junt

I was wondering, how titanium rotors would affect preformance? Would I even be able to get my hands on blueprints? Also would titanium apex seal be better than most?

Sled Driver

iTrader: (9)

If you had the ability & $, lots of $$$, to get a chunk of titanium big enough to make rotors you would be smart enough to realize that it is not the right type of material to construct rotors or apex seals out of.

Plus you could buy a house with the money a specialist machine shop would charge you to make them.

IM sure there are some metallurgist out there that will concur with me that steel & titanium have vastly different properties.
So it wouldn't work in the first place.

Did you pick Ti to save weight?

You can buy lightened steel rotors from Racing Beat & use ceramic apex seals. Add an aluminum flywheel & that baby will rev like a two stroke dirt bike.

Hey, how about carbon fiber rotors with magnesium apex seals?

junt

It would have only cost me the price of the metal because I have a friend that has alot of free time in his shop. But I was just thinking about the light weight and heat resistant properties of titanium. Why wouldn't it work?

JoeD

think about it this way...if they were so good, you would see them being produced and sold by RX-7 tuners by now.

junt

I just thought I remembered reading that the porche carrera gt was going to have a titamium engine. It just gave me the idea.

ghiaracer

Bullshit.

The reason you dont see ti in production is because manufacturing TI stuff is difficult. Its hard on the cutting tools (very expensive) not to mention that the raw TI is more expensive.

If you acctually know someone who will make you TI rotors and e shaft then do it

All boingers that are at the top tier use Ti internals. The c-rods, pistons, wristpins, valves, valve springs, retainers, ect...

I think no ones tried to make a billet TI rotor

The 787 used pretty exotic stuff with that motor.

93blackr1

you gotta be kiddin' me...

i think bill gates is the only one who can afford to build one...
it's not impossible, it just it needs someone who has the budget, the time for it, and the right tools and machines.

robert.

djantlive

Ti isn't THAT expensive. C5's exhaust is Ti.

Ti is extremely light and heat resistent. Of couse, it's hard on the cutting tools so mass manufacturing is a challenge.

If someone can do it, it'll be truely exotic!

Crackers

Yes you could make titanium roters.
It will be exspensive like every one said..

Now here is the real problem. You have to make the roters exactly the same and be perfectly ballenced or you will just shove the roter through the other side... Like they said its hard on tools so it will be even harder.

Ohh and SledDriver, get an attitude cheack you are far from being right.
Why don't you cut the attitude with people who asked a fair enough question. you inconsiderate punk.

Crackers

The covete exhaust is produced by a company called Arvin meritor INC. they own several plants called RollCoater... Reason I know this is My dad works for them =] and you're right its not damn exspensive.

pedro kim

What I have read is that the best material for rotors is carbon fiber and is it used in F1, cart and others, because of their wonderfull propeties to absorb heat. I used to race on motocross bikes and some top teams use titanium parts to make their bike lighter, in does days I was ask by a father of a friend that work on a big company to buy in some quantity of titanium in order to get a better price, I did'nt paid anymore attention.

But have another friend that also works titanium in a big company, I don't see it very often I will keep you in touch about prices.

He told me that people from the african continent were paid about 80 dls a kilo of Ti, but have hear also that is very expensive here.

pedro kim

It will be a very good idea to make some parts that weight a lot in the rx7, or get a better significant weight, 2,800lbs is a lot of pounds compared with 1,800 supercharge rice rabbits, in the track you see this advantage.

atihun

Are you guys forgetting the 787b? I believe that has titanium rotors.

I've machined titanium before, it is not that hard to work with, just takes longer. It is very expensive.

DomFD3S

The rotors in this case are brake rotors. You have to consider the purpose which a specific item will be designed for. Just because a material in a certain application does not mean it will be good in another.

