Titanium's melting point is around 3000 degrees not 800!

 

Nono, Shaunv is right, it combusts with oxygen, not melt. at 800
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They are cast. Then the faces, sides, and bearing seats are machined and the seal grooves cut out.

 

See the Japanese video, they show you Mazda's RE factory (rotary engine workshop) on how they put Renesis together.

 

Yep, its on my harddrive=d
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KinkyCollege live

 

Where do i find this link? You can buy a GURU 2 piece excentric shaft that weighs around 4.8 kg then you can rew to 13k rpm!

/Lasse

 

I hope you have an aftermarket clutch plate if you are revving to 13k

 

Are you writing a term paper or something lol

 

once again I am ignored. Oh well I will ask my teenage son--he knows everything.
olddragger

 

Not quite sure what you mean on the first part. Coating the combustion face would theoretically lower oil temps but make a little better use of wasted heat. The exhaust would be hotter as well.

 

Who me? I wish I could write like that back in school.

 

Pure titanium will burn just like magnesium, titanium alloys don't. I'm not familiar with what alloys are typically used for the automotive applications though. According to wikipedia: Titanium is used in strong light-weight alloys (most notably with iron and aluminium). So its probably one of those. Interestingly enough though its still 60% heavier than aluminum.

 

not to be ignored, this is an interesting question. Are you suggesting that they be ceramic coated? RG would that work?

 

Maybe Teflon coating? Coating Pistons with teflon is pretty common practice these days to decrease friction and create a surface that carbon will not easily stick too. Nissan uses teflon in several engines including the VQ.

Since the rotor itself does not touch anything (only the seals do), the only benefit I would see from coating it with something would be to reduce carbon buildup. Now coating the seals is a possibility - but I imagine it would be impossible to know if it would be beneficial without a tremendous amount of R&D.

 

My thoughts on Old Dragger's question:

I would think that if you coat the combustion face with an insulating material like a ceramic you lower the rotor metal temp and you would see less expansion of the metal allowing you to build with tighter tolerances. Most modern gas turbines coat all the hot section gaspath parts with a thin ceramic coating in order to reduce the metal temps so they need less cooling, expand and contract less, and can operate with higher gas temperatures. I'm not familiar with the benefits of higher combustion temps in rotaries. Is there a benfit to being able to turn up the combustion temp?

 

Turbos.. haha.. but the exhaust gas temp is already so high in rotaries, I am not sure if the consequences would out weight the benefits. Hmm with less heat absorbed I can see a little more power, less energy lost in the form of heat. I dont think the catalysts would like the high exhaust temps...
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Just to give you an idea, I have a custom machined set of exhaust sleeves for a 13B. It holds the exhaust port shape all the way into the header. The stock 13B sleeves expand greatly, doubling their area in about 2" of distance. This slows down the gas speed. The first set of sleeves that were installed were on a turbo 13B. It was a friend's car and he was the one that machined the sleeves for me after I told him what I wanted. He had a large single turbo and the first time he got on it he noticed that the turbo spooled up very fast with the new sleeves installed. Much faster than with the stock sleeves. After only a few minutes though he noticed power fall off and he could no longer make boost. As it turns out, the added heat from the much higher exhaust velocity completely melted the turbine and folded over the blades! This was after only a few minutes. Admittedly that wasn't an inconel exhaust wheel but he ran that turbo for a long time with the stock sleeves in place. Exhaust temps exceeded 2000*F going into the turbo!

 

Wow! That's pretty cool. Yeah at that temp you need an Inconel turbine wheel and probably some kind of ceramic coating as well. I'm not sure how much heat is lost through a turbo but I could see melting the exhaust too!

 

Ouch for the turbo..
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RoyalBrunette

 

Seems the future of the Renesis is in Advanced Materials, alloys, ceramic coatings and seals. Is Mazda willing to spend $$$$ in R&D or will it die?

 

Interesting, Buick back in the late 80's made a turbo for the Grand National with a ceramic turbine. This sounds like a perfect application for it. I know weight would also be lower which would help with the turbines turbo lag.

 

Well--thanks--I wasn't ignored.
RG what I meant was the leading edges of the combustion "chamber" on the rotary sometimes (per my research--NO experience with this)are "slightly" off as far as being the same distance from edge of the rotor itself. So in theory each face of the rotory's timing would be just a little off. The Renasis engine may be better build than the older ones and not have this but my reading informs me that on the earier models this was something that was looked at and corrected during modding/rebuilds.
One thing about the combustion chamber coating--it would have to be thing as the clearance is not very big. I agree that it may be interesting to do this.
RG do an old man a favor--I know some are tired of me mentioning the electric water pump--what are your thoughts on that concept--and sorry dont mean to hijack your thread. Just brief. With the Renasis internals/combustion process being so well thought out I just wonder why the peripherals are so ordinary when there is a lot of room for improvment.
olddragger

 

Ceramic coating of the rotor faces was initially considered for the Renesis, (the initial 184kW/250hp dry sump design) but on further study the coating was found to only be needed inside the new side exhaust ports, then eventually dropped entirely in the production version, along with the dry sump concept.

S

 

Well I've got some good side by side comparison pictures between the Renesis rotors and the 13B rotors thanks to Jim Langer at Racing Beat letting me play with them. When I get a chance tonight, I'll post them. You can definitely see the side seal differences in terms of size and location. You can also see the apex seal groove depth difference. The interesting thing is that while the side seals are wedge shaped, the grooves are not.

 

fred- i was thinking about the side seal position change. since the reason for the new shape is for improved carbon scraping, i think the reason for the new placement if the same. having it closer to the edgedoesnt allow as much of a lip for the carbon to bunch up in. also looking at my new 2004 service highlights hard copy- it looks like the groove is narrower at the bottom but the cross section is different than the cross section of the seal