Lexus IS250 front F-Sport BBK
08-01-2011, 04:16 AM
#21
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That is an impressive project. I personally wouldn't go the same route, but then, different strokes.
Do you think you will also be spending the 4k for the rear brakes as well? How is the stability of the car with only the front brakes done, say stopping hard from 55-60mph, would there be any risk of the back end slipping out?
Do you think you will also be spending the 4k for the rear brakes as well? How is the stability of the car with only the front brakes done, say stopping hard from 55-60mph, would there be any risk of the back end slipping out?
Thanks...
I got the front F-Sport BBK for $2,600 and it cost me $1,900 for two sets of brackets and shims...I have a spare set...that is why it was so expensive.
The stability is fine...the back end tries to come forward only when you have too much rear braking...that is why you never do the rears first. My braking distance has probably came down a little bit, but not as much as you would think with such huge brakes.
I broke in (bedding in) the brakes from 60 and 80 miles/hour, trying to brake as hard as it can, yet not letting the ABS kick in. I had to do that 10 time...I only kissed the windshield twice...
08-01-2011, 05:09 AM
#22
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are you sure that the lines will fit the stock?
the TRD description goes:
Description:
Replacement Part only for Big Brake Kit. Use if you need to replace your brake lines that were included in the TRD Big Brake Kit. DOES NOT FIT OEM SIZE BRAKE KIT.
the TRD description goes:
Description:
Replacement Part only for Big Brake Kit. Use if you need to replace your brake lines that were included in the TRD Big Brake Kit. DOES NOT FIT OEM SIZE BRAKE KIT.
08-01-2011, 05:19 AM
#23
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08-03-2011, 02:41 AM
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Nice brake kit. Definitely unique!
Unfortunately, bigger brakes will not stop your car faster, just more consistently. The tires are what will control a lot of his stopping distance. The grippier the tire, the shorter the stops (in short). He's on pretty grippy tires now, but even they will give up at the amount of braking energy applied.
Look at this as a benefit for excessive stopping from high speed. These are a little overkill and the potential of them will never be realized, but they are a cool, unique mod.
TRD and F-Sport brakes are developed in collaboration with StopTech using Toyota supplied specifications and testing methods. As a result, the lines that fit the caliper are the same for both the TRD and F-Sport calipers, as well as any StopTech product.
That is an impressive project. I personally wouldn't go the same route, but then, different strokes.
Do you think you will also be spending the 4k for the rear brakes as well? How is the stability of the car with only the front brakes done, say stopping hard from 55-60mph, would there be any risk of the back end slipping out?
Do you think you will also be spending the 4k for the rear brakes as well? How is the stability of the car with only the front brakes done, say stopping hard from 55-60mph, would there be any risk of the back end slipping out?
Look at this as a benefit for excessive stopping from high speed. These are a little overkill and the potential of them will never be realized, but they are a cool, unique mod.
TRD and F-Sport brakes are developed in collaboration with StopTech using Toyota supplied specifications and testing methods. As a result, the lines that fit the caliper are the same for both the TRD and F-Sport calipers, as well as any StopTech product.
08-03-2011, 02:52 AM
#26
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This was for SoulShinobi
This thread is on the front brakes…
I will be working on the rears next…I haven’t even looked at the rears yet. I am looking for stainless steel braided lines for the rears though. Do you know anybody who is making them?
This thread is on the front brakes…
I will be working on the rears next…I haven’t even looked at the rears yet. I am looking for stainless steel braided lines for the rears though. Do you know anybody who is making them?
08-03-2011, 03:14 AM
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haha sorry it was me using my friends account cuz i was at his house.
i just assumed that it was 4 brake lines since it was $125! but then again it said it is only for the BBK which mean fronts only
Most of us are thinking accelerating faster with a turbo for $4500. He's working on stopping for that price!
08-03-2011, 04:57 AM
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Not quite…stopping is just one aspect of absolute confidence and therefore control of the car…anybody up for a run on US129 (Tail of the Dragon)?
Last edited by 2tCornot2tC; 08-03-2011 at 05:00 AM. Reason: added US129
08-03-2011, 12:14 PM
#31
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Юрий,
No...you can have a BBK for the rear and there is a BBK for the rear of the IS250. BBK just means Big Brake Kit...most of the time it is just put on the front though.
