http://www.autoblog.com/2010/09/08/r...-sky-g-rotary/

Report: Next Mazda RX-8 to use Sky G rotary
by Zach Bowman (RSS feed) on Sep 8th 2010 at 3:28PM



Mazda has big plans for the future of its rotary engine. According to GoAuto, the company is currently hard at work on improving the powerplant's fuel economy by a full 50 percent. If it can pull it off, the new mill will proudly wear the same "Sky" designation as its traditional four-cylinder counterparts. The site quotes Seita Kanai, Mazda's director of R&D and program management, as saying that upping the rotary's fuel economy is essential for the engine's survival.

From the sound of things, Mazda is wholly committed to keeping a rotary in its stable. In the report, Kanai says the company is investigating every possible aspect of the engine's design to look for ways to increase efficiency, down to the very principles behind the design. Even so, he stopped short of saying whether or not the company is toying with an electric turbocharger as part of development.

Even with word that the Japanese automaker is stoking the rotary flames, GoAuto reports the company currently has no plans for a legitimate RX-7 successor. While designers and engineers within the company may be itching to jump onto a new sports car, the company's decision makers are currently more occupied with slimming its corporate average fuel economy.

 

it will undoubtedly use the stop/start system to reduce idling. That's a big improvement by itself. If you look at all the old 13B's, they had to idle rich to prevent misfire. Then Mazda went to the Renesis which could idle at the normal 14.7:1 range. Now it will hardly have to idle at all.

 

Do the Renesis motors suffer from the same carbon lock issues as the 13B motors did?

I'm specifically referring to starting a cold motor, running it for 10 seconds and shutting it down... I remember this was a weak point on the older cars.

 

If you mean flooding, the 04-05 RX-8 had an issue. There was a more powerful starter on the subsequent years and it hasn't been a problem since.

 

yes the renesis motors carbon more so than the 13B-rew due to the exhaust port design. The exhaust port is more of an emissions thing. Its the biggest draw back on the renny. There are a lot of good things about it though. Best port work ever to come from the factory.

 

Very true since the carbon can't just blow out the exhaust as easily when compared to a PP exhaust rotary. Build-up has always been a huge rotary problem (especially on NA's). I've recently come to find out that premixing completely eliminates the carbon build-up problem. I'm getting ready to pull apart my 91 vert engine that I rebuilt back in 05 that has 45K on it for inspection of the Orginal Ra apex seals. This engine was granny driven with me shifting at 3k all the time. This engine should be carbon infested but I have a VERY strong feeling it's not since my aux port sleeves still move freely. Oh yea, I haven't ran the engine in over a yr and it recently fired up no problems. My omp doesn't work so it's been premix only. Based on the results, I'm going to open a thread stating the importance of premixing on ALL rotarys period. Even the 2009 Rx8 with it's upgraded OMP set-up could really benefit from premixing on a regular bases. I know there are many threads on the subject, but I've never seen one on a higher mileage abused example. Stay tuned!

 

I am interested to see this. I have opened a couple of my motors I premixed only on and there was still carbon, but hey let's see what you find. Of course these motors were on a modded turbo motor w/ aggressive porting. Some carbon comes from unburnt fuel, IMO.

 

I have blocked off the stock oil metering pump and use only idemitsu premix in attempt to eliminate carbon buildup

I road in a Mazda 3 today with 2 liter Sky G engine. It has much more torque then the current 2 liter engine. Gas mileage is unbelievable. Close to 44 mpg on highway. Gov't EPA ratings should prvoide the Mazda 3 with Sky G engine at least 20% better gas mileage than closest competitor in class.