[Racer X]

I was watching Chop Cut Rebuild on Speed Channel and they were doing a WRX build up. I thought I heard them say they were putting titanium brakes on it. Well after some internet searching I found two places that make titanium brake rotors.

They weigh about half of iron rotors do. However, they are not cheap. So those dedicated to lightness, how light do you want to go?


http://www.zmibrakes.com/
http://www.reddevilbrakes.com/page/page/903312.htm

Neither shows Elise parts. One (Red Devil) indicates almost any rotor can be duplicated in titanium.

Does anyone know if the Elise rotors are from some other car?

The other kit requires know calipers as well, because they are non-vented rotors. They save more weight through lighter calipers as well.

I thought the show said they were saving 120 pounds overs the stock braking system on the WRX!!!! Still it probably cost $8K to do it.


Greg

 

[Randy Chase]

Interesting idea, but no way was the stock braking system 240 pounds.

 

[smoseley]

Maybe they meant the equivalent of 120 pounds... because of the sprung / unsprung ratio?

 

[Racer X]

I have the show on TiVo. It talked about the old 12" rotors weighing 16 pounds each and the new ones weighing 4 pounds.

I thought at one point I thought I heard them say it weighs 9 pounds total a corner (caliper bracket, caliper, and rotor) That would imply the brakes removed weighed 39 pounds a corner.

This may have been versus a 6 pot WearPower brake system and not stock. It was not clear.

The show is showing one more time at 8 AM central on Sunday.

The half the the weight for rotors was the Red Devil rotors that are internally vaned stock thickness rotors. The ZMI brakes are a thin non-vented rotor, which must save more weight.

The Red Devil kit suggests a 25% increase in stopping power.

They compare against a Chevrolet website 60-0 distance of 125 to their 80-85 feet. It is a faulty comparison as the surface was nt the same and no indication that the tires were either. What about temperature? Nonetheless if they can get 80-85 foot stopping distances with street tires that is something. The best distance on a Z06 I have seen on OEM tires is 105-6 feet.

All in all, interesting for those with the desire and the cash.

Anybody have the weights on the Elise braking system?

A big decrease in unsprung and rotational mass would be significant to handling, braking and acceleration.

Greg

 

[Tripledigits]

If titanium was up to the task of being rotor material, I think F1 or some other high end race series would be using it already. I bet there's a big downside.

The Porsche's ceramic brakes are becoming less popular with people who track their cars, because of their short life and outrageous price.

Carbon/carbon brakes are great for racing, but unsuitable for street use. They are quite expensive as well.

Jeff

 

[Racer X]

I believe that titanium has only recently been able to be produced in a cost effective manner for a few years. I remember when they put a titanium exhuast on the 2001 Z06 and it was a big deal. Now I see a lot of companies offering titanium exhuasts in the aftermarket.

I look forward to reduced costs for brake parts soon.

Your right they use carbon-carbon brakes in F1. However they have hugh budgets so they use the best for the circumstance. 1000 degrees C and 4.5G stops. Maybe titaium is only good for 800C and 2 Gs stops and that is good enough for the street.

What problems have they had on the Porsche ceramic brakes? Cracking? One website indicates good life on the titanium with ceramic coating. I was reading a F1 magazine and they indicated in normal street use carbob-carbon brakes would give about 160K miles of life. But they would be too grabby(technical term ) for the street.

I always look for racing technology to come to the street in a cost effective fashion.

Greg

 

[Tripledigits]

Carbon brakes aren't efficient until they've got some heat in them, which is one reason they're not great for street use.

I've been told the Porsche ceramic brakes wear quickly at the track, and due to the high cost of rotors and pads have fallen out of favor with the track people. Supposedly it's become popular for the track people to retrofit to the standard braking system.

Maybe some of the Porsche guys here can quote some of the pricing on the ceramic pads and rotors. I don't want to quote what I heard, because I can't believe it.

Jeff

 

[_JD_]

Carbon brakes aren't efficient until they've got some heat in them, which is one reason they're not great for street use.

I've been told the Porsche ceramic brakes wear quickly at the track, and due to the high cost of rotors and pads have fallen out of favor with the track people. Supposedly it's become popular for the track people to retrofit to the standard braking system.

Maybe some of the Porsche guys here can quote some of the pricing on the ceramic pads and rotors. I don't want to quote what I heard, because I can't believe it.

Jeff

I've heard $15K for front rotor replacement on the GT2.

 

[Ruediger]

Also Ferraris you can get with Si-carbide (Ceramic) brake rotors and these are not baked in Germany but in Slovenia, using a different processing technology

The German representative is http://www.sicom-brakes.de Herr Ilmberger.

For the S2 –Elise he can make such brake kits for 5 to 6 k $ depending on the amount of firm orders. (at least 5 ).So far this number has not been reached but in case somebody over there is interested ( ?) he should contact Nobbi, the guy who is coordinating this little project.
Nobbi already has the lightest S 2 over here.

 

[frayed]

I'm with Jeff and remain quite skeptical.

Further, there is no way in the world a change of a braking system will shorten stopping distances as noted above (120ft to 80 ft). No way in hell.

