natnut

Here's my idea for a cost-effective BBK which has minimal unsprung weight penalties using the LS400 calipers as a base :

1995-2000 LS400 4-pot calipers : get cheap from CL forum member aliga(pm him). Lighter than the supra TT 4-pots and cheaper to boot. Less unsprung mass so less handling penalty. In fact, I think it is lighter than the stock GS 2-pots so handling actually improves. Price : 200-220 US$

RCA(roll center adaptor) : allows the bigger LS400 caliper to clear cotter pin.
pay through the nose for the original Japanese model or get cheaper from Exact Motorsports. As for me, I got cheap HK copies of the Japanese versions from ebay. Contact CL member HKGS300 for the HK versions. Alternative : shave the cotter pin(whatever that is).Ask CL member Gsteg for advice.
Price : 180-200+ USD. Free if going the shaving pin route.

Lightweight 2-piece LS400 rotors : this is where it all falls apart and is making me consider selling off my RCAs. The stock 1 piece LS400 rotors are apparently 12.4". I know that you need more rotor mass as a heatsink to prevent brake fade but the weight penalty and fact that it is unsprung rotational mass just worsens the suspension trade-off.

I have been thinking that the solution would be lightweight 2 piece LS400 rotors but I have scoured the internet and can't find anyone that makes after-market 2 piece LS400 rotors.The probable reason is that LS400 owners aren't concerned with braking/handling improvement.

The only realistic users of 2 piece LS400 rotors would be us : LS400 BBK users fitting our SC300/400 and GS300/400/430.

The only way a rotor manufacturer would make the LS400 2-piece rotor is if there is enough orders to ensure that the manufacturer would invest in the tooling-up and research costs and still make money.

Hence I propose that all of those who are serious about the LS400 caliper upgrade band together to make a mass order and then approach the relevant manufacturer. I have one in mind(see my sig) but anyone who is credible and willing is fine.

Mods : can you post this in the SC300/400 forums so that enough critical mass of potential buyers are informed?

Also : how does one start an officially sanctioned Mass Buy on CL?

kit cat

iTrader: (6)

NO


do not shave or take off the cotter pin itself. that's gonna be some hardcore


The GB 2 piece rotor sounds like a good plan but it better be from a reliable brand. If not, my GS is a street driven car, I'll just use the OEM LS rotors.

PS: changing just the front with 4pot may (and probably will) throw off the balance/distribution of the brakes.

GSteg

iTrader: (15)

yea. You definitely need the cotter pin . However, you can shave the top portion of the bolt as long as there is still metal for the cotter pin to sit in place. Unless the nut is not torqued correctly, it shouldn't unscrew itself anyways. If the tie-rod wears out and break, the joint inside the rod itself goes loose, not the nut.

Also, more mass isn't necessarily better for heat dissipation. Heat dissipation depends on surface area, type of material, and how well those cooling vents work. Copper dissipates heat better than steel, but can you imagine having copper rotors? You'll break them in no-time.

There is a reason why most aftermarket brakes company utilizes 2-piece rotors. The rotor itself is usually the same kind of material on our OEM rotors, but the hub portion is aluminum. I haven't found a 1-piece design that's lightweight and strong.

DBA makes 2-piece rotors for the GS300/400/430, but have you seen the outrageous price? One version of their rotors cost $300 each while the other one cost $700 each. Imagine how much it'll cost to produce 2-piece LS400 rotors.

LexFather

In theory, it should be better but without evidence on the track or without video testing of stock brakes vs this system, we really are guessing.

Maybe contact Carson or Sewell and see how many LS brakes they can get for us?

natnut

Point taken but that hasn't prevented reputable brands like Stoptech/Brembo/AP/Endless from making FRONT only 4pot BBK for our GS. Even the Supra BBK is front only.What I gather from this is that the shift in brake balance is non-critical.

Our cars aren't race cars. There should be a lot of leeway in built into passenger sedans' brake balance since having an additional front passenger or 2 rear passengers(which causes substantial changes in brake balance) hasn't caused widespread accidents yet among sedans!


I'd like to start a group buy listing of those interested in LS400 2-piece rotors with the oem LS400 diameter size. If we can get a substantial waiting list, we can convince Carson,Sewell or Racingbrake to manufacture the rotor at a reasonable price.

Can I put Gsteg and Coco-bun on the listing?

1.natnut
2.Gsteg


****2nd-gen GS300/400/430, SC300/400, LS400 members please feel free to add your names to this list--the larger we are, the more leverage we have in convincing the rotor makers to start production and to give us better prices.

Mods--am I allowed to repost this in the LS400/SC forums without infringing the forum rules?

kit cat

iTrader: (6)

no thanks for me. I don't see a problem with a conventional 1 piece for my daily driven GS.

dejacky

iTrader: (2)

I started a group-buy interest thread on the RacingBrake two-piece open slotted rotors for the 1995-2000 Lexus LS400 cars, but your favorite moderator DaveGS4 shut the thread down...I'm happy you got this one up without him closing it down..yet Count me in for the group-buy on 1995-2000 LS400 two-piece open-slot rotors.

LexFather

natnut, you cannot start a GB per forum rules. You have to get an authorized vendor to start it.

SoCalSC4

So, you're in the the high performance brake business full time?

Brake bias and balance ARE important and companies like StopTech and
Brembo manipulate this for each application by changing the piston size.
You don't have this luxury with an OE caliper.

If you want to have special rotors made, how about engineering
a brake system and having a run made to your specifications. You'll have
to make a minimum quantity of them and pay tooling and set-up costs,
but that's part of being in the automotive aftermarket business.
Trust me, brake rotor manufacturers depend on VOLUME to make
money, making 25 pairs of rotors will not interest them.

I think it's a little insulting that you would presume that issues of brake
balance, bias, torque, etc. are not important. If these items are not
carefully considered, you can very easily end up with a brake kit that
won't perform as well as the stock brakes. Professionals at brake
companies take this VERY seriously... you're dealing with people's
lives here!

Another thing you'll want to have: product liability insurance.

natnut

Nice to see I'm not alone in wanting weight savings for our LS400 BBK. I started this same topic over in the Racingbrake messageboard. Can you chime in over there to give the manufacturer the necessary push?

bachde

so.....

this is a 4 years old topic but...
no one has found the manufacture who make the LS400 2-piece rotors?

De

AVSRacing

I remember reading somewhere that there's not many pads or disc options to choose from for the LS400 due to the fact that its a luxury car not a performance car, that's one of the reasons why TT calipers is a better options to go with.

bachde

I see...

But talking about decent price for a BBK then the LS400 is best.

For TT those caliper alone cost more than 400, the caliper only not with rotors...

Thanks for the respond man!

De

bachde

I do some searches and found...

the crazy thing is they made for LS400 older model not the 95 up
http://products.vividracing.com/raci...1013809850.php

Sonic_RC

iTrader: (15)

Ya I've seen those rotors before. I've been to the RacingBrake forum and they mentioned back in '07 that they were gonna make them for the 94-00 LS400. They said they rotor disc diameter and thickness was the same as the E36 M3 which they make already but they would need to make the "top hat" so its the appropriate height, bore and bolt pattern. But 5 years later still nothing. Too bad they looked nice

I bet you could just buy the disc bring it to a CNC machine shop and have the top hat custom fabricated as long as you gave them a OEM LS rotor for measurements. Might not be cheap going this way but certainly can be done. According to this chart the hat sits 26mm higher than the disc. But I would recommend the hub bore should be 60.06 (60.1) and bolt hole size 13mm. So if anyone wants to venture out and have it made good luck.