Mazda Rotary anyone?

Aussie Ninja · Post by **Aussie Ninja** » Sun Oct 01, 2006 8:23 am

It was the Eunos Cosmo. When talking about torque a rotary is an engine with a small recipricating mass and thus like a 250 must be revved high to make power. So with the big cosmo what do you do to make torque, increase displacement. It's kinda hard to bore and stroke a rotary (although the 12a to 13b is like a bore job as the rotor is 10mm wider) so add an extra rotor.

Burky · Post by **Burky** » Sun Oct 01, 2006 8:35 am

How a rota works link
http://en.wikipedia.org/wiki/Wankel_engine#How_it_works

Here is the 20B the big mumma

photomike666 · Post by **photomike666** » Sun Oct 01, 2006 10:21 am

So, considering all the above mentioned points and looking at the web page describing how a Wankel engine works - how good would one be in a bike?

The perform better in lighter machines (bikes), rev higher (bikes), generate more power by displacement and more power by physical engine size. Anyone for a 600cc rotary with a 15k redline?

Post by **icebreaker** » Sun Oct 01, 2006 12:16 pm

I'd say it's be higher than 15K..

Generally the smaller the engine the higher the rev's, and a decently worked rota prob hits 15K anyway, kut the engine capacity by half and I'd say it's rev pretty high. a 250cc ZX2 hits 19K no worries..

Neka79 · Post by **Neka79** » Sun Oct 01, 2006 12:21 pm

photomike666 wrote:So, considering all the above mentioned points and looking at the web page describing how a Wankel engine works - how good would one be in a bike?

The perform better in lighter machines (bikes), rev higher (bikes), generate more power by displacement and more power by physical engine size. Anyone for a 600cc rotary with a 15k redline?

umm it was done and failed....

there kinda like a 2 stroke- no valves/cams..intake /export ports....

suzi did one back in abt 70s...in a bike...

Aussie Ninja · Post by **Aussie Ninja** » Sun Oct 01, 2006 5:43 pm

It was back when rotaries used carbon apex seals (rings) so they were shagged in 20k miles. Suzuki also tried to give it a high tech look (and failed miserably) by having a flash instrument cluster in a tube across the top clamp. When you turned on the ignition it would open to reveal the instruments. It looked crap and buyers voted with their feet. http://www.suzukicycles.org/RE5/RE5-Rotary.shtml
I think a rotary bike could be done sucessfully now. You can get ceramic apex seals that last forever and go fast bits like titanium rotors.

rotaboy · Post by **rotaboy** » Mon Oct 02, 2006 12:35 pm

Neka79 wrote:
rotaboy wrote:the series 6 rx7 are about 1600kg std weight but you are right the do like the lighter car better rx3's are around the 800kg mark
but.. (again, limited rotor knowledge)..didnt they run 13b turbo's on them bigger cars??..also..what abt the 20b...didnt that go in to the last rx7??

the 20b only came out in the cosmo (929) however with all rotaries there isnt much work to put the bigger motor in so a very worthwile coversion if u dont want to do much work inside but still want power

and yes the turbo motors were used in rx7's from mid series 4 on (1986ish)

Benno · Post by **Benno** » Mon Oct 02, 2006 1:49 pm

Speaking of rotaries, I may have acquired a 1974 RX4 13bt

*fingers crossed*

rotaboy · Post by **rotaboy** » Mon Oct 02, 2006 8:20 pm

Benno wrote:Speaking of rotaries, I may have acquired a 1974 RX4 13bt

*fingers crossed*

sweet mate i currently own 2 of them 1 a 74 and the other a 73
the 73 in the shop getting the race prep job...
what sort of turbo/ engine work if u dont mind me asking

ohh and pics when u get it

Benno · Post by **Benno** » Tue Oct 03, 2006 7:17 am

It's a bit of a sleeper. Has a 13bt in it, standard rx4 13b diff and a S1 5 speed. S5 turbo for the time being, and a MTX8 running the show. Will post some pics up when I get some

Aussie Ninja · Post by **Aussie Ninja** » Tue Oct 03, 2006 9:12 am

rotaboy wrote:
Benno wrote:Speaking of rotaries, I may have acquired a 1974 RX4 13bt

*fingers crossed*
sweet mate i currently own 2 of them 1 a 74 and the other a 73
the 73 in the shop getting the race prep job...
what sort of turbo/ engine work if u dont mind me asking

ohh and pics when u get it

Where are you getting it done?

rotaboy · Post by **rotaboy** » Tue Oct 03, 2006 7:34 pm

quickmaz in brisbane ive known him for a few years now and worked on my prevous car now going alittle more serious with this 1

Aussie Ninja · Post by **Aussie Ninja** » Tue Oct 03, 2006 8:46 pm

Just thought I'd ask because I grew up with Ben Hunt from Rotary Motorsport. Haven't heard of Quickmaz. Must be getting old. Lets see... Selectmaz, Pac Performance, Mazfix, Mazspeed, Ian Botcher, Mazsprint are a few that come to mind.

rotaboy · Post by **rotaboy** » Tue Oct 03, 2006 9:01 pm

hey isnt a big name company. he does alot of work behind the scenes so to speak
thing i like about him is he is honest he wont sell u s**t and tells u how it is to ur face...
i seen many motors that have been built through a couple of the companies u mentioned... sold as race motors (no waranty) and the things braking b4 the run in period has finished! these motors were $15k and i could do a better job at building them