On a given car, assuming they left the ABS system intact, and they did not appreciably change brake bias, you can only shorten braking distance by going to super sticky tires. Like. . . a pure racing slick heated to optimal temperatures. Even if braking bias were changed to generate more optimal staightline braking performance than the factory setup, only small changes in braking distance will be effected.

Once ABS is engaged or, on a non-ABS equiped car, you have the power to lock up the tires, extra braking torque doesn't do anything to shorten braking distance.

A company that makes such claims is a company that I'd be *highly* suspect of.

 

[frayed]

For background information:

"Well, let's look at why we upgraded the front brakes in the first place. Contrary to popular belief, the real reason sports- and racing cars use big brakes is to deal with heat. Period. There has been a bunch of stuff published which will disclaim this, but when you look at the braking system from a design standpoint, making them 'bigger' doesn't fundamentally do anything for stopping distance. It's all about the heat. "

link

And:

“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 do stop the car. So while changes to different parts of the brake system may affect certain characteristics or traits of the system behavior, using stickier tires is ultimately the only sure-fire method of decreasing stopping distances.”

link 2

I've seen a lot of misinformation on internet boards revolving around braking systems over the years. The stoptech articles are a pretty good primer for anyone interested.

 

[Randy Chase]

frayed, my most heated debates on the internet have been over brakes. People think if they improve my brake pads, rotors, or whatever, they will stop faster.

I eventually quit debating it.

 

[frayed]

frayed, my most heated debates on the internet have been over brakes. People think if they improve my brake pads, rotors, or whatever, they will stop faster.

I eventually quit debating it.

I don't quite get it. It's crazy. I moderate an BMW forum and I see the same ol' crap all the time.

Since the Elise community is and will continue to be rather small, perhaps we won't got bogged down with such blather.

One can only hope.

For those who have not come across these threads in the past, the all time greatest thread on crossdrilled assclownery can be seen here.

http://www.altimas.net/forum/showthread.php?s=&threadid=32327&pagenumber=1

Although, the wavy rotor thread from the S2000 forum is entertaining.

http://forums.s2ki.com/forums/showthread.php?s=&postid=746607#post746607

--------------

Now Ti rotors? Hmmmmm.

 

[frayed]

Did some digging. Here's a post in response to my questions on the Ti brakes. It might be BS, but I remain hugely skeptical.

This guy did a monster ground up overhaul on his STI a few months back. He got these brakes for free Bc his car ended up going in lots of magazines. Long story short, they were horrible for stoping. He said they would not work properly ever, on the street, at the track, he said it was like hauling a 10 ton car to a stop when not heated, and at the track when up to temp he could not keep the heat down enough to prevent fade... He also mentioned that while they looked cool, he said that after every time he got the brakes to work well, the fluid would boil causing faded pedal pressures, this was the reason he removed them and went back to the AP setup..

 

[James A]

Exactly right Jeff, if your current brakes can lock up your current tires, your braking is tire limited. Nothing you do will make much difference in stopping distance. Now as far as cooling, making changes may make a difference as the brakes may not fade as easily. But you and Randy are right very few poeple get it. We had the debate on this forum, where people think the Elise will stop in 80 feet from 60 mph or something like that on stock street tires. It's not the car and it's not the brakes it is the stock street tires that determine stopping distance on the Elise. When the road tests come out the Elise will stop in somewhere around 100 feet from 60 mph.

 

[frayed]

But you and Randy are right very few poeple get it. We had the debate on this forum, where people think the Elise will stop in 80 feet from 60 mph or something like that on stock street tires.

[sigh] Hopefully, we create a better, more sophisticated knowledge base here than the average car forum [/sigh]

 

[Need4Speed]

frayed,

I think your "crossdrilled assclownery" reference may have supplanted Randy's "angle of suckitude" as Phrase Of The Month. LOL. :bow:

 

[frayed]

LOL.

Seriously, let's not screw up our cars with foolish schit, and be reasonable and realistic about the stuff we do to our cars.

 

[ConeFusion]

I liked the "crossdrilled assclownery" phrase, too! :clap:

Anyway, there is an explanation why a better braking system could improve stopping distances. It might be able to apply force more consistently. The force could fluctuate with a bad braking system, e. g. because the caliper flexes. You could only brake hard enough to avoid lockup when the maximum force is applied, and would not use the maximum grip of the tire during the rest of the time.

Making up some numbers: Say the perfect braking system enables you to apply 100% of the force that still allows the tires to grip at all times. If a poor braking system has a 10% variation of the force, you apply between 90% and 100% of the maximum, with an average of around 95%. This would make your braking distance longer.

I'm not sure if the above is happening, and certainly not to what degree. I just wanted to throw it out there as a possibility why the quality (not size!) of the braking system could matter.

 

[andykeck]

For those who have not come across these threads in the past, the all time greatest thread on crossdrilled assclownery can be seen here.

http://www.altimas.net/forum/showthread.php?s=&threadid=32327&pagenumber=1

Oh man, I just read 15 pages of that thread and now I don't feel so good. Can I please have that half-hour back now?