No...you can have a BBK for the rear and there is a BBK for the rear of the IS250. BBK just means Big Brake Kit...most of the time it is just put on the front though.
Last edited by 2tCornot2tC; 08-03-2011 at 12:41 PM.
08-03-2011, 04:01 PM
#33
Theory: Install BBK, car decreasing stopping distance from X to Y, correct?
You are stopping a car: Curb weight: 3,060 lb (1,387 kg) (manual); 3,102 lb (1,407 kg) (automatic) (+ Weight of dude behind the wheel)
If you drop the hood, roof, and hatch... and replace it with the Carbon Fiber bits. Would you then decrease your braking distance by more? I think you would, but since I have no cash to buy CF bits... no way to test.
You are stopping a car: Curb weight: 3,060 lb (1,387 kg) (manual); 3,102 lb (1,407 kg) (automatic) (+ Weight of dude behind the wheel)
If you drop the hood, roof, and hatch... and replace it with the Carbon Fiber bits. Would you then decrease your braking distance by more? I think you would, but since I have no cash to buy CF bits... no way to test.
08-03-2011, 04:20 PM
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momentum = mass x velocity,
force = mass x acceleration.
Both formulas have mass in em so if mass is reduced then you will stop faster/shorter distance! as long as the tires are good of course
force = mass x acceleration.
Both formulas have mass in em so if mass is reduced then you will stop faster/shorter distance! as long as the tires are good of course
08-03-2011, 05:27 PM
#35
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No…tires and tire contact patch would make the biggest difference in stopping distances…all other things left unchanged.
Yes, weight is your biggest enemy…but those are such minuscule examples that you would not see or feel a difference there. If you would decrease the unsprung mass (anything that follows the road…tires, wheels suspension arms, brakes, etc.), if you reduce that weight, even a miniscule amount, will make a significant difference. Taking 5% off of your unsprung mass is equivalent to taking 5% off the total weight of your car…in your case, about 300-lbs.
Last edited by 2tCornot2tC; 08-05-2011 at 08:44 AM. Reason: spelling
08-03-2011, 11:00 PM
#36
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Thanks!
I wish! That’s what cost me so much. I submitted the 3D model to two machine shops to bid on this job. One bid was for $4,300 for 4 brackets and 4 shims!
08-04-2011, 01:53 AM
#37
08-04-2011, 02:31 AM
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You’ve got to understand one thing…all brakes do, is convert kinetic energy into heat energy. Once you understand that, then you can start to figure out how to dissipate that energy. You can do that in one of two ways; you can absorb that energy, or you can conduct it away.
Absorption: the only way to absorb it is by having mass. The more mass, the more heat energy you can absorb away. But that is only for one stop! One panic stop…that is all the OEMs design for. The bigger, the heavier…usually not a good thing.
Conduction; this is drawing the heat out. One path is through the center of the disc, through the hub and into the bearing…everything heats up! Another way is by forced convection…this is where the fins in the center of the disc come in…the bigger, the bigger the radiator is.
Now, if you could get a larger disc, you will have a larger mechanical advantage and therefore less heat.
The short answer is that when you go fast, or race, you do the equivalent of a panic stop every time you slow the car down fast. Big brakes dissipate that energy so you can keep doing that repeatedly. Repetitive control!
Absorption: the only way to absorb it is by having mass. The more mass, the more heat energy you can absorb away. But that is only for one stop! One panic stop…that is all the OEMs design for. The bigger, the heavier…usually not a good thing.
Conduction; this is drawing the heat out. One path is through the center of the disc, through the hub and into the bearing…everything heats up! Another way is by forced convection…this is where the fins in the center of the disc come in…the bigger, the bigger the radiator is.
Now, if you could get a larger disc, you will have a larger mechanical advantage and therefore less heat.
The short answer is that when you go fast, or race, you do the equivalent of a panic stop every time you slow the car down fast. Big brakes dissipate that energy so you can keep doing that repeatedly. Repetitive control!
Last edited by 2tCornot2tC; 08-05-2011 at 08:49 AM. Reason: spelling - word usage
08-04-2011, 03:17 PM
#40
Ok, just trying to clear up any lingering thoughts about buying a BBK from any maker. The overall goal of a BBK is for consistent control, not for faster stopping.
Essentially for a daily driver the BBK will have minimal impact, however it will look hella sweet.
Essentially for a daily driver the BBK will have minimal impact, however it will look hella sweet.