Time to step up the Brake Game
06-05-2013, 03:49 PM
#62
Now you've done it...actual data that won't serve to satisfy all the people who think too ******* much. I love it how people can arbitrarily "find" problems when there aren't any. ABS or Stability Control have no way of knowing how effective the result of this blind output actually was, other than having to not compensate for an over correction which is possible even with stock components.
The system has no way of knowing how much brake force is actually being applied to the rotor as it will vary greatly under many conditions (cold brakes, hot brakes, wet brakes, sticky race pads, etc). When the channel is activated, it is done blindly until the opportunity that called for the output no longer exists. No more, no less. There is no way to measure temperature, there is no rheostat attached to the brake pedal...we're not driving the Mars lander here.
I get the feeling that Barrok would be too afraid to cut the tags off his mattress.
The system has no way of knowing how much brake force is actually being applied to the rotor as it will vary greatly under many conditions (cold brakes, hot brakes, wet brakes, sticky race pads, etc). When the channel is activated, it is done blindly until the opportunity that called for the output no longer exists. No more, no less. There is no way to measure temperature, there is no rheostat attached to the brake pedal...we're not driving the Mars lander here.
I get the feeling that Barrok would be too afraid to cut the tags off his mattress.
06-05-2013, 03:51 PM
#63
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06-05-2013, 04:00 PM
#65
06-06-2013, 01:21 AM
#67
I'm not trying to discourage anybody from improving on existing components. I think the innovation is great and that is why I am contributing useful information to this thread from somebody experience and is knowledgeable on the subject. I am simply bringing up concerns from doing this swap that may negate the entire point of doing the swap in the first place.
There is a great episode of Top gear where they pimp out a car with a bunch of go fast performance parts and expect to get better track times..to much of their dismay.
Positive feedback is as useful to me as **** on a bull. Get me objective data that says if makes you faster around a track or that your stopping distance has decreased X amount and I'll acknowledge that the swap will net you gains even though it isn't optimized in our setups. I have no doubts that the system WORKS for those few people that are running it. That is one datapoint in time. Typically for me modding a car is a bit more involved than just slapping on parts and hoping they work. I want them to work in every scenario possible, street, track etc. I want them to work for the life of the vehicle so acknowledging the shortcomings early on is beneficial to understanding how and why they will fail later.
I'm trying to entertain a technical discussion here which some people have a hard time grasping.
It would be nice if one of the dealer peoples that troll these forums could get us specs on the parts between both vehicles to compare measurements.
Things like master cylinder bore, booster part#'s, min thickness difference between rotors, caliper volumes etc etc.
Instead of just trying on parts that fit and maybe only getting 1% gain by chance. Do some maths! and turn the gain to 25% !
Most of you guys know what you are doing, I have no doubt about that. But I'm of the opinion, do things right once, don't worry about it ever again.
I'm not sure where you got that from but it should read Decreasing clamp loads will neuter your ABS system. From the context i was using, doing this swap will lower your effective clamp load if the displacement volume is increased by going to the V2 caliper.
Think of if like this.
1- with a V1 Caliper you push your brake pedal halfway to get a full pressure abs stop.
2- with a V2 Caliper you would have to push your brakes all the way to the floor to get the same results and potentially not even get to full pressure abs stop because you ran out of fluid to push in the master cylinder so your piston is bottomed out and has nowhere left to go potentially only getting you 3/4 the pressure of the OEM system.
These are just made up numbers, but highlight the risks of just slapping on parts without actually measuring things.
The bigger surface area of V2 parts could just be masking the systems inefficiencies for a while up until your lining thickness is reduced when you will actually see situations like this where you could be at max pedal travel and have nothing left to push.
I think I've beat this to death.
There is a great episode of Top gear where they pimp out a car with a bunch of go fast performance parts and expect to get better track times..to much of their dismay.
Positive feedback is as useful to me as **** on a bull. Get me objective data that says if makes you faster around a track or that your stopping distance has decreased X amount and I'll acknowledge that the swap will net you gains even though it isn't optimized in our setups. I have no doubts that the system WORKS for those few people that are running it. That is one datapoint in time. Typically for me modding a car is a bit more involved than just slapping on parts and hoping they work. I want them to work in every scenario possible, street, track etc. I want them to work for the life of the vehicle so acknowledging the shortcomings early on is beneficial to understanding how and why they will fail later.
I'm trying to entertain a technical discussion here which some people have a hard time grasping.