SanJoRX7

Isn't titanium sort of brittle? I'm no metalurgist or machinist, but as I recal it's got a great strength to weight ratio, and it's extremely stiff, but I thought it was brittle (i.e. not malleable like steels tend to be). Am I off here? If not, this would be one good reason that it wouldn't be a good idea for rotors.

Another point to make is...if you're thinking about making Ti parts, go for the big ticket items that are taking up a ton of weight currently as steel part...things like your shifter linkage, your strut tower braces, your mounting hardware (yes, even nuts and bolts add up to a lot of weight). As a cyclist, I used to put Ti mounting hardware everywhere I could and on my 15lb mountain bike I saved ~2 lbs after all was said and done with the mounting hardware.

pedro kim

Thank you for your profesional advice

Crackers

Yeah Titanium is brittal but I only think its brittle too shearing.

Ohh and Titanium is an alloy not a metal found in earth. Ohh and CarbonFiber can't withstand that kindof pressure and heat reasitance inside of a moter.. Its a plastic compound and would only last a few hundrend miles.. Rember when Ford made its plastic engine It was said to only last roughly around 4000 miles if that.. It was a through away race engine that never did work. Great Ideah but couldn't be perfected right.

Sled Driver

iTrader: (9)

Ahh, I was joking about the Carbon Fiber Engine rotors with Magnesium apex seals.

Titanium tubing is mass produced (Z06 Exhaust) & more affordable.

You wouldn't just machine one set of rotors. I would think you would have to make quite a few, slightly differant sizes, to experiment with thermal expansion & durability.

Plus the rotors are forged then machined, got a source for that?

Are you sure the 4 rotor 787 used ti engine rotors?

Yea, you can buy ti valves, wrist pins & connecting rods, but not a ti crankshaft or piston. Why? because the stress, loads & thermal requirements eliminate ti from the equation.

I thought I was being quite conservitive in my previous responce.
If I pissed anyone off with my remarks, toughen up nancy boy!

SanJoRX7

Are you high? Have you looked at a periodic table? Titanium is element number 22. ELEMENT. That means it's naturally ocurring and is not a mixture of anything.

Also, if i recall correctly many race cars use CF brake parts, so that might be doable, but CF engine parts are probably not a good idea, particularly if they're subject to abrasion, since CF is simply a laminate, and not a solid piece of something. Anything short of metal is unlikely to last long in an engine simply due to the abrasion involved. Things like ceramics are also usable becuase of their resistance to abrasion and their metal-like qualities (while at the same time being lighter).

Check yo'self

SanJoRX7

Oh yeah, my source:

http://www.webelements.com/webelemen...xt/Ti/key.html

ScrapFC

iTrader: (5)

I really don't see any good reason that you couldn't use Ti for a rotor.
I've taken some machining and Metallurgy classes and done a bit of study on my own. Most steel alloys have a maximum tensile strenght in the neighborhood of 40K to 60K Ft/lb's per Sq In. Ti is around 110K-120K. One of the tests we performed in the Metallurgy class was a sample-destructive relative tensile strength test. We cut our samples on a lathe, threaded them and put them on a tester, which pulled them until they snapped. One felow brought a Ti connecting bolt from a Huey helicopter rotor. The instructor made him use his own cutting bit.
All of the high carbon steels snapped abruptly between 50K-60K. The low carbon steels stretched a bit and let go around 40K. The Ti piece stretched a bit at about 100K and let go abruptly between 110K-115K and sounded like a rifle shot when it finally broke(Pretty sure it work-hardened as it stretched). I don't think the shear strength is far behind the tensile. As far as thermal limits go, Ti can take a LOT more than steel. NASA has been using for years on their spacecraft. The tiles on the shuttle are a Ti-ceramic composite. The fuselage on the SR-71 is some kind of Ti alloy. I think it starts to soften right around the point that stainless becomes a puddle.
The main limitations I've seen for Ti in engines are cost and thermal expansion/stretch. The cost is coming down as newer, cheaper methods are found for extraction/purification of the raw ore. The thermal expansion and stretch are more than steel but less than aluminum. Just means your clearances have to be a little looser. Racers are using Ti pistons, con rods, and engine fasteners with good success. Check out Summit Racing's catalog.

