BBK: upgrade stock IS250 Brakes to 2019 GS350 F-Sport Brakes
02-05-20, 08:53 AM
#1
Rookie
Thread Starter
BBK: upgrade stock IS250 Brakes to 2019 GS350 F-Sport Brakes
A friend of mine just totaled her 2019 GS350 F-Sport. I decided to remove her front brakes/rotors and use it to upgrade mine. This is a task given how big the brakes and rotors compare to stock. I'll keep you guys updated on the progress if you follow along.
Here's a write up to share with you all. check it out
https://teamrpmblog.wordpress.com/20...lipers-rotors/
Here's a write up to share with you all. check it out
https://teamrpmblog.wordpress.com/20...lipers-rotors/
Last edited by xxbowiexx; 03-01-20 at 07:35 AM. Reason: update link
02-05-20, 03:50 PM
#2
I've got this GS/RC F-sport 14' upgrade coming up on my YouTube too. Still collecting parts but I got the calipers and will be doing a basecoat clearcoat in probably orange including the rotor hats.
The $500 rotors are what I'm waiting on and probably get IS-F dust shields.
The $500 rotors are what I'm waiting on and probably get IS-F dust shields.
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Aspect (02-06-20)
02-06-20, 07:45 AM
#3
Rookie
Thread Starter
I have the GS350 F Sport dust shields but it has a different mounting point so I can't use it. I bet the ISF dust shields would work well for you. what's ur youtube, I'll follow you.
02-06-20, 05:15 PM
#4
www.youtube.com/tunerwithkids
02-07-20, 10:29 AM
#6
Glad someone is finally making this happen! I had this "dream" back in 2014 of doing this "budget" BBK kit. Perhaps additional info needed can be had on my old thread :
https://www.clublexus.com/forums/sus...0-f-sport.html
PLEASE continue to update us on your progress and the parts list!
PS : SICK Works wheels bro!
https://www.clublexus.com/forums/sus...0-f-sport.html
PLEASE continue to update us on your progress and the parts list!
PS : SICK Works wheels bro!
02-09-20, 07:20 AM
#7
Rookie
Thread Starter
it was actually your initial post that inspired me to go this route. so kudos to you sir
Glad someone is finally making this happen! I had this "dream" back in 2014 of doing this "budget" BBK kit. Perhaps additional info needed can be had on my old thread :
https://www.clublexus.com/forums/sus...0-f-sport.html
PLEASE continue to update us on your progress and the parts list!
PS : SICK Works wheels bro!
https://www.clublexus.com/forums/sus...0-f-sport.html
PLEASE continue to update us on your progress and the parts list!
PS : SICK Works wheels bro!
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02-10-20, 02:06 PM
#8
Just realize you're going to decrease your performance by doing this. You are adding a larger, heavier rotor to the car in the way that impacts it the most: rotational weight. This means every time you accelerate, your car is now going to have to fight the extra weight that you added. Same thing for the suspension: you have a larger weight on there, meaning that the inertia is greater and therefore your suspension will be less reactive.
On top of that, the stock brakes are capable of locking up the front tires, meaning you're not actually going to get more braking performance outside of reducing brake fade: something that only track goers are going to use.
On top of that, the stock brakes are capable of locking up the front tires, meaning you're not actually going to get more braking performance outside of reducing brake fade: something that only track goers are going to use.
Cool! Glad someone with more time and effort was able to move forward with this!
02-11-20, 06:01 AM
#9
Thats the same thread that inspired me to research this. I just ordered StopTech lines, just need to pull the trigger on the rotors and shields. But waiting till I have some more time.
Gonna basecoat clearcoat the calipers and rotor hats. I've been looking at those hats on the stock GS and RC's and they get nasty with brake dust so want to match them to the calipers.
I'm doing this more for aesthetics than the performance.
Gonna basecoat clearcoat the calipers and rotor hats. I've been looking at those hats on the stock GS and RC's and they get nasty with brake dust so want to match them to the calipers.
I'm doing this more for aesthetics than the performance.
Glad someone is finally making this happen! I had this "dream" back in 2014 of doing this "budget" BBK kit. Perhaps additional info needed can be had on my old thread :
https://www.clublexus.com/forums/sus...0-f-sport.html
PLEASE continue to update us on your progress and the parts list!
PS : SICK Works wheels bro!
https://www.clublexus.com/forums/sus...0-f-sport.html
PLEASE continue to update us on your progress and the parts list!
PS : SICK Works wheels bro!
