Is250 to IS350 rear brake conversion questions
#1
Racer
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I'm going to install the IS350 fronts brakes and I want to do the rears as well mainly for aesthetics. Can anyone help answer some of these questions? Does this list look about right?
NEW IS350 rear calipers
NEW IS350 rear rotors
NEW IS350 rear dustshields
REUSE stock IS250 rear pads, shims, fit kit, brakelines, caliper bolts?
Will I still retain my parking brake function? Not sure since the rear rotor is different.
NEW IS350 rear calipers
NEW IS350 rear rotors
NEW IS350 rear dustshields
REUSE stock IS250 rear pads, shims, fit kit, brakelines, caliper bolts?
Will I still retain my parking brake function? Not sure since the rear rotor is different.
Last edited by Coconut; 04-29-09 at 10:18 AM.
#3
Racer
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I agree, changing to IS350 rear brakes is useless function wise BUT I just can't get over how tiny our brakes are. The IS350's rear rotors are larger than my fronts!![EEK!](https://www.clublexus.com/forums/images/smilies/eek1.gif)
IS250 Stock Rotors:
Front: 11.6" ventilated
Rear: 11.2" solid
IS350 Stock Rotors:
Front: 13.1" ventilated
Rear: 12.2" ventilated
![EEK!](https://www.clublexus.com/forums/images/smilies/eek1.gif)
IS250 Stock Rotors:
Front: 11.6" ventilated
Rear: 11.2" solid
IS350 Stock Rotors:
Front: 13.1" ventilated
Rear: 12.2" ventilated
#4
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is350 - 12.1" ventilated discs
is250 - 11.4" solid discs
with the larger is350 discs in the rear the rear brakes will have more braking power.
mis-matching is350 brakes up front and is250 brakes in the rear will throw off the balance of the car in braking situations.
of course, this is just my guess.
maybe the 2is brake experts can chime in on this...
#6
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rear brakes:
is350 - 12.1" ventilated discs
is250 - 11.4" solid discs
with the larger is350 discs in the rear the rear brakes will have more braking power.
mis-matching is350 brakes up front and is250 brakes in the rear will throw off the balance of the car in braking situations.
of course, this is just my guess.
maybe the 2is brake experts can chime in on this...
is350 - 12.1" ventilated discs
is250 - 11.4" solid discs
with the larger is350 discs in the rear the rear brakes will have more braking power.
mis-matching is350 brakes up front and is250 brakes in the rear will throw off the balance of the car in braking situations.
of course, this is just my guess.
maybe the 2is brake experts can chime in on this...
#7
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it's the same reason why even on BBKs... we would have a smaller rear rotor and a smaller calipers... i doubt it would develop on any problems... and seriously.. it's not a worth it investment for that/// if you're looking tto do a F&R conversion might as well get a BBK
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#8
Racer
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If I get any BBK I'll be getting both the front and rear. I'm not going to just get the fronts.
Major price difference between IS350 and a true BBK. IS350 front and rear would be around $1400. The cheapest BBK front and rear would be the Brembo IS-F kit for $3900 and that sales over.
Major price difference between IS350 and a true BBK. IS350 front and rear would be around $1400. The cheapest BBK front and rear would be the Brembo IS-F kit for $3900 and that sales over.
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dpending on what you're going to do.. for the same size pistons... you might get away with 2-3k and get better looking ones than the stock 350..... it also depends on who you get it from.... well.. for me if i were to change all 4... i rather change to a BBK and it's all cosmetics.. better braking and looks.... well that's my 2 cents..
#14
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if that's true, then assuming the same exact identical (repetitive, but you get my point) tires for two 2is's - one w/ is250 front/rear brakes and one w/ is350 front/rear brakes - wouldn't the 2is w/ the is350 brakes would have more braking power, and as a result stop the car in a shorter distance?
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if that's true, then assuming the same exact identical (repetitive, but you get my point) tires for two 2is's - one w/ is250 front/rear brakes and one w/ is350 front/rear brakes - wouldn't the 2is w/ the is350 brakes would have more braking power, and as a result stop the car in a shorter distance?
Because the brakes don't stop the car, the tires do.
And they have the same tires.
BOTH cars braking systems are already more than powerful enough to engage ABS. Adding any braking power past that point is completely, totally, and 100% useless and does nothing to stop the car any shorter.
There's pages and pages of engineering, physics, and math that all support this point that's been posted in several other threads if you care to look for it. But the fundamental point is as long as your braking system can engage ABS then nothing you do to "upgrade" them will stop the car any shorter. Hence for the purpose of things like stopping distance big brake kits are entirely cosmetic upgrades.
Anyone who tells you differently is trying to sell you a brake upgrade.