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"big brake kit" info?
- Thread starter skikir
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in my case, yes.
before i couldn't lock all the wheels.
after i could, and could leave 4 lines of rubber in the road.
can't guarantee the brakes were in tip-top shape before (they looked ok though when i took them off) but there was a big difference in how scary it was in traffic.
before i couldn't lock all the wheels.
after i could, and could leave 4 lines of rubber in the road.
can't guarantee the brakes were in tip-top shape before (they looked ok though when i took them off) but there was a big difference in how scary it was in traffic.
swift6
Yoda
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My front brakes are still stock. I do have Morgan rear wheel cylinders though. That is the single largest improvement. A fairly accurate testing situation took place a few years ago by some members of 6-pack.
The stock calipers were even rebuilt before hand so that they knew they were good. Tested on the same car with the same braking system. A baseline stock system was tested first. Then the front brakes were changed, test was conducted again, then the rear wheel cylinders were changed to the Morgan units and the test was run again.
The test showed that the Toyota calipers offered no reliably significant change in stopping distance.
The area of the four pistons in the Toyota caliper is nearly identical to the area of the two pistons on the stock TR6 caliper. Which should equal nearly identical pressures against the rotor. The four pistons in the Toyota caliper spread that force out a bit more evenly though. Which should result in less fade during extended periods of heavy braking.
The largest improvement came in the Morgan rear wheel cylinders. They showed a significant decrease in stopping distance.
Oh, and being able to lock up you tires doesn't necessarily mean good brakes as much as it could mean poor tires. After all, the tires actually stop your car, your brakes convert kinetic energy into heat. When your tires lock, you just lost control and became a passenger. Threshold breaking is an art best learned in advance if you intend to push the limits.
/ubbthreads/images/graemlins/cheers.gif
The stock calipers were even rebuilt before hand so that they knew they were good. Tested on the same car with the same braking system. A baseline stock system was tested first. Then the front brakes were changed, test was conducted again, then the rear wheel cylinders were changed to the Morgan units and the test was run again.
The test showed that the Toyota calipers offered no reliably significant change in stopping distance.
The area of the four pistons in the Toyota caliper is nearly identical to the area of the two pistons on the stock TR6 caliper. Which should equal nearly identical pressures against the rotor. The four pistons in the Toyota caliper spread that force out a bit more evenly though. Which should result in less fade during extended periods of heavy braking.
The largest improvement came in the Morgan rear wheel cylinders. They showed a significant decrease in stopping distance.
Oh, and being able to lock up you tires doesn't necessarily mean good brakes as much as it could mean poor tires. After all, the tires actually stop your car, your brakes convert kinetic energy into heat. When your tires lock, you just lost control and became a passenger. Threshold breaking is an art best learned in advance if you intend to push the limits.
/ubbthreads/images/graemlins/cheers.gif
There was another test that showed better braking with the Toyota calipers, just read it a week ago but cant remember what site it was on---I will look for it when I get a chance. I could never lock my brakes up before and it never stoped that well either, hopefully now I will be able to, It will just show that they have the ability to grab better and maybe be more efficient at stoping when using controled ("threshold") braking.
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[ QUOTE ]
Oh, and being able to lock up you tires doesn't necessarily mean good brakes as much as it could mean poor tires.
[/ QUOTE ]
I was talking apples:apples on a set of new Yoko Avids. Before not able to lock under any circumstances : after could lock the wheels if I wanted to.
I'm not trying to suggest this shortens the stopping distance, but it hints that there is additional clamping force on the rotors and the drums.
How one chooses to use that force is of course up to the individual /ubbthreads/images/graemlins/grin.gif In my case it was to make sure the brakes were roughly equally proportioned on all 4 wheels.
Oh, and being able to lock up you tires doesn't necessarily mean good brakes as much as it could mean poor tires.
[/ QUOTE ]
I was talking apples:apples on a set of new Yoko Avids. Before not able to lock under any circumstances : after could lock the wheels if I wanted to.
I'm not trying to suggest this shortens the stopping distance, but it hints that there is additional clamping force on the rotors and the drums.
How one chooses to use that force is of course up to the individual /ubbthreads/images/graemlins/grin.gif In my case it was to make sure the brakes were roughly equally proportioned on all 4 wheels.
JamesWilson
Yoda
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[ QUOTE ]
There was another test that showed better braking with the Toyota calipers, just read it a week ago but can't remember what site it was on---
[/ QUOTE ]
This was on the VTR site, the link is:
https://www.vintagetriumphregister.org/maintain/brake-conversion.shtml
They found:
[ QUOTE ]
All tests were performed with a newly rebuilt master cylinder, using DOT 5 brake fluid. The variations tested and the results of the testing were:
1. Early (prior to metric calipers, Girling 16PB) stock configuration with semi metallic pads, composite shoes and 0.70" rear wheel cylinders: 262 feet with a standard deviation of 19; 6 data points, tossed out both the minimum and maximum measurements.
2. Toyota front calipers with semi metallic pads, composite shoes: 243 feet with a standard deviation of 9; 8 data points, tossed out minimum and maximum.
