IS-F Brakes
04-25-08, 11:39 AM
#31
Pole Position
It's because of the drilled holes that make the rotors look non-directional. The rotors on the ISF are, in fact, NOT directional and it's obvious by the cross drilling. Look at the left side, then look at the right side. The cross drilled holes are going in opposite directions.
04-25-08, 11:45 AM
#32
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i disagree. it's done if it's needed. if the brakes can be done for CHEAPER (meaning not directional) but achieve the same kind of cooling, then that's a smart move.
like i said the is-f rotors LOOK directional from outside coz' of the drilled holes, however it's not directional inside at all. therefore it's pointless to have 2 different designs.
however the wheels are different stories. they are directional coz' each side help to draw air INTO the brakes to help cooling.
look at the prices for the is-f brakes and the fsport brakes, and see how much more expensive f sport is. f sport has directional (from what i know), 2 piece rotors. if instead of 61k, people see 63k on the is-f, that wouldn't look good right? (as if we don't have enough people saying the is-f is too expensive)
like i said the is-f rotors LOOK directional from outside coz' of the drilled holes, however it's not directional inside at all. therefore it's pointless to have 2 different designs.
however the wheels are different stories. they are directional coz' each side help to draw air INTO the brakes to help cooling.
look at the prices for the is-f brakes and the fsport brakes, and see how much more expensive f sport is. f sport has directional (from what i know), 2 piece rotors. if instead of 61k, people see 63k on the is-f, that wouldn't look good right? (as if we don't have enough people saying the is-f is too expensive)
^^ Henry..
I really don't think it cost THAT much more to flip the drill hole pattern on the CNC machine before a run of rotors are made..
It would just be a flipped or mirrored pattern re-program.
I mean if Brembo cuts 5,000 rotors (front) one way..
It doesn't take much to flip the pattern a 2,500 and drill the other 2,500 in the other direction..
Just my opinion..
Jz
Last edited by Joe Z; 04-25-08 at 11:58 AM.
04-25-08, 11:57 AM
#33
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It's because of the drilled holes that make the rotors look non-directional. The rotors on the ISF are, in fact, NOT directional and it's obvious by the cross drilling. Look at the left side, then look at the right side. The cross drilled holes are going in opposite directions.
https://www.clublexus.com/forums/sho...d.php?t=341928
04-25-08, 12:10 PM
#34
It's because of the drilled holes that make the rotors look non-directional. The rotors on the ISF are, in fact, NOT directional and it's obvious by the cross drilling. Look at the left side, then look at the right side. The cross drilled holes are going in opposite directions.
04-25-08, 12:13 PM
#35
i don't know the exact answer joe, but are you sure the holes are drilled? as far as i know, that's very bad ideas, and that should NOT be the way to make rotors.
the rotors should be cast with the holes in them already, that's how you maintain the strengths. drill a plain rotors can affect the structure of the rotors.
and from my understanding, brembo GT kits and ap racing rotors, those holes are there from casting already?
the rotors should be cast with the holes in them already, that's how you maintain the strengths. drill a plain rotors can affect the structure of the rotors.
and from my understanding, brembo GT kits and ap racing rotors, those holes are there from casting already?
04-25-08, 12:39 PM
#36
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We can always call Brembo.....
I'm just going with what Lexus provides us.. from the Official Lexus Tech Sheet...
Type
Four-wheel power-assisted disc brakes (Brembo manufactured for Lexus) [3] with Anti-lock Braking System (ABS) and Electronic Brake force Distribution (EBD) and Brake Assist [12]
Front
14.2-in. drilled rotors with six-piston opposed aluminum calipers, drilled and ventilated discs, 1.2 in. thickness, high-friction brake pads [3]
Rear
13.6-in. drilled rotors with two-piston opposed aluminum calipers, drilled and ventilated discs, 1.1 in. thickness, high-friction brake pads [3]
[3] High-friction brakes are standard equipment for the front brakes only and require periodic inspection and measurement as outlined in the Warranty and Services Guide. The pads and rotors are expected to experience greater wear than conventional brakes. Pad life may be less than 20,000 miles, and brake rotor life may be less than 50,000 miles depending on driving conditions.
I'm just going with what Lexus provides us.. from the Official Lexus Tech Sheet...
Originally Posted by Lexus IS-F Tech Data on Brakes
Type
Four-wheel power-assisted disc brakes (Brembo manufactured for Lexus) [3] with Anti-lock Braking System (ABS) and Electronic Brake force Distribution (EBD) and Brake Assist [12]
Front
14.2-in. drilled rotors with six-piston opposed aluminum calipers, drilled and ventilated discs, 1.2 in. thickness, high-friction brake pads [3]
Rear
13.6-in. drilled rotors with two-piston opposed aluminum calipers, drilled and ventilated discs, 1.1 in. thickness, high-friction brake pads [3]
[3] High-friction brakes are standard equipment for the front brakes only and require periodic inspection and measurement as outlined in the Warranty and Services Guide. The pads and rotors are expected to experience greater wear than conventional brakes. Pad life may be less than 20,000 miles, and brake rotor life may be less than 50,000 miles depending on driving conditions.
Last edited by Joe Z; 04-25-08 at 12:48 PM.