It would be nice if one of the dealer peoples that troll these forums could get us specs on the parts between both vehicles to compare measurements.
Things like master cylinder bore, booster part#'s, min thickness difference between rotors, caliper volumes etc etc.
Instead of just trying on parts that fit and maybe only getting 1% gain by chance. Do some maths! and turn the gain to 25% !
Most of you guys know what you are doing, I have no doubt about that. But I'm of the opinion, do things right once, don't worry about it ever again.
I'm not sure where you got that from but it should read Decreasing clamp loads will neuter your ABS system. From the context i was using, doing this swap will lower your effective clamp load if the displacement volume is increased by going to the V2 caliper.
Think of if like this.
1- with a V1 Caliper you push your brake pedal halfway to get a full pressure abs stop.
2- with a V2 Caliper you would have to push your brakes all the way to the floor to get the same results and potentially not even get to full pressure abs stop because you ran out of fluid to push in the master cylinder so your piston is bottomed out and has nowhere left to go potentially only getting you 3/4 the pressure of the OEM system.
These are just made up numbers, but highlight the risks of just slapping on parts without actually measuring things.
The bigger surface area of V2 parts could just be masking the systems inefficiencies for a while up until your lining thickness is reduced when you will actually see situations like this where you could be at max pedal travel and have nothing left to push.
I think I've beat this to death.
are things better with the largest rotor you can fit? sure, but you still get positives from running the larger caliper
06-06-2013, 08:29 AM
#68
Lets also not forget the subjective portion of braking like pedal feel and response. Not everything in a modification has an objective measurable benefit, i.e. porting a throttle body. While objective data is great, it only tells part of the story.
06-06-2013, 09:48 AM
#69
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Considering barrock69 wanted to have a technical discussion, I don't see any tech in his posts at all - just a bunch of suppositions. The brake balance is just math. Before I went forward with this swap on my own car, I did that math and posted it in the big "V2 brakes on a V1" thread on cadillacforums 18 months ago:
The added piece of information folks dug up and posted in this thread (that the V2 uses the same MC bore as the V1) further cements the fact that all of the hand wringing is much ado about nothing.
The brakes feel exactly the same during daily driving, as I would expect. On track there is no question that the brakes gave me the additional performance that I was looking for. As I explained over on CF.com, with the V1 brakes I felt that I was asking for every last bit of effort from the brakes, and sometimes it felt like it might not be enough. If I caught someone up in a braking zone, there wasn't that extra bit of braking capacity to account for someone who maybe checks up more than I expected them to. With the V2 brakes, that capacity is there. I can take a pass signal from a 911 going into the braking zone at VIR's turn 1 and very easily haul the car down. That prompted the following conversation between me and my instructor buddy who was riding along:
Him: "Brakes work!"
Me: "Yeah."
(Followed shortly thereafter, albeit hard to hear...)
Him: "These seats are horrible!"
Me: "Yeah."
OK, some brake math:
V1 setup: 40 & 44mm pistons, 355mm rotor diameter, pad height ~61mm
V2 setup, 30, 34 & 38mm pistons, 370mm rotor diameter, pad height ~65mm
V1 caliper piston area = 5554.3mm^2
V2 caliper piston area = 5497.8mm^2
The V2 setup will require slightly less pedal movement to generate the same clamping force. (Since the piston area is a wee bit smaller, the master cylinder has to move a little bit less to push enough fluid to make the pistons move a certain distance. Less master cylinder movement = less pedal movement.) The effect should be barely perceptible (if at all), I would think.
V1 rotor effective radius ~157.5mm
V2 rotor effective radius ~163.5mm
The effective radius isn't quite in the center of the pad - it's a bit closer to the outer edge of the rotor. Somewhere there's a formula for the effective radius, but I wasn't able to find it during a quick search, so I just assumed it's 2/3 of the pad height. Close enough for government work. I also assumed the outer edge of the pad is right on the outer edge of the rotor, which isn't quite true, but again, close enough for government work.
End result is a ~2.75% shift in brake bias to the front. That, too, should be barely perceptible. If you assume the effective radius is at the center of the pad height, then that drops to 2.3% shift to the front. The actual number is probably somewhere in between.
So, the 6-pot calipers should work just fine with the V1 master cylinder, and won't throw the car's brake bias all out of whack.