3. Toyota front calipers with semi metallic pads, composite shoes with a 7/8 inch rear wheel cylinder: 215 feet with a standard deviation of 9; 9 data points, tossed out minimum and maximum.
As you can see, there was a significant performance advantage to the four piston caliper conversion. Since the pad surface area is much larger, this performance differential should increase if the brakes are used a lot and begin to heat up.
[/ QUOTE ]
Using the Toyota calipers alone there was, in general terms, a roughly 10% reduction in stopping distance (262->243) and more consistent braking performance (standard deviation halved: 19->9).
A two sample t test could be run to determine whether there was a statistically signioficant difference in the braking performance of the two set ups:
t = 262-243 / (((19^2)/8)+((9^2)/6)))^.5
t = 19 / 8.38 = 2.27
Looking at the appropriate statistical tables yields an estimate that there's a 97.5% likelihood that average braking distances are improved over stock.
Of course this combined with the rear cylinders makes braking all that much better....
There was another test that showed better braking with the Toyota calipers, just read it a week ago but can't remember what site it was on---
[/ QUOTE ]
This was on the VTR site, the link is:
https://www.vintagetriumphregister.org/maintain/brake-conversion.shtml
They found:
[ QUOTE ]
All tests were performed with a newly rebuilt master cylinder, using DOT 5 brake fluid. The variations tested and the results of the testing were:
1. Early (prior to metric calipers, Girling 16PB) stock configuration with semi metallic pads, composite shoes and 0.70" rear wheel cylinders: 262 feet with a standard deviation of 19; 6 data points, tossed out both the minimum and maximum measurements.
2. Toyota front calipers with semi metallic pads, composite shoes: 243 feet with a standard deviation of 9; 8 data points, tossed out minimum and maximum.
3. Toyota front calipers with semi metallic pads, composite shoes with a 7/8 inch rear wheel cylinder: 215 feet with a standard deviation of 9; 9 data points, tossed out minimum and maximum.
As you can see, there was a significant performance advantage to the four piston caliper conversion. Since the pad surface area is much larger, this performance differential should increase if the brakes are used a lot and begin to heat up.
[/ QUOTE ]
Using the Toyota calipers alone there was, in general terms, a roughly 10% reduction in stopping distance (262->243) and more consistent braking performance (standard deviation halved: 19->9).
A two sample t test could be run to determine whether there was a statistically signioficant difference in the braking performance of the two set ups:
t = 262-243 / (((19^2)/8)+((9^2)/6)))^.5
t = 19 / 8.38 = 2.27
Looking at the appropriate statistical tables yields an estimate that there's a 97.5% likelihood that average braking distances are improved over stock.
Of course this combined with the rear cylinders makes braking all that much better....
Information is available at the following web pages:
https://www.turbo-tr6.info/tr6_brake_install.html
https://www.turbo-tr6.info/tr6_brake_test.html
Please let me know if there are any corrections or omissions.
Thanks
Lee
https://www.turbo-tr6.info/tr6_brake_install.html
https://www.turbo-tr6.info/tr6_brake_test.html
Please let me know if there are any corrections or omissions.
Thanks
Lee
Simon TR4a
Jedi Knight
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While I must say I have been able to lock brakes with stock calipers and really grippy R compound tyres there should also be a benefit in more precise modulation of braking effort because the multiple pistons will apply pressure more evenly over the surface of the pad.
Pushing just in the centre may cause the pad to "warp" slightly under heavy braking.
It is also possible that a modern caliper designed for a heavier vehicle may also be stiffer than the Triumph caliper, though it does look pretty substantial! Caliper deflection is sometimes a problem with lightweight calipers, and also causes uneven pressure application across the surface of the pad.
This all seems pretty extreme, though, for normal driving!
Simon.
Pushing just in the centre may cause the pad to "warp" slightly under heavy braking.
It is also possible that a modern caliper designed for a heavier vehicle may also be stiffer than the Triumph caliper, though it does look pretty substantial! Caliper deflection is sometimes a problem with lightweight calipers, and also causes uneven pressure application across the surface of the pad.
This all seems pretty extreme, though, for normal driving!
Simon.
swift6
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[ QUOTE ]
there should also be a benefit in more precise modulation of braking effort because the multiple pistons will apply pressure more evenly over the surface of the pad.
Pushing just in the centre may cause the pad to "warp" slightly under heavy braking.
[/ QUOTE ]
Which for me is the best reason to change to the Toyota calipers and why I might eventually do it. IMHO the 10% change is barely enough to justify the change in and of itself. In todays world most cars will still stop shorter than a TR6 (on normal, non high performance tires). Your decreased stopping distance doesn't mean a lot when the guy in front still stops quicker than you.
Which is why I always look for ways to drive around accidents instead of hopping on the brakes and praying. But then again, sometimes your a passenger no matter what you try or how well you plan.
/ubbthreads/images/graemlins/cheers.gif
there should also be a benefit in more precise modulation of braking effort because the multiple pistons will apply pressure more evenly over the surface of the pad.
Pushing just in the centre may cause the pad to "warp" slightly under heavy braking.