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sinister2c (02-12-20)
02-12-20, 12:24 PM
#12
02-13-20, 12:10 PM
#13
Based on my research the larger 2-piece rotors from the GS/RC are approximately 1.5 lbs lighter than the smaller rotors from the IS/GS/RC.
Note that the lighter weight comes from the aluminum hat, so while that affects the unsprung mass in a positive way, the overall moment of intertia may still be worse because the heavy iron weight is further from the axis. Without doing the calculations though, I would say that there is probably a net benefit to the larger brakes from an unsprung mass perspective, at least from an IS350. The IS250 has smaller, lighter rotors but uses a steel caliper instead of an aluminum one. (IS250 rotors are about 5.5 lbs lighter than IS350 rotors, though the calipers are about 3.5 lbs heavier).
Long story short: the larger 2-piece rotors with their aluminum hats and aluminum monoblock calipers are about the same weight as the IS250 brakes while being almost 2.5" larger and four-piston instead of single-piston.
These brakes will likely fit well on AWD models as well.
Jeff
Note that the lighter weight comes from the aluminum hat, so while that affects the unsprung mass in a positive way, the overall moment of intertia may still be worse because the heavy iron weight is further from the axis. Without doing the calculations though, I would say that there is probably a net benefit to the larger brakes from an unsprung mass perspective, at least from an IS350. The IS250 has smaller, lighter rotors but uses a steel caliper instead of an aluminum one. (IS250 rotors are about 5.5 lbs lighter than IS350 rotors, though the calipers are about 3.5 lbs heavier).
Long story short: the larger 2-piece rotors with their aluminum hats and aluminum monoblock calipers are about the same weight as the IS250 brakes while being almost 2.5" larger and four-piston instead of single-piston.
These brakes will likely fit well on AWD models as well.
Jeff
Last edited by Jeff Lange; 02-13-20 at 12:17 PM.
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xxbowiexx (02-26-20)
02-14-20, 07:39 AM
#14
I been having this setup from few years sitting in my basement. Was going to install into my IS350 but ended up trading in for a bigger family suv. But i still have and is250 awd to put it on. I can conform it fits but has a little wiggle on the hub of the AWD but once tighten with lug nut it good. Another note it doesn't clear oem 18 rims. It hits the top edges that need to shave to fit. Rotor itself feel heavier to me than my is350 oem but that just me. All i done was a test fit not yet to do the full install since it hasn't been a priority. I have talked to Jeff about the install to the AWD also a year ago too.
02-14-20, 09:00 AM
#15
Based on my research the larger 2-piece rotors from the GS/RC are approximately 1.5 lbs lighter than the smaller rotors from the IS/GS/RC.
Note that the lighter weight comes from the aluminum hat, so while that affects the unsprung mass in a positive way, the overall moment of intertia may still be worse because the heavy iron weight is further from the axis. Without doing the calculations though, I would say that there is probably a net benefit to the larger brakes from an unsprung mass perspective, at least from an IS350. The IS250 has smaller, lighter rotors but uses a steel caliper instead of an aluminum one. (IS250 rotors are about 5.5 lbs lighter than IS350 rotors, though the calipers are about 3.5 lbs heavier).
Long story short: the larger 2-piece rotors with their aluminum hats and aluminum monoblock calipers are about the same weight as the IS250 brakes while being almost 2.5" larger and four-piston instead of single-piston.
These brakes will likely fit well on AWD models as well.
Jeff
Note that the lighter weight comes from the aluminum hat, so while that affects the unsprung mass in a positive way, the overall moment of intertia may still be worse because the heavy iron weight is further from the axis. Without doing the calculations though, I would say that there is probably a net benefit to the larger brakes from an unsprung mass perspective, at least from an IS350. The IS250 has smaller, lighter rotors but uses a steel caliper instead of an aluminum one. (IS250 rotors are about 5.5 lbs lighter than IS350 rotors, though the calipers are about 3.5 lbs heavier).
Long story short: the larger 2-piece rotors with their aluminum hats and aluminum monoblock calipers are about the same weight as the IS250 brakes while being almost 2.5" larger and four-piston instead of single-piston.
These brakes will likely fit well on AWD models as well.
Jeff
A nice deep dive regarding moment of inertia. If acceleration is important; this stuff matters..Equally true when decelerating too.
Anyone notice things like motorcycle forks, off road shocks and things like that getting inverted? All efforts to reduce unsprung weight so the axle can react quicker.
I would like to see this conversion done with data logs of before and after acceleration and braking times and distances....
And what about brake bias and master cylinder bore dia? Anyone look the GS MC diameter? Do these calipers use the same MC?