V1 setup: 40 & 44mm pistons, 355mm rotor diameter, pad height ~61mm
V2 setup, 30, 34 & 38mm pistons, 370mm rotor diameter, pad height ~65mm
V1 caliper piston area = 5554.3mm^2
V2 caliper piston area = 5497.8mm^2
The V2 setup will require slightly less pedal movement to generate the same clamping force. (Since the piston area is a wee bit smaller, the master cylinder has to move a little bit less to push enough fluid to make the pistons move a certain distance. Less master cylinder movement = less pedal movement.) The effect should be barely perceptible (if at all), I would think.
V1 rotor effective radius ~157.5mm
V2 rotor effective radius ~163.5mm
The effective radius isn't quite in the center of the pad - it's a bit closer to the outer edge of the rotor. Somewhere there's a formula for the effective radius, but I wasn't able to find it during a quick search, so I just assumed it's 2/3 of the pad height. Close enough for government work. I also assumed the outer edge of the pad is right on the outer edge of the rotor, which isn't quite true, but again, close enough for government work.
End result is a ~2.75% shift in brake bias to the front. That, too, should be barely perceptible. If you assume the effective radius is at the center of the pad height, then that drops to 2.3% shift to the front. The actual number is probably somewhere in between.
So, the 6-pot calipers should work just fine with the V1 master cylinder, and won't throw the car's brake bias all out of whack.
The brakes feel exactly the same during daily driving, as I would expect. On track there is no question that the brakes gave me the additional performance that I was looking for. As I explained over on CF.com, with the V1 brakes I felt that I was asking for every last bit of effort from the brakes, and sometimes it felt like it might not be enough. If I caught someone up in a braking zone, there wasn't that extra bit of braking capacity to account for someone who maybe checks up more than I expected them to. With the V2 brakes, that capacity is there. I can take a pass signal from a 911 going into the braking zone at VIR's turn 1 and very easily haul the car down. That prompted the following conversation between me and my instructor buddy who was riding along:
Him: "Brakes work!"
Me: "Yeah."
(Followed shortly thereafter, albeit hard to hear...)
Him: "These seats are horrible!"
Me: "Yeah."
06-06-2013, 09:58 AM
#70
Considering barrock69 wanted to have a technical discussion, I don't see any tech in his posts at all - just a bunch of suppositions. The brake balance is just math. Before I went forward with this swap on my own car, I did that math and posted it in the big "V2 brakes on a V1" thread on cadillacforums 18 months ago:
The added piece of information folks dug up and posted in this thread (that the V2 uses the same MC bore as the V1) further cements the fact that all of the hand wringing is much ado about nothing.
The brakes feel exactly the same during daily driving, as I would expect. On track there is no question that the brakes gave me the additional performance that I was looking for. As I explained over on CF.com, with the V1 brakes I felt that I was asking for every last bit of effort from the brakes, and sometimes it felt like it might not be enough. If I caught someone up in a braking zone, there wasn't that extra bit of braking capacity to account for someone who maybe checks up more than I expected them to. With the V2 brakes, that capacity is there. I can take a pass signal from a 911 going into the braking zone at VIR's turn 1 and very easily haul the car down. That prompted the following conversation between me and my instructor buddy who was riding along:
Him: "Brakes work!"
Me: "Yeah."
(Followed shortly thereafter, albeit hard to hear...)
Him: "These seats are horrible!"
Me: "Yeah."
]
The added piece of information folks dug up and posted in this thread (that the V2 uses the same MC bore as the V1) further cements the fact that all of the hand wringing is much ado about nothing.
The brakes feel exactly the same during daily driving, as I would expect. On track there is no question that the brakes gave me the additional performance that I was looking for. As I explained over on CF.com, with the V1 brakes I felt that I was asking for every last bit of effort from the brakes, and sometimes it felt like it might not be enough. If I caught someone up in a braking zone, there wasn't that extra bit of braking capacity to account for someone who maybe checks up more than I expected them to. With the V2 brakes, that capacity is there. I can take a pass signal from a 911 going into the braking zone at VIR's turn 1 and very easily haul the car down. That prompted the following conversation between me and my instructor buddy who was riding along:
Him: "Brakes work!"
Me: "Yeah."
(Followed shortly thereafter, albeit hard to hear...)
Him: "These seats are horrible!"
Me: "Yeah."
]
Barrok69...do you approve?
