as we try to make a better and more reliable engine,some times we miss new materials!!

a new and better material for Rotors, CGI(compacted graphite iron) is big in Europe.

anyway,, lighter than grey cast iron,20%, stronger by 50%, and good wear characteristics.

in Quantity could be cast and machined without the short comins of Aluminum. costs!!

thinkin about it,, Mazda is probably R&Din already.

 

Id like to see a Ti rotor. But material cost, and its tough machining would make it kinda tough.

 

The only reason Mazda would perform R&D is because they have the money to do so.

You're looking at $20,000 in tooling alone for anything that needs to be cast. Definitely more for a specialized material where there is limited experience/expertise.

 

Titanium is a poor material for anything that gets hot. It oxidizes above about 1000F, and loses strength above about 850F.

 

A couple of companies have already done this, but used billet and others used aluminum I believe...but charge upwards of 2k per rotor.

 

Aluminum melts at 1220F, and many people see EGT's up to and over 2000F. Go figure. Rotors don't run at combustion temperature, I'm not that sure that titanium would be that bad a material to use. But pricey!

Recently, E&J auto made BILLET ALUMINUM rotors, completely machined. Very different process than stock (cast iron) or the proposed CGI which would likely be cast as well.

Also, this new stuff probably wouldn't have the same thermal expansion that billet aluminum rotors would.

 

maybe missed the topic ,cast iron rotors, CGI-CGI,, Compacted Graphite Iron, castings
stronger and lighter than standard cast iron, and much lighter than Nodular iron(flexible).

 

mazda rotors have to be oil cooled, any type solid rotor(aluminum) would not pull heat out of chamber surface fast enough,to control EGTs, and dreaded detonation. also coatings on surface are not a good idea, insulates coolin oil. heat then is pushed into water system=overheat.

mazda uses 60% water coolin, and 40% oil cooling, thats why they have such a large oil coolers, in case you wonder why!

 

Well, maybe you could tell that to the professionals that have solid Billet aluminum rotors that are being tested and have lasted no problem so far? https://www.rx7club.com/showthread.p...tor+technology

http://www.youtube.com/watch?v=2ZOHdimyPmc
http://www.youtube.com/user/enjauto

 

Yeah I know about those. Those rotors don't have the internal oil cavities that the cast Mazda rotors have. I'm specifically interested in how the billet rotors would hold up in a road racing application where they would be subjected to high heat over a prolonged period of time. I think this is where the oil cooling of the cast rotor would show it's value and where those billet rotors would show their limited application.

 

If you read that thread, you should know that oil temps went down and power up...

 

Oh really?? So why R26B has everything inside cermet coated?? Why people with ceramic coatings seeing drop in water/oil temp?? Everything you said is just wrong assumption.

 

i was under the assumption that it was mostly oil cooling not water....hence why dual oil coolers provide great results in engine temps

 

Obviously the oil temps are going to go down since the oil isn't removing heat from the face of the rotors. And power going up is debatable since that could be attributed to a countless number of factors beyond lightweight rotors... i.e. a fresh rebuild using the aluminum rotors, or a better seal between the apex or side seals with the aluminum rotors versus the used OEM rotors, both cases resulting in less blow-by.

Sorry to seem like a 'hater' but there are simply too many factors to just say "yeah they make more power" and I seriously doubt the company making them has the followed the same method and used the same testing procedures as Mazda did when they test and validate rotor materials.

Run them in an endurance race car for a season then maybe I'll be a believer. Until then, I won't even waste my time making a Mastercam program for the 13B rotor I've had drawn up in Solidworks since 2004.

 

Those rotors might be good with a cooler burnng fuel like alky or meth...would think they would be nice in a set up with one of those fuels...

Just food for thought

 

There is a WHOLE world outside the box...... You should come out and give it a try!

-J

 

I just read that they'll be using CGI for the new Ford Powerstroke diesel block. over 650ft-lbs of torque stock.

I only thought of this thread because if it's being used in OEM, it must be worth it's weight in...iron?

 

I just thought that CGI has some potential,for rotors(lighter), and still iron,hollow cast, for long life street engines.

I must have a way of startin pissin contests!! sorry

 

also it must have some merit, NASCAR teams group buy, ordered up 100 block castings,partly machined, finished in USA.
course they dont know anythin about racin,, 800hp NA, close to 10,000rpm

 

[QUOTE=B6T;9686372]And power going up is debatable since that could be attributed to a countless number of factors beyond lightweight rotors... i.e. a fresh rebuild using the aluminum rotors, or a better seal between the apex or side seals with the aluminum rotors versus the used OEM rotors, both cases resulting in less blow-by.




Becides being a fresh rebuild does it matter why it makes more power if it does? But i do agree i would like to see the long term testing.

 

Seems to work well up to 1100. Alot of aircraft use Ti around higher heat areas. Not in the hot section of the combustion section, but in the compressor section where temps do get quite high. I think even though expensive, and mazda most likely will never do it, internal coatings would be ideal to combat heat for use of light weight materials.

 

CGI is indeed a new material being used in engine parts.

What are current rotors made out of? I should cut one apart and take a microstructure.

 

Water temps will go down if you don't route it through the engine, too.

I'm not sold on the aluminum rotors if they have no cooling passages. You can get away with a lot of things in a drag engine that you can't get away with on the street or in any kind of circuit racing. Lots of drag engines don't even have radiators, since there are no water jackets...

I also don't believe in Ti for many internal engine parts. It gets "soft" and doesn't really tolerate sliding friction. (You have to specially treat valvespring faces so they don't chew Ti retainers up... what would apex seals do to them?)

 

Quote:
Originally Posted by SmogSUX
Titanium is a poor material for anything that gets hot. It oxidizes above about 1000F, and loses strength above about 850F.


The temps for the rotor faces are not that high. Yamamoto's research shows about 200*C max.

Also, I don't understand the resistance to using coatings. The less heat absorbed by the engine the more power that will be made.

Barry

 

man I gotta read that book someday.