Yes. you can swap left/right to solve the issue as long as the caliper pistons are not staggered sizing. If they are staggered it wont work right because you'll actually be reversing the direction of brake rotor travel through the caliper by flipping sides.

 

[TheBlondeFella]

Does anyone have the definitive best option ... is it the 3.0 or the 2.0 litre?

There's a guy on the R owners club FB page that reckons the 2.0 is the option he used rather than the 3.0 option mentioned on here

 

[TheBlondeFella]

Does anyone also know how the piston size on these callipers compare to the TTRS / RS3 calliper pistons?

 

[LBmk7r]

3.0L caliper = 345mm rotors
2.0L caliper = 320mm rotors, you could use this on a non-PP GTI since it has the smaller rotors already.

the 3.0L caliper has 42mm piston according to the rebuild kits available.
https://www.zeckhausen.com/catalog/index.php?cPath=44_2617_5959_5962

 

[DAS_STIG]

3.0L caliper = 345mm rotors
2.0L caliper = 320mm rotors, you could use this on a non-PP GTI since it has the smaller rotors already.

the 3.0L caliper has 42mm piston according to the rebuild kits available.
https://www.zeckhausen.com/catalog/index.php?cPath=44_2617_5959_5962

The non-PP uses 312mm rotors, so that doesn't seem like it would work.

LoL, if those piston sizes are correct you have an area twice as large as the GTI front calipers. I believe the GTI uses 54mm piston on non-PP and 57mm on PP (someone provide correct numbers if those are off).

PP = 3.14 * (57mm / 2) ^ 2 = 2550
3.0L = 4 * 3.14 * (42mm / 2) ^ 2 = 5540

That'll give you an extremely soft pedal I believe.

 

[LBmk7r]

Interesting, how about that data vs the TT-RS caliper upgrade? those have 40mm / 44mm pistons and the same master cylinder as the mk7 R?

 

[Cuzoe]

I don't have any input as far as fitment for these calipers but I have Brembo 17z's up front on my Golf TDI. It has a smaller master cylinder than the GTI/R and the pedal feel is fine.

The initial bite isn't as hard as stock but actual braking performance is world's better, obviously. I prefer the way the pedal feels now; it's more progressive, not as touchy. For what it's worth I haven't driven a GTI/R so maybe you folks' pedal is already progressive, but mine wasn't in the Golf.

Sent from my ONEPLUS A6013 using Tapatalk

 

[DAS_STIG]

The non-PP uses 312mm rotors, so that doesn't seem like it would work.

LoL, if those piston sizes are correct you have an area twice as large as the GTI front calipers. I believe the GTI uses 54mm piston on non-PP and 57mm on PP (someone provide correct numbers if those are off).

PP = 3.14 * (57mm / 2) ^ 2 = 2550
3.0L = 4 * 3.14 * (42mm / 2) ^ 2 = 5540

That'll give you an extremely soft pedal I believe.

Interesting, how about that data vs the TT-RS caliper upgrade? those have 40mm / 44mm pistons and the same master cylinder as the mk7 R?

I realized I might have done this wrong. I do not believe you have to consider both sides of a fixed caliper in this equation since the pistons in a fixed caliper would travel half the distance of the floating caliper when the brake pedal is depressed. So the math should have been:

non-PP = 3.14 * (54mm / 2) ^ 2 = 2290 mm^2

PP = 3.14 * (57mm / 2) ^ 2 = 2550 mm^2

3.0L = 2 * 3.14 * (42mm / 2) ^ 2 = 2770 mm^2

TTRS = 3.14 * [(40mm / 2) ^ 2 + (44mm / 2) ^ 2] = 2775 mm^2

So looks like the 3.0L Q5 and TTRS are very similar and actually as far away from the PP as the non-PP ones are. The Q5 brakes being non-staggered piston sizing would also allow for the left/right calipers to be flipped to correct for the rearward of rotor vs front caliper mounting between the Q5/GTI.

 

[jmblur]

I believe the correct Audi part numbers are
8R0615107G
8R0615108G

Brembo 345mm calipers. More expensive than the Macan ones despite being unpainted... Go figure.

 

[victorofhavoc]

I realized I might have done this wrong. I do not believe you have to consider both sides of a fixed caliper in this equation since the pistons in a fixed caliper would travel half the distance of the floating caliper when the brake pedal is depressed. So the math should have been:

non-PP = 3.14 * (54mm / 2) ^ 2 = 2290 mm^2

PP = 3.14 * (57mm / 2) ^ 2 = 2550 mm^2

3.0L = 2 * 3.14 * (42mm / 2) ^ 2 = 2770 mm^2

TTRS = 3.14 * [(40mm / 2) ^ 2 + (44mm / 2) ^ 2] = 2775 mm^2

So looks like the 3.0L Q5 and TTRS are very similar and actually as far away from the PP as the non-PP ones are. The Q5 brakes being non-staggered piston sizing would also allow for the left/right calipers to be flipped to correct for the rearward of rotor vs front caliper mounting between the Q5/GTI.

Doesn't the master cylinder and ABS also regulate the amount of fluid pushed into the caliper to create the movement of the pistons? The volume of the caliper would then also determine percent change with depression and determine the distance the pistons move overall.

 

[DAS_STIG]

Doesn't the master cylinder and ABS also regulate the amount of fluid pushed into the caliper to create the movement of the pistons? The volume of the caliper would then also determine percent change with depression and determine the distance the pistons move overall.

Brake fluid is supposed to be a non-compressible fluid so i do not believe that the volume of fluid in the caliper would have any impact.

 

[victorofhavoc]

Brake fluid is supposed to be a non-compressible fluid so i do not believe that the volume of fluid in the caliper would have any impact.

right, but the larger piston area that the fluid presses on determines the stroke, and if the larger caliper has a smaller displacement percentage based on the volume and stroke, the piston wouldn't travel as far. That's where the oversized calipers for a system get their soft pedal, right?

I guess in theory, the caliper is just a full displacement chamber, and the piston is the only part that matters. In that case 2770/2550 = 1.086, so 8.6% less travel per pedal depression compared to stock.

 

[DAS_STIG]

right, but the larger piston area that the fluid presses on determines the stroke, and if the larger caliper has a smaller displacement percentage based on the volume and stroke, the piston wouldn't travel as far. That's where the oversized calipers for a system get their soft pedal, right?

I guess in theory, the caliper is just a full displacement chamber, and the piston is the only part that matters. In that case 2770/2550 = 1.086, so 8.6% less travel per pedal depression compared to stock.

I believe only the piston area determines the stroke as that is the only place the fluid can actually go. I don't understand what impact the volume of the caliper would have on this though. In theory you could put a 1 gallon jug of fluid with a piston at the end and as long as that piston is the same size as stock, the overall movement/pedal feel should not change. The soft pedal feel would be from the piston sizing being off.

I believe your last bit is reversed, you would have 8.6% more pedal travel for the same distance of piston travel.