06-06-2013, 11:16 AM
#72
06-06-2013, 11:54 AM
#75
TECH Fanatic
I can agree to this as well. I started working as a GM mechanic while I was still in HS and quickly became an ASE/GM Master with an L-1. Hell, I was a line tech at 17 lol. I often worked on many problem cases from the area with Nick D (a GM EE and drivability specialist) so I was afforded the opportunity to learn more than average techs at the time. While I no longer turn wrenches for a living, I still have access to GM Dealerworld through my old dealership, and they still claim my certs lol...a fair trade IMO.
I would however, refer to most of this as baseless speculation since the theory of operation (which was used as reference) was completely wrong.
Doesn't matter to me, I'm on my way home so I can finish logging/tuning my new combo!
I would however, refer to most of this as baseless speculation since the theory of operation (which was used as reference) was completely wrong.
Doesn't matter to me, I'm on my way home so I can finish logging/tuning my new combo!
06-06-2013, 01:59 PM
#77
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Did anyone measure the distance between the center of the mounting holes to the top of the pad between the v1 and v2 calipers? This would give an idea of overlap expected when using a v2 caliper on a v1 rotor. This difference could be minimal or it could be a lot and it really doesn't matter how big the rotor is that the caliper was originally designed for.
06-06-2013, 03:36 PM
#78
Did anyone measure the distance between the center of the mounting holes to the top of the pad between the v1 and v2 calipers? This would give an idea of overlap expected when using a v2 caliper on a v1 rotor. This difference could be minimal or it could be a lot and it really doesn't matter how big the rotor is that the caliper was originally designed for.
already been done.
06-06-2013, 03:54 PM
#79
TECH Enthusiast
I design, develop, and test entire vehicle chassis(wheels, tires, bushings, brakes, swaybars, springs, steering, shocks, etc...and then some) systems for a living. And then I track test the end results year round all over the country. It's only natural for me to ask the question that nobody has the answer to especially on a system that is kind of critical to the operation of a vehicle. I love stopping power and I love having more than the guy next to me. I don't dive in head first without knowing what's down there. Hence my passion for the topic.
I'm only trying to help here, not trying to **** on anybodies work. Even if I don't have the specifics to the problem at hand.
I didn't catch whoever's earlier post from back when, so I'm getting up to speed on this swap because I'm also interested in doing it. And when I see guys using V2 calipers with V1 rotors and they don't fit right etc etc... doesn't leave much to the imagination of what else they didn't take into consideration.
I am not allowed to give out any data that I have, otherwise I would. all the vehicles I work on are fully instrumented with yaw sensors, pressure transducers at every place possible, instrumented and thermocoupled custom double bleeder calipers, wearing/rubbing thermocouples on the rotors, tc's on the caliper surfaces, tc's through the pads etc etc...datalogging all in parallel to the vehicles CAN system and an external GPS system to paint a very accurate picture of the extensive track tests I do and whats happening every time the brake pedal is pressed. So to say the least.. it's a bit more than saying "it works". Let's just say I've seen my fair share of parts failures due to poor engineering or improper parts used and I don't wish the end results of that on anybody.
I'm glad some people can get some insight from my posts.
At the end of the day, you can only stop as good as the tires you have on your car
I'm only trying to help here, not trying to **** on anybodies work. Even if I don't have the specifics to the problem at hand.
I didn't catch whoever's earlier post from back when, so I'm getting up to speed on this swap because I'm also interested in doing it. And when I see guys using V2 calipers with V1 rotors and they don't fit right etc etc... doesn't leave much to the imagination of what else they didn't take into consideration.
I am not allowed to give out any data that I have, otherwise I would. all the vehicles I work on are fully instrumented with yaw sensors, pressure transducers at every place possible, instrumented and thermocoupled custom double bleeder calipers, wearing/rubbing thermocouples on the rotors, tc's on the caliper surfaces, tc's through the pads etc etc...datalogging all in parallel to the vehicles CAN system and an external GPS system to paint a very accurate picture of the extensive track tests I do and whats happening every time the brake pedal is pressed. So to say the least.. it's a bit more than saying "it works". Let's just say I've seen my fair share of parts failures due to poor engineering or improper parts used and I don't wish the end results of that on anybody.
I'm glad some people can get some insight from my posts.
At the end of the day, you can only stop as good as the tires you have on your car
06-07-2013, 02:40 PM
#80
AS a notice for anyone considering this swap. The caliper mounting bolt were incredibly hard for me to find at any dealer. had to go to 2 dealers to buy all four. also the part number for them is #11570788. I just finished bolting the calipers on. Now i just need to put the lines on and bleed these things. pictures to follow. Also i measure the over hang of the pad and it is almost dead on .25"