IS 300H F-Sport 2017" to RC-F full brake sett (all in)

[S.H.]

The OEM were always a little picky for my taste and faded 2 times so a decision was made after a one heck of a brainstorming... here  are some pic but I will update the details when I got more time

Pros and Cons etc and what to not do in this swap.

 

[RichGS11]

Interesting upgrade for an IS3. How are they?

[S.H.]

2 hours ago, RichGS11 said:

Interesting upgrade for an IS3. How are they?

I have used them for about 1500km but the wheels and tires 3k km. In short this is how the car should have been made but it comes with a price tag.. Hybrid feels flawless in transition and on    4x Michelin 19" R 255/35PA4 I can lock at any speed but in a controlled manner. They are always cold and rust cleans quickly (groves in rotors). I could barely get heat in the rotors when I broke in the pads (Temp +6c)  but calipers not even warm. Are they overkill yes but they never give me a surprise.

[RichGS11]

Oh all mods come at a cost on these cars definitely. After having a GS300 and GS430 I can see why you'd say the breaks weren't enough from factory. 

[S.H.]

On 9/15/2024 at 1:02 PM, S.H. said:

The OEM were always a little picky for my taste and faded 2 times so a decision was made after a one heck of a brainstorming... here  are some pic but I will update the details when I got more time

Pros and Cons etc and what to not do in this swap.

 

It took me about a year to gather the parts and for comparison I used this auction number to compare with my car,  USA VIN NUMBER AUCTION VVIN NUMBER JTHHP5BC7H5006443 and the best Lexus conversion brake info I found + the bracket for the rear caliper was 350phi. com except I did go for Powerstop Z23 brake pads (hybrid pads wider temp and no dust). There is one exemption and that is both rotor hub dia are 62mm BUT wheel hub dia is 60,1mm on my 300H. Bought the wheels from fitmentindustries (USA). You need to measure your wheel hub dia before ordering the wheels. There went alot of time finding the correct wheels cos US sides usually do not have EU models in there programs as was in my case. I went for Konig Ampliform Wheels, front wheels no problem but my calculations for the rear was different from theres cos I wanted no scrub/rub formula but they told me my rear wheels would not fit my calipers... I do not know how they got that simply cos the rotor slot in the caliper is tight ... but my choise was correct and the rear tire extends only about 5mm from the original but front extended about 29mm. See the Pic of the wheels the part numbers I got. The rear tires could be wider but I could not get them in my tire line (wanted 265-275mm) but the front tires have a slight touch under turns and touch the inner (what do you call it.. inner fender well) both in front and rear of the wheel, the material is soft but I could not bend it to stay in the right form... (paper.. fiber something) when it rubs through after about 7k km.. I will take them out and form them permanently, 4x Michelin 19" R 255/35PA4 P.S. these winter tires have only 8mm depth instead of the std 10mm for snow tires. I bought the brembo rotors from a brembo dealer in my country and the calipers from US 250-350$ a piece + taxes. Work per wheel about 4 hours (cutting the dust cover..)

Changes from the original setup.. used less than 2k km and temp +1c - +12c, understeer almost gone (expected, wider front tires) the brake feeling is super + even surface rust after a rain no problem. The G picture (under speed limits) max 0.8g is probably close to the max I can get out of these tires but as long the road is close to dry, temp does not matter ether in turns or under braking yes I could get these numbers under the old setup (same tire type) but not constantly. On the OEM setup under hard braking I did want a stiffer lower arm bushing but not on the new setup.. it looks like fr/rear brake bias is just a little more to the rear... just tiny but I can not feel it except better steering control under hard braking.      What next.. hmm the car is 12mm higher now (more practical..). I want to stiffen the chassy with TRD parts but other than that (yes I want a HUD did try one, not happy with it) I think the car is perfect for my needs as it is now. In my climate using 2 sets of tires is just not practical. The rest will be cosmetics..

P.S. why manufacturers use only dualside calipers on high end cars is cos of practicality, cost and no need for special wheels for the big calipers + few other minor benefits of narrow calipers.

 

 

[steve2006]

Very nice to see a great brake upgrade which has been well thought out and basically self designed.

This makes a great change from the usual “ I’m going to fit dual turbos and a super charger on my engine” and do no other upgrades regarding stopping.