IS250 with IS F and IS350 brakes
11-09-10, 08:32 PM
#16
I know I've learned a lot from Kurtz. He's been very helpful to me and is not one to be mean or belittle someone like a lot of people might do. All he's trying to do is educate us, teach us. I have not found anything that he's helped out with to be a lie or a lead to the wrong direction. I think we are very lucky to have him on board here. I for one, appreciate all that he's contributed.
Oh and by the way, I have the bigger brakes as well....but it came like that when I bought it.
Last edited by Micaiah; 11-12-10 at 08:08 AM.
11-12-10, 06:53 AM
#20
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LOL, who cares about the rear, your the only person driving around in the US with bigger rotors in the back then the front. It probably looks ridiculous.
And instead of just hating on that guy that posted the link, why don't you learn something. Why anyone needs brake upgrades on a is250 anyway is beyond me, but thats a whole new convo.
And I call BS on you didn't spend ANYTHING. I dont care if you installed them yourself, you still had to buy the parts and time = money (or at least my time does) so you spend "money" putting them on.
Bigger brakes for show = R.I.C.E. check my sig
And instead of just hating on that guy that posted the link, why don't you learn something. Why anyone needs brake upgrades on a is250 anyway is beyond me, but thats a whole new convo.
And I call BS on you didn't spend ANYTHING. I dont care if you installed them yourself, you still had to buy the parts and time = money (or at least my time does) so you spend "money" putting them on.
Bigger brakes for show = R.I.C.E. check my sig
11-13-10, 10:56 AM
#24
So you perpetually risk blowing your motor to be almost as fast as if you'd just bought a 350? NOS really has nothing to do with your brake upgrade though as larger brakes won't help at all with stopping from speed once... you'll still stop in exactly the same distance as the stock brakes would.
Oh, so you are installing used parts taken off other peoples cars that they don't want... gotcha!
On a car that doesn't actually see significant track use they're the definition of rice.
They're only there for looks, and actually functionally inferior to the original parts (since they don't stop you any shorter, and drilled rotors not only crack they also wear through brake pads 25% faster than blank rotors do).
On a car that does see significant track use there can be some advantage to larger brakes, but even then you'd really want slotted rotors over drilled ones because again drilled rotors crack.
(go check out some of the IS-F guys who have been to the track on their stock drilled rotors to see pics of the microfractures they're developing, often after just 1 day on the track). Unless you're driving a car with 1950s brake pads there's really no good reason to have holes drilled in your rotors besides the looks.
On a car that doesn't actually see significant track use they're the definition of rice.
They're only there for looks, and actually functionally inferior to the original parts (since they don't stop you any shorter, and drilled rotors not only crack they also wear through brake pads 25% faster than blank rotors do).
On a car that does see significant track use there can be some advantage to larger brakes, but even then you'd really want slotted rotors over drilled ones because again drilled rotors crack.
(go check out some of the IS-F guys who have been to the track on their stock drilled rotors to see pics of the microfractures they're developing, often after just 1 day on the track). Unless you're driving a car with 1950s brake pads there's really no good reason to have holes drilled in your rotors besides the looks.
Last edited by Kurtz; 11-13-10 at 11:11 AM.
11-13-10, 12:50 PM
#25
the brakes made a huge diff. am not sure if you ever drove a is250 stock at 100mph not the best braking . now the nos gained me over 265hp to the wheels so stock brake cant hold that , but with the set up have now it stop on the dime . Also kurtz whats up with hateing on every thing I post chill out bro its just for fun
11-13-10, 01:12 PM
#27
the brakes made a huge diff. am not sure if you ever drove a is250 stock at 100mph not the best braking . now the nos gained me over 265hp to the wheels so stock brake cant hold that , but with the set up have now it stop on the dime . Also kurtz whats up with hateing on every thing I post chill out bro its just for fun
I'm not sure why you think hp has anything to do with braking distance.
I'm not hating on you, I'm hating on your total lack of understanding of basic physics.
Your car stops in exactly the same distance it did before. There might well be a "feel" a difference in the system (possibly a bad one since your brake proportioning is probably kinda whacky right now with larger rear brakes than front) but there's NOT a stopping distance change.
Once you engage ABS (which the stock brakes can do) then additional braking force is 100% wasted, useless, force. Because the car is at the limits of the tires ability to slow down. "more brakes" doesn't help. At all.
That's why brake upgrades are worthless on street cars for anything but the bling factor.
They're only useful on the track for heat management because you will have a problem the -10th- time you stop from 100 mph in a 5 minute period, not the first time.
On the street you never do that, unless you're involved in the chase scene from a Jason Bourne movie. On a track, you do.
That's why Brembo doesn't provide braking distance data on their products. They say right in their own FAQ that brake upgrades do not reduce braking distance in street use so there's no point in testing it.
That's why the brake engineer I refered you to earlier has this to say on "more" braking force-
As the brake pedal force is gradually increased, the deceleration rate will also increase until the point at which the tires lock. Beyond this point, additional force applied to the brake pedal does nothing more than make the driver's leg sore. The vehicle will continue to decelerate at the rate governed by the coefficient of friction between the tires and the road.
You can take this one to the bank. Regardless of your huge rotor diameter, brake pedal ratio, magic brake pad material, or number of pistons in your calipers, your maximum deceleration is limited every time by the tire to road interface. That is the point of this whole article. Your brakes do not stop your car. Your tires stop the car. So while changes to different parts of the brake system may affect certain characteristics or traits of the system's behavior, using stickier tires is ultimately the only sure-fire method of decreasing stopping distances.
You can take this one to the bank. Regardless of your huge rotor diameter, brake pedal ratio, magic brake pad material, or number of pistons in your calipers, your maximum deceleration is limited every time by the tire to road interface. That is the point of this whole article. Your brakes do not stop your car. Your tires stop the car. So while changes to different parts of the brake system may affect certain characteristics or traits of the system's behavior, using stickier tires is ultimately the only sure-fire method of decreasing stopping distances.
(tires lock in the above is equivalent to ABS engagement for cars with ABS)
And that is why big drilled rotors on a street car are rice. They don't improve anything but looks. They simple eat brake pads faster and insure you'll need to replace rotors more often too.
Last edited by Kurtz; 11-13-10 at 01:19 PM.
11-13-10, 03:16 PM
#28
Kurtz am a lexus master asc tech and worked on car all my life I dont care book or form you get your info from ,but the is250 stock brakes are not going to brake the same as a is350 13.5 front and isf 14.2 rear ,sorry kurtz no way bro .its oways good to talk to kurtz 
11-13-10, 09:57 PM
#30
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Intake and Exhaust doesnt make your car faster, physics does!!!
Also Kurtz is right. I put geo metro brakes all around on my GTR because it stops the same distance at the track and it helped me save weight. As long as I buy good tires, I am good.
Also Kurtz is right. I put geo metro brakes all around on my GTR because it stops the same distance at the track and it helped me save weight. As long as I buy good tires, I am good.