DamonB

Titanium for a rotor would be mega expensive. The Corvette exhausts mentioned are made from sheet. Fasteners are made from rod or tubing. These are common "raw" forms of the material and working with them is therefore cheaper since they can be attained at lower prices due to the fact that they are mass produced as sheets, rods or tubes.

A rotor couldn't reasonably be welded up from sheet. The inner bearing surfaces could be machined from solid stock, but I think the majority would need to be forged in order to make sense and reap enough benefit over aluminum. Forging is an entirely different animal than casting or machining and requires specialized tooling. I don't see this as something anyone could do in their spare time; regardless of their shop's ability. It would take a real commitment to the project and I don't think the gains justify the exspense. It would be novelty only considering that with the money involved you could stay "low tech" with a 20B or something else that would be a much more efficient engineering solution.

Tim McCreary

Titanium, like magnesium, is a flammable metal. When particles are hot enough (normal blow torch temperature will work) and have enough exposed surface,(like dust or shavings), the metal catches on fire with a white-hot burn. Once they are on fire, the only thing that can put it out is dry sand or a Type-D fire extinguisher. If you add any water, consider yourself at ground zero for a violent explosion. Using them on a brake rotor may not be the wise choice for this reason. If you make one mistake causing heat (obviously at the rotors), a spark (like brake pad wearing out or a rivet), and some shavings or dust (wear), you are setting up for a nice wienie roast.

The US Army gives a block of titanium to front line soldiers to use against tanks. They shave the block enough to get a small pile and they just set it on a tank body and light it. The shavings burn hot enough to catch the block on fire, and it just melts right through the thickest armor. A hand grenade follows down the hole to dismember the tank inhabitants.

Titanium currently is mined in the USSR. Russia used Titanium instead of Steel to build their submarines and equipment since it was more readily available. With the demise of the communist block, Titanium has become a valuable commodity for the Russians to sell. Their production is in high gear, thus availability is rising and price is continuing to drop. Applications are increasing due to the shear volume available and the reduced pricing due to the market being "flooded".

Eccentric shafts, rotors, rotor housings, etc should definitely be investigated in the near future. Talk about a possible solution to blown engines, this might be the ticket.

Tim

DamonB

Could someone explain to me why a titanium rotor housing or endplate or rotor is going to keep the engine from blowing? The only gains would be in performance due to lighter weight (especially moving parts i.e. rotors). Actually, what are titanium's thermal characterisitcs compared to aluminum or iron? Other than its higher melting point? If it is poorer than alum or iron at exchanging heat, combustion temps could actually go up; increasing detonation possibilities.

bajaman

I have been machining titanium alloys for over 24 years. Titanium alloys are very light, very strong, and have high heat resistance. The skin of the SR-71 Blackbird is all titanium alloy, by the way.
The most common aircraft version of titanium is called 6Al-4V, which is simply a 6% aluminum, 4% vanadium alloy (90% titanium). The various alloys are what separates the way titanium is used. Sometimes silicon, tin, and zirconium are added for a really exotic mix. The main advantage of Titanium is its tremendous strength to weigh ratio. It is roughly 1/3 the weight of steel, yet 3 times as strong. When I raced r/c boats, I made some titanium connecting rods that worked out really well in those applications, the crank counterweight had to be altered to allow for the lower weight of the rod.
As for having lightweight titanium rotors....man, I don't know.....there would be certain drawbacks to using titanium, but the right alloy might give you a very fast revving, durable engine. There are ways to surface harden the key areas of wear, even add a very hard chrome flame sprayed on for even greater wear resistance.
Titanium is not all that difficult to machine, it is tough rather than hard, yet nowhere near as tough as Inconel or Monel or the other high nickel alloys. The use of carbide tools greatly simplifies the milling.