[/ QUOTE ]
Which for me is the best reason to change to the Toyota calipers and why I might eventually do it. IMHO the 10% change is barely enough to justify the change in and of itself. In todays world most cars will still stop shorter than a TR6 (on normal, non high performance tires). Your decreased stopping distance doesn't mean a lot when the guy in front still stops quicker than you.
Which is why I always look for ways to drive around accidents instead of hopping on the brakes and praying. But then again, sometimes your a passenger no matter what you try or how well you plan.
/ubbthreads/images/graemlins/cheers.gif
When I got my first TR6, a 1970, on the test drive, when I came to the first stop sign and stepped on the brakes they almost locked up. They were strong not touchy. I thought that was normal for a TR6. I had a trailer hitch put on and never thought anything about pulling my 15 foot sailboat with it. Boat and trailer must have weighed 1000 punds. White boat and white TR looked matched. On a trip to Reno, Nevada from Eugene, Oregon the brake booster diaphram blew. I clamped the vaccuum line and continued the trip and no problem stopping the car. I replaced the booster with a used one and all was fine again. The PO had set the car up for road racing but I don't know what he had done to it other than putting on 14" rims and upgraded anti roll bar on the front and putting on REPCO pads. I know the repco pads were direct replacements because the originals were in the repco box with a bunch of spare/used parts I got with the car and kept after I traded in the TR. I had to rebuild the master cylinder and used standard parts with no change to the brakes. Got married and had to get something sensible, a factory ordered 5.0L HO V8 5spd Mustang GT convertable - hey, it did have four seats! Unfortunately it did everything so well it was boring! Gave it to the wife and found another TR.
My second, a 74.5 and third, a 72 are both braking challenged. Even with EBC green pads, which helped, they are nothing like the first one. Like I said, I thought they were normal and never really investigated the difference. I bought the car in Portland in about 1983 so I don't know what was available back then. If the PO is out there I'd like to know what was done!
My second, a 74.5 and third, a 72 are both braking challenged. Even with EBC green pads, which helped, they are nothing like the first one. Like I said, I thought they were normal and never really investigated the difference. I bought the car in Portland in about 1983 so I don't know what was available back then. If the PO is out there I'd like to know what was done!
Simon TR4a
Jedi Knight
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It just occurred to me that noone has mentioned the role of shock absorbers in braking.
Having worn out shocks means the tyre does not stay firmly planted on the road and braking distances can increase considerably.
Of course, people who drive around with worn shocks probably don't maintain anything else on the car either, so that wouldn't be us!
Simon. /ubbthreads/images/graemlins/nonono.gif
Having worn out shocks means the tyre does not stay firmly planted on the road and braking distances can increase considerably.
Of course, people who drive around with worn shocks probably don't maintain anything else on the car either, so that wouldn't be us!
Simon. /ubbthreads/images/graemlins/nonono.gif
Re: Performance pads for the Toyota calipers
FYI, The only performance pads that seems to be availible for the Toyota calipers, Axxis part number n1010-119099 (Ultimate Ceramics) available at www.drivewire.com
FYI, The only performance pads that seems to be availible for the Toyota calipers, Axxis part number n1010-119099 (Ultimate Ceramics) available at www.drivewire.com
swift6
Yoda
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Re: Performance pads for the Toyota calipers
The test referenced above showed a drop of 262 feet to 243 feet with the Toyota calipers alone. I didn't see where the test mentioned speed but showed 3000rpm with 205/70R15's and 3.45 rear differential ratio. A WAG would put that to around 70-80mph. The Toyota calipers AND the Morgan wheel cylinders dropped the stopping distance to 215.
In the August issue of Road&Track, Road Test Summary, 126 new models ('06) vehicles are represented. Including sports cars, SUV's, sedans, mini-vans and trucks etc... The average stopping distance of these vehicles from 80 mph was 212 feet.
So the whole kit & kaboodle of four piston calipers and larger rear wheel cylinders can put the TR6 down near the average stopping distance of those 126 new vehicles represented.
Freely admitting that my earlier opinion may have been misplaced. I may just have to reconsider my position on the whole matter.
Mia Culpa...
/ubbthreads/images/graemlins/cheers.gif
The test referenced above showed a drop of 262 feet to 243 feet with the Toyota calipers alone. I didn't see where the test mentioned speed but showed 3000rpm with 205/70R15's and 3.45 rear differential ratio. A WAG would put that to around 70-80mph. The Toyota calipers AND the Morgan wheel cylinders dropped the stopping distance to 215.
In the August issue of Road&Track, Road Test Summary, 126 new models ('06) vehicles are represented. Including sports cars, SUV's, sedans, mini-vans and trucks etc... The average stopping distance of these vehicles from 80 mph was 212 feet.
So the whole kit & kaboodle of four piston calipers and larger rear wheel cylinders can put the TR6 down near the average stopping distance of those 126 new vehicles represented.
Freely admitting that my earlier opinion may have been misplaced. I may just have to reconsider my position on the whole matter.
Mia Culpa...
/ubbthreads/images/graemlins/cheers.gif