04-25-08, 12:47 PM
#37
Tires contain the vast majority of your cars braking potential
04-25-08, 02:40 PM
#38
but from my understanding of building brakes, having a plain rotors and then drill, that's a big no no
04-25-08, 02:56 PM
#39
Looks like Brembo GT is drilled.
FAQ
Are discs with cast-in-place holes better than cross-drilled discs?
Brembo has extensively studied and tested cross-drilling versus casting the holes in place and found no significant effect on performance or durability.
FAQ
Are discs with cast-in-place holes better than cross-drilled discs?
Brembo has extensively studied and tested cross-drilling versus casting the holes in place and found no significant effect on performance or durability.
04-25-08, 05:26 PM
#40
and i remember you said they crack just as easily?
if that's the case, meaning the rotors are drilled afterwards, then i don't know why they only have one. but for sure it's only cosmetic issue which i don't see the big deal. if anything, the functional tailpipes are more of an eye sore imho anyway
if that's the case, meaning the rotors are drilled afterwards, then i don't know why they only have one. but for sure it's only cosmetic issue which i don't see the big deal. if anything, the functional tailpipes are more of an eye sore imho anyway
04-25-08, 05:56 PM
#41
Well they cracked at the track. These will be fine on the street. You just gotta watch out for cracks on the rotors. They usually will get little hairline surface cracks but I would worry and replace the friction rings if the surface cracks spread to hole-to-hole or to outer edges.
Me being the BMW M3 fanboy, I think IS-F have alot to make up but brakes wouldn't be one of the things. No one is gonna be able to push the brakes on IS-F over the limit on public street without getting arrested.
Me being the BMW M3 fanboy, I think IS-F have alot to make up but brakes wouldn't be one of the things. No one is gonna be able to push the brakes on IS-F over the limit on public street without getting arrested.
and i remember you said they crack just as easily?
if that's the case, meaning the rotors are drilled afterwards, then i don't know why they only have one. but for sure it's only cosmetic issue which i don't see the big deal. if anything, the functional tailpipes are more of an eye sore imho anyway
if that's the case, meaning the rotors are drilled afterwards, then i don't know why they only have one. but for sure it's only cosmetic issue which i don't see the big deal. if anything, the functional tailpipes are more of an eye sore imho anyway
04-25-08, 07:38 PM
#42
Well they cracked at the track. These will be fine on the street. You just gotta watch out for cracks on the rotors. They usually will get little hairline surface cracks but I would worry and replace the friction rings if the surface cracks spread to hole-to-hole or to outer edges.
Me being the BMW M3 fanboy, I think IS-F have alot to make up but brakes wouldn't be one of the things. No one is gonna be able to push the brakes on IS-F over the limit on public street without getting arrested.
Me being the BMW M3 fanboy, I think IS-F have alot to make up but brakes wouldn't be one of the things. No one is gonna be able to push the brakes on IS-F over the limit on public street without getting arrested.
04-26-08, 11:38 AM
#44
Tech Info Resource
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A picture is worth a thousand words - see below. AFA "bigger" being better - that's total crap. You want (from a pure performance perspective) the smallest lightest brake that will withstand the amount of heat needed to shed at the track you are running. Anything more increases unsprung weight and overall weight - and even if there is a minimum weight for the car, lighter is better because you can rearrange your ballast weights to make the car handle better.
Lexus went way beyond what is necessary for good brakes on the IS-F. Also, the discs are fundamentally different from the IS350 - the vane type (see below) is completely different, and therefore no directionality is necessary. Personally, I think they'd have done us all a favor if they'd left out the cosmetic holes, but they're trying to appeal to their market studies which show ordinary people still believe drilled looks better and performs better (despite practical experience in motorsports indicating exactly the opposite.)
Lexus went way beyond what is necessary for good brakes on the IS-F. Also, the discs are fundamentally different from the IS350 - the vane type (see below) is completely different, and therefore no directionality is necessary. Personally, I think they'd have done us all a favor if they'd left out the cosmetic holes, but they're trying to appeal to their market studies which show ordinary people still believe drilled looks better and performs better (despite practical experience in motorsports indicating exactly the opposite.)
04-26-08, 12:05 PM
#45
Lexus Fanatic
A picture is worth a thousand words - see below. AFA "bigger" being better - that's total crap. You want (from a pure performance perspective) the smallest lightest brake that will withstand the amount of heat needed to shed at the track you are running. Anything more increases unsprung weight and overall weight - and even if there is a minimum weight for the car, lighter is better because you can rearrange your ballast weights to make the car handle better.
Lexus went way beyond what is necessary for good brakes on the IS-F. Also, the discs are fundamentally different from the IS350 - the vane type (see below) is completely different, and therefore no directionality is necessary. Personally, I think they'd have done us all a favor if they'd left out the cosmetic holes, but they're trying to appeal to their market studies which show ordinary people still believe drilled looks better and performs better (despite practical experience in motorsports indicating exactly the opposite.)
Lexus went way beyond what is necessary for good brakes on the IS-F. Also, the discs are fundamentally different from the IS350 - the vane type (see below) is completely different, and therefore no directionality is necessary. Personally, I think they'd have done us all a favor if they'd left out the cosmetic holes, but they're trying to appeal to their market studies which show ordinary people still believe drilled looks better and performs better (despite practical experience in motorsports indicating exactly